characteristicsofbiodegradablepolylactide/thermoplastic...

Research ArticleCharacteristics of Biodegradable PolylactideThermoplasticStarchNanosilica Composites Effects of Plasticizer andNanosilica Functionality

Regina Jeziorska 1 Agnieszka Szadkowska1 Ewa Spasowka1 Aneta Lukomska2

and Michal Chmielarek3

1Department of Polymer Technology and Processing Industrial Chemistry Research Institute Rydygiera 8 St01-793 Warsaw Poland2Department of Biomedical Technology Cosmetic Chemicals and ElectrochemistryIndustrial Chemistry Research Institute Rydygiera 8 St 01-793 Warsaw Poland3Faculty of Chemistry Warsaw University of Technology Koszykowa 75 St 00-662 Warsaw Poland

Correspondence should be addressed to Regina Jeziorska reginajeziorskaichppl

Received 6 April 2018 Accepted 22 July 2018 Published 27 August 2018

Academic Editor Rajaram S Mane

Copyright copy 2018 Regina Jeziorska et al (is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

(e effect of plasticizer (polydimethylsiloxanol) and neat (SiO2) or modified (having amine functional groups) silica (A-SiO2) onmorphology thermal mechanical and rheological properties of PLATPS blends compatibilized by maleated PLA (MPLA) wasinvestigated Toughened PLAMPLATPS (601030) blend containing 3wt of plasticizer and various contents (1 3 or 5wt)of silica were prepared in a corotating twin-screw extruder From SEM it is clear that plasticized PLAMPLATPS blendcontinuous porous structure is highly related to the silica content and its functionality (e results indicate that poly-dimethylsiloxanol enhances ductility and the initial thermal stability of the plasticized blend DSC and DMTA analyses show thatnucleation ability and reinforcing effect of A-SiO2 on plasticized blend crystallization are much better than those of SiO2 Silicapractically had no effect on the thermo-oxidative degradation However the composites with A-SiO2 had better thermal stabilitythan those with SiO2 Moreover silica significantly improved the elongation at break

1 Introduction

Polylactide (PLA) a biodegradable linear aliphatic polyesteris one of the most potential materials with great environ-mental benefits since it offers very low toxicity and highmechanical performance (erefore PLA can be broadlyapplied in the fields of drug delivery systems sutures or-thopaedic implants tissue engineering and packaging ma-terials [1ndash4] However a low glass transition temperature(about 60degC) relatively high brittleness and higher cost ifcompared to conventional polymers limit its applications [5](ere are many ways of improving PLA toughness includingcopolymerization and melt blending with other more flexiblecommodity polymers such as linear low-density polyethylene

or natural rubbers as well as plasticizers [6ndash10] Generally anefficient plasticizer decreases the glass transition temperature(Tg) and melting point (Tm) of polymers It was reported thatthe addition of plasticizers such as polyethylene glycol citrateoligomeric lactic acid and triacetine could overcome PLArsquosbrittleness [11ndash14] Unluckily plasticization decreases PLAstiffness limiting its constructional applications (ereforean efficient impact modifier is required to improve toughnesswithout extensive loosening of PLA stiffness

(ermoplastic starch (TPS) is one of the well-knownbiopolymers and is often used in order to lower the cost ofthe final product and enhance the biodegradable character-istics of polymer composites [15ndash17] Swierz-Motysia et alreported that TPS increased the biodegradation rate of PLA in

HindawiAdvances in Materials Science and EngineeringVolume 2018 Article ID 4571368 15 pageshttpsdoiorg10115520184571368

so-called soil test which was enhanced as a function of TPS[18] (us melt compounding TPS with PLA is one of themost promising methods to solve PLA limitations or to lowerits high price [19] Nevertheless incompatibility betweenhydrophobic PLA and hydrophilic starch results in poormechanical properties due to inadequate interfacial in-teraction between these polymers To improve the adhesion ofPLA and TPS chemical modification of the starch beforeblending is performed and compatibilizers such as maleicanhydride (MA) and epoxy resins have been used [4 20ndash24]

It has been previously suggested that the intensive in-terfacial interactions among hydrogen bonds of the anhy-dride groups of the maleated polylactide (MPLA) and thehydroxyl groups of the starch are responsible for the increasein tensile flexural and impact properties of PLA andthermoplastic potato or corn starch blends [25]

Recent results show that the nanoscale distribution ofmontmorillonite [18 26ndash28] fumed silica (SiO2) [29ndash32]and calcium carbonate [33] within the PLA matrix signifi-cantly enhances their thermal mechanical and rheologicalproperties as well as reduces permeability and flammabilitycompared to conventional micro- and macrocomposites Inorder to reach the nanoscale distribution the naturallyhydrophilic nanofiller has to be organically modified to bemore compatible with the organic polymer matrix Howeveronly few studies have been conducted in the development ofplasticized PLAthermoplastic starch nanocomposites re-cently [34ndash36]

In a previous work [37] we have studied the influence ofthe core-shell polymeric nanofiller and maleated polylactideused as a compatibilizer on the structural mechanical andbarrier properties of PLA and TPS blends (e addition ofthe core-shell polymeric nanofiller in the presence of MPLAimproved adhesion between PLA and starch Melting pointand crystallinity temperature of PLA were found to decreaseby adding TPS and the polymeric nanofiller (e nano-composites showed significantly lower stiffness compared toneat PLA However the storage modulus increased asa function of nanofiller content Moreover the addition ofthe core-shell polymeric nanofiller strongly improved im-pact strength the elongation at break and barrier propertiesof PLATPS blends

To the best of our knowledge no systematic studieshave been done so far to investigate the properties of pol-ydimethylsiloxanol toughenedPLATPSsilica nanocomposites(erefore the objective of this paper is to investigate thethermal mechanical rheological and morphological propertiesof polydimethylsiloxanol toughened PLATPSsilica nano-composites in the presence of MPLA used as a compatibilizerIn particular the effects of plasticizer spherical silica contentand its functionality were also studied

2 Materials and Methods

21 Materials Polylactide polymer (PLA 2003D) wasprovided by Nature Works USA with melt flow rate of69 g10min (ISO 1133 at 210degC and 216 kg) (e charac-teristics of PLA are described in Table 1 Maleated poly-lactide (MPLA) containing 068wt of grafted maleic

anhydride with melt flow rate of 38 g10min (ISO 1133 at210degC and 216 kg) was obtained according to the procedurepublished elsewhere [18 38] and it was used as a compa-tibilizer for PLATPS blends at the concentration of 10wtMaleic anhydride (MA) as coupling agent and dicumylperoxide (DCP) as initiator were purchased from Sigma-Aldrich Italy

(ermoplastic corn starch (TPS) was obtained by meltblending according to the procedure published elsewhere[18 39] and used as a biodegradable additive Standard cornstarch with about 23 of amylase 11ndash13 humidity and pH65 was purchased from Cargill Germany (e glycerol with995 purity was the product of Rafineria Trzebinia Poland(e characteristics of TPS are shown in Table 1

Plastosil M-2000 the commercial name of poly-dimetylsiloxanol containing 004wt of reactive silanolgroups η 2000plusmn 500 cP d 097 gcm3 supplied byChemical Plant Polish Silicones Ltd was used as a plasticizer(P) for the PLAMPLATPS (601030) blend

Neat (SiO2) and modified (having amine functionalgroups) spherical silica (A-SiO2) nanoparticles synthesizedaccording to the previously reported sol-gel process [40ndash42]were used as nanofillers Tetraethoxysilane (TEOS) tech-nical grade commercial product name TES 28 was suppliedby Wacker Chemie (Germany) Ethyl alcohol (reagentgrade) and aqueous ammonia (reagent grade 25wtd 091 gcm3) were supplied by POCh SA (Poland) andused as received (e characteristics of silica are described inTable 2

22 PLA Functionalization In order to improve compati-bility between PLA and TPS PLA was grafted with maleicanhydride via reactive extrusion to obtain a grafting yield of068 wt according to the procedure published elsewhere[18 38] MPLA was prepared as follows PLA MA (2wtPLA basis) and DCP (18wt MA basis) were mixed in theinternal mixer and subsequently the mixture was extrudedusing a corotating twin-screw extruder (Berstorff Germany)with a screw diameter of 25mm and length to diameter ratioof 33 To prevent the degradation of the polymer during theprocessing time a nitrogen purge flow was used Differentscrew elements along the screw worked in order to inducepolymer melting [43] (e three mixing sections enhancedthe compounding and increased the residence time of themixture in the barrel (e barrel pressure in these parts aswell as at the section before the die could be increased (eextruder also had a vacuum degassing port to remove anymoisture traces or other volatile products formed duringcompounding (e process was carried out at a barreltemperature 130ndash140degC (e output was 4 kgh and thescrew speed was 100 rpm

