study of the influence of some polymeric additives as viscosity index improvers and pour point...

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Study of the influence of some polymericadditives as viscosity index improvers andpour point depressants – synthesis andcharacterization

Pranab Ghosh, Moumita Das

PII: S0920-4105(14)00102-8DOI: http://dx.doi.org/10.1016/j.petrol.2014.04.014Reference: PETROL2642

To appear in: Journal of Petroleum Science and Engineering

Received date: 3 April 2012Revised date: 21 February 2014Accepted date: 25 April 2014

Cite this article as: Pranab Ghosh, Moumita Das, Study of the influence ofsome polymeric additives as viscosity index improvers and pour pointdepressants – synthesis and characterization, Journal of Petroleum Science andEngineering, http://dx.doi.org/10.1016/j.petrol.2014.04.014

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Study of the influence of some polymeric additives as viscosity index improvers and pour point depressants – synthesis and characterization

Pranab Ghosh* and Moumita Das

Natural Product and Polymer Chemistry Laboratory

Department of Chemistry, University of North Bengal, Darjeeling-734013, India

Tel No.: +91 353 2776381, Fax No.: + 91 353 2699001

E-mail address: [email protected]

ABSTRACT

Homopolymers of decyl acrylate and isooctyl acrylate and copolymers of each of them with 1-

decene were synthesized and characterized by viscosity measurement, thermogravimetric and

spectral analysis. Viscometric methods were used to determine the intrinsic viscosity of each of

them. Pour point depressant (PPD) and Viscosity index improver (VII) properties were tested

with additive doped base oil in terms of pour point (PP) and viscosity index (VI), respectively.

Although the decyl acrylate polymers were thermally more stable than the isooctyl acrylate

polymers, the latter showed higher VI and pour point depression efficiency. VI and PP values of

the additive doped base oils depend on the nature of mineral base oils as well as on the type and

concentration of VI improvers.

Study of the influence of some polymeric additives as viscosity index improvers and pour point depressants – synthesis and characterization

Pranab Ghosh* and Moumita Das

Natural Product and Polymer Chemistry Laboratory

Department of Chemistry, University of North Bengal, Darjeeling-734013, India

Tel No.: +91 353 2776381, Fax No.: + 91 353 2699001

E-mail address: [email protected]

ABSTRACT

Homopolymers of decyl acrylate and isooctyl acrylate and copolymers of each of them with 1-

decene were synthesized and characterized by viscosity measurement, thermogravimetric and

spectral analysis. Viscometric methods were used to determine the intrinsic viscosity of each of

them. Pour point depressant (PPD) and Viscosity index improver (VII) properties were tested

with additive doped base oil in terms of pour point (PP) and viscosity index (VI), respectively.

Although the decyl acrylate polymers were thermally more stable than the isooctyl acrylate

polymers, the latter showed higher VI and pour point depression efficiency. VI and PP values of

the additive doped base oils depend on the nature of mineral base oils as well as on the type and

concentration of VI improvers.

Keywords: Rheological properties, Pour point depressant, Viscosity index improver,

Thermogravimetric analysis

1. Introduction

The performance of lubricant base oils is often governed by their rheological properties

such as low temperature fluidity, viscosity and viscosity temperature relationship. For example,

to provide an effective performance at low as well as at high temperatures, an engine lubricant

should have good low temperature fluidity and minimal variations of its viscosity with

temperature. Properties of such base oils can be improved by the incorporation of suitable

performance polymers, generally called additives. The additives are mixed within these base oils

to impart additional desirable properties already present in them. In addition, additives play an

important role in compounding of lubricants for steam turbines, gas turbines, jet aircraft turbines,

railroad and marine diesel engines, aircraft piston engines, stationary piston engines, and

relatively low-power two-cycle engines. They are also used in compounding hydraulic oils,

industrial gear lubricants, and cutting oils (O’Conner and Boyd, 1968).

Among the main types of lube oil additives i.e., detergents, dispersants, antioxidants,

corrosion inhibitors, extreme pressure agents (EP), viscosity index improvers (VII) and pour

point depressants (PPD), VII and PPD are of having utmost importance.

Viscosity is a very important property of a lubricant (Anwar et al., 1999) and an ideal

lubricant should possess the same viscosity at all temperatures (Santos et al., 2004). Viscosity

index improvers (VIIs) are chemicals that are added to lubricating oils to make them conform

more closely to the ideal lubricant. Although a few non-polymeric substances such as metallic

soaps exhibit VI improving properties (Ghosh et al., 2011a), all commercially important VI

improvers today are oil-soluble organic polymers. The efficiency of the VIIs is measured by a

parameter known as Viscosity index (VI). It is an indicator of the change in viscosity as the

temperature is changed. The higher the VI, the less the viscosity of an oil changes for a given

temperature change. Viscosity index improvers are used to limit the rate of change of viscosity

with temperature. These improvers have little effect on oil viscosity at low temperatures.

