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Al-Khwarizmi 

Engineering   

Journal Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, March, (2018) 

P.P. 29-38 

 

Evaluation the Mechanical Properties of Kaolin Particulate 

Reinforced Epoxy Composites 
 

Jabbar Hussein Mohmmed 
Department of Materials Engineering / University of Technology/ Baghdad 

Email: Jabbaraljanaby@yahoo.com 

 
(Received 26 March 2017; accepted 3 August 2017) 

https://doi.org/10.22153/kej.2018.08.003 

 

 

Abstract 

 
Epoxy resin has many chemical features and mechanical properties, but it has a small elongation at break, low 

impact strength and crack propagation resistance, i.e. it exhibits a brittle behavior. In the current study, the influence of 
adding kaolin with variable particle size on the mechanical properties (flexural modulus E, toughness Gc, fracture 
toughness Kc, hardness HB, and Wear rate WR) of epoxy resin was evaluated. Composites of epoxy with varying 
concentrations (0, 10, 20, 30, 40 weights %) of kaolin were prepared by hand-out method. The composites showed 
improved (E, Gc, Kc, HB, and WR) properties with the addition of filler. Also, similar results were observed with the 
decrease in particle size. In addition, in this study, multiple regression models were developed by utilizing (SPSS) 
package to predict the properties of kaolin reinforced epoxy composites. Good agreement was obtained between the 
predicted and the experimental results. The accuracy of prediction was (89.71%, 80.58%, 85.82%, 92.27%, and 
94.49%) for E, Gc, Kc, HB, and WR, respectively. 
 
Keywords: Epoxy resins, Kaolin, Particulate composites, SPSS. 
 

 

1. Introduction 
 
The incorporation of particulate fillers into 

thermosets have a wide use in industry to extend 
the thermosets and to enhance specific features. 
Fillers usually improve the efficiency and 
quality of polymeric products. The degree of 
development relies on the filler origin, shape and 
particle size, and the volume or weight fraction 
of filler that will be chosen [1, 2]. The addition 
of fillers to polymers is a quick and cheap way 
to change the features of the matrix materials. 
Hence, particulate filled polymer has been, and 
continue to be, the subject of growing interest in 
both modern technology and industrial research. 
In this way, strength, stiffness, toughness and 
fracture toughness, among other properties can 
be tailored to the desired values [3]. 

Epoxy resins are one of the most extensive 
thermoset materials in the world because of their 
valuable properties, large applications, inert 
chemical properties, barrier properties and low 
cost [4]. however, these materials exhibit a low 
elastic modulus, toughness, and fracture 
toughness. In this respect, a great deal of effort 
was devoted to the enhancement of the 
toughness of epoxy resins in the last few 
decades aiming at enlarging their field of 
applications [5]. 

Approaches to improve the toughness of 
epoxy resins involve mainly the incorporation of 
solid particles [6-9]. The most useful fillers in 
epoxy are glass fiber [10], silica powder and 
aramid fiber [11]. 

The present work reports the results of the 
incorporation of kaolin with different contents 
and different particle sizes into epoxy resins. 
Epoxy/kaolin composite was prepared by hand 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

30 

 

out method. In addition to, in this study, the 
mathematical models for influence of kaolin 
content and particle size on the flexural 
modulus, toughness, fracture toughness, 
hardness, and wear rate were created. 
 
 

2. Experimental Work 
2.1. Materials 

2.1.1. Preparation of Matrix Material 
 

The matrix material used for current work 
was Epoxy type (CY233) having density in 
range of (1.1-1.2 g/cm3) at 25˚C and its hardener 
was (HY956). Chemical structure of uncured 
epoxy is presented in Fig.1 [12]. 
 

 
 

Fig. 1. Chemical Structure of uncured epoxy [12] 

 

 

2.1.2. Preparation of Reinforcement     

Material 

 
Raw Kaolin with a density of 2.64 g/cm³, 

sourced from Iraqi National Company for 
Geological Survey and Refinery, was used as 
reinforcement in the current work. The kaolin 
powder was milled and sieved by a stack of 
sieves to obtain different particle sizes. The 
milled and sieved kaolin was then placed into a 
ceramic crucible and calcined in an electrical 
furnace at 700oC for 6 h to remove traces of 
moisture from the kaolin. Hence, the calcined 
kaolin powder was packaged in a sealed 
cellophane bag and kept in a desiccator. The 
typical composition and general properties of 
kaolin are presented in Tables 1, and 2 [13]. 
 
