Sayed Ibrahim Faculty at Technical University of Liberec, Department

of Textile Technology Ph.D from Technical University of Liberec, Czech

Republic Research Interest: Textile Technology and Quality

Control Topic

Characterization of Basalt Filaments in Characterization of Basalt Filaments in Longitudinal Compression Longitudinal Compression

CHARACTERIZATION OF BASALTCHARACTERIZATION OF BASALT FILAMENTS IN LONGITUDINAL FILAMENTS IN LONGITUDINAL

COMPRESSIONCOMPRESSION

Jiří Militký, Vladimír Kovačič, Sayed IbrahimTextile Faculty, Technical University of Liberec

461 17 Liberec, Czech Republic

(approx. 8000 students)

Faculty of Mechanical Engineering

Textile Faculty Faculty of Education Faculty of Economics Faculty of

Mechatronics Faculty of Architecture

Technical University of Liberec

Staff 120 teachers1.MSc Studies (technology,

material engineering, clothing) 800

2.BSc Studies (chemistry, marketing, design, mechanics, clothing) 600

3.Part time studies (textile technology) 60

4. Ph.D. (technology, material engineering, clothing) 60

Technical University of Liberec Textile Faculty

Basics of textile engineering

• Fibers are the fundamental and the smallest elements constituting textile materials. The mechanical functional performance of garments are very much dependent on the fiber mechanical and surface properties, which are largely determined by the constituting molecules, internal structural features and surface morphological characteristics of individual fibers. Scientific understanding and knowledge of the fiber properties and modeling the mechanical behavior of fibers are essential for engineering of clothing and textile products. Molecula

r properties

Fiber Properties

Yarn Properties

Fabricproperties

Fiber Structure

Yarn Structure

Fabric Structure

Garment Structure

• Demands of using textiles in industrial application are very high and risk should be minimum i.e. precise characterization

OUTLINE Basalt rocks  Fibers formation Basic properties Compressive creep Strength statistics Tempering Textile structures  Fibrous fragments

Basaltic rocks

Basalt is generic name for solidified lava which poured out the volcanoes

Basalt is 1/3 of earth Crust Basaltic rocks are melted

approximately in the range 1500 – 1700 C.

When this melt is quickly quenched, it solidificated to glass like nearly amorphous solid.

Slow cooling leads to more or less complete crystallization, to an assembly of minerals.

Augite Plagioclase

Olivine

Basaltcomposition

Chemical composition:silicon oxide SiO2 (optimal range 43.3 – 47 %) Al2 O3 (optimal range 11 – 13 %) CaO (optimal range 10 – 12 %)MgO (optimal range 8 – 11 %) Other oxides are almost always below 5 % levelEssential minerals plagiocene and pyroxene

(augite) make up perhaps 80% of basalts

Fiber Forming ProcessSimilar to E-glass forming Except: Only one material, crushed rock No “flux” like boric oxide added for processing Higher melting temperature 1400 C + vs. 1200 C Harder to process, but better properties(Silane-based sizing agent is added to facilitate post processing)

Basalt Furnace

1) Crushed stone Silo, 2)Loading station, 3) Transport system, 4)batch charging station, 5) Initial melt zone, 6) Secondary contrlled heat zone, 7) Filament forming, 8) Sizing applicator, 9) Strand formation, 10) Fiber tensioning, 11) Winding

Filaments formation

Classical procedure Heat transfer from walls

to center High power (4 kWh/kg) Long pre heating 8 hours Spinneret materials

(Platinum, rhodium)

Microwave heating Heat transfer from

center to walls Low power (1 kWh/kg) Short pre heating 3

hours Spinneret materials

(ceramics)Melt after 5 min at 1300oC

Properties of Basalts

Basalts are more stable in strong alkalis that glasses.

Stability in strong acids is low Basalt products can be used from very low

temperatures (about –200 C) up to the comparative high temperatures 700 – 800 C.

At higher temperatures the structural changes occur.

Basalt Glass Comparison

Property Basalt E-glass

Diameter[m] 8.63 9 - 13

Density[kgm-3] 2733 2540

Softening temp. [C] 960 840

Typical composition of basalt fiber vs. E-glass fiber

Chemical components Basalt Weight %

E-Glass Weight %

SiO2 (silica) 58 55

Al2O3 (alumina) 17 15

Fe2O3(ferric oxide) 10 0.3

CaO 8 18

MgO 4 3

Na2O 2.5 0.8

TiO2 1.1 -

K2O 0.8 0.2

B2O3 - 7

F - 0.3

standard E-glass fibres from non-alkali glass (to 1% alkali), manufactured at 1550 oC

Manufacturing cost is between E-glass and S-glass

Sio2 Al2O3 CaO MgO B2O3

Applications

The basalt-reinforced PP composite meets disposal requirements without incinerator contamination issues

Samples Preparation

The marbles and filament roving are prepared.