However, at higher temperature, the polymer molecules changes from tight coils to an open

configuration and thus exerting a greater thickening effect on oil at higher temperatures than they

do at lower temperatures (Pedersen and Ronningsen, 2003).

Again, the n-paraffin waxes contained in the lube oil, when cooled, separate out as plate-

like crystals which interact together to form a three-dimensional network in which liquid oil

becomes trapped which results - an increase in viscosity and a decrease in oil flow ability (Wang

et al., 1999). At a certain lower temperature, the flow ability of the oil is totally ceased. The

temperature is known as pour point for lube oils. Several options are available to counteract the

problems which include the use of chemical additive treatment (Andre and Elizabete, 2001; Al-

Sabagh et al., 2002), known as Pour point depressant (PPD). These additives function by

modifying wax crystal size and shape during their growth. The additives do not entirely prevent

wax crystal growth, but rather lower the temperature at which a rigid structure is formed (Anwar

et al., 1999; Florea et al., 1999).

Flow improvers of different polymeric structures have been published in patent reviews

such as long alkyl chain fatty acid esters (El-Gamal et al., 1991), polyacrylates (El-Gamal et al.,

1993), polymethacrylate (Andre and Elizabete, 2002), α-olefin-maleate copolymers (El-Gamal

and Al-Sabbagh, 1996) etc.

It appears from the literature that long chain polyacrylates may provide excellent additive

performance when added to lube oil. Keeping this view in mind, we have chosen 1-decene to be

introduced into the acrylate backbone through copolymerisation in anticipation that they may

offer useful performances for petroleum and synthetic base oil.

The results of our investigation including the synthesis, characterization (Spectral and

Thermogravimetric analysis), viscometric measurements and performance evaluation (VII and

PPD) of 2-ethylhexyl acrylate (isooctyl acrylate, IOA) + 1-decene copolymers and decyl acrylate

(DA) + 1-decene copolymers in comparison to the homopolymer of 2-ethylhexyl acrylate and

decyl acrylate have described in this paper.

Viscometric measurements were carried out using graphic extrapolation as well as by

single point determination method (Ghosh et al., 2011b; Abdel-Azim et al., 1998). The later

method has the advantage of being considerably faster and can be adequate when a large number

of samples must be analysed in short period of time, practically in industrial laboratories.

Among the graphic extrapolation method, the most commonly used equations are (1- 4):

Huggins (H) [ ] [ ] CkC hhhsp 2ηηη

+= (1)

Kraemer (K) [ ] [ ] CkC kkkr2ln ηηη −= (2)

Martin (M) [ ] [ ] CkC mmmsp ηηη

+=⎟⎠⎞

⎜⎝⎛ lnln

(3)

Schulz-Blaschke (SB) [ ] [ ] spsbsbsbsp kC ηηηη

+= (4)

Where, ηr = t/to, relative viscosity or viscosity ratio

ηsp = ηr –1, specific viscosity

[η]h = intrinsic viscosity, respective to Huggins equation

[η]k = intrinsic viscosity, respective to Kraemer equation

[η]m = intrinsic viscosity , respective to Martin equation

[η]sb= intrinsic viscosity or limiting number, respective to Schulz-Blaschke

equation kh, kk, km and ksb are Huggins, Kraemer, Martin and Schulz-Blaschke coefficients,

respectively.

For single point determination method, the equations used are (5-6):

Solomon-Ciuta (SC) [ ] [ ] Crsp /)ln(2 21ηηη −= (5)

Deb-Chatterjee (DC) [ ] ( ) Cspspr

312 323ln3 ηηηη −+= (6)

The use of these equations has been derived under the supposition of the validity of the

relationship kh+ kk = 0.5. The unit of intrinsic viscosity and concentration are dL g−1 and g cm−3

respectively.

2. Experimental

2. 1. Materials

Details of the materials used to synthesise the polymers and their specification are

tabulated below in Table 1. Two different base oils were collected from IOCL, Dhakuria,

Kolkata and their Physical properties were tabulated in Table 2 below.

2. 2. Esterification

Decyl acrylate was prepared by reacting 1.1 mole of acrylic acid with 1 mole of decyl

alcohol. The reaction was carried out in a resin kettle in the presence of concentrated sulphuric

acid as a catalyst, 0.25 % hydroquinone as polymerization inhibitor for acrylic acid and toluene

as a solvent. The esterification reaction was carried out under a slow stream of deoxygenated

nitrogen. The reactants, which were mixed with toluene, were heated gradually from room

temperature to 403 K using a well-controlled thermostat. The extent of reaction was followed by

monitoring the amount of liberated water to give the ester, decyl acrylate (DA). Under the same

procedure isooctyl acrylate (IOA) was also prepared from acrylic acid and 2-ethylhexanol

(isooctanol).

