INVESTIGATION OF MECHANICAL PROPERTIES OF POLYESTER FIBER, ACRYLIC FIBER AND POLYAMIDE FIBER REINFORCED COMPOSITES

Yıl 2019, Cilt: 3 Sayı: 1, - , 10.07.2019

Yalçın Boztoprak

Öz

Abstract

Composite materials are materials
obtained by combining materials with two or more different properties that are
used by people for thousands of years to solve problems without being aware of
them. Polymer based composite materials have recently been developed to improve
the properties of these materials, as they have many superior properties as
well as insufficient strength. Depending on technological developments, different
types of composites have been produced using different types of matrix and
reinforcement.

The
purpose  of this study, a new composite material using by polyester
fibers, acrylic fibers and polyamide fibers  combining with araldite resin
is  produced  and  examined its  mechanical properties. The
new  composites were produced by the method of  hand lay-up . The
mechanical properties such as tensile strength, impact strength, flexural strength
and interlaminar shear strength (ILSS) were performed. Based on the applications of the
mechanical tests of the composite samples, increasing of the fiber type and
rate were seen an increase or decrease in mechanical properties.

Keywords: Polyester Fiber, Acrylic Fiber, Polyamide
Fiber, Araldite Resin, Composite Materials

PACS: 72.80.Tm

1. INTRODUCTION

The
polymers play very important role in our daily life. They can be combined with
different materials to achieve special properties according to end use
applications. Polymer based composites are being used more and more intensively
in space, aviation, medicine, automotive, textile, construction, building and
other developing technologies. Reinforcing fibers, which are generally used in
polymer composites, provide strength and other desirable properties to the
composite material [1,2]. In parallel with these developments, working on
fibers with better mechanical properties and higher heat-resistant,
non-cracking, high impact strength and hard polymer matrices continue in the
world [3-7].

Today, most of the
synthetic polymer fibers in use span applications such as clothing, carpets,
ropes and reinforcement materials. Some of these fibers include polyamides such
as nylon, polyesters (as PET, PBT), PP, PE, vinyl polymers (as PVA, PVC), PU
and acrylic fibers (e.g. PAN), [8,9].

Polyamide refers to family of polymers called linear polyamides made
from petroleum. The generic name polyamide fibre has the same meaning as nylon
fibre, but nylon fibre is used principally in countries [10]. Polyamides generally are tough,
strong, durable fibers useful in a wide range of textile applications. The
distinguishing characteristics are high elasticity, tear and abrasion free, low
humidity absorption capability, fast drying, no loss of solidity in a wet
condition, crease free, and rot and seawater proof. Application areas range
from underwear to outdoor sports clothing [11], from automotive to aerospace [12].

PET is the world's most widely used fiber in a variety
of forms. PET is widely used in both fiber and filament forms as a strong,
dimensionally stable fiber. Large quantities of PET fibers are also used for
both woven and nonwoven fabrics used for industrial and technical applications.
Polyester fibers have many excellent
properties such as high strength, good stretchability, durability and easy care
characteristics [13].

Acrylic fiber is named as
acrylonitrile containing at least 85% of its chemical structure according to
ISO (International Standards Organization) definition. Since acrylonitrile,
which is predominantly homopolymerized with 100% acrylonitrile polymerization,
is hard, brittle and difficult to paint, it has been converted into copolymers
by the addition of a second monomer and is particularly suitably used in
textiles. Acrylic fibers have a wide range of uses such as knitting, hand
knitting, carpet, blankets, velvet, socks [14]. Also acrylic fibre has been
extensively used in a number of industrial applications for example as a cursor
for carbon fiber, as substitute for asbestos in-fibre reinforced cement, and in
hot gas and wet filtration [15].

 

2. EXPERIMENTAL PROCEDURE

2.1. Experimental Preparation and Mechanical
Analysis

RENLAM LY113 araldite
resin (Huntsman) as the resin, Ren HY97 (Huntsman) as reaction initiator and Benzyldimethylamine
(BDMA-Eastman) as accelerator were used in the composite matrix formulation.
Acrylic fiber (Acrylic Tow, Type Extra / Gloss Dtex 2,2 - Lotno / Apre E-4316 /
RA-01 Ktex 97) supplied from Aksa Acrylic Industry Company and polyester fiber and
aramid fiber supplied from private sector were used as reinforcing materials.