From marbles the thick rods were prepared by grinding.

The roving contained 280 single filaments are used.

Mean fineness of roving was 45 tex.

Fibers Strength

The cumulative probability of fracture F(V, ) depends on the tensile stress level and fiber volume V. F(V, ) = 1 - exp(- R())

The specific risk function R() for Weibull distribution (conditional failure function)R() = [( - A)/B]C

A is lower strength limit, B is scale parameter and C is shape parameter model (WEI 3)

Shape parameter, location parameter, scale parameter.

Strength distributions For brittle materials A = 0 (model WEI 2). Kies more realistic risk function (model KIES)

R() = [(-A)/(A1-) ]C Here A1 is upper strength limit.

For brittle materials A = 0 (model KIES2). Phani (model PHA5)

R() = [(-A)/B1]D/ [(A1-)/B ]C). Gumbell model (GUM)

R() = exp[(-A)/(B)]

Statistical analysis Main aim of the statistical analysis is

specification of R() and parameter estimation based on the experimental strengths (i) i=1.....N.

Based on the preliminary computation it has been determined that for basalt fibers strength the Weibull distribution is suitable

Testing

The individual basalt fibers removed from roving were tested.

The loads at break were measured under standard conditions at sample length 10 mm

. Load data were transformed to the stresses at break i [GPa]

Sample of 50 stresses at break

Maximum likelihood estimation

When i i=1,...N are independent random variables with the same probability density function f() = F’(i, a) the logarithm of likelihood function has the formln L = ln f((i, a)

The a are parameters of corresponding risk function.

The MLE estimators a* can be obtained by the maximization of ln L(a).

Parameter estimatesModel A [GPa] B [GPa] C [-] ln L(a*)

WEI3 0.0641 0.230 1.370 33,50

WEI2 - 0.301 1.829 29.164

TThe differences between three and two parameters he differences between three and two parameters Weibull distribution are identified by the values of Weibull distribution are identified by the values of maximum likelihood function ln L(a*). maximum likelihood function ln L(a*). The three-parameter Weibull distribution was The three-parameter Weibull distribution was selected as suitable for glass and tempered basalt selected as suitable for glass and tempered basalt samples as wellsamples as well

Failure mode

Modes of fracture - scanning electron microscopy.

Untreated Basalt Longitudinal view

Mechanism of fracture Surface is very smooth

without flaws or crazes

Fracture occurs due to nonhomogenities in fiber volume (probably near the small crystallites of minerals)

glassglass

basaltbasalt

Thermal exposition I Tempering temperature 50, 100, 200, 300oC was used. Time of

exposition 60 min. Thermal exposition influence on the ultimate mechanical

properties and dynamic acoustical modulus (DMA) has been evaluated.

tensile strength [N.tex-1] deformation to break [%] dynamic acoustic modulus [Pa] (determined from sound wave

spread velocity in the material) For 300oC tempering only results statistically significant drop of

strength and dynamic acoustical modulus. The changes of these properties are based on the changes of

crystalline structure of fibers.

Resonance frequency technique (RFT)Acoustic Pulse Method (APM)

Sample

Thermal exposition II Basalt filament roving tempered

at TT = 20, 50, 100, 200, 300, 400 and 500oC in times tT = 15 and 60 min.

The dependence of the roving strength on the temperature exhibits two nearly linear regions.

One at low temperature to the 180oC with nearly constant strength and one up to the 340oC with very fast strength drop

T e m p e ra tu re

Thermal exposition III1.Tempered basalt fibers from roving were tested.2. The apparatus based on the torsion pendulum principle was used. (fiber of length lo hanged with pendulum period P and amplitude A, successive oscillations were measured, the shear modulus of circular fiber is calculated) 3. The shear modulus G =11-21 GPa

is comparatively high.