23 TPS Preparation To obtain TPS destructurization andplasticization of native corn starch were performed in one-step extrusion process in the earlier mentioned Berstorfftwin-screw corotating extruder using 30wt of glycerol asa plasticizer [18 39] (e process was carried out at a barreltemperature 130ndash170degC and screw speed of 80 rpm (e TPS

2 Advances in Materials Science and Engineering

was cooled in ambient air and then was pelletized Figure 1shows SEM micrographs of native and thermoplastic cornstarch It is obvious from Figure 1 that the starch particlesgrains disappeared after compounding with a glycerolsuggesting that thermoplastic starch was successfully plas-ticized and TPS presented a homogeneous morphology

24 Synthesis of Neat and Modified Spherical NanosilicaNeat (SiO2) and modified (heavy amine functional groups)spherical silica (A-SiO2) were synthesized according to thedeveloped sol-gel process using tetraethoxysilane (TEOS) asalkoxysilane precursor at room temperature (23degC) witha stirring speed of 250 rpm [40ndash42] (e process was carriedout in an aqueous ammonia-ethyl alcohol reaction mixtureusing molar ratio of TEOSEtOHH2O as 002305000477and the initial pH ranged from 104 to 113 (e final pHrange was 75ndash108 (e pH of the reaction mixture wasmeasured using a pH meter (Schott Instruments LAB 850)Modified silica was synthesized by adding drop by dropc-aminopropyltriethoxysilane (Momentive PerformanceMaterials USA) to the reaction mixture according to thereaction (Figure 2)

(e final product of neat or modified silica was dried ina spray dryer for 2 hours at 50ndash90degC Particle size andparticle size distribution in resulting sols were measured byphoton correlation spectroscopy (PCS) using a Malvernapparatus (Zetasizer Nano ZS UK) (e monomodal par-ticle size distribution and very low polydispersity of particlesize were observed for homogeneous sols obtained by the

sol-gel process [40] It is clear from Figure 3 that sphericalshape and uniform sized (about 30 nm) silica nanoparticleswere obtained (e amine groups content was determinedbased on nitrogen content measurement by the Kjeldahlmethod (e characteristics of the neat and modified silicaare presented in Table 2

25 Blend Preparation (e PLAMPLATPS 601030blends without or with 3wt silicone rubber plasticizerwere melt blended using the earlier mentioned twin-screwcorotating extruder PLA MPLA TPS and plasticizer (P)were fed into the throat of the extruder using separategravimetric feeders (e temperatures of the ten zones were35degC160degC175degC180degC180degC180degC180degC185degC185degC and190degC for the sequential heating zones from the hopper tothe die (e screw speed was 100 rpm (e melt temperatureand pressure were continuously recorded during com-pounding (e extrudate was immersed immediately ina cold-water bath (20degC) and pelletized with an adjustablerotating knife located behind the water bath into 5mmpellets

26 Composite Preparation (e various composites con-taining 1 3 or 5 wt of SiO2 or A-SiO2 silica nanoparticleswere prepared through melt-direct dispersion by usinga conventional polymer extrusion process and optimizedparameters Firstly PLA pellets with 10wt of silica wereblended using the earlier mentioned twin-screw corotatingextruder based on the reported method [44] Prior to the

Table 2 Characteristics of nanosilica fillers

Nanosilica Size (nm) Polydispersity Surface area (m2g) Amine groups content (wt)Neat silica 30 016 2744 0Modified silica 30 002 2744 035

(a) (b)

Figure 1 SEM images of (a) native corn starch and (b) thermoplastic corn starch

Table 1 Characteristics of PLA and TPS

Sample Tensile strength (MPa) Elongation at break () Tensile modulus (MPa)PLA 67plusmn 15 61plusmn 03 3930plusmn 64TPS 19plusmn 07 27plusmn 06 1550plusmn 60

Advances in Materials Science and Engineering 3

melt processing this masterbatch was dried for 12 hours at80degC and thenmelt blended with pure PLAMPLA TPS andplasticizer (e process was carried out using a screwspeed of 150 rpm and also a temperature profile of35degC165degC175degC180degC180degC180degC175degC185degC185degC and200degC for the sequential heating zones from the hopper to thedie (en the material was cooled in water and pelletized

27 Fourier Transform Infrared (FTIR) Spectra and theGrafting Degree Fourier transform infrared spectroscopy(FTIR) spectra were recorded using a (ermo Scientificspectrometer model Nicolet 6700 for a frequency rangebetween 4000 cmminus1 and 500 cmminus1 An average of 64 scans ata resolution of 2 cmminus1 was conducted at room temperature Tocollect the spectra of the polymers and composites thin filmswere prepared in a hydraulic hot press (e nanosilica spec-trum was taken using KBr pellets (e spectra presented werebaseline corrected and converted to the absorbance mode

(e MA grafting degree was measured by Fouriertransform infrared (FTIR) spectroscopy FTIR was per-formed on a spectrometer PerkinElmer System 2000 on films007mm thick (e spectra were obtained by collecting 64scans between 500 and 4000 cmminus1 with a resolution of2 cmminus1(e absorbance of the analytical band was determinedand theMA content was calculated from the calibration curve(e measured grafting yield was 068wt [18]

28 Scanning Electron Microscopy (e microstructures ofsilica nanoparticles TPS blends and composites were ex-amined using a JEOL JSM-6490LV scanning electron mi-croscope (SEM) Fractured surface of TPS blends andcomposites were gold-coated prior to observation to avoidelectrical charging and to increase image contrast

29 Differential Scanning Calorimetry (ermal analysis wasperformed by differential scanning calorimetry (DSC) usinga DSC-7A apparatus of PerkinElmer (Switzerland) undernitrogen All measurements were carried out according tothe following cycle heating from 20 to 180degC at a rate of10degCmin 3min isothermal step at 180degC cooling down to0degC at a rate of minus10degCmin 3min isothermal step at 0degC andfinal heating up from 0 to 180degC at a rate of 10degCmin (eamount of sample placed in the DSC aluminium pans wasabout 6mg An empty pan was used as a reference (e glasstransition temperature (Tg) crystallization temperature (Tc)and melting temperature (Tm) were determined from thesecond heating scans(e degree of crystallinity (Xc) of PLAblends and composites was evaluated from the melting

enthalpy results (ΔHm) of each sample using (1) where ΔHmis the experimental melting enthalpy and ΔHdeg

m is the meltingenthalpy for 100 crystalline PLA 93 Jg [45]

Xc ΔHm

ΔHdegm 1minus wtfiler100( 1113857( 1113857

1113888 1113889100 (1)

210 ltermogravimetric Analysis (ermogravimetric anal-ysis (TGA) was performed using a thermogravimetric an-alyzer (TGASDTA 851e Mettler Toledo) at a rate of10degCmin from 20 to 600degC under flowing air (50mlmin)(e precision on temperature measurements is plusmn05degC

211 Tensile Properties (e test specimens were prepared byinjection moulding using an Arburg 420M single screwinjection machine (Allrounder 1000-250 Germany) con-taining five different heating zones (e temperatures ofthese were 180190195195200degC from the feeding zone tothe die when the mould was cooled with water at 25degC

Tensile strength and elongation at break were de-termined using an extensometer clip-on incremental (Ins-tron series 5500 R UK) at a cross-head speed of 5mmminwhereas tensile modulus was measured at the speed of2mmmin All tests were performed at standard atmosphereconditions (23degC and 50 HR) Prior to testing the sampleswere stored at 23degC and 50 RH for 48 h according to ISO527 and ISO 179 standards All the results represent anaverage value of a minimum 5 tests

212 Dynamic-Mechanical ltermal Analysis (DMTA)(e dynamic mechanical properties of samples were testedusing a dynamic mechanical analyzer model RheometricsRDS 2 (e torsion method was used with a frequency

