www.jart.ccadet.unam.mxJournal of Applied Research and Technology 15 (2017) 190–204
Review
Elaboration and characterization of composite material based on epoxy resinand clay fillers
Dalila Laouchedi a,b,∗, Boudjema Bezzazi a,b, Chouaib Aribi a
a Research Unit Materials, Processes and Environment (RU-MPE), University M’Hamed Bougara, Boumerdes 35000, Algeriab Coating Laboratory, Materials and Environment, University M’Hamed Bougara, Boumerdes 35000, Algeria
bstract
The present work aims at investigating the effect of locally produced clay (Algeria), along with the effect of their size and rate on physical andechanical properties of the composite material. This study is divided into two parts: The first one is devoted to the study of the composite material
ased on epoxy resin with kaolin, using different size fractions at rates ranging from 2% to 20%. The second part examines epoxy resin-basedomposite with calcined kaolin (metakaolin) with regard to the influence of the structure, the particle size and the charge rate on the properties ofhe material. It is shown that the clay fillers give the epoxy resin different properties compared to the epoxy resin alone and, additionally, reducehe cost of materials. It was also observed that the fillers enhance the mechanical properties by increasing the rigidity of the material. There is
maximum value of 2.4 GPa to 18% kaolin, or more than 325% increase in the modulus of elasticity with respect to unfilled resin for the finerarticle size. It was also found that the modulus of elasticity increases with increasing the loading rate. Indeed, the rigidity increases with increasinghe filler rate. Moreover, for both fillers, lower fraction yields better results. Moreover, for both types of added fillers, lower fraction yields better
esults.
2017 Universidad Nacional Autónoma de México, Centro de Ciencias Aplicadas y Desarrollo Tecnológico. This is an open access article underhe CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Performance optimization of materials is very importantn providing a competitive advantage, which basically meansmproving properties while reducing cost (Bardonnet, 1992;ho, Joshi, & Sun, 2006). Many modern technologies make usef new materials with properties that out perform traditionalnes (metals, ceramics and polymers). The search for betterlternatives to those materials has led to continuous improve-ent to ward either less expensive or more efficient materials.et, combining both remains the most desirable outcome.
A composite is a multiphase material that combines the prop-rties of its constituents to acquire better properties than itsarent components (Berthelot, 1996; Glossaire des matériaux,006). It consists of a reinforcement which contributes to theechanical properties and a binder called matrix. The matrix
∗ Corresponding author.E-mail address: [email protected] (D. Laouchedi).
Peer Review under the responsibility of Universidad Nacional Autónoma deéxico.
nsures the cohesion between the elements of the reinforcement,ransfers the strain and makes the material resistant to environ-
ental elements (corrosion, aging) and temperature (Berthelot,996).
The properties of a composite material depend on the natureKornmann, Lindberg, & Berglund, 2001), the shape of the rein-orcement, the input amounts, the quality of the matrix/fillersnterface and finally, on the synthesis process. The integrationf reinforcement into matrix to obtain new specific functions is
y the presence of two epoxide groups or more in their moleculartructure (Freddy, 2000).
Epoxy resins are thermosetting polymers, widely used in higherformance composites in many industrial applications, suchs high performance adhesives in airplanes, pipe coatings in the
il industry, printed circuit boards, and many other applicationsn construction, automotive and aerospace industries (Fu, Feng,auke, & Mai, 2008; Solihin, Tongamp, & Saito, 2011).
Aplicadas y Desarrollo Tecnológico. This is an open access article under the
Their insulating electrical properties and their relatively highhermal resistance (Du & Yang, 2012; Galán & Martín Vivaldi,972) are the main reasons for using those materials in suchpplications. However, from a mechanical perspective, epoxyolymers show a brittle fracture mode.