Table 1,  
Chemical composition of kaolin [13] 

Element Wight % 
SiO2 52.48 
Al2O3 31.31 
Fe2O3 2.094 
TiO2 1.43 
MgO 0.33 
Na2O 0.28 
CaO 0.462 
L.O.I 10.93 

 

Table 2,  
General properties of kaolin [13]. 

Properties  Quantity  
Density, g/cm3 2.64 
Powder color White 
Melting point, oC 1755 
Fracture resistance  Higher 225 MPa 

Thermal properties 
Endothermic at 260 oC 
Isothermic at 980 oC 

 
 

2.1.3. Preparation of Composites 

 
17 kaolin reinforced epoxy composite 

samples were prepared for the current study. 
Particle sizes of (d<8, 18<d<25, 33<d<45, 
50<d<62 μm) with varying content of weight 
percent (0, 10, 20, 30, 40 %wt) of kaolin were 
used in making samples. Hand out method was 
used to prepare the composite in this work.  

For preparation the samples, the required 
amounts of calcined kaolin and epoxy were 
mixed mechanically for 10 min to ensure 
suitable and even distribution of kaolin in the 
mixture phase. Afterward, Hardener was added 
in the ratio of 3:1 by weight of epoxy resin and 
gently but thoroughly stirred manually with the 
mixture for 15 min to obtain homogeneous 
mixture and to minimize the gas entrapment. 
The final mixture was gradually and gently 
poured into steel molds until the cavity of the 
molds was completely filled with the composite 
material. These molds were allowed to cure for 
24 h at room temperature. After this, the sample 
was evacuated from the mold and post cured at 
100˚C for 4 hr. Finally, the sample was left to 
cool to lab temperature in the oven itself. 
 
 

2.2. Mechanical Tests  

2.2.1. Flexural Test  

 
For the three-point flexural test, specimens 

were manufactured according to ASTM D790. 
The span to depth ratio of test samples was 32:1. 
The tests were performed by using universal 
testing machine with a crosshead speed of 0.5 
mm/min. All the tests were made at room 
temperature. The flexural modulus E was 
calculated as follows [14]: 
 

 
 

Where E: Young modulus (MPa), L: support 
span (mm), D: width of sample (mm), B: depth 
of sample (mm), and m: slope of the tangent to 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

31 

 

the initial straight line portion of the load-
deflection curve (N/mm) of deflection. 

 

 

2.2.2. Impact Test  

 
Impact specimens were manufactured 

according to ISO-179 standard suitable to 
Charpy Impact Instrument. Notch depth was 
equal for all specimens with (1.5 mm), and 
notch base radius was (0.25 mm). One edge of 
each specimen was polished so that crack could 
be readily discerned. The energy absorbed at 
fracture (Uc) can be obtained from impact tests, 
from which, the value of toughness (Gc) was 
calculated based on the following equation [14]: 
 

 
 

Where: 
B is depth of sample (mm), D is width of sample 

(mm),  is geometry function. 

When the ratio between length of sample 
exposed to impact to cross section of sample 

equal to 4, the geometry function ( ) can be 

calculated from the following equation [14]: 
 

 
Where: 

  : Ratio of notch depth to cross section of 

sample. 
In addition to, the values of fracture toughness 
Kc can be calculated from the following 
equation [14]: 

 
 

 

2.2.3. Hardness Test 
 

The hardness tests, using Brinell hardness 
test instrument, were conducted at lab conditions 
and the measurements were performed at least 
three different locations on the samples, and the 
mean value was considered. The indenter was 
spherical ball with diameter of 5 mm. The test 
load used in this test was 1500 N and maintained 
for 15 sec. The resulted diameter from the 
indentation was measured by microscope, and 
HB number was calculated as following [14]: 

 
 