2. 3. Purification of prepared esters

The prepared esters were purified according to the following procedure: a suitable

amount of charcoal was added to the ester, allowed to reflux for 3 h and then filtered off. The

filtrate was washed with 0.5 N sodium hydroxide in a separating funnel and then shaken well.

The entire process was repeated several times to ensure complete removal of unreacted acid. The

purified ester was then washed several times with distilled water to remove any traces of sodium

hydroxide, the ester was then left over night on calcium chloride and was then removed by

distillation under reduced pressure and was used in the polymerization process.

2.4. Preparation of copolymer and homopolymer

Homopolymer of DA and IOA (HDA and HIOA, respectively) were prepared and in the

preparation of DA + 1-decene and IOA + 1-decene copolymers, different mole fractions of 1-

decene were used (Table 3). The polymerization was carried out in a four necked round bottom

flask equipped with a stirrer, condenser, thermometer, an inlet for the introduction of nitrogen

and a dropping funnel through which to add 1-decene drop wise. In the flask, desired mass of

DA and initiator (BZP) was placed followed by desired mass of 1-decene was added drop wise

for 2 h in the presence of toluene as solvent. The reaction temperature was maintained at 353 K

for 6 h. At the end of the reaction time, the reaction mixture was poured into methanol with

stirring to terminate the polymerization and precipitate the polymer. The polymer was further

purified by repeated precipitation of its hexane solution by methanol followed by drying under

vacuum at 313 K.

Homopolymer of DA, homopolymer of IOA and also copolymer of IOA with 1- decene

were similarly prepared and purified under the same condition for use in reference experiments.

3. Measurements

3. 1. Spectroscopic measurements

Spectroscopic IR spectra were recorded on a Shimudzu FT-IR 8300 spectrometer using

0.1 mm KBr cells at room temperature within the wave number range 400 to 4000 cm-1. NMR

spectra were recorded in Brucker Avance 300 MHz FT-NMR spectrometer using 5 mm BBO

probe. CDCl3 was used as solvent and TMS as reference material.

3. 2. Viscometric measurements

Viscometric properties were determined at 313 K in toluene solution, using an Ubbelohde

OB viscometer having viscometer constant values K = 0.00268 cm2.s−2, L = −19.83 cm2, the

volume of the bulb is 3 cm3 and length of the capillary 11.3 cm and manufactured by Rheotek

(UK). Experimental determination was carried out by counting time of flow of at least eight

different concentrations of the sample solution. The time of flow of the solutions was manually

determined by using a chronometer. In the single point measurement, the lowest value of

solution concentration was chosen for calculation.

3. 3. Thermogravimetric analysis (TGA)

The thermograms in air were obtained on a mettler TA-3000 system, at a heating rate of

10 K·min-1 at room temperature under atmospheric pressure taking 0.2 g of each polymer sample

in a platinum crucible.

3. 4. Evaluation of PPD properties of the additives in lube oil

The prepared compounds were evaluated as pour point depressants (PPD) using two

different base oils through the pour point test according to the ASTM D97-09 on a Cloud and

Pour Point Tester model WIL-471(India).

3. 5. Evaluation of the prepared additives as Viscosity Index Improver in lube oil

The Viscosity index values of the polymeric oil solutions have been determined

according the ASTM D2270 method and by using the following equations (Tanveer et al, 2006).

VI = 3.63(60-10n)

Where, n = (ln v1- ln k)/ ln v2

For which, v1 and v2 are the kinematic viscosities (cSt) of the solution at lower and higher

temperature, respectively. The kinematic viscosity of the oil containing the different

concentrations of the tested polymers was determined at 313 K and 373 K and k is a constant

which is equal to 2.714 for the temperature range performed. Different concentrations ranging

between 1.0 and 6.0 wt % were used to study the effect of copolymer concentration on the VI.

4. Results and discussion

4. 1. Spectroscopic analysis

FT-IR spectrum of the homo polymer of Decyl acrylate (HDA) exhibited absorption at

1732 cm-1 due to ester carbonyl stretching vibration. Peak at 1260 and at 1175cm-1 can be

explained owing to the C-O (ester bond) stretching vibration and the absorption bands at 975,750

and 711 cm-1 were due to the bending of C-H bond. The broad peak ranging from 2900-3100 cm-

1 was due to the presence of stretching vibration (C-H).

In its 1H-NMR spectra, homo polymer of DA showed a multiplet centered at 3.2 ppm due

to the proton of -OCH2- group; a broad singlet at 0.73 ppm was due to methyl groups of decyl

chain. The proton decoupled 13C-NMR of the above sample was in complete agreement with the

homopolymer which shows the presence of ester carbonyl group at 171 ppm and absence of any

sp2 carbon in the range 130-150 ppm.