Therefore, they usually fail by brittle fracture mechanismsnder normal conditions of use. To address this issue andncrease the properties of the brittle polymer, several approachesre possible. This can be achieved by firstly adding rubber par-icles (Castrillo, Olmos, Torkelson, & González-Benito, 2010;u & Yang, 2012; Galán & Martín Vivaldi, 1972; Lee & Yee,001; Sue & Yee, 1993) and then a thermoplastic polymer inhe epoxy matrix (Boo, Liu, & Sue, 2006; Boo et al., 2007). Yetnother alternative is to modify epoxy resins by adding particlesr inorganic fillers (silica, kaolin, montmorillonite) (Castrillo,lmos, Sue, & González-Benito, 2015), which generally lead
o lower costs without deteriorating the properties of the mate-ial, and sometimes it can also bring further improvements inhe final material, such as barrier properties, flammability resis-ance, thermal stability and solvent absorbance (Fellahi, Chikhi,
Bakar, 2001; Garg & Mai, 1988).The integration of inorganic fillers in polymer matrices is
subject extensively investigated (Irekti, 2011; Wang, Tian,ang, & Han, 2005; Zapata-Massot, 2004).The inorganic fillers are used as reinforcement in epoxy resin
ystems. They significantly increase the mechanical, electricalnd thermal properties. These inorganic fillers are chosen forheir availability. They are highly sought after as powders ineveral scientific fields as a way improving some of the fea-ures mentioned above and also to reduce the cost of the desired
aterials. The final properties of the composite depend on thentrinsic characteristics of each component, quantity, shape andize of loads and the nature of the interfaces many studies haveeen devoted to the study of loaded composite materials and sev-ral types of inorganic fillers were used in this work to improveertain characteristics of the matrix.
The role of charges is multiple, it can more cost effectivelyll a volume if the load is much cheaper than the polymer, and
t can modify the macroscopic properties as well.The main objective of this work is to develop composite
aterials based on epoxy resin and inorganic fillers, in thisase, treated (physical treatment) Tamazert kaolin (Algeria) andntreated kaolin (metakaolin) at different rates and with differ-nt particle sizes. The purpose is hence to highlight the influencef the structure, the rate and size of the fillers on the specificroperties of the material (mechanical strength, thermal stability,imensional stability).
. Experimental procedure
.1. Materials used characterization
.1.1. Matrices characterization
The matrix consists of two elements, element A the monomer
s the resin injected medapoxy 812 A, and element B calledardener is the hardener of the resin injected medapoxy 812aromatic amine) gives the mixture a cross linked resin.
fis
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In the present work, we used MEDAPOXY 812INJ fromranitex (ALGERIA), which is an efficient product with numer-us qualities utilized in many advanced technology applications.he mass ratio (MR) between the monomer and the hardenerrovided by Granitex is MR = 2.
The resin characteristics MEDAPOXY 812INJ according tohe supplier’s data sheet are shown in Table 1.
.1.2. Clay fillers characterizationThe untreated kaolin and kaolin physically treated
metakaolin) were used as fillers in the present study. The pow-ers were mechanically milled through a ball mill process. Webtained three ratios of different granulometry for both fillers.
The kaolinPre-treated Tamazert kaolin was used (deposit of Tamazert
near MILA Algeria, 200 km east of Constantine).Metakaolin
The metakaolin was obtained by calcination of kaolin at hightemperatures (500–550 ◦C) for 5 h. Calcination causes dehy-droxylation and destruction of the initial crystalline structureof the kaolinite (Brindley & Nakahira, 1959; Brindley, Sharp,Patterson, & Narahari, 1967; Horvath & Kranz, 1980).
The obtained fillers were characterized using granulometry,-ray diffraction (XRD), with X-ray fluorescence.
.1.2.1. Granulometriy. The particle size is crucial in mechan-cal and esthetic properties of composite resins and a keyarameter in different classifications; the most commonlydopted classifications are indeed based on the shape and size ofarticles. The granulometry of kaolin and metakaolin was doney means of a Mastersizer 2000 laser particle type of URMPEesearch unit of Boumerdes Algeria.
The results are shown in Figure 1 (K1). From these resultse can see that the particle size distribution K1 (kaolin particlesave the biggest size) varies between 0.1 �m and 300 �m.
The kaolin sample (K1) shows a multimodal distributionade up of 4 medium size fractions, (1) is <1 �m with ∼20%
f volume, (2) is 4 �m with >40% of volume, (3) is 30 �m with0% of volume and (4) is 200 �m with >15% of the volume.he whole volume is filled with particles <300 �m.