Where: HB is Brinell value, P is applied load 
(Kg), D is Ball diameter (mm), d is Indention 
diameter on the sample surface (mm) 
 
 

2.2.4. Wear Test 
 

Wear test was done according to the ASTM 
G99 for dry sliding wear test by using a pin on 
drum tester instrument. The test was performed 
at a sliding speed of 2 cm/s and pressure of 
1MPa at ambient in room conditions. After the 
end of specified sliding distances (50 m), the 
testing device was stopped; the surfaces of 
samples were cleaned thoroughly with brush, 
and the surface particles (or debris) were 
removed and the weight loss was determined. 
The wear rate expressed in (mg/cm) of the 
material was calculated as follows: 

 
Where:  is wear rate,  is weight loss in 

(mg), and  is sliding distance in (m). 

 
 

2.3. Mathematical Modeling 
 

Regression model is a common statistical 
procedure used for modelling the relationship 
among several independent variables (variation 
factors) and a particular dependent (or response 
functions) variable of interest. Regression 
models can be used to save the time and the cost 
associated with the development and selection of 
new composite materials. The basic issue of 
model building in this project is to create a 
reliable relationship among mechanical 
properties and some factors affected on the 
resultant composite.  The independent variables 
(explanatory factors) used in this work to predict 
the dependent variables, composite properties 
(E, Gc, Kc, HB, and WR), are presented in 
Table 3. The available experimental data (Table 
4) were randomly divided into two groups; the 
training data group (Table 5) which found for 
prediction model building and the testing data 
group (Table 6) which found to test the 
flexibility and the validity of the prediction 
model.  

 

 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

32 

 

Table 3,  
Definition and values of independent variables used in regression equation. 

Designations of independent 

variable 

Variable name  Value 

 
kaolin concentration (% wt) 0,10, 20, 30, 40 

 Particle size (μm) d ≤ 8, 18 ≤ d ≤ 25, 33 < d < 45, 50 < d < 
62 

 
Table 4,  
Original experimental data for predicted and measured properties of epoxy composite. 

No. 

Kaolin 

added 

(%) 

Particle 

size 

(μm) 

Measured 

E (GPa) 

Predicted 

E (GPa) 

Measured 

Gc 

(KJ/m2) 

Predicted 

Gc 

(KJ/m2) 

Measured 

Kc 

(MPa√m) 

Predicted 

Kc 

(MPa√m) 

Measured 

HB 

Predicted 

HB 

Measured 

WR 

(mg/cm) 

Predicted 

WR 

(mg/cm) 

1 0 0 1.5 1.72652 1.16 1.09822 1.29 1.47088 13.02 13.12127 17.34 14.0044 
2 10 d ≤ 8 2.93 2.58406 1.55 1.52185 2.15 1.98661 17.12 16.71474 8.2 11.10932 
3 20 d ≤ 8 3.46 3.52369 1.95 2.12716 2.44 2.68983 19.49 21.72005 7.46 8.91932 
4 30 d ≤ 8 4.28 4.46332 2.63 2.73246 3.22 3.39305 26.55 26.72537 6.88 6.72932 
5 40 d ≤ 8 5.66 5.40295 3.5 3.33776 4.64 4.09627 33.89 31.73069 5.72 4.53931 
6 10 18 ≤ d 