H2O

(CH2)3 NH2

SiSi

OC2H5

OC2H5OC2H5OC2H5

OC2H5

OC2H5

OC2H5

+ +mn HO(SiO2)n(SiO2)m(CH2)3NH2 + 3(n + m)C2H5OH

Figure 2 (e reaction scheme for the preparation of A-SiO2

Figure 3 SEM micrograph of A-SiO2


of 1Hz a strain level of 01 in the temperature range ofminus150degC to 100degC (e heating rate was 3degCmin (e testingwas performed using rectangular bars measuring approxi-mately 38times10times 2mm prepared by injection moulding

3 Results and Discussion

31 FTIR Analysis Figure 4 shows FTIR spectra of the purepolymers (PLA MPLA and TPS) plasticizer A-SiO2 andcomposite with 5wt A-SiO2 (e strong absorption bandwhich appears at around 1750 cmminus1 in the spectrum of bothPLA and MPLA is assigned to CO carbonyl stretchingvibration (e spectrum of MPLA shows the new relativelyweak absorption band at around 1850 cmminus1 which is ascribedto the carbonyl group (CO) stretching of the succinicanhydride ring (or saturated cyclic anhydride ring) [4 18 46](e new absorption band indicated that MA was grafted ontothe PLA backbone during which MA was transformed toa saturated anhydride (succinic anhydride) (e typical an-hydride band at 1780 cmminus1 could not be observed because ofoverlapping of the intense PLA band at 1750 cmminus1 [47] In thespectrum of TPS the peaks at 1020 cmminus1 and 1075ndash1150 cmminus1were attributed to CndashO stretching of the CndashOndashC group andCndashO stretching of the CndashOndashH group respectively [48] (epeak at 1650 cmminus1 was due to the bound water present in thestarch A broad band due to the hydrogen bonded hydroxylgroup (OndashH) appeared at 3040ndash3640 cmminus1 and is attributedto the complex vibrational stretching associated with freeinter- and intramolecular bound hydroxyl groups [49] (espectrum of the plasticizer shows a strong absorption band at1260 cmminus1 and a weak absorption band near 860 cmminus1 at-tributed to the SindashCH3 stretching Moreover the peaks at2910 cmminus1 and 2960 cmminus1 were attributed to CndashH stretchingof the methyl group However the typical silanol groups(SindashOH) band at 3500 cmminus1could not be observed becausethey were in very small amount (004) In the spectrum ofA-SiO2 there is a strong band at 1060 cmminus1 attributed to theSindashO groups and a broad peak with a maximum at 3435 cmminus1

corresponding to the surface hydroxyl groups [50] Howeverthe peak of amine functional groups was not recorded due totheir presence in very small amount (035)

From Figure 4 it is clear that the characteristic peakassigned to the anhydride group (1850 cmminus1) in MPLA isdiminished in the spectrum of composite maybe due to thevery small amount that the composite contains (0068wtMAgroups of the whole composite)(e newweak absorptionband at 1260 cmminus1 attributed to the SindashCH3 stretching fromthe plasticizer was observed (e typical SindashO groups band at1060 cmminus1could not be observed because of overlapping of theintense PLA band at 1180 cmminus1 TPS band at 1120 cmminus1 andplasticizer band at 996 cmminus1 (e intensity of the peak centredat 3310 cmminus1 corresponding to OH groups of starch issuppressed in the spectrum of the composite (is may be dueto reaction between the OH groups of starch and anhydridegroups of MPLA (e formation of hydrogen bonds betweenthe hydroxyl groups of the carbonyl groups of TPS and PLA isone of the possible reactions [48] (e complex interactionsbetween A-SiO2 plasticizer MPLA and TPS also could haveoccurred

32 Morphological Analysis It is well known for polymerblends that the morphology control of the respective phasesis a key factor in achieving the desired material properties[26 34 37] Figure 5 shows cross-sectional images of thenonplasticized and plasticized PLAMPLATPS (601030)blends As expected the PLA and thermoplastic starch blendin the presence of compatibilizer (MPLA) shows individualgrains of starch forming dispersed phase in the PLA matrixFrom those images it is obvious that the phase morphologyof the samples can be depicted as continuous and porousMoreover the addition of the plasticizer results in lessporous structure suggesting improved toughness It is wellknown that filler dispersion and adhesion to the polymermatrix are of great importance for the mechanical propertiesof composites improvement Good control of the interfacemorphology of the composite is one of the most criticalparameters to achieve the desired mechanical properties ofsuch materials [26 34 37] Scanning electron microscopywas performed to explain the behaviour of the silica-filledPLAMPLATPSP composites

Figure 6 shows the dispersion state of silica-filledPLAMPLATPSP composites

In our previous work we found that silica nanoparticleswere agglomerated at higher content thus reducing theiravailable surface area for reinforcing effect [51] MoreoverA-SiO2 shows bigger tendency to form agglomerates thanSiO2

From the SEM images (Figure 6) it is clear that thePLAMPLATPSP porous structure is highly related to thesilica content as well as its functionality However pores sizedistribution could not be analyzed because of their irregularshape (e neat silica results in more porous structure thanthe modified one Furthermore the composites with ofA-SiO2 had more regular shape and smaller size of poresthan those with SiO2 (is may be due to the result ofcomplex chemical reactions that occur mainly among hy-droxyl groups of neat silica MPLA and TPS which seems tobe more favoured than reactions among amine functionalgroups of modified silica MPLA and TPS (ese behavioursare highly proportional to the trend observed in the stress-strain behaviour of the composites with neat or modifiedsilica as depicted in Figure 7

5001000150020002500300035004000Wave number (cmndash1)

1

23

4

5

6

1260860

1650

18501750

3435 1060

1260

3640ndash3040

29602910

1750 1080ndash9403640ndash3040

Figure 4 FTIR spectra of PLA (1) MPLA (2) TPS (3) P (4)A-SiO2 (5) and PLAMPLATPSPA-SiO2 (6)


(a) (b)

Figure 5 SEM images of PLAMPLATPS (a) and PLAMPLATPSP (b) blends

(a) (b)

(c) (d)

(e) (f )

Figure 6 SEM images of the PLAMPLATPSP composite (a) 1 wt of SiO2 (b) 3wt of SiO2 (c) 5wt of SiO2 (d) 1 wt of A-SiO2(e) 3wt of A-SiO2 and (f) 5wt of A-SiO2


33 ltermal Properties (e second heating of differentialscanning calorimetry (DSC) thermograms of neat PLA TPSnonplasticized and polydimethylsiloxanol plasticizedPLAMPLATPS (601030) blends are displayed in Figure 8It is clear from the above figure that the temperatureaccording to the endothermic peak for each sample isconsidered to be the glass transition temperature (Tg) ofPLA Moreover all the samples show an exothermic peakthat can be correlated to the crystallization of PLA thecorresponding temperature is known as crystallizationtemperature (Tc) (e neat PLA showed a clear glass tran-sition temperature at 621degC crystallization temperature at1125degC andmelting point (Tm) at 1536degC corresponding toresidual crystallinity as also discussed by Martin andAverous [14] It is interesting to know that the Tc peak ofPLA did not appear during cooling of PLA and its blends Itis believed that the main reason for this occurrence was dueto a very slow crystallization rate of PLA during cooling [52](e crystallinity (Xc) of pure PLA is only 33 after meltblending which indicates that the material is almostamorphous It can be also observed in Figure 8 that there areno discernible changes in the DSC thermograms of TPSsuggesting that the thermoplastic starch is in the amorphousphase