This particle size curve shows that the particle size distribu-ion of the load K2 (kaolin particles have an average particleize) is between 0.1 �m and 100 �m, the results are presentedn Figure 1 (K2).
The kaolin sample K2 has a multi-modal distribution whichs composed of 3fractions particle size, (1) a fraction of averageize less than 1 �m with about 25%, (2) a fraction of averageize of 4 �m with more than 40% by volume, and (3) a fractionf average size of 30 �m with more than 20% by volume. Theotal volume is occupied by particles <100 �m.
The results are shown in Figure 1 (K3 (kaolin particles have a
ne particle size)). From these results we can see that the particleize distribution K3 varies between 0.1 �m and 50 �m.
The kaolin sample K3 has a bimodal distribution consistingf two size fractions, (1) a fraction of average size less than 1 �m
192 D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204
Table 1The resin characteristics MEDAPOXY 812INJ according to the supplier’s data sheet.
Mass ratio Characteristics
Monomer (resin injected medapoxy 812 A): 1 kgHardener (hardener of the resin injected medapoxy 812 B): 0.5 kg
Density (ISO758)Working time (NFP18 810)Compressive strength (NA 427)Flexural strength (NA 234)
1.1 ± 0.11800 s at293 K>70 × 106 Pa>57 × 106 Pa
Particle size distribution Particle size distribution Particle size distribution
wWdirto achieve good dispersion and load distribution. We next incor-
Fig. 1. The size distri
ith about 25% and (2) a fraction of average size of 3 �m withore 60% by volume. The total volume is occupied by particles50 �m.
The results of particle size distribution metakaolin particlesre shown in Figure 2.
This particle size curve shows that the particle size distribu-ion of the load MK1 (metakaolin particles have the biggest size)s between 0.1 �m and 100 �m.
The sample of Metakaolin MK1 has a multi-modal distribu-ion which is composed of three particle size fractions, (1) araction of average size less than 1 �m with about 20%, (2) araction of average size of 4 �m with more 30% by volume, and3) a fraction of average size of 30 �m with more than 40% byolume. The total volume is occupied by particles <100 �m.
The particle size distribution of the load MK2 (Metakaolinarticles have an average particle size) is between 0.1 �m and0 �m.
The sample of Metakaolin MK2 has a multi-modal distribu-ion which is composed of three particle size fractions, (1) araction of average size less than 1 �m with about 20%, (2) araction of average size of 4 �m with more 35% by volume, and3) a fraction of average size of 20 �m with more than 40% byolume. The total volume is occupied by particles <60 �m.
From these results we can see that the particle size distribu-ion MK3 (Metakaolin particles have a fine particle size) variesetween 0.1 �m and 40 �m.
The sample of Metakaolin MK3 has a multi-modal distribu-ion which is composed of three particle size fractions, (1) araction of average size less than 1 �m with about 45%, (2) araction of average size of 3 �m with more 45% by volume, and
3) a fraction of average size of 20 �m with more than 10% byolume.
pb
s of kaolin particles.
.1.2.2. Chemical composition. The chemical composition ofhe mineral fillers was determined by X-ray fluorescence spec-rometer X Panalytical Magix Pro of CRTSE method.
The results are shown in Table 2.In our case, it was observed that the kaolin exhibits a loss on
gnition of about 11.86% (H2O).
.1.2.3. Mineralogy composition by XRD. The structural inves-igation was carried out using an X-ray diffractometry (Philipsiffractometer X’pert of URMPE).
From a mineralogical perspective, the XR diffraction showshat the used kaolin is essentially composed of kaolinite JCPDSard no: 83-971, halloysite JCPDS card no: 29-1489 anduartz JCPDS card no: 78-1252. The results are presented inigure 3.
The presence of metakaolin resulting from the under-curingf kaolin, along with the dehydroxylation, can disturb the ALO, OH) octahedral sheets, but no critical impact is observed forhe SiO4 tetrahedral sheets, the results are presented in Figure 4.