≤ 25 
2.77 2.44041 1.3 1.20393 2 1.65851 16.51 14.24399 8.98 10.43982 

7 20 18 ≤ d 
≤ 25 

3.08 3.38005 1.82 1.80924 2.34 2.36173 18.43 19.24931 8.12 8.81419 

8 30 18 ≤ d 
≤ 25 

4.11 4.31968 2.25 2.41454   2.99 3.06495 22.92 24.25463 7.22 7.18855 

9 40 18 ≤ d 
≤ 25 

5.31 5.25931 3.11 3.01984 3.42 3.76817 29.09 29.25995 6.01 5.56291 

10 10 33 < d 
< 45 

2.53 2.26598 1.12 0.81789 1.01 1.2601 13.13 11.2438 9.54 962686 

11 20 33 < d 
< 45 

2.99 3.20561 1.35 1.42319 1.82 1.96332 15.44 16.24912 8.66 8.68653 

12 30 33 < d 
< 45 

3.82 4.14524 1.78 2.02849 1.98 2.66654 19.79 21.25443 8.06 7.74619 

13 40 33 < d 
< 45 

4.76 5.08487 2.15 2.6338 3.01 3.36976 25.35 26.25975 7.55 6.80586 

14 10 50 < d 
< 62 

1.58 2.09155 0.79 0.43184 0.99 0.86169 9.62 8.24361 9.97 8.8139 

15 20 50 < d 
< 62 

2.87 3.03118 1.18 1.03714 1.41 1.56491 12.98 13.24892 8.87 8.55887 

16 30 50 < d 
< 62 

3.95 3.97081 1.47 1.64245 2.11 2.26813 17.35 18.25424 8.11 8.30384 

17 40 50 < d 
< 62 

4.43 4.91044 1.88 2.24775 2.89 2.97135 21.78 23.25956 7.21 8.04881 

 

Table 5,  
Training data for properties of epoxy composite. 

No. 

Kaolin 

added 

(%) 

Particle 

size 

(μm) 

Measured 

E (GPa) 

Predicted 

E (GPa) 

Measured 

Gc 

(KJ/m2) 

Predicted 

Gc 

(KJ/m2) 

Measured 

Kc 

(MPa√m) 

Predicted 

Kc 

(MPa√m) 

Measured 

HB 

Predicted 

HB 

Measured 

WR 

Predicted 

WR 

1 0 0 1.5 1.72652 1.16 1.09822 1.29 1.47088 13.02 13.12127 17.34 14.0044 
2 10 d ≤ 8 2.93 2.58406 1.55 1.52185 2.15 1.98661 17.12 16.71474 8.2 11.10932 
3 20 d ≤ 8 3.46 3.52369 1.95 2.12716 2.44 2.68983 19.49 21.72005 7.46 8.91932 
4 30 d ≤ 8 4.28 4.46332 2.63 2.73246 3.22 3.39305 26.55 26.72537 6.88 6.72932 
5 40 d ≤ 8 5.66 5.40295 3.5 3.33776 4.64 4.09627 33.89 31.73069 5.72 4.53931 
6 10 18 ≤ d 

≤ 25 
2.77 2.44041 1.3 1.20393 2 1.65851 16.51 14.24399 8.98 10.43982 

7 20 18 ≤ d 
≤ 25 

3.08 3.38005 1.82 1.80924 2.34 2.36173 18.43 19.24931 8.12 8.81419 

8 30 18 ≤ d 
≤ 25 

4.11 4.31968 2.25 2.41454 2.99 3.06495 22.92 24.25463 7.22 7.18855 

9 40 18 ≤ d 
≤ 25 

5.31 5.25931 3.11 3.01984 3.42 3.76817 29.09 29.25995 6.01 5.56291 

 
 

 

 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

33 

 

Table 6,  
Testing data for properties of epoxy composite. 

No. 

Kaolin 

added 

(%) 

Particle 

size 

(μm) 

Measured 

E (GPa) 

Predicted 

E (GPa) 

Measured 

Gc 

(KJ/m2) 

Predicted 

Gc 

(KJ/m2) 

Measured 

Kc 

(MPa√m) 

Predicted 

Kc 

(MPa√m) 

Measured 

HB 

Predicted 

HB 

Measured 

WR 

Predicted 

WR 

1 10 33 < d 
< 45 

2.53 2.26598 1.12 0.81789 1.01 1.2601 13.13 11.2438 9.54 962686 

2 20 33 < d 
< 45 

2.99 3.20561 1.35 1.42319 1.82 1.96332 15.44 16.24912 8.66 8.68653 

3 30 33 < d 
< 45 

3.82 4.14524 1.78 2.02849 1.98 2.66654 19.79 21.25443 8.06 7.74619 

4 40 33 < d 
< 45 

4.76 5.08487 2.15 2.6338 3.01 3.36976 25.35 26.25975 7.55 6.80586 

5 10 50 < d 
< 62 

1.58 2.09155 0.79 0.43184 0.99 0.86169 9.62 8.24361 9.97 8.8139 

6 20 50 < d 
< 62 

2.87 3.03118 1.18 1.03714 1.41 1.56491 12.98 13.24892 8.87 8.55887 

7 30 50 < d 
< 62 

3.95 3.97081 1.47 1.64245 2.11 2.26813 17.35 18.25424 8.11 8.30384 

8 40 50 < d 
< 62 

4.43 4.91044 1.88 2.24775 2.89 2.97135 21.78 23.25956 7.21 8.04881 

 