(e DSC data for various blends and composites aresummarized in Table 3 It is well known that the value of Tgdepends primarily on chain flexibility molecular weightbranchingcrosslinking intermolecular attraction and stericeffects (e glass transition temperature of PLA (621degC) wasreduced to 603degC with the introduction of TPS and MPLA(is emphasized that the chain mobility of PLA has beenincreased owing it to the plasticizing effect brought bygelatinized starch with glycerol [53] Moreover a smallreduction of melting temperature of PLA was observed(from 154degC to 1532degC) and there was a significant increasein crystallization temperature (from 1125degC to 128degC) aswell as in the degree of crystallinity (from 33 to 72) (eaddition of plasticizer to the PLAMPLATPS blend further

decreased the Tg value from 603degC to 596degC (e reductionof Tg affected other two temperatures that is Tm and Tc (eaddition of plasticizer decreased the Tm value from 1532degCto 1489degC while the Tc value was reduced from 128degC to1267degC resulting in significantly lower crystallinity of thePLA phase (is may have occurred due to the preferableinteraction between plasticizer silanol groups and TPS hy-droxyl groups and carboxyl groups of the PLA chains [54]Hence the thermal characteristics of plasticizedPLAMPLATPS blend compared to that unplasticizeddemonstrated that polydimethylsiloxanol could be regardedas the efficient plasticizer for the PLAMPLATPS blend(ese results are in agreement with their tensile propertiesFigure 8(b) shows DSC traces for the PLAMPLATPSPblend and composites differing in A-SiO2 content It can beobserved from Table 3 that the addition of neat as well asmodified silica had only little influence on the glass tran-sition temperature of the composites However the Tg ofPLA increased from 596 to 615degC at 5wt of A-SiO2 Itshould be noted that Tc strongly depends upon the contentas well as functionality of silica Table 3 also shows that the Tcdecreases with increasing loading of silica and is lower for thecomposites with modified silica Moreover the degree ofcrystallinity increases with silica content and is significantlyhigher for the composites with modified silica(is behaviourindicates that the large surface of the dispersed silica acts asa nucleating agent for the PLA phase crystallization It shouldbe noted that modified silica is a more efficient nucleatingagent for the toughened PLAMPLATPS blend than neatsilica Wu et al [55] also reported similar results where the Tcof PLA decreased with increasing MMT loadings (ey alsosuggested that the difference in the dispersion state of MMTmight also be an important factor influencing the crystalli-zation behaviour of PLA nanocomposites

Table 3 also shows that the melting temperature of thecomposites with neat silica is higher (28ndash33degC) whencompared to the PLAMPLATPSP blend However Tmdecreases in SiO2 function In the contrary Tm increases

0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)

0 wt A-SiO21 wt A-SiO2


0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)

Figure 7 Stress-strain curves of PLAMPLATPSP composites with (a) SiO2 and (b) A-SiO2


with A-SiO2 content (e melting temperature of thecomposites with modified silica is 23ndash41degC higher than thatfor the blend without silica However Tm of PLAM-PLATPSPA-SiO2 composites is 1ndash3degC lower as comparedto that of pure PLA

Figure 9 shows the TGA curves of neat PLA TPSnonplasticized and plasticized PLAMPLATPS (601030)blends without or with 5wt A-SiO2 (e initial thermalstability is characterized by the temperature that occurred at10 weight losses referred to as T10 (see Table 4) As shownin Figure 8 TPS dramatically reduces thermal stability ofPLA Petinakis et al [56] reported that small molecules suchas CO CO2 H2O CH4 C2H4 and CH2O were producedwhen starch was decomposed (ese molecules could breakdown the PLA chain resulting in lower thermal decompo-sition temperatures of PLA During thermal degradation theTGA curves display triple-step degradation processes for allthe blends Addition of polydimethylsiloxanol resulted insignificant improvement in the initial thermal stability of thePLAMPLATPS blend As shown in Table 4 the T10 increasesdramatically from 236degC to 296degC with the incorporation of3wt of plasticizer However there is practically no effect of

the plasticizer on the other degradation temperatures (at 50weight loss Tmax1 and Tmax2) Moreover the addition of silicapractically had no effect on the thermal degradation of theplasticized PLAMPLATPS blend However the compositeswith A-SiO2 had better thermal stability than those with SiO2(e best thermal stability showed the composite with 5wtof A-SiO2 (Figure 8) where T10 reached 296degC (an incrementof 3degC) Moreover the Tmax2 was 5degC higher when comparedto neat PLA

34 Mechanical Properties Neat PLA has high tensilemodulus (3930MPa) and tensile strength (67MPa) How-ever it is a brittle material with the elongation at thebreak of 6 (us it is needed to be improved by some

exo

60

TgTc

Tm

80 100Temperature (degC)

120 140 160

PLATPS

PLAMPLATPSPLAMPLATPSP

(a)

exo

60 80 100Temperature (degC)

120 140 160



Tg TcTm

(b)

Figure 8 DSC curves of PLA TPS and various blends (a) and composites (b) second heating scan

Table 3 DSC data of PLA TPS and various blends andcomposites

Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()

PLA 621 1540 1125 33TPS mdash mdash mdash mdashPLAMPLATPS 601030 603 1532 1280 72PLAMPLATPSP 6010303 596 1489 1267 41PLAMPLATPSP1wt SiO2 603 1523 1294 122PLAMPLATPSP3wt SiO2 605 1519 1292 137PLAMPLATPSP5wt SiO2 607 1517 1278 195PLAMPLATPSP1wt A-SiO2 605 1512 1284 167PLAMPLATPSP3wt A-SiO2 608 1517 1223 230PLAMPLATPSP5wt A-SiO2 615 1530 1194 222

100

80

60

40

20

0100 200 300 400

Temperature (degC)500 600

Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS

PLAMPLATPSP5 wt A-SiO2

Figure 9 TGA curves of PLA TPS and various blends andcomposites


additives To investigate the effect of interfacial modificationon the mechanical performance of the polydimethylsiloxanoltoughened PLAMPLATPS blends the tensile stress-strainbehaviour was characterized It is clear from Table 5 that theaddition of plasticizer caused a significant increase in anelongation at break indicating that the polydimethylsiloxanolis an efficient plasticizer for PLAMPLATPS blends Based onthe abovementioned results it can be supposed that usingplasticizer can improve intermolecular interactions amongthe blend components through the reactive SiOH groups

Moreover tensile strength and modulus increasedcompared to the blend without plasticizer

(e similar results and the dependency of poly(ethyleneglycol) (PEG) on mechanical properties of PLATPS blendswere reported by other researchers [57] (e optimizedmechanical properties were obtained for the blend with 3wt PEG Szadkowska et al [54] used two types of reactiveplasticizers with silanol groups to obtain blends of PLAmaleinated PLA (MPLA) and thermoplastic corn starch(TPS) (e incorporation of plasticizer with silanol groupsinto PLAMPLATPS blends resulted in enhanced me-chanical properties (especially elongation at break andimpact strength) compared to the nonplasticized blend(isis a consequence of the chemical reactions that occurredbetween silanol groups of the plasticizer and functionalgroups of TPS and MPLA which improved compatibilitybetween PLA and TPS

Silica further increased the elongation at break of thematerial However the improvement strongly depends onsilica content as well as its functionality For neat silicaelongation increased whereas for the modified one it de-creased as silica content increased Significantly higher valuewas observed for 1ndash3wt of the chemically modified silicaindicating most probably intensive interfacial interactionsamong the hydrogen bonds of the anhydride groups of theMPLA the hydroxyl groups of the starch and amine groupsof the silica (e improvement in elongation was also ob-served for plasticized PLA and organically modifiedmontmorillonite nanocomposites [27] However Arroyoet al reported an opposite behaviour for PLAthermoplasticstarchmontmorillonite nanocomposites [28] Moreovercomposites show lower tensile strength and modulus thanthat of the plasticized PLAMPLATPS blend which in-creased with increasing silica content (is anomalous be-haviour may be resulting from preferential or virtually

unpredictable distribution characteristics of silica aroundthe micropores within the toughened PLAMPLATPSstructure with respect to weight content and functionality[18] Recalling DSC findings we should also take into ac-count the PLA crystallization behaviour as well In polymerssurfaces are known to act as catalysts for the nucleation ofcrystals In polymers patterned with pores as in our case it ispossible that the shape of the pores sizes of which showsdependence on silica content and functionality can controlthe kinetics of surface-induced crystal nucleation Moreoverit is well known that the degree of crystallinity may sig-nificantly influence on the mechanical properties since itaffects the extent of the intermolecular secondary bonding(eoretically higher crystallinity could reduce the elonga-tion at break But the kind of physical crosslinking formedthrough physical hypobonds made the composite elastic andhave a high elongation at break [58] For crystalline regionswherein molecular chains are packed in an ordered arrange-ment wide-ranging secondary bonding occurs between ad-jacent chain segments (ese bonds lead to significant increaseof polymer tensile modulus with the growing degree ofcrystallinity [26 51]

35 Dynamic Mechanical ltermal Analysis (DMTA)DMTA measures the response of a given material to anoscillatory deformation (here in torsion mode) as a functionof temperature DMTA results are expressed by two mainparameters the storage modulus (Gprime) corresponding to theelastic response to the deformation and tan δ that is theGPrimeGprime ratio useful for determining the occurrence of mo-lecular mobility transitions such as the glass transitiontemperature Figure 10 shows the temperature dependenceof Gprime and tan δ of pure PLA TPS and unplasticized andplasticized PLAMPLATPS blends As can be seen thestorage modulus of the toughened blend was lower than thatof the blend without a plasticizer It is known that the storagemodulus detected by DMTA relates to composite stiffness(e stiffness of the PLAMPLATPS blend decreased withthe addition of the plasticizer (Table 6) (is is a typicalbehaviour for plasticized thermoplastics