.2. Composite material synthesis
.2.1. Elaboration of the samplesThe composite samples were prepared according to the
eight ratio between the monomer and the hardener (MR = 2).e mixed 100% of the injected resin, 50% of the hardener and a
esired fuller’s ratio. The rate of the fullers is measured accord-ng to the weight percent of the resin and dried at 80 ◦C. First, theesin and the filler were mixed in an ultrasonic bath for 15 min
orated the hardener and agitated during 15 min to eliminate theubbles formed during the mixing phase.
D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204 193
Particle size distribution Particle size distribution Particle size distribution
.2.2.1. Density determination. True density was determinedsing a hydrostatic balance according to the NF T51-561tandard.
The densities of the samples were determined as the averagef two samples, double weighing at 22 ◦C using the followingormula:
= ρe · mr
mr − (mf − mp)(1)
here ρ and ρe are, respectively, the densities of the sam-le and the liquid of immersion. We used water at 22 ◦C withe ≈ 1 g/cm3.
mr, mf and mp are, respectively, the masses of the samplen open air, the mass of the test tube together with the test tubeolder and the mass of test tube holder in the liquid of immersion.
We used an analytical balance fitted with software that giveshe density of the sample by introducing the mass values in openir and in water.
The experimental results for all samples of composites (resinnjected/Kaolin, resin injected metakaolin) are given in Table 3.
From these results we observe that the density increase byhe incorporation of kaolin and metakaolin into the resin. Wean see that the density increases when the filler rates increase.
.2.2.2. Mechanical characterization. a. Tensile testThe tensile tests were performed by means of a Zwick/Rolle
esting machine of the University of Boumerdes Algeria. Theoading capacity is 10 kN and the applied loading speed was
mm/min. All measurements were taken at room temperature.a.1. Specimens geometryThe specimens were dumbbell shaped in accordance with
N ISO 527-4 Type B standard. The samples were prepared inluminum molds, Figure 5 shows the specimens used.
a.2. Mechanical tensile behavior of composite (resinnjected/kaolin)
m
t
45 0.48 0.34 0.09 0.07 0.08
All measurements represent the changes in the stress versuslongation applied to the specimens. The Figure 6 representshe tensile mechanical behavior of resin loaded with kaolin) inject /K1, b) inject /K2, c) inject /K3.
The mechanical properties of the resin loaded with kaolin areummarized in Table 4.
The results show an increase of the breaking stress and theodulus of elasticity with a decrease of the elongation at break
s a function of the filler rates.Compared to unfilled samples, an increase of the tensile
trength and a decreased elongation at break are observed forlled resins. The tensile at break and the modulus of elasticity
ncrease as a function of the fillers rate, concomitantly with aecrease of the elongation.
The maximum stress at break of loaded samples stronglyncreases with the increase of the fillers rate. A maximum valuef 26.47 × 106 Pa was observed for 16% of the fillers rate, i.e.207% of the unfilled.
Remarkably, a charging rate beyond 16% has a reverses effectn the increase of the tensile at break in traction.
The elongation at tensile breaking strength of the loaded sam-les significantly decreases with raising the filler rates, achieving
minimal value of 2.84% while it decreases by over 86% forate filler of 18% compared to unfilled samples. The modulusf elasticity increases with increasing filler rates, a maximumalue of 1.9 × 109 Pa for 18% of fillers was observed, i.e. >258%ncrease in modulus of elasticity compared to unfilled resin.
a.3. Mechanical tensile behavior of composite (resinnjected/metakaolin)
Figure 7 represents the tensile mechanical behavior of resinoaded with metkaolin: (a) inject/MK1, (b) inject/MK2 and (c)nject/MK3.
The mechanical properties of the resin loaded with
etakaolin are summarized in Table 5.The effect of the filler rate is remarkable with increasing
he tensile strength and Young’s modulus with a decrease in
194 D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204
200
150
100
50
200
150
100
50
10
200
150
100
50
10
10 20 30 40 50
10 20 30 40 50
100 20
Quartz
Halloysite
Kaolinite
2 theta
2 theta
2 theta
Inte
nsity
Inte
nsity
Inte
nsity
30 40 50
Fig. 3. Mineralogy composition of kaolin.