3. Results and Discussion  
3.1. Experimental Work 
3.1.1. Flexural Modulus 

 
Figure 2 shows the variation of flexural 

modulus of the material with kaolin filler 
content for different particle sizes. Generally, 
the flexural modulus (E) is referred to the 
relative stiffness of composite [15]. Thus, the 
growing in E value with increasing filler loading 
is expected since the addition of filler improves 
the stiffness of composites. This enhancing can 
be attributed to the stiff nature of filler. A 
similar observation was made by many 
researchers [13, 16-17]. 

The rate of increasing in E values was 
comparable to the increasing in weight fraction 
of kaolin and the decrease in particle size. 
Therefore, it was conformed that the total area 
available to deformation stress played an 
important role. The increasing in E values is 
mainly attributed to the restriction of chain 
mobility, this can be explained by plastic 
deformation mechanism. Capability of any 
material to plastic deformation is mainly 
specified by the mobility of the molecular chain 
(molecular motion) to occur under applied force. 
The existence of solid particles like kaolin in 
this case has restricted the mobility of the 
molecular chain to pass each other and the 
orientation that consequently resulted in increase 
in rigidity (stiffness). 
 
 
 
 

 

0

1

2

3

4

5

6

0 10 20 30 40

Y
o

u
n

g
 M

o
d

u
lu

s
, 

G
P

a

Kaolin Content, %

d ≤ 8

18 ≤ d ≤ 25

33 < d < 45

50 < d < 62

 
 

Fig. 2. Variation in flexural modulus of different 

particle sizes and weight fractions of kaolin 

 

 

3.1.2. Toughness and Fracture Toughness 

 
The variation of toughness (Gc) and fracture 

toughness (Kc) for the composites with filler 
loading for different particle sizes are presented 
in figures (3, and 4), respectively. It can be seen 
that the Gc and Kc increases, as the kaolin 
content increases and the particle size decreases. 
The maximum improvement is attained with 
40%wt kaolin and (d<8μm) particle size, and 
represents more than (203) % and (259) % in 
comparison with Gc and Kc of neat resin, 
respectively 

The improvement of impact properties was 
reported in literature with different modifier [16, 
18].  
 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

34 

 

0

0.5

1

1.5

2

2.5

3

3.5

4

0 10 20 30 40

T
o

u
g

h
n

e
s
s
, 

K
J/

m
2

K aolin Content, %

d ≤ 8

18 ≤ d ≤ 25

33 < d < 45

50 < d < 62

 
 

Fig. 3. Variation in toughness of different particle 

sizes and weight fractions of kaolin 

 

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 10 20 30 40

F
ra

c
tu

re
 T

o
u

g
h

n
e

s
s
, 

M
P

a
√

m

Kaolin Content, %

d ≤ 8

18 ≤ d ≤ 25

33 < d < 45

50 < d < 62

 
 

Fig. 4. Variation in fracture toughness of different 

particle sizes and weight fractions of kaolin 

 
 

The Gc and Kc improvement by the addition 
of kaolin particles can be due to the formation of 
small sized crystallites, i.e. spherulites, and the 
capacity to absorb much energy by the enlarge 
of portion of matrix. Also, this enhancing can be 
explained by the crack pinning mechanism [19]. 
Impact strength is an indication of tolerability 
for a sudden impact. As the composites are 
exposed to the impact load, rapid crack 
propagation is initiated through the material. 
When such crack propagation encounters solid 
particles in the filled composite, the filler can 
absorb the energy and stop the crack 
propagation. In other hand, Nakagawa and Sano 
[20] have shown the existence of small and fine 
particles dispersed into the matrix makes plastic 
deformation more easy. So, during the fracture 
of the composite in which the solid filler is fine 
and well dispersed, i.e., in which the material is 
more homogeneous, the stress will have to be 
bigger to begin a micro crack on particles and 
the impact energy will strongly be absorbed by 

plastic deformation. Hence, finer particles lead 
to better impact properties of the composite. 