In general the storage modulus decreased as the tem-perature increased However in the region corresponding tothe maximum of tan δ plot the decrease in storage moduluswas usually rapid Figures 10(b) and 10(c) show the curves of

Table 4 TGA data of PLA TPS and various blends and composites in air

Sample T10 (degC) T50 (degC) Tmax1 (degC) Tmax2 (degC) Weight loss ()PLA 330 362 mdash 364 1000TPS 226 320 318 mdash 997PLAMPLATPS 236 356 311 367 975PLAMPLATPSP 296 357 312 366 9771wt SiO2 296 357 310 365 9803wt SiO2 295 356 310 365 9655wt SiO2 295 357 311 365 9501wt A-SiO2 296 357 311 365 9783wt A-SiO2 296 358 311 366 9665wt A-SiO2 299 358 312 369 950


the loss factor (tan δ) as a function of temperature for PLATPS and PLAMPLATPS (601030) blend without or withplasticizer (e loss factors were sensitive to molecularmotion and their peak was related to the glass transitiontemperature (e curve of TPS revealed one thermal tran-sition located at minus42degC corresponding to a glycerol-rich

phase of TPS and represented the glass transition temper-ature of glycerol [18 37 59]

It can be noted that the tan δ curves of PLAMPLATPSblends revealed three thermal transitions (α β and c) In αtransition for the blend without the plasticizer a tan δ peaklocated at about 22degC could be ascribed to the glass transition

Table 5 Tensile properties of PLAMPLATPS and various blends and composites

Sample Tensile strength (MPa) Elongation at break () Tensile modulus (MPa)PLAMPLATPS 33plusmn 15 4plusmn 03 3264plusmn 64PLAMPLATPSP 41plusmn 07 22plusmn 06 3450plusmn 601wt SiO2 36plusmn 06 60plusmn 18 2660plusmn 293wt SiO2 33plusmn 04 63plusmn 73 3060plusmn 515wt SiO2 34plusmn 04 88plusmn 59 3210plusmn 331wt A-SiO2 34plusmn 14 91plusmn 02 2990plusmn 443wt A-SiO2 33plusmn 10 72plusmn 20 3110plusmn 355wt A-SiO2 30plusmn 07 45plusmn 02 3130plusmn 28

000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10

ndash150 ndash100 ndash50 0 50 100Temperature (degC)

Gprime (

Pa)

PLATPS


(a)

ndash150 ndash100 ndash50 0 50Temperature (degC)

0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3

50 60 70 80 90 100Temperature (degC)

α

(c)

Figure 10 Dependence of Gprime and tgδ of PLA TPS and various blends on temperature


temperature of the starch-rich phase [13 18 60] whereasthat of the blend containing plasticizer occurred at 5degC (isindicates that the Tg value of the TPS phase has shifted tosignificantly lower temperatures after the plasticization dueto the enhanced chain mobility of the starch moleculesAnother tan δ peak in α transition located at 64degC rep-resented the glass transition temperature of PLA (e valueis slightly lower than that of the pure PLA (67degC) (is isa typical behaviour of plasticized thermoplastics whereplasticizers can reduce the Tg by increasing the free volumeand thus chain mobility of the polymeric molecules may alsopromote their crystallinity due to the enhanced chain mo-bility (ese results are in agreement with thermal andmechanical properties (Tables 3ndash5)

As shown in Figures 11(a) and 11(b) the storagemodulus for the various composites increased with theaddition of silica nanoparticles However the modified silicais more efficient reinforcement for the investigated blendcomparing with neat silica due to the higher storagemodulus (Table 6) Figures 11(c)ndash11(f ) show the curves ofthe loss factor (tan δ) as a function of temperature for thecomposites containing neat or modified silica respectively(e addition of silica significantly increases α and β-re-laxation temperatures of the TPS phase due to the improvedintermolecular interaction of TPS in both the starch-richand starch-poor phases However the values of the abovetemperatures strongly depend on the silica functionality andcontent It can be observed from Table 6 that the Ta1 of TPSincreases dramatically from 5 to 20degC and to 30degC with 3wt of neat or modified silica respectively Since modifiedsilica particles were more reactive than neat silica A-SiO2increased the glass transition temperature higher than that ofSiO2

Moreover Table 6 shows that the Ta of the PLA phase ofthe composites with neat silica is slightly higher as comparedto that of the PLAMPLATPSP blend as well as to thecomposites with A-SiO2 However there is practically noeffect of the silica content and functionality on the α re-laxation temperature

Simultaneously the β-relaxation of a glycerol-rich phaseof TPS can be observed as a clear maximum in tan δ(Figure 11(c)) for the blends and represents the glass

transition temperature of glycerol [59] (e β-relaxationappears as a maximum at minus42degC in tan δ for the blendwithout plasticizer whereas β-relaxation of the plasticizedblend Tβ is about 10degC lower (is is related to increasedinterfacial interactions between the TPS phase and plasticizer

Moreover for the blend without the plasticizer a tan δpeak located at about minus107degC could be ascribed to the βtransition temperature of the PLA whereas that of the blendcontaining the plasticizer occurred at about minus121degC (isindicates that the Tβ value of the PLA has shifted to lowertemperatures after the plasticization Functioning likea physical joint the plasticizer enhanced the chain mobilityof the PLA molecules and hence increased the free volumeand reduced glass transitions of the blends (ese resultsindicate that the polydimethylsiloxanol played a significantrole as a plasticizer in the PLATPS blends

4 Conclusions

Toughened PLAMPLATPSsilica composites were suc-cessfully prepared by melt blending in the twin-screwcorotating extruder (e morphological analysis of theplasticized blends showed that the addition of plasticizerresulted in less porous structure with increase in its con-tent suggesting improved toughness More porous struc-ture was observed for neat silica than that for the modifiedone Moreover at the same contents of silica the shape ofpores was more regular and the size was smaller in thecomposites with modified silica than with the neat one(ermal and mechanical properties demonstrated thatpolydimethylsiloxanol can be used as the efficient plasti-cizer for the PLAMPLATPS blend DSC analysis showedthat glass transition temperature and melt temperaturewere not significantly affected by the addition of silicaHowever the strong effect of silica content and func-tionality on crystallization temperature and crystallinity ofPLAMPLATPSP blend was observed From TGA anal-ysis it is clear that the plasticizer greatly improved theinitial thermal stability of the PLAMPLATPS blendHowever the addition of silica had no effect on the thermaldegradation of the plasticized blend (e tensile strengthand tensile modulus of plasticized PLAMPLATPS blendsdecreased as the content of plasticizer increased Howeverthe plasticized blend had higher tensile properties ascompared to the unplasticized one Meanwhile the elon-gation at break reached up to 26 (e addition of silicasignificantly increased the elongation at break of the ma-terial (up to 91) However the improvement stronglydepends on the silica content and functionality For neatsilica elongation increased whereas for the modified oneit decreased as silica content increased (e highest valuewas observed for 1 wt of the A-SiO2 (is was due to theintensive interfacial interactions among the hydrogenbonds of the anhydride groups of the MPLA the hydroxylgroups of the starch and amine groups of the silica More-over the composites showed lower tensile strength and tensilemodulus than that of the plasticized PLAMPLATPS blendwhich increased with the increasing silica content (is wasresulting from preferential or virtually unpredictable

Table 6 DMTA results of PLA TPS and various PLAMPLATPSblends and composites

Sample

Storagemodulus (MPa)

tgδ peakposition (degC)

Atminus120degC

Atminus50degC

At23degC α α1 β c

PLA 2480 2170 1920 67 mdash mdash minus109TPS 8990 4690 711 mdash mdash minus42 mdashPLAMPLATPS 3780 2960 1490 64 22 minus42 minus109PLAMPLATPSP 3830 2470 1190 63 5 minus52 minus1211 SiO2 3670 2570 1310 64 14 minus47 minus1203SiO2 3650 2630 1340 64 19 minus47 minus1215 SiO2 3910 2730 1390 63 20 minus48 minus1211 A-SiO2 3810 2640 1320 64 19 minus48 minus1213 A-SiO2 3780 2580 1380 63 28 minus49 minus1215 A-SiO2 4000 2690 1480 63 30 minus49 minus120