D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204 195
eformation. The best result for Young’s stress modulus isbtained at 18% filler rates, with a minimum value of elongationt break.
The maximum stress at break of loaded samples greatlyncreases with increasing the filler rates and a maximum valuef 24.55 × 106 Pa was observed for 18% of the filler rates, i.e.212% of the unfilled.
The elongation at tensile breaking strength of the filled sam-les significantly decreases with raising the filler rates to achieve
minimal value of 5.14%,and which decreases by ∼75% for aller rate equal to 16% compared to unfilled samples.
The modulus of elasticity increases with increasing the filler
ates, a maximum value of 2.4 × 109 Pa for 18% of fillers wasbserved, meaning that more than 325% increase in the modulusf elasticity compared to unfilled resin.
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Strain in,
Strain in,
Str
ess
in M
Pa
Str
ess
in M
Pa
Str
ess
in M
Pa
a
b
c
Fig. 6. The tensile mechanical behavior of resin loaded with
Fig. 5. Specimens used.
16 18 20 22 24 26 28
14 16 18 20 22 24 26
%
%
%
0%2%4%6%8%10%12%14%16%18%20%
0%2%4%6%8%10%12%14%16%18%20%
0%2%4%6%8%10%12%14%16%18%20%
14 16 18 20 22 24 26
kaolin: (a) inject/K1, (b) inject/K2, and (c) inject/K3.
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Deformation in, %
a
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ess
in M
Pa
Str
ess
in M
Pa
Str
ess
in M
Pa
14 16 18 20 22 24
0%2%4%6%8%10%12%14%16%18%20%
0%2%4%6%8%10%12%14%16%18%20%
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26
20 64 10 8 12 14 16 18 20 22 24 26
20 64 10 8 12 14 16 18 20 22 24 26
met k
(mclotc
Yt
kt(
2e4
Fig. 7. The tensile mechanical behavior of resin loaded with
In conclusion, we have investigated the effect of fillers ratekaolin and metakaolin) and the granulometry effect on theechanical properties of epoxy resin. At low rate, fine parti-
le sizes permit a good dispersion of the particles in the matrix,eading to improvements in the mechanical properties. On thether hand, particles with larger size exhibit poor dispersion ofhe filler because of its own weight, which in turn requires a highharging rate to achieve improvements.
Adding metakaolin to the resin yields the best results foroung’s modulus, stress at break and elongation, compared to
he low rate kaolin. The presence of water molecules in the
otot
in in, %
aolin: (a) inject/MK1, (b) inject/MK2, and (c) inject/MK3.
aolin can notably degrade the bonds at the interface, leadingo a degradation of the mechanical properties of the compositeVaddadi, Nakamura, & Singh, 2003).
.2.2.3. Thermal analysis by DSC of filled composites. Differ-ntial scanning calorimetery (DSC) was conducted using a STA09 PC NETZSCH LUXX (Simultaneous Thermal Analysis)
f URMPE. It is based on the differential determination of thehermal effect using two thermopiles and on the measurementf the mass drop under the effect of temperature. This analysisechnique is part of the NF-EN31357-3 standard (plastic).
198 D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204
–2
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–840 60 80 100 120 140 160 180 200 220 240
40 60 80 100 120 140
Temperature in, º C
Temperature in, º C
Temperature in, º C
uv/m
guv
/mg
uv/m
g
a
b
c
160 180 200
0%2%4%6%8%10%12%14%16%18%20%
2%4%6%8%10%12%14%16%18%20%
2%4%6%8%10%12%14%16%18%20%
220 240
40 60 80 100 120 140 160 180 200 220 240
ed res
nh
a
b
a
b. TGA resultsThe resin filled by metakaolin TGA results is shown in
Fig. 8. Differential scanning calorimetry analysis of the fill
The different types of samples were analyzed by this tech-ique. The samples were annealed at 353 K for 28,800 s. Theeating rate during thermal analysis testing was 4.71 K/s.