FT-IR spectrum of the homo polymer of Isooctyl acrylate (HIOA) exhibited absorption at

1731 cm-1 due to ester carbonyl stretching vibration. Peak at 1260 and at 1164cm-1 can be

explained owing to the C-O (ester bond) stretching vibration and the absorption bands at 961,775

and 720 cm-1 were due to the bending of C-H bond. The broad peak ranging from 2929-2950 cm-

1 was due to the presence of stretching vibration (C-H). 1H and 13C-NMR was also in complete

agreement with the homopolymer.

In its 1H-NMR spectra, homo polymer of IOA showed a broad singlet centered at 4.01

ppm due to the proton of -OCH2- group; a broad singlet at 0.89 ppm was due to methyl groups of

isooctyl chain. The proton decoupled 13C NMR of the above sample shows no peak between

130-150 ppm which indicated the absence of any sp2 carbon. The presence of ester carbonyl

group was indicated by the peak at 170 ppm.

No peak between 4 to 6 ppm in the 1H-NMR and that between 130 to 150 ppm in the 13C

NMR spectrum indicated the absence of the sp2 hydrogen and sp2 carbon, respectively which

clearly indicated the formation of the copolymers (DA + 1-decene and IOA + 1-decene

copolymers).

The value of extent of incorporation of 1-decene in the copolymer composition, as

determined from IR and FT-NMR method is tabulated in Table 3.

4. 2. Thermogravimetric analysis

Table 4 and a corresponding graphical presentation (Figure 1) present a comparison

between the TGA data for homo and copolymers. The TGA data shows that in case of DA

polymers, the copolymers are better in thermal stability than the homopolymer and with

increasing concentration of 1-decene in the feed, the stability increases. But the trend is reversed

for the polymers of IOA. The homopolymer is thermally more stable than the copolymers and

with increasing concentration of 1-decene, thermal stability decreases. Also, comparison among

the TGA values indicates that the values for DA polymers are thermally more stable than the

IOA polymers.

4. 3. Viscometric analysis

Viscometric data were obtained using the six equations mentioned. A linear relation for

the plot of log ηsp vs. log C [η], obtained for all samples (Figure 2), indicated that measurements

were performed in Newtonian flow (ηsp, C, [η] represents specific viscosity, concentration and

intrinsic viscosity of the polymer solutions corresponding to the Huggins equation, respectively)

(Mello et al., 2006; Ghosh et al., 2009).

Using the graphic extrapolation method, respective intrinsic viscosities and constants

were evaluated (Table 5 and Table 6). In single point determinations, Schulz-Blaschke (SB),

Solomon-Ciuta (SC) and Deb-Chatterjee (DC) equations were employed to determine the

intrinsic viscosity (Table 5). Although dependent on a constant, the SB equation is commonly

applied in single point determination because the constant ksb is found to be very close to 0.28 in

most of the polymer solvent systems (Ghosh et al., 2011b). The same is used here also.

Table 5 presents intrinsic viscosity values related to all equations for the studied samples.

Taking into account the data for homo and all copolymer samples, it can be noticed that the

values are consistent. Comparison among the homo and copolymers of DA indicated that, the

homopolymer has greater [η] values than the copolymers with 1-decene and for the copolymers,

the [η] values decrease with increasing concentration of 1-decene in the feed. This indicates a

more extended conformation of the homopolymer chain compared to the copolymers. For the

polymers of IOA, the [η] values for the homopolymer are lower than the copolymers and

comparison among the [η] values of the copolymers showed that the [η] values increase with

increasing concentration of 1-decene in the feed. So, there is a more extended conformation of

the copolymer chain compared to the homopolymer and in the case of copolymers, stretching of

the chain is more and more with increasing percentage of 1-decene in the feed.

Both homopolymer and copolymer viscosities in toluene medium indicate poor solvation

(Table 6), as is evident from the respective viscometric constant values, and thus points to the

formation of spherical structures as discussed earlier (Oliveira et al., 1991). This conclusion is

further supported by the positive values of the Kraemer coefficient for all the systems analysed.

The maximum deviation for both of the homopolymers may be attributed to the more coiled

nature of the homopolymers and comparatively poor solubility of these polymers in toluene.

However, it is interesting to note that for most of the polymers in toluene, the ksb values were

close to 0.28. Thus it can be concluded that the relation kh + kk ≠0.5 did not restrict application

of the SB equation. The relation kh + kk = 0.5 was not found for most of the samples analysed

(Table 6), but the present findings are similar to those reported elsewhere (Ghosh et al., 2011b). 4. 4. Efficiency of the prepared compounds as pour point depressant

The efficiency of the prepared polymers as pour point depressant were tested by using 0.1

wt % to 3 wt % polymer doped base oils and the experimental data are grouped in Table 7 (in

base oil, BO1) and Table 8 (in base oil, BO2). The data indicate that the prepared compounds

may be considered as efficient pour point depressants. The results for most of the polymers

indicate that their efficiency as PPD go on increasing from 0.1 % to 0.5 %, beyond that there is a

gradual decrease of their PPD performance. Thus it can be concluded that the pour point

depression efficiency of the investigated polymers, initially increases and then gradually

decreases with the increasing additive concentration. However, in few cases the trend is found

opposite (P1, P5 and P6 in Table 8). The case where the pour point depression efficiency

increases by decreasing additive concentration may be explained by considering the solvation

power of the oil (Abdul Azim et al., 2009; Ghosh et al., 2011c). The reduction in solvation power

becomes more obvious when the concentration of the polymer increases. Also, homopolymer of

isooctyl acrylate acts as a better PPD than homopolymer of decyl acrylate.