Composite materials using by polyester fibers, acrylic fibers and
polyamide fibers combining with araldite resin is
produced and examined its mechanical properties. Composite
materials were produced by the method of hand lay-up. The mechanical
properties such as tensile strength, impact strength, 3-point bending strength
and interlaminar shear strength (ILSS) were investigated.

In this study, two-piece semi-open
mold made of stainless steel was produced to prepare standard tensile and
impact samples (Figure 1). Surfaces of the mold that are in contact with the
composite are grind to prevent adhesion.

 

Figure 1. Mold in which composite
samples are produced.

 

2.1.1. Tensile analysis

The tensile tests of
composite specimens were subjected to uniaxial tension with a constant tensile
speed of 5 mm/min and corresponding stress-strain values were recorded for maximum
tensile strength determination with respect to fiber orientation. Tensile
analysis was applied on a Zwick Z010 universal tensile device.

 

2.1.2. Flexural analysis

Flexural strength of the
composite laminates were determined via 3-point bending tests done according to
ASTM D790-02 standart. Flexural analysis was applied with test speed of 5
mm/min on a Zwick Z010 universal tensile device. Span to depth ratio was hold
as 16:1.

 

2.1.3. Interlaminar shear strength (ILSS)
analysis

The interlaminar shear
strength test samples (ILSS) according to ASTM D2344 standard was prepared and
all of the tests made on a Zwick Z010 universal tensile device and applied with
a test speed of 5 mm/min.

 

2.1.4. Impact analysis

The impact strength of
the unnotched specimens was tested using a 5.4 J izod impact hammer on the
Zwick B5113.30 Izod Impact Device according to the ASTM D 256 standard.

 

2.2. Calculation
of mold volume and resin formulation

Volume of the mold: V = a x b x c= 11,5 x 19,5 x 0,4 =
89,7 cm³

                                          Resin
formülation: 100 gr araldite resin (LY113)

 32 gr hardener
(HY97)

            15
drops BDMA (accelerator)

 

2.3. Density
of Fibers

Table 1. Density
of Fibers

	Polyester fiber	Polyamide fiber	Acrylic fiber
Density (gr/cm3)	1,15	1,076	1,23

 

2.4. Calculation of the weights of the fibers
in the mold

2.4.1. Mass account for Acrylic Fibers

%40
Acrylic Fiber:                       %50
Acrylic Fiber:                 %60
Acrylic Fiber:

m = d . v . 0,4                                  m = d . v .
0,5                           m = d . v .
0,6

m = 1,23 . 89,7 . 0,4                        m = 1,23 . 89,7 .
0,5                 m = 1,23 . 89,7 . 0,6

m = 44,132 gr.                                 m =
55,165 gr.                          m =
66.199 gr              

 

2.4.2. Mass account for Polyester Fiber

 

%40
Polyester Fiber:                 %50 Polyester Fiber:             %60 Polyester Fiber:

m = d . v . 0,4                               m = d . v .
0,5                            m = d . v
. 0,6

m = 1,15 . 89,7 . 0,4                     m = 1,15 . 89,7 . 0,5                  m = 1,15 . 89,7 . 0,6

m = 41,262 gr.                              m = 51,577
gr.                           m = 61,893
gr.

 

2.4.3. Mass account for Polyamide
Fiber

 

%40
Polyamide Fiber:           %50 Polyamide Fiber:           %60 Polyamide Fiber:

m
= d . v . 0,4                                 
m = d . v . 0,5                                   m = d . v .
0,6

m
= 1,076 . 89,7 . 0,4                     
m = 1,076. 89,7 . 0,5                       m = 1,076. 89,7 . 0,6                  

m
= 38,606 gr.                               
m = 48,258 gr.                                 m = 57,910 gr.