On the other hand, the increasing of the 
kaolin content to higher levels (beyond 40%wt) 
may be brought the inverse effects on the 
properties because of the brittleness problem. 
 
 

3.1.3. Hardness 

 
It is clearly seen from Figure (5) that the 

hardness increases with the decrease in particle 
size and increase in weight percent of filler. The 
addition of kaolin filler improves the hardness 
value of composite material because of the 
increasing in the resistance strength of polymer 
to plastic deformation. The results agree well 
with those obtained by Saleh and Mustafa [13], 
who showed that the hardness increases with 
increasing weight percent and decreasing 
particle size. 
 

0

5

10

15

20

25

30

35

40

0 10 20 30 40

H
a

rd
n

e
s
s
, 

H
B

Kaolin Content, %

d ≤ 8

18 ≤ d ≤ 25

33 < d < 45

50 < d < 62

 
 

Fig. 5. Variation in hardness of different particle 

sizes and weight fractions of kaolin 

 
 

3.1.4. Wear Rate 

 
The results presented in Fig. (6) show that 

the wear rate was less when reinforcing the 
epoxy resin with kaolin particles in the range of 
(0-40%). This enhancement may be explained 
by that the kaolin particles will absorb a portion 
of applied stress and heat generated by friction 
as a result of slip between the surface of samples 
and the surface of the rotating disk. Thus, the 
applied stress and heat generated will be 
distributed on the matrix and reinforcing 
particles, and this will improve the ability of the 
epoxy resin to resist the wear. 

Also, the same trend was observed with the 
decrease in the particle size. This is because the 
increasing in particle size increases the interface 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

35 

 

surface and this leads to impede the process of 
transfer of stresses and heat of the matrix to the 
reinforcing particles, and then increases the 
concentration of stress, heat, thus this will 
increase the wear rate with increasing the 
particle size.  
 

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40

W
e

a
r 

R
a

te
, 

m
g

/
c
m

Kaolin Content, %

d ≤ 8

18 ≤ d ≤ 25

33 < d < 45

50 < d < 62

 
 

Fig. 6. Variation in wear rate of different particle 

sizes and weight fractions of kaolin 

 
 

3.2. Results and Discussion of 
Mathematical Model 

 
Regression models of composite properties 

were developed from the processing of 
experimental results. These analyses were 
performed by using SPSS software. The 
following equations represent the relationship 
between composite properties and all 
independent variables involved in this work: 
 

      

 

 

 
 

Where: 

 : flexural modulus,  : toughness,  : 

fracture toughness. 
All equations confirmed a high value of 

multiple correlation coefficient R which were 
(0.981, 0.989, 0.953, 0.976, and 0.851) for 
equations (7, 8, 9, 10 & 11) respectively. 

The error value of the training data group 
was (7.25%, 4.72%, 8.84%, 5.13%, and 14.43%) 
for (E, Gc, Kc, HB, and WR), respectively and 
for the testing data group was (10.29%, 19.42%, 
14.18%, 7.73%, and 5.51%) for (E, Gc, Kc, HB, 
and WR), respectively. 

This reveals that the statistical model could 
predict the epoxy composite properties with 
about (92.75%, 95.28%, 91.16%, 94.87%, and 
85.57%) accuracy of the training data set and 
approximately (89.71%, 80.58%, 85.82%, 
92.27%, and 94.49%) accuracy of the testing 
data set for properties (E, Gc, Kc, HB, and WR), 
respectively. 

Figures (5, 6, 7, 8, and 9) present the 
comparison between the predicted and 
experimental values of 17 original data for 
mechanical properties, respectively by (SPSS) 
package. 
It can be noticed from these figures that the 
predicted values are in a close match with the 
experimental values for all properties. 