4. 5. Efficiency of the prepared compounds as viscosity index improvers

Table 9 and Table 10 present the Viscosity index values of the prepared homo and

copolymers in two base oils BO1 and BO2, respectively. The data obtained clearly shows that

the homopolymer of decyl acrylate is of having lower VI values than the respective copolymers

and with the increase of 1-decene content in the feed, the VI is found to decrease. Again,

homopolymer of isooctyl acrylate is of having higher VI values than the respective copolymers

and with the increase of 1-decene content in the feed, the VI is found to increase. The data reveal

that the VI values of the isooctyl acrylate polymers are higher in comparison to the respective

decyl acrylate polymers in both the base oils. Again, with increasing concentration of the

polymer solution, VI is found to increase in all cases. This may be because of the fact that, at a

higher temperature, while the lube oil viscosity gets decreased, the polymer molecules change

from tight coil to expanded ones as a result of increase in the interaction between the polymer

chain and the solvent molecule (Amal et al., 2005). This increase in volume causes an increase in

the viscosity of the mixture and offsets the normal reduction in viscosity of the oil with

increasing temperature. The increase in concentration of the polymer also leads to an increase in

total volume of polymer coils in the oil solutions as was reported elsewhere (Nassar, 2008;

Nassar and Ahmed, 2010). Consequently, a high concentration of polymer will impart a high

viscosity index rather than a low concentration of the same polymer (Abdel-Azim et al., 1998).

5. Conclusion

1) DA polymers are thermally more stable than the IOA polymers.

2) In general the PPD properties of the additives, doped in the base oils, initially increases and

then gradually decreases with the increasing additive concentration in most of the polymer-

oil blends.

3) Homopolymer of decyl acrylate showed lower VII properties than the DA+1-decene

copolymers but homopolymer of isooctyl acrylate exhibit higher VII properties than the

corresponding copolymers with 1-decene. Also, isooctyl acrylate polymers have higher VI

values than the respective decyl acrylate polymers. Again, with increasing concentration of

the polymer doped in oil, VII properties increase in all the cases.

4) The prepared polymers can effectively be used as multifunctional lube oil additives.

6. Acknowledgement

Authors are thankful to CSIR, New Delhi for financial support.

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Table 1

Specification of chemicals.

Chemical name Source Mole fraction purity

Toluene Merck Specialities Pvt. Ltd. 0.995

Hydroquinone Merck Specialities Pvt. Ltd. 0.990

H2SO4 Merck Specialities Pvt. Ltd. -

Acrylic acid SRL Pvt. Ltd. 0.990

Decanol S. D. Fine-Chem Ltd. 0.970

Hexane S. D. Fine-Chem Ltd. 0.995

1-Decene Across Organics. 0.950

Methanol Thomas Baker Pvt. Ltd. 0.980

Benzoyl peroxide LOBA chemicals 0.980

2-ethylhexanol LOBA chemicals 0.990

Table 2

Base oil properties.

Properties Base oils

BO1 BO2

Density (kg.m-3) at 313 K 836.98 868.03

viscosity at 313 K in Pa·s 5.97 × 10-3 20.31 × 10-3


Cloud point, 0C -10 -8

Pour point, 0C -3 -6

Table 3

Specification of prepared polymer samples.

Sample Mole fraction of 1-decene in the feed

Mole fraction of 1-decene By NMR method By IR method

P-1 0.0000 0.0000 0.0000 P-2 0.0146 0.0138 0.0143 P-3 0.0421 0.0411 0.0415 P-4 0.0717 0.0695 0.0702 P-5 0.0000 0.0000 0.0000 P-6 0.0130 0.0116 0.0121 P-7 0.0390 0.0364 0.0372 P-8 0.0647 0.0613 0.0622

P-1 = homopolymer of decyl acrylate; P-2 to P-4 = copolymer of decyl acrylate + different mole fractions of 1-decene; P-5 = homopolymer of

isooctyl acrylate; P-6 to P-8 = copolymer of isooctyl acrylate + different mole fractions of 1-decene.

Table 4

TGA values of all polymers.