000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09

ndash150 ndash100 ndash50 0 50 100

Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01

ndash150 ndash100 ndash50 0 50

tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )

Figure 11 Dependence of Gprime and tgδ of various composites on temperature


distribution characteristics of silica around the microporeswithin the toughened PLAMPLATPS structure with respectto concentration and functionality From DMTA it wasfound that the modified silica is more efficient reinforcementthan the neat one due to the higher storage modulus of thecomposites

(e plasticized PLAMPLATPSsilica composites canbe one of the good candidates in the potential applicationsuch as packaging materials disposable goods electronicsmaterials tissue engineering materials surgical sutures anddrug delivery systems

Data Availability

(e presented research results are protected by patents PL216 930 and PL 216 295

Conflicts of Interest

(e authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

(e authors are very grateful to Professor Maria Zielecka forsilica modification and the evaluation of the results and toMaciej Studzinski MSc for providing DMTA analyses (ework was fonded by the statutory resources of the IndustrialChemistry Research Institute

References

[1] H Tsuji and Y Ikada ldquoBlends of aliphatic polyesters IIHydrolysis of solution-cast blends from poly(L-lactide) andpoly(E-caprolactone) in phosphate-buffered solutionrdquo Jour-nal of Applied Polymer amp Science vol 67 no 3 pp 405ndash4151998

[2] C Zhang LWang T Zhai XWang Y Dan and L-S Turngldquo(e surface grafting of grapheme oxide with poly (ethyleneglycol) as a reinforcement for poly(lactic acid) nanocompositescaffolds for potential issue engineering applicationsrdquo Journalof Mechanical Behaviour of Biomedical Materials vol 53pp 403ndash413 2016

[3] Z Liu Y Lei Z Hu W Kong C Zhou and J Lei ldquoPrep-aration characterization and properties of poly(lactic acid)poly(14-butylene adipate) blends for biodegradable packag-ing materialsrdquo Macromolecular Research vol 25 no 5pp 439ndash445 2017

[4] M R A Moghaddam S M A Razavi and Y Jahani ldquoEffectof compatibilizer and thermoplastic starch (TPS) concen-tration on morphological rheological tensile thermal andmoisture sorption properties of plasticized polylactic acidtPSblendsrdquo Journal of Polymers and the Environment vol 26no 8 pp 3202ndash3212 2018

[5] S Jacobsen and H G Fritz ldquoPlasticizing polylactidemdashtheeffect of different plasticizers on the mechanical propertiesrdquoPolymer Engineering and Science vol 39 no 7 pp 1303ndash13101999

[6] G (eryo F Jing L M Pitet and M A Hillmayer ldquo(oughpolylactide graft copolymersrdquoMacromolecules vol 43 no 18pp 7394ndash7397 2010

[7] S Ishida R Nagasaki K Chino et al ldquoToughening ofpoly(l-lactide) by melt blending with rubbersrdquo Journal ofApplied Polymer amp Science vol 113 no 1 pp 558ndash566 2009

[8] C Zhang W Wang Y Huang et al ldquo(ermal mechanicaland rheological properties of polylactide toughened by ep-oxidized natural rubberrdquo Materials and Design vol 45pp 198ndash205 2013

[9] S Pichaiyut C Nakason and S Wisunthorn ldquoBio-degradability and thermal properties of novel natural rubberlinear low density polyethylenethermoplastic starch ternaryblendsrdquo Journal of Polymers and the Environment vol 26no 7 pp 2855ndash2866 2018

[10] H Younes and D Cohn ldquoPhase separation in poly(ethyleneglycol)poly(lactic acid) blendsrdquo European Polymer Journalvol 24 no 8 pp 765ndash773 1988

[11] M Bariado G Frisoni M Scandola et al ldquo(ermal andmechanical properties of plasticized poly(L-lactic acid)rdquoJournal of Applied Polymer amp Science vol 90 no 7pp 1731ndash1738 2003

[12] Z Kulinski and E Piotrowska ldquoCrystallization structure andproperties of plasticized poly(L-lactide)rdquo Polymer vol 46no 23 pp 10290ndash10300 2005

[13] N Ljungberg and B Wesslen ldquo(e effects of plasticizers onthe dynamic mechanical and thermal properties of poly(lacticacid)rdquo Journal of Applied Polymer amp Science vol 86 no 5pp 1227ndash1234 2002

[14] O Martin and L Averous ldquoPoly(lactic acid) plasticizationand properties of biodegradable multiphase systemsrdquo Poly-mer vol 42 no 14 pp 6209ndash6219 2001

[15] J Korol J Lenza and K Formela ldquoManufacture and researchof TPSPE biocomposites propertiesrdquo Composites Part BEngineering vol 68 pp 310ndash316 2015

[16] H Pan D Ju Y Zhao et al ldquoMechanical properties hydro-phobic properties and thermal stability of the biodegradablepoly(butylenes adipate-co-terephthalate)maleated thermo-plastic starch blow filmsrdquo Fibers and Polymers vol 17 no 10pp 1540ndash1549 2016

[17] M Sabetzadech R Bagheri and M Masoomi ldquoEffect ofoxidized starch on morphology rheological and tensileproperties of low-density polyethylenelinear low-densitypolyethylenethermoplastic oxidized starch blendsrdquo Journalof Polymers and the Environment vol 26 no 6 pp 2219ndash2226 2018

[18] B Swierz-Motysia R Jeziorska A Szadkowska et al ldquoSyn-thesis and properties of biodegradable polylactide and ther-moplastic starch blendsrdquo Polimery vol 56 no 4 pp 271ndash2802011

[19] L Chen X Y Qiu Z G Xie et al ldquoPoly(L-lactide)starch blendscompatibilized with poly(L-lactide)-g- starch copolymerrdquo Car-bohydrate Polymers vol 65 no 1 pp 75ndash80 2006

[20] C W Obiro M E Naushad and S R Suprakas ldquoIncludingPLAstarch compatibility through butyl-etherification ofwaxy and high impact amylose starchrdquo Carbohydrate Poly-mers vol 112 pp 216ndash224 2014

[21] P Dubois and R Narayan ldquoBiodegradable compositions byreactive processing of aliphatic polyesterpolysaccharideblendsrdquo Macromolecular Symposia vol 198 no 1 pp 233ndash244 2003

[22] J F Zhang and X Sun ldquoMechanical properties of poly(lacticacid)starch composites compatibilized by maleic anhydriderdquoBiomacromolecules vol 5 no 4 pp 1446ndash1451 2004

[23] J Wootthikanokkhan N Wongta N Sombatsompop et alldquoEffect of blending conditions on mechanical thermal andrheological properties of plasticized poly(lactic acid)maleated


thermoplastic starch blendsrdquo Journal of Applied Polymer ampScience vol 124 no 2 pp 1012ndash1019 2012

[24] S W Hwang J K Shim S Selke H Soto-Valdez M Rubinoand R Auras ldquoEffect of maleic-anhydride grafting on thephysical and mechanical properties of poly(L-lactic acid)starch blendsrdquo Macromolecular Materials and Engineeringvol 298 no 6 pp 624ndash633 2013

[25] Z Xiong S Ma L Fan et al ldquoSurface hydrophobic modi-fication of starch with bio-based epoxy resins to fabricatehigh-performance poly(lactide) composite materialsrdquo Com-posite Science and Technology vol 94 no 1 pp 16ndash22 2014

[26] H Balakrishnan A Hassan M U Wahit et al ldquoNoveltoughened polylactic acid nanocomposite mechanical ther-mal and morphological propertiesrdquo Materials and Designvol 31 no 7 pp 3289ndash3298 2010

[27] C (ellen C Orroth D Froio et al ldquoInfluence of mont-morillonite layered silicate on plasticized poly(L-lactide)blown filmsrdquo Polymer vol 46 no 25 pp 11716ndash11727 2005

[28] O H Arroyo M A Huneault B D Favis and M N BureauldquoProcessing and properties of PLAthermoplastic starchmontmorillonite nanocompositesrdquo Polymer Compositesvol 31 pp 114ndash127 2010

[29] M R Aghjeh V Asadi P Mehdijabbar H A Khonakdarand S H Jafari ldquoApplication of linear rheology in de-termination of nanoclay localization in PLAEVAClaynanocomposites correlation with microstructure and ther-mal propertiesrdquo Composites Part B Engineering vol 86pp 273ndash284 2016