0

600100

250

0

5

10

15

20

25

shea

r m

odul

us [G

Pa]

time[min]

temperature[oC]

The prolongation of tempering leads to high drop of G.

lo

Thermal exposition IV Fragility - ratio of critical

loop diameter Dc and fiber diameter d Fr = Dc / d

critical loop diameter - by deformation of basalt loop under microscope to failure

temperature 50, 150, 250, 350oC was evaluated

time of exposition 60 min In accordance with

assumption are fragilities increasing function of tempering temperature

0

5

10

15

20

25

30

35

40

45

50 150 250 350

temperature [oC]

frag

ility

[-]

the quality or state of being easily broken or destroyed

Thermo mechanical analysis (TMA)

In TMA the dimensional changes are measured under defined load and chosen time

Special device TMA CX 03RA/T has been used

Sample is placed on the movable holder (in oven) connected with displacement sensor, which measures dimensional changes

Thermal expansion

Dependence of basalt rod height on the temperature was measured.( heating rate 10 deg min-1 , compressive load 10 mN).

The coefficients of thermal expansions a for region below and above Tg

L = Lg + a1*(T - Tg) for T below Tg

L = Lg + a2*(T - Tg) for T above Tg Parameter estimates: Tg = 596.3 oC ,

a1 = 4.9 10-6 deg-1, a2 = 19.1 10-6 deg-1.

TTh

l

)(1

0

rate of material expansion as a function of temperature

DMA

Compressive creep

For the basalt rods and linear composites the dependence of sample height L on the time t were measured. L = Lp + L1 exp (-k1* t) + L2 exp(-k2* t)

Parameters Lp, L1, L2, k1 and k2 estimated by LS

The maximum dilatation D = L1 + L2

Half time of dilatation t1/2 (it is time for which is dilatation equal to Lp + (L1+ L2)/2.

Compressive creep parameters

T [oC]

D[mm] t1/2 [s] D [mm] t1/2 [s]

3050100250300

0.0030.0280.0530.035 -

145.136.9029.8041.10-

0.015-0.008- 0.042

16015-21.30- 51.7

30 50 100 250 300

0

0,01

0,02

0,03

0,04

0,05

0,06

temperature [oC]

maximum dilatation D[mm] = L1 + L2

Linear composite (C)

Basalt rod (R)

30 50 100 250 300

0

0,01

0,02

0,03

0,04

0,05

0,06

temperature [oC]

maximum dilatation D[mm] = L1 + L2

Linear composite (C)

Basalt rod (R)

Non-isothermal compressive creep

The responses of basalt to the compressive loads under non-isothermal conditions were investigated from creep type experiments.

The load was 200 mN. For the basalt rod the dependence of sample height L on the

temperature T (increased linearly with time t )were measured. Starting temperature was To = 30 oC and rate of heating was

10 oC/min. For avoiding the initial The dilatation di = Lo – L has been recorded

Data SmoothingThe experimental points were smoothed by Reinsch smoothing spline (parameter s = 1)

deltatation

temperature

Creep model IFrom isothermal experiments is deduced that the rate of creep only is markedly temperature dependent. The rate of height changes can be expressed by differential equation

t),L,Lf(K, = dt

Ld

K is the rate constant L is sample height in equilibrium. Function f(.) is creep rate model.

Creep model IIThe classical reaction kinetics the creep rate can be

expressed in the form n)LL(K* =

dtLd

where n is constant (order of reaction). For n=1 the simple exponential model of creep (rate process of first order) results. Temperature dependence of the creep rate constant K

)RTEexp(-K = K 0

Creep model IIIIn non-isothermal conditions it is assumed that temperature dependent is rate constant only

) ,f( K(T) = dt

d t LLL

By the formal integration of this eqn. for exponential type model (n = 1) the following relation results

F(t)) exp(*)LL(L= L o

Creep model IVFor the case of linear heating during creep is valid

)TG( - G(t) = F(t) 0

Symbol To denotes initial temperature and G(x) is the integral

dx E/Rx)exp(- K = G(x)x

0

0

where is rate of heating

Approximation of integral

Simple and precise approximation of temperature term has the form

)RTE(-exp

)E

RT5(-1

)E

RT2(-1

ERT)dT

RTE(-exp

2

The relative error of approximation is for E/RT<7 under 1%.

Parameter estimationThese should be estimated from experimental data. The nonlinear regression have to be used. More simple is to use rate equation for first order model combined with Arrhenius dependence in the linearized form

ln( ) ln( ) ln( )( * )o

dL EL L Kdt R To t

Application of this equation requires knowledge of L and computation of creep rate dL

dt

Creep rateThe rate of creep curve can be derived from Reinsch smoothing procedure (s=1)

Estimation of activation parameters

1 1.5 2 2.5 3 3.5

x 10-3

-3.9

-3.8

-3.7

-3.6

-3.5

-3.4

-3.3

-3.2

-3.1Ko and E are: 0.047727 and -2.2036

on 1/T (in absolute temperature scale) was created.