 

5.004.003.002.00

E_Predicted

6.00

5.00

4.00

3.00

2.00

1.00

E
_
M

e
a
s
u

re
d

R Sq Linear = 0.947

 
 

Fig. 7. Experimental and predicted values of 

flexural modulus 

 

3.002.001.000.00

Gc_Predicted

3.50

3.00

2.50

2.00

1.50

1.00

0.50

G
c
_
M

e
a
s
u

re
d

R Sq Linear = 0.93

 
 
Fig. 8. Experimental and predicted values of 

toughness 
 



Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

36 

 

4.003.002.001.00

Kc_Predicted

5.00

4.00

3.00

2.00

1.00

K
c
_
M

e
a
s
u

r
e
d

R Sq Linear = 0.913

 
 

Fig. 9. Experimental and predicted values of 
fracture toughness 

 

35.0030.0025.0020.0015.0010.005.00

HB_Predicted

35.00

30.00

25.00

20.00

15.00

10.00

5.00

H
B

_
M

e
a
s
u

r
e
d

R Sq Linear = 0.959

 
 

Fig. 10. Experimental and predicted values of 

hardness 

 

16.0014.0012.0010.008.006.004.00

WR_Predicted

17.50

15.00

12.50

10.00

7.50

5.00

W
R

_
M

e
a

s
u

re
d

R Sq Linear = 0.724

 
 
Fig. 11. Experimental and predicted values of 

wear rate. 

4. Conclusions  
 

From the experimental results it can conclude 
the following:  

• The addition of kaolin particles into epoxy 
resin can remarkably alter the material’s 
mechanical properties. The material 
properties (E, Gc, Kc, HB, and WR) increase 
with the increasing filler content. 

• The properties of epoxy composite decreased 
as the particle size of kaolin increased. 

• The multiple regression models could predict 
the properties of epoxy composite with 
higher accuracy for different kaolin 
additions, and particle sizes. 

 
 

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Jabbar Hussein Mohmmed            Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 29- 38 (2018) 

37 

 

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  )2018( 29-38، صفحة 1د، العد14دجلة الخوارزمي الهندسية المجلم                                                          جبار حسين محمد

38 

 

 

 

 

 الكاؤولينبدقائق االيبوكسي المقواة  لمتراكبات الميكانيكية الخواص تقييم
 

 جبار حسين محمد
 قسم هندسة المواد / الجامعة التكنولوجية

  Jabbaraljanaby@yahoo.comالبريد االلكتروني:
   

 
 

 الخالصة
 

 للصدمة ضعيفة ومقاومة محدودة مطيلية لكتمي نفسه الوقت في لكنه جداً، مهمةال كيميائيةالو ميكانيكيةال خواصيد من الالعد االيبوكسي راتنجيمتلك 
ً  بديي آخر بمعنى الشق، ولتوسع  معامل (الميكانيكية  الخواص على مختلفة حبيبية بأحجام الكاؤولين اضافة تأثير يموتق تم البحث هذا في .هشاً  سلوكا

، ٣٠، ٢٠، ١٠، ٠من االيبوكسي بتراكيز مختلفة ( متراكبات تحضير تم لراتنجات االيبوكسي. )البلى ومعدل الصالدة، الكسر، متانة المتانة، االنحناء،
الصالدة، من الوزن) من الكاؤولين باستخدام طريقة القولبة اليدوية. اظهرت المتراكبات تحسنا في خواص (معامل االنحناء، المتانة، متانة الكسر،  %٤٠

 البحث تطوير موديل انحدار متعدد هذا في ايضا كما تمالحبيبي.  الحجم بتقليل وتمت مالحظة النتائج نفسهاومعدل البلى) عند اضافة حشوة الكاؤولين.  
تم الحصول على توافق جيد عند مقارنة القيم العملية و بالكاؤولين المقواة االيبوكسي متراكبات بخواص التنبؤ ) من اجلSPSSبرنامج ( باستعمال
 الصالدة، الكسر، متانة المتانة، االنحناء، ) لمعامل%٩٤٫٤٩، و%٩٢٫٢٧، %٨٥٫٨٢، %٨٠٫٥٨، %٨٩٫٧١حوالي ( التنبؤ دقة كانت فقد والمتنبئة.

 .التوالي على البلى ومعدل