[30] J Zhang J Lou S Ilias P Krishnamachari and J Yanldquo(ermal properties of poly(lactic acid) fumed silica nano-composites experiments and molecular dynamics simula-tionsrdquo Polymer vol 49 no 9 pp 2381ndash2386 2008

[31] F Wu X Lan D Ji Z Liu W Yang and M Yang ldquoGraftingpolymerization of polylactic acid on the surface of nano-SiO2and properties of PLAPLA-grafted-SiO2 nanocompositesrdquoJournal of Applied Polymer amp Science vol 129 no 5pp 3019ndash3027 2013

[32] J Ch H Lai M R Rahman and S Hamdan ldquoComparativestudies of thermo-mechanical and morphological prop-erties of polylactic acidfumed silicaclay (128E) andpolylactic acidfumed silicaclay (134 TCN) nano-compositesrdquo Polymer Bulletin vol 75 no 1 pp 135ndash1472018

[33] V Kumar A Dev and A P Gupta ldquoStudies of poly(lacticacid) based calcium carbonate nanocompositesrdquo CompositesPart B Engineering vol 56 pp 184ndash188 2014

[34] E Jalalvandi R A Majid and T Ghanbari ldquoProcessingmorphological thermal and absorption behavior of PLAthermoplastic starchmontmorillonite nanocompositesrdquoWorld Academy of Science Engineering and Technology vol 6no 12 pp 715ndash719 2012

[35] B Ayana S Suin and B B Khatua ldquoHighly exfoliated eco-friendly thermoplastic starch (TPS)poly(lactic acid)(PLA)clay nanocomposites using unmodified nanoclayrdquo Carbohy-drate Polymers vol 110 pp 430ndash439 2014

[36] I Petersson and K Oksman ldquoBiopolymer based nano-composites comparing layered silicates and microcrystallinecellulose as nanoreinforcementrdquo Composites Science andTechnology vol 66 no 13 pp 2187ndash2196 2006

[37] R Jeziorska A Szadkowska B Swierz-Motysia andJ Kozakiewicz ldquoEffect of ldquocore-shellrdquo polymeric nanofillerstructure and properties of polylactide and thermoplasticcorn starch blendrdquo Polimery vol 57 no 5 pp 354ndash3632012

[38] B Swierz-Motysia R Jeziorska A Szadkowska et al ldquoBio-degradable composition with thermoplastic starchrdquo PolishPatent 214 329 2013

[39] B Swierz-Motysia R Jeziorska A Szadkowska et alldquoMethod for obtaining thermoplastic starchrdquo Polish Patent216 930 2014

[40] M Zielecka K Bajdor A Szulc et al ldquoMethod for obtainingsilica nanopowder also functionalizedrdquo Polish Patent 198 1882007

[41] M Zielecka E Bujnowska B Kepska et al ldquoAntimicrobialadditives for architectural paints and impregnatesrdquo Progressin Organic Coatings vol 72 no 1-2 pp 193ndash201 2011

[42] M Zielecka E Bujnowska K Suwała and M Wenda ldquoSol-gel-derived silicon-containing hybridsrdquo in Recent Applica-tions in Sol-Gel Synthesis INTECH London UK 2017

[43] R Jeziorska ldquoFunctionalization of low density polyethylenewith ricinol-2-oxazoline methyl maleate in a twin-screw ex-truderrdquo International Polymer Processing vol 22 no 2pp 122ndash131 2007

[44] B Swierz-Motysia R Jeziorska A Szadkowska et al ldquoBio-degradable polymer composites containing powder nano-fillerrdquo Polish Patent 216 295 2014

[45] J F Turner A Riga A OrsquoConnor J Zhang and J CollisldquoCharacterization of drawn and undrawn poly-L-lactide filmsby differential scanning calorimetryrdquo Journal of ltermalAnalysis and Calorimetry vol 75 no 1 pp 257ndash268 2004

[46] R Mani M Bhattacharya and J Tang ldquoFunctionalization ofpolyesters with maleic anhydride by reactive extrusionrdquoJournal of Polymer Science Part A Polymer Chemistry vol 37no 11 pp 1693ndash1702 1999

[47] J Prachayawarakorn P Ruttanabus and P Boonsom ldquoEffectof cotton fiber contents and lengths on properties of ther-moplastic starch composites prepared from rice and waxy ricestarchesrdquo Journal of Polymers and the Environment vol 19no 1 pp 274ndash282 2010

[48] M P Guaras V A Alvarez and L N Luduena ldquoProcessingand characterization of thermoplastic starchpolycarbonatecompatibilizer ternary blends for packaging applicationsrdquoJournal of Polymer Research vol 22 no 9 pp 165ndash176 2015

[49] J Prachayawarakorn S Chaiwatyothin S Mueangta andA Hanchama ldquoEffect of jute and kapok fibers on properties ofthermoplastic cassava starch compositesrdquo Materials andDesign vol 47 pp 309ndash315 2013

[50] R Jeziorska B Swierz-Motysia M Zielecka A Szadkowskaand M Studzinski ldquoStructure and mechanical properties oflow-density polyethylenespherical silica nanocompositesprepared by melt mixing the joint action of silicarsquos sizefunctionality and compatibilizerrdquo Journal of Applied PolymerScience vol 125 no 6 pp 4326ndash4337 2012

[51] R Jeziorska B Swierz-Motysia M Zielecka et alldquoPolyamidespherical nanosilica nanocompositesrdquo Polimeryvol 54 no 10 pp 647ndash656 2009

[52] W S Chow and S K Lok ldquoFlexural morphological andthermal properties of poly(lactic acid)organo-montmorillonitenanocompositesrdquo Polymers and Polymer Composites vol 16no 4 pp 263ndash270 2008

[53] H J Lee T G Park H S Park et al ldquo(ermal and me-chanical characteristics of poly(l-lactic acid) nanocompositescaffoldrdquo Biomaterials vol 24 no 16 pp 2773ndash2778 2003

[54] A Szadkowska R Jeziorska M Zubrowska E Spasowka andP Rosciszewski ldquoEffect of plasticizer with silanol groups onthe structure and properties of polylactide and thermoplasticcorn starch blendrdquo Polimery vol 61 no 10 pp 683ndash6922016


[55] T M Wu and C Y Wu ldquoBiodegradable poly(lactic acid)chitosan-modified montmorillonite nanocomposites prepa-ration and characterizationrdquo Polymer Degradation and Sta-bility vol 91 no 9 pp 2198ndash2204 2006

[56] E Petinakis X Liu L Yu et al ldquoBiodegradation and thermaldecomposition of poly(lactic acid)-based materials reinforcedby hydrophilic fillersrdquo Polymer Degradation and Stabilityvol 95 no 9 pp 1704ndash1707 2010

[57] X Ping W Kejian J Mingryin and Y Meijuan ldquoBio-degradation and mechanical property of polylactic acidthermoplastic starch blends with poly(ethylene glycol)rdquoJournal of Wuhan University of Technology-Materials ScienceEdition vol 28 no 1 pp 157ndash162 2013

[58] Z Ren L Dong and Y Yuming ldquoDynamic mechanical andthermal properties of plasticized poly(lactic acid)rdquo Journal ofApplied Polymer Science vol 101 no 3 pp 1583ndash1590 2006

[59] D Lourdin H Bizot and P Colonna ldquoAntiplasticization instarch-glycerol filmsrdquo Journal of Applied Polymer Sciencevol 63 no 8 pp 1047ndash1053 1997

[60] P Sarazin G Li W J Orts and B D Favis ldquoBinary andternary blends of polylactide polycaprolactone and ther-moplastic starchrdquo Polymer vol 49 no 2 pp 599ndash609 2008


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ria

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Submit your manuscripts atwwwhindawicom

so-called soil test which was enhanced as a function of TPS[18] (us melt compounding TPS with PLA is one of themost promising methods to solve PLA limitations or to lowerits high price [19] Nevertheless incompatibility betweenhydrophobic PLA and hydrophilic starch results in poormechanical properties due to inadequate interfacial in-teraction between these polymers To improve the adhesion ofPLA and TPS chemical modification of the starch beforeblending is performed and compatibilizers such as maleicanhydride (MA) and epoxy resins have been used [4 20ndash24]