2.2.2.3.1. Thermal analysis of samples filled by kaolin.
. DTA resultsThe results are displayed in Figure 8.
. TGA resultsThe results are displayed in Figure 9.
in by kaolin: (a) inject/K1, (b) inject/K2, and (c) inject/K3.
2.2.2.3.2. Thermal analysis of samples filled by metkaolin.
. DTA resultsThe resin filled by metakaolin DTA results is shown in
Figure 10.
Figure 11.
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9040 60 80 100 120 140 160 180 200 220 240
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2%4%6%8%10%12%14%16%18%20%
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Wei
ght l
oss
in, %
Wei
ght l
oss
in, %
Wei
ght l
oss
in, %
160 180 200 220 240
Temperature in, %
Temperature in, º C
mper
: (a) i
Wtfi
rsottt
ytfimftb
Te
Fig. 9. TGA of epoxy resin filled by kaolin
The glass transition temperature varies from 403 to 413 K.e notice that the clay filler has no influence on the resin, and
here is no chemical interaction between the resin and the clayllers.
We observed that the mineral fillers utilized, as well as theirates and sizes, do not affect the inject resin (Lehuy, 1990) hashown that the presence of charge has no significant influencen the glass transition temperature. These results indicate that
here are no strong chemical interactions between the resin andhe mineral filler with consequently a poor adhesion betweenhe resin and the inorganic filler incorporated.
ficm
ature in, º C
nject/K1, (b) inject/K2, and (c) inject/K3.
The TGA plot of the materials gives us a comparative anal-sis of filled and unfilled samples. These studies show thathe degradation starting temperature is identical to that of thelled composite and the charged resins have a weight lossore important than that of the unfilled ones which varies
rom 7 to 9, while the resin without charges DM/M is equalo −7. Such difference is mainly due to humidity absorbedy the incorporated fillers in the matrix. These results con-rm previous work (Giannelis, 1996) which showed that the
orresponding micro composite (immiscible system to a micro-etric scale) indicates no improvement in thermal stability.
200 D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204
a
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2%4%6%8%10%12%14%16%18%20%
2%4%6%8%10%12%14%16%18%20%
2%4%6%8%10%12%14%16%18%20%
uv/m
guv
/mg
uv/m
g
b
c
Temperature in, º C
Temperature in, º C
eratu
n: (a)
Ts
2C6wDk
bpa
ntfi
tt
L
w
Temp
Fig. 10. DTA plot of the resin filled by metakaoli
his confirms that dispersion is critical for improved thermaltability.
.2.2.4. Dimensional stability study by used dilatometer.ylinder-shaped samples were used; the diameter was about
× 10−3 m and the length 25 × 10−3 m while the heating rateas set at 4.63 K/s, the test was performed using a dilatometerIL 402 C-NETZSCH of URMPE, results of resins charged byaolin are presented in Figure 12.
Figure 13 shows the results of resins loaded with metakaolin.
The filled and unfilled resins exhibit an identical dilatation
ehavior and have a linear behavior up to 413 K (transition tem-erature domain). Above which the dilatometry curve showsn abrupt change inducing a reduction of the elongation. We
a
dT
re in, ºC
inject/MK1, (b) inject/MK2, and (c) inject/MK3.
oticed a considerable shrinkage due to the presence of a cer-ain amount of diluent in the resin and humidity absorbed by thellers incorporated.
For temperature ranging from 273 K to glass transition Tg,he matrix was in a vitrified state. It allow us to calculate thehermal expansion coefficient by using the following formula:
= L0(1 + αT ) =>L − L0
L0= αT (2)
here L0 and L are, respectively, the initial length and the length
t T temperature and α is the thermal dilatation coefficient.
We can conclude that the unfilled resin has a higher thermalilatation coefficient compared to the filled resins (Lehuy, 1990).he thermal dilatation coefficient decreases with increasing the
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b
c
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oss
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Wei
ght l
oss
in, %
Wei
ght l
oss
in, %
Temperature in, º C
Temperature in, º C
Temperature in, º C
Fig. 11. TGA epoxy resin filled by metakaolin: (a) inject/MK1, (b) inject/MK2, and (c) inject/MK3.