From parameters of this fit: preexponential factor Ko = 0.04772 activation energy of creep E = 2.203 kJ/mol

The dependence of

)LLln()dtdL

ln(

Creep discussion More precisely it will be necessary to use general

order of rate process and investigate n as well Thermally stimulated creep is successfully used in

the area of polymers. In non-polymeric solids where compressive creep

is due to rearrangements of molecular clusters and structural reordering are rate models quite useful.

Longitudinal compressive modulus

Linear composite (C) from the phase of Basalt fibers (K) and epoxy resin matrix (E). Both phases are deformed elastically The volumetric ratio of Basalt fibers is K.

The simple rule of mixture  

EKKKC E1EE

Ec is creep modulus of linear composite E E is creep modulus of epoxy resin,E K is creep modulus of basalt fibers

F M

a) b)

Modulus estimation The K was estimated by the image analysis

value K = 0,9 was obtained. The modulus EC at individual temperatures

30ECC A

FE

F = 200 mN is load, AK = 20.725 mm2 is cross sectional area K(10) is deformation under compressive creep in time t = 10 s.

By the same way the modulus EE was estimated from the compressive creep curve of pure epoxy resin

Estimated moduli

T[oC]

EK

(Basalt) [GPa]

EC(Composite)[GPa]

EE (Resin) [GPa]

25 112.27 105.41 40.5129

50 95.256 87.49 17.5076

100 114.084 108.575 58.9869

200 99.76 90.95 11.6239 

25 50 100 200

0204060

80

100

120

temperature [oC]

Longitudinal Compressive Modulus E[Gpa]

EE (Resin) [GPa]

EK (Basalt) [GPa]

EC(Composite) [GPa]

Textile structures The basalt filament yarns were prepared

with fineness 40x2x3. Knits and sewing thread were created. Utilization of basalt for preparation of

knitted fabric was without problems During sewing tests the basalt yarns were

frequently broken due to its brittleness. The composite basalt thread coated by PET

was prepared.

Sewing threads properties

Property Basalt/PETfineness [tex] 283.3 ± 1.6yarn twist 1[m-1] 208 ± 7.4yarn twist 2[m -1] 400 ± 9.8yarn twist 3 [m-1] 180 ± 5.6break strength [N.tex-1] 0.34Break deformation [%] 2.3 ± 0.2abrasion resistance[cycle] 180 ± 49.8

breaks at sewing test 0

Emitted particles analysis

Some characteristics of the basalt fibers are similar to the asbestos.

Since the mechanisms for asbestos carcinogenicity are not fully known it cannot be excluded that basalt fibers may also be hazardous to health.

Thus there is a need for analysis of fibrous fragment characteristics in production and handling in order to control their emission.

Fragmentation The weave from basalt filaments was used. The fragmentation was realized by the abrasion

on the propeller type abrader. Time of abrasion was 60 second. It was proved by microscopic analysis that basalt

fibers are not split and the fragments have the cylindrical shape.

Analysis Fiber fragments were analyzed by the

image analysis, system LUCIA M. The fragments shorter that 1000 m were

analyzed. Results were lengths Li of fiber fragments. For comparison the diameters Di of fiber

fragments were measured as well.

Fragments length Basic statistical characteristics fiber

fragments lengths aremean value LM = 230.51 mstandard deviation L = 142.46 m skewness g1 = 0.969 kurtosis g2 = 3.97

These parameters show that the distribution of fiber fragments is unimodal and positively skewed.

Fragments diameterBasic statistical characteristics of fragments

diameters are:mean value DM = 11.08 m standard deviation L = 2.12 m skewness g1= 0.641kurtosis g2= 2.92

Because the mean value of fiber fragment diameter is the same as diameter of fibers no splitting of fibers during fracture occurs.

Fragmentation conclusion

It is known, that from point of view of cancer hazard the length/diameter ratio R is very important.

For basalt fiber fragments is ratio R = 230.51/11.08 = 20.8.

Despite of fact that basalt particle are too thick to be respirable the handling of basalt fibers must be carried out with care.

Thank youThank youfor your attention . . . .for your attention . . . .