It has been previously suggested that the intensive in-terfacial interactions among hydrogen bonds of the anhy-dride groups of the maleated polylactide (MPLA) and thehydroxyl groups of the starch are responsible for the increasein tensile flexural and impact properties of PLA andthermoplastic potato or corn starch blends [25]

Recent results show that the nanoscale distribution ofmontmorillonite [18 26ndash28] fumed silica (SiO2) [29ndash32]and calcium carbonate [33] within the PLA matrix signifi-cantly enhances their thermal mechanical and rheologicalproperties as well as reduces permeability and flammabilitycompared to conventional micro- and macrocomposites Inorder to reach the nanoscale distribution the naturallyhydrophilic nanofiller has to be organically modified to bemore compatible with the organic polymer matrix Howeveronly few studies have been conducted in the development ofplasticized PLAthermoplastic starch nanocomposites re-cently [34ndash36]

In a previous work [37] we have studied the influence ofthe core-shell polymeric nanofiller and maleated polylactideused as a compatibilizer on the structural mechanical andbarrier properties of PLA and TPS blends (e addition ofthe core-shell polymeric nanofiller in the presence of MPLAimproved adhesion between PLA and starch Melting pointand crystallinity temperature of PLA were found to decreaseby adding TPS and the polymeric nanofiller (e nano-composites showed significantly lower stiffness compared toneat PLA However the storage modulus increased asa function of nanofiller content Moreover the addition ofthe core-shell polymeric nanofiller strongly improved im-pact strength the elongation at break and barrier propertiesof PLATPS blends

To the best of our knowledge no systematic studieshave been done so far to investigate the properties of pol-ydimethylsiloxanol toughenedPLATPSsilica nanocomposites(erefore the objective of this paper is to investigate thethermal mechanical rheological and morphological propertiesof polydimethylsiloxanol toughened PLATPSsilica nano-composites in the presence of MPLA used as a compatibilizerIn particular the effects of plasticizer spherical silica contentand its functionality were also studied

2 Materials and Methods

21 Materials Polylactide polymer (PLA 2003D) wasprovided by Nature Works USA with melt flow rate of69 g10min (ISO 1133 at 210degC and 216 kg) (e charac-teristics of PLA are described in Table 1 Maleated poly-lactide (MPLA) containing 068wt of grafted maleic

anhydride with melt flow rate of 38 g10min (ISO 1133 at210degC and 216 kg) was obtained according to the procedurepublished elsewhere [18 38] and it was used as a compa-tibilizer for PLATPS blends at the concentration of 10wtMaleic anhydride (MA) as coupling agent and dicumylperoxide (DCP) as initiator were purchased from Sigma-Aldrich Italy

(ermoplastic corn starch (TPS) was obtained by meltblending according to the procedure published elsewhere[18 39] and used as a biodegradable additive Standard cornstarch with about 23 of amylase 11ndash13 humidity and pH65 was purchased from Cargill Germany (e glycerol with995 purity was the product of Rafineria Trzebinia Poland(e characteristics of TPS are shown in Table 1

Plastosil M-2000 the commercial name of poly-dimetylsiloxanol containing 004wt of reactive silanolgroups η 2000plusmn 500 cP d 097 gcm3 supplied byChemical Plant Polish Silicones Ltd was used as a plasticizer(P) for the PLAMPLATPS (601030) blend

Neat (SiO2) and modified (having amine functionalgroups) spherical silica (A-SiO2) nanoparticles synthesizedaccording to the previously reported sol-gel process [40ndash42]were used as nanofillers Tetraethoxysilane (TEOS) tech-nical grade commercial product name TES 28 was suppliedby Wacker Chemie (Germany) Ethyl alcohol (reagentgrade) and aqueous ammonia (reagent grade 25wtd 091 gcm3) were supplied by POCh SA (Poland) andused as received (e characteristics of silica are described inTable 2

22 PLA Functionalization In order to improve compati-bility between PLA and TPS PLA was grafted with maleicanhydride via reactive extrusion to obtain a grafting yield of068 wt according to the procedure published elsewhere[18 38] MPLA was prepared as follows PLA MA (2wtPLA basis) and DCP (18wt MA basis) were mixed in theinternal mixer and subsequently the mixture was extrudedusing a corotating twin-screw extruder (Berstorff Germany)with a screw diameter of 25mm and length to diameter ratioof 33 To prevent the degradation of the polymer during theprocessing time a nitrogen purge flow was used Differentscrew elements along the screw worked in order to inducepolymer melting [43] (e three mixing sections enhancedthe compounding and increased the residence time of themixture in the barrel (e barrel pressure in these parts aswell as at the section before the die could be increased (eextruder also had a vacuum degassing port to remove anymoisture traces or other volatile products formed duringcompounding (e process was carried out at a barreltemperature 130ndash140degC (e output was 4 kgh and thescrew speed was 100 rpm

23 TPS Preparation To obtain TPS destructurization andplasticization of native corn starch were performed in one-step extrusion process in the earlier mentioned Berstorfftwin-screw corotating extruder using 30wt of glycerol asa plasticizer [18 39] (e process was carried out at a barreltemperature 130ndash170degC and screw speed of 80 rpm (e TPS










(a) (b)












Xc ΔHm


1113888 1113889100 (1)





H2O

(CH2)3 NH2

SiSi

OC2H5

OC2H5OC2H5OC2H5

OC2H5

OC2H5

OC2H5















1

23

4

5

6

1260860

1650

18501750

3435 1060

1260

3640ndash3040

29602910

1750 1080ndash9403640ndash3040



(a) (b)


(a) (b)

(c) (d)

(e) (f )







0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)



0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)







exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls












(a) (b)












Xc ΔHm


1113888 1113889100 (1)





H2O

(CH2)3 NH2

SiSi

OC2H5

OC2H5OC2H5OC2H5

OC2H5

OC2H5

OC2H5















1

23

4

5

6

1260860

1650

18501750

3435 1060

1260

3640ndash3040

29602910

1750 1080ndash9403640ndash3040



(a) (b)


(a) (b)

(c) (d)

(e) (f )







0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)



0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)







exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls











Xc ΔHm


1113888 1113889100 (1)





H2O

(CH2)3 NH2

SiSi

OC2H5

OC2H5OC2H5OC2H5

OC2H5

OC2H5

OC2H5















1

23

4

5

6

1260860

1650

18501750

3435 1060

1260

3640ndash3040

29602910

1750 1080ndash9403640ndash3040



(a) (b)


(a) (b)

(c) (d)

(e) (f )







0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)



0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)







exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls














1

23

4

5

6

1260860

1650

18501750

3435 1060

1260

3640ndash3040

29602910

1750 1080ndash9403640ndash3040



(a) (b)


(a) (b)

(c) (d)

(e) (f )







0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)



0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)







exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




(a) (b)


(a) (b)

(c) (d)

(e) (f )







0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)



0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)







exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls








0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

Stre

ss (M

Pa)

(a)



0

5

10

15

20

25

30

35

40

45

0 20 40 60 80 100Strain ()

Stre

ss (M

Pa)

(b)







exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls








exo

60

TgTc

Tm


120 140 160

PLATPS


(a)

exo


120 140 160



Tg TcTm

(b)



Sample Tg(degC)

Tm(degC)

Tc(degC)

Xc()


100

80

60

40

20

0100 200 300 400


Wei

ght l

oss (

)

TPSPLA

PLAMPLATPS



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls



















000E + 00

200E + 09

400E + 09

600E + 09

800E + 09

100E + 10


Gprime (

Pa)

PLATPS


(a)


0

005

01

015

02

025

03

tgδ

PLATPS


γ

β

α1

(b)

tgδ

PLATPS


0

05

1

15

2

25

3


α

(c)









4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls










4 Conclusions



Sample



Atminus120degC

Atminus50degC




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

(a)



000E + 00

100E + 09

200E + 09

300E + 09

400E + 09

500E + 09


Gprime (

Pa)

Temperature (degC)

(b)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

0

002

004

006

008

01


tgδ

Temperature (degC)

α1

β

γ

(c)



tgδ

0

002

004

006

008

01


α1

β

γ

(d)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(e)

0 wt SiO21 wt SiO2

3 wt SiO25 wt SiO2

tgδ

0

05

1

15

2

25

3


α

(f )





Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls






Data Availability




Acknowledgments


References



































































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls














































Advances in



Journal of

Chemistry















Journal of





Volume 2018









Journal of


Na

nom

ate

ria

ls




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