Sample Decom. Temp./ K PWL

P-1 523/613 23/86

P-2 523/633 12/82

P-3 533/653 14/85

P-4 523/653 13/80

P-5 533/593 14/80

P-6 513/593 14/86

P-7 513/593 13/87

P-8 523/593 14/90

P-1 = homopolymer of decyl acrylate); P-2 to P-4 = copolymer of decyl acrylate + different mole fractions of 1-decene; P-5 = homopolymer of

isooctyl acrylate; P-6 to P-8 = copolymer of isooctyl acrylate + different mole fractions of 1-decene. Decom. Temp. = decomposition

temperature, PWL = percent weight loss. The uncertainties for temperature and PWL were within the range ± 10 K and ± 1.5 %, respectively.

Table 5 Intrinsic viscosity values at 313 K for all prepared homo and copolymer samples calculated by using different equations.

Sample [η]ah [η]a

k [η]am [η]a

sb [η]bsb [η]b

sc [η]bdc

P-1 4.34 5.00 4.18 5.37 6.49 6.70 7.34

P-2 4.30 4.44 4.48 4.61 4.64 4.60 4.77

P-3 3.81 3.89 3.92 4.01 4.04 4.01 4.14

P-4 3.41 3.56 3.55 3.65 3.67 3.64 3.74

P-5 6.37 6.50 6.77 7.08 6.63 6.62 6.99

P-6 7.29 7.31 7.77 8.12 7.38 7.39 7.85

P-7 7.58 7.68 8.17 8.60 7.82 7.84 8.44

P-8 7.75 8.13 8.61 9.19 8.30 8.36 8.94

[η] is Intrinsic viscosity, a- extrapolation of graph, b- single point determination (ksb

= 0.28). h, k, m, sb, sc and dc refers Huggins, Kraemer,

Martin, Schulz-Blaschke, Solomon-Ciuta and Deb-Chatterjee equations, respectively. The uncertainty in determining the intrinsic viscosity is

within the range ± 0.13%.

Table 6

Viscometric constants (k) at 313 K obtained for all prepared homo and copolymer samples.

Sample kh kk km ksb kh +kk

P-1 1.57 -0.13 2.08 0.46 1.44

P-2 0.53 0.10 0.37 0.29 0.63

P-3 0.51 0.10 0.38 0.30 0.61

P-4 0.68 0.04 0.48 0.37 0.72

P-5 0.48 0.11 0.31 0.22 0.59

P-6 0.43 0.12 0.27 0.19 0.55

P-7 0.46 0.11 0.28 0.19 0.57

P-8 0.56 0.10 0.30 0.20 0.66

kh

, kk

, km

and ksb

are Huggins, Kraemer, Martin and Schulz- Blaschke coefficients, respectively. The uncertainty in determining the viscometric

constants is within the range ± 11.0 %.

Table 7

Dependence of pour point (PP) on the concentration of additives in base oil (BO1).

Conc. PP in presence of

P1 P2 P3 P4 P5 P6 P7 P8

0 % -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0

0.1% -6.2 -8.2 -9.1 -12.1 -15.0 -12.3 -13.2 -13.7

0.25 % -6.4 -8.3 -9.1 -12.2 -15.3 -12.4 -13.2 -13.8

0.5 % -6.9 -8.5 -9.5 -12.6 -15.8 -12.6 -13.4 -13.9

1 % -6.6 -8.1 -9.4 -12.1 -15.2 -12.4 -12.9 -13.6

2 % -6.0 -7.8 -9.2 -11.6 -15 -11.6 -12.2 -13.4

3 % -6.0 -6 -8.6 -11.2 -14.6 -9.4 -11.1 -11.9

The uncertainty in determining the pour point temperature is within the range ± 0.1°.

Table 8



P1 P2 P3 P4 P5 P6 P7 P8

0 % -6 -6 -6 -6 -6 -6 -6 -6

0.1% -7.5 -12.8 -13.1 -13.3 -15.5 -17.9 -17.2 -14.6

0.25 % -8.8 -14.1 -13.5 -13.8 -16.7 -19.3 -18.6 -15.2

0.5 % -7.9 -14.8 -14.1 -14.5 -16.5 -18.8 -18.3 -15.6

1 % -8.4 -14.6 -13.8 -14.2 -16.4 -18.5 -17.9 -15.4

2 % -9 -13.5 -13.2 -13 -17 -19.4 -17.2 -14.8

3 % -9.8 -13.1 -12.4 -12 -17.7 -20 -16.1 -14


Table 9

Dependence of VI on the concentration of additives in base oil (BO1).

Conc. VI in presence of

P1 P2 P3 P4 P5 P6 P7 P8

0% 85 85 85 85 85 85 85 85

1% 90 92 88 86 91 86 89 98

2% 92 95 90 88 103 87 93 102

3% 94 99 93 90 119 89 97 108

4% 95 101 95 94 125 91 103 111

5% 99 105 101 97 130 97 107 114

6% 102 109 103 100 136 103 112 120

The uncertainty in determining the viscosity index is within the range ± 0.53 %.