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a
0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.030
0.025
0.020
0.015
0.010
0.005
0.000
20 40 60 80 100 120 140 160 180 200 220
20 40 60 80 100 120 140 160 180 200 220
20 40 60 80 100 120 140 160 180 200 220
0%2%8%14%20%
0%2%8%14%20%
0%2%8%14%20%
b
c
ΔL/L
0, %
ΔL/L
0, %
ΔL/L
0, %
Temperature in, º C
Temperature in, º C
Temperature in, º C
Fig. 12. The dilatometer curves of the resins filled with kaolin.
D. Laouchedi et al. / Journal of Applied Research and Technology 15 (2017) 190–204 203
ΔL/L
0ΔL
/L0
ΔL/L
0
a
b
c
0%2%8%14%20%
0%2%8%14%20%
0%2%8%14%20%
0.030
0.025
0.020
0.015
0.010
0.005
0.000
40 60 80 100 120 140 160 180 200 220
40 60 80 100 120 140 160 180 200 220
40 60 80 100 120 140 160 180 200 220
0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.030
0.025
0.020
0.015
0.010
0.005
Temperature in, º C
Temperature in, º C
Temperature in, º C
rves r
fid
3
rpdtaicad
gm
ci
eb
pwt
Fig. 13. The dilatometer cu
llers rate. For resins filled with finer particles, a lower thermalilatation coefficient is obtained.
. Conclusion
The present paper reports the study of a composite mate-ial based on epoxy resin filled with local clay fillers powdersossessing different structures; the study was conducted withifferent sizes at variable rates. The results obtained highlighthe impact of kaolin and metakaolin, with respect to their sizend rate, on improving the properties of the resin. The mechan-
cal analysis shows a significant improvement of the filled resinompared to the unfilled one. We have additionally observedn increase of the elasticity modulus, the stress, as well as aecrease in the breaking elongation.
o
o
esins filled by metakaolin.
In the case of the kaolin filler, a low granulometry induces aood dispersion in the matrix, which in turn leads to an enhance-ent of mechanical properties.Conversely, larger size particles negatively impact on the
harge dispersion because of their own weight. To achievemproved properties, a high rate is required.
Metakaolin filled resins result in improved mechanical prop-rties starting from 2%, thus reflecting a good compatibilityetween the filler and the inject resin.
The resins loaded with metakaolin give better results com-ared to kaolin-loaded. One may conclude that the presence ofater molecules in the kaolin can notably degrade the bonds at
he interface and thereby causing a degradation of the properties
f the composite.
With regard to differential scanning calorimetry, it wasbserved that the glass transition temperature varies from 403 K
2 Resea
tficncti
caiweet
tTtda
sfi
C
R
A
B
B
B
B
B
B
B
C
C
C
D
F
F
F
G
G
G
G
G
H
I
J
K
L
L
S
S
V
W
04 D. Laouchedi et al. / Journal of Applied
o 413 K. In other words, there is no significant influence of thellers, or their rate and size, on the glass transition temperatureompared to the unfilled resin. These results show that there iso strong chemical interaction between the resin and the addedlay fillers, resulting in a weak adhesion between the resin andhe clay filler. According to previous studies, a good interactions obtained when the fillers are treated.
The thermal analysis of the different materials provides aomparative assessment of the filled and unfilled resin samplesnd shows that the filled resin has a similar degradation start-ng temperature to the unfilled one whereas it displays a highereight loss. This weight loss lies between 7 and 9 whereas it is
qual to −7 for the resin without charges DM/M. This differ-nce is due to humidity absorbed by the incorporated fillers inhe matrix.
Observations made during the dilatometry analysis show thathe fillers have a positive influence on the dilatation coefficient.he filled resins have a dilatation coefficient lower than that of
he unfilled ones. From these results, it can be observed that theilatation coefficient decreases with decreasing the particles sizend with increasing the filler rate.
Finally, it can be concluded that for obtaining a good disper-ion and interaction between the resin and the fillers, the clayllers cannot be used without prior chemical treatment.
onflict of interest
The authors have no conflicts of interest to declare.
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