Table 10



P1 P2 P3 P4 P5 P6 P7 P8

0% 80 80 80 80 80 80 80 80

1% 85 98 97 95 90 87 93 98

2% 88 100 99 98 94 89 98 100

3% 89 103 101 100 97 92 100 102

4% 93 105 102 101 100 95 101 103

5% 95 106 103 102 112 97 104 106

6% 98 108 106 104 124 100 106 111

The uncertainty in determining the viscosity index values is within the range ± 0.47%.

Fig. 1. Plot of Temperature vs. PWL. PWL represents percent weight loss. The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Fig. 2. Plot of log ηsp vs. log C[η]. ηsp, C, [η] represents Specific viscosity, concentration and intrinsic viscosity of the polymer solutions in toluene obtained by using the Huggins equation The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Figure caption:

Figure 1:

Title: Plot of Temperature vs. PWL.

Description: The plot is illustrated to show the decomposition temperature of the polymers synthesised. PWL represents percent weight loss. The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Figure 2:

Title: Plot of log ηsp vs. log C[η]

Description: The plot is illustrated to show that the measurements were performed in Newtonian flow. ηsp, C, [η] represents Specific viscosity, concentration and intrinsic viscosity of the polymer solutions obtained by using the Huggins equation. The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Table 1

Specification of chemicals.

Chemical name Source Mole fraction purity

Toluene Merck Specialities Pvt. Ltd. 0.995

Hydroquinone Merck Specialities Pvt. Ltd. 0.990

H2SO4 Merck Specialities Pvt. Ltd. -

Acrylic acid SRL Pvt. Ltd. 0.990

Decanol S. D. Fine-Chem Ltd. 0.970

Hexane S. D. Fine-Chem Ltd. 0.995

1-Decene Across Organics. 0.950

Methanol Thomas Baker Pvt. Ltd. 0.980

Benzoyl peroxide LOBA chemicals 0.980

2-ethylhexanol LOBA chemicals 0.990

Table 2

Base oil properties.

Properties Base oils

BO1 BO2

Density (kg.m-3) at 313 K 836.98 868.03



Cloud point, 0C -10 -8

Pour point, 0C -3 -6

Table 3

Specification of prepared polymer samples.

Sample Mole fraction of 1-decene in the feed

Mole fraction of 1-decene By NMR method By IR method

P-1 0.0000 0.0000 0.0000 P-2 0.0146 0.0138 0.0143 P-3 0.0421 0.0411 0.0415 P-4 0.0717 0.0695 0.0702 P-5 0.0000 0.0000 0.0000 P-6 0.0130 0.0116 0.0121 P-7 0.0390 0.0364 0.0372 P-8 0.0647 0.0613 0.0622

P-1 = homopolymer of decyl acrylate; P-2 to P-4 = copolymer of decyl acrylate + different mole fractions of 1-decene; P-5 = homopolymer of

isooctyl acrylate; P-6 to P-8 = copolymer of isooctyl acrylate + different mole fractions of 1-decene.

Table 4

TGA values of all polymers.

Sample Decom. Temp./ K PWL

P-1 523/613 23/86

P-2 523/633 12/82

P-3 533/653 14/85

P-4 523/653 13/80

P-5 533/593 14/80

P-6 513/593 14/86

P-7 513/593 13/87

P-8 523/593 14/90

P-1 = homopolymer of decyl acrylate); P-2 to P-4 = copolymer of decyl acrylate + different mole fractions of 1-decene; P-5 = homopolymer of

isooctyl acrylate; P-6 to P-8 = copolymer of isooctyl acrylate + different mole fractions of 1-decene. Decom. Temp. = decomposition

temperature, PWL = percent weight loss. The uncertainties for temperature and PWL were within the range ± 10 K and ± 1.5 %, respectively.

Table 5 Intrinsic viscosity values at 313 K for all prepared homo and copolymer samples calculated by using different equations. Sample [η]a

h [η]ak [η]a

m [η]asb [η]b

sb [η]bsc [η]b

dc

P-1 4.34 5.00 4.18 5.37 6.49 6.70 7.34

P-2 4.30 4.44 4.48 4.61 4.64 4.60 4.77

P-3 3.81 3.89 3.92 4.01 4.04 4.01 4.14

P-4 3.41 3.56 3.55 3.65 3.67 3.64 3.74

P-5 6.37 6.50 6.77 7.08 6.63 6.62 6.99

P-6 7.29 7.31 7.77 8.12 7.38 7.39 7.85

P-7 7.58 7.68 8.17 8.60 7.82 7.84 8.44

P-8 7.75 8.13 8.61 9.19 8.30 8.36 8.94

[η] is Intrinsic viscosity, a- extrapolation of graph, b- single point determination (ksb

= 0.28). h, k, m, sb, sc and dc refers Huggins, Kraemer,

Martin, Schulz-Blaschke, Solomon-Ciuta and Deb-Chatterjee equations, respectively. The uncertainty in determining the intrinsic viscosity is

within the range ± 0.13%.

Table 6

Viscometric constants (k) at 313 K obtained for all prepared homo and copolymer samples.

Sample kh kk km ksb kh +kk

P-1 1.57 -0.13 2.08 0.46 1.44

P-2 0.53 0.10 0.37 0.29 0.63

P-3 0.51 0.10 0.38 0.30 0.61

P-4 0.68 0.04 0.48 0.37 0.72

P-5 0.48 0.11 0.31 0.22 0.59

P-6 0.43 0.12 0.27 0.19 0.55

P-7 0.46 0.11 0.28 0.19 0.57

P-8 0.56 0.10 0.30 0.20 0.66

kh

, kk

, km

and ksb

are Huggins, Kraemer, Martin and Schulz- Blaschke coefficients, respectively. The uncertainty in determining the viscometric

constants is within the range ± 11.0 %.

Table 7



P1 P2 P3 P4 P5 P6 P7 P8

0 % -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0

0.1% -6.2 -8.2 -9.1 -12.1 -15.0 -12.3 -13.2 -13.7

0.25 % -6.4 -8.3 -9.1 -12.2 -15.3 -12.4 -13.2 -13.8

0.5 % -6.9 -8.5 -9.5 -12.6 -15.8 -12.6 -13.4 -13.9

1 % -6.6 -8.1 -9.4 -12.1 -15.2 -12.4 -12.9 -13.6

2 % -6.0 -7.8 -9.2 -11.6 -15 -11.6 -12.2 -13.4

3 % -6.0 -6 -8.6 -11.2 -14.6 -9.4 -11.1 -11.9


Table 8



P1 P2 P3 P4 P5 P6 P7 P8

0 % -6 -6 -6 -6 -6 -6 -6 -6

0.1% -7.5 -12.8 -13.1 -13.3 -15.5 -17.9 -17.2 -14.6

0.25 % -8.8 -14.1 -13.5 -13.8 -16.7 -19.3 -18.6 -15.2

0.5 % -7.9 -14.8 -14.1 -14.5 -16.5 -18.8 -18.3 -15.6

1 % -8.4 -14.6 -13.8 -14.2 -16.4 -18.5 -17.9 -15.4

2 % -9 -13.5 -13.2 -13 -17 -19.4 -17.2 -14.8

3 % -9.8 -13.1 -12.4 -12 -17.7 -20 -16.1 -14


Table 9



P1 P2 P3 P4 P5 P6 P7 P8

0% 85 85 85 85 85 85 85 85

1% 90 92 88 86 91 86 89 98

2% 92 95 90 88 103 87 93 102

3% 94 99 93 90 119 89 97 108

4% 95 101 95 94 125 91 103 111

5% 99 105 101 97 130 97 107 114

6% 102 109 103 100 136 103 112 120

The uncertainty in determining the viscosity index is within the range ± 0.53 %.

Table 10



P1 P2 P3 P4 P5 P6 P7 P8

0% 80 80 80 80 80 80 80 80

1% 85 98 97 95 90 87 93 98

2% 88 100 99 98 94 89 98 100

3% 89 103 101 100 97 92 100 102

4% 93 105 102 101 100 95 101 103

5% 95 106 103 102 112 97 104 106

6% 98 108 106 104 124 100 106 111

The uncertainty in determining the viscosity index values is within the range ± 0.47%.

Fig. 1. Plot of Temperature vs. PWL. PWL represents percent weight loss. The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Fig. 2. Plot of log ηsp vs. log C[η]. ηsp, C, [η] represents Specific viscosity, concentration and intrinsic viscosity of the polymer solutions in toluene obtained by using the Huggins equation The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Figure caption:

Figure 1:

Title: Plot of Temperature vs. PWL.

Description: The plot is illustrated to show the decomposition temperature of the polymers synthesised. PWL represents percent weight loss. The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

Figure 2:

Title: Plot of log ηsp vs. log C[η]

Description: The plot is illustrated to show that the measurements were performed in Newtonian flow. ηsp, C, [η] represents Specific viscosity, concentration and intrinsic viscosity of the polymer solutions obtained by using the Huggins equation. The symbols signify: ○, P-1; □, P-2; ∆, P-3; ◊, P-4; ●, P-5; ■, P-6; ▲, P-7; ▼, P-8.

• Multifunctional acrylate based polymeric additives for lubricating oil. • Branching in the acrylate chain showed better additive performance. • Linear acrylates are thermally stable compared to branched acrylates. • VI increased with the increase in additive concentration in lube oil. • Polymer solvent interaction is more prominent in case of branched acrylate

polymers.

study of the influence of some polymeric additives as viscosity index improvers and pour point...

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