 

Table 2. Weights
of Fibers In The Mold

Materials	Fiber Weights of Fibers In The Mold (gr)
	% 40	% 50	% 60
Polyester fiber	41,262	51,577	61,893
Polyamide fiber	38,606	48,258	57,910
Acrylic fiber	44,132	55,165	66,199

 

2.5.
Preparation of the composite samples

The prepared composite matrix resin consists of 100 gr
of araldite resin (Renlam LY113), 32% (32 gr) of Ren HY97 and 15 drops of BDMA.
Composite samples were prepared by hand lay-up method. After addition of one
coat of resin into the open mold, the fibers cut according to the mold size to
provide the weights indicated in Table 2 were placed as shown in Figure 1. The
resin was applied to the intermediate layer and the top layer with the aid of a
brush. The same procedures were applied to all fibers to produce composite
platters containing 40%, 50% and 60% of individually polyester, acrylic and
aramid fibers. Due to the difficulty of wetting the fibers of resin, it was not
possible to prepare samples with more than 60% by weight of fibers.

The upper mold was closed and compressed with
the help of tacks to allow the resin to wet the fibers well and to remove air
bubbles in the structure. After standing for 24 hours at room temperature, the
composite layers removed from the mold were first of all edge trimmed, then the
layers were cut according to the standards specified in the relevant standards
and the burrs formed at the edges were sanded.

3.
RESULTS and DISCUSSION

In this study, the
mechanical properties of the composite materials were investigated in
consideration of the weight and fiber volume fractions at different ratios. For
each result given in the tables, five samples were produced for each test and
averaged.

Table 3. and Figure 2.
demonsrates tensile strength of composites molded at different rate. The fiber
ratio started at 40% and ended at 60%. In composite samples reinforced
polyamide fiber and polyester fiber, the tensile strength increased with
increasing fiber amount. The maximum tensile strength value was reached in the
composite sample of 50% polyamide fiber reinforced. After this, the tensile
strength was reduced. For polyester fiber reinforced composite samples, the
maximum tensile strength value was observed in the sample with 60% polyester
fiber. In the acrylic fiber reinforced composite samples, the tensile strength
value decreased as the fiber ratio increased. The highest tensile strength
value was in the composite sample with 40% acrylic fiber.

The tensile
test results show that the highest tensile strength in all composite samples
was found in composite materials containing 60% polyester fibers.  

Table 3. Tensile test results of
composite materials

Materials	40% Fmax (N)	50% Fmax (N)	60% Fmax (N)
Polyamide fiber	140,82	144,4	111,3
Polyester fiber	95,27	172,63	177
Acrylic fiber	51,3	45,65	40,78

 

Figure 2. Tensile strength graphics
of composite materials

 

 

 

Table 4. and Figure 3. show the flexural strength values obtained by the
3-point bending test of all the composite samples. Composite samples with
polyamide and acrylic fiber reinforcement showed a decrease in flexural
strength as the amount of fiber increased. Composite specimens with 40%
polyamide fiber reinforcement and 40% acrylic fiber reinforcement showed
maximum flexural strength. At the 60% reinforcement ratio, the lowest flexural
strength value was observed in both types of fibers. The maximum flexural
strength value of polyester fiber reinforced composite specimens was 50%. 60%
polyester fiber reinforcement showed lower flexural strength but higher than
40%.

Composite material reinforced 50% polyester fiber in all composite
specimens has the highest flexural strength value.

 

Table 4. Three point bending test
results of composite materials

 

Materials	40% σfm(Mpa)	50% σfm(Mpa)	60% σfm(Mpa)
Polyamide fiber	86,69	85,49	82,94
Polyester fiber	92,00	140,01	131,13
Acrylic fiber	113,02	97,09	89,76

 

Figure 3. Flexural
strength
graphics of composite materials

 

Table 5. and Figure 4. show the interlaminar shear strength (ILSS) of
the composite specimens at the different rates. It has been observed that for
every 3 types of fibers used in this study, the ILSS strength is reduced by
increasing the amount of fiber. Polyamide, polyester and acrylic fiber
reinforced composite samples with 40% ratio showed the highest ILSS strength,
while 60% fiber reinforced composite samples had the lowest ILSS strength
value.

The composite specimen reinforced 40% polyester fiber in all composite
materials showed the highest interlaminar shear strength value.

 

Table 5. ILSS test results of composite materials

Materials	40%     σfm(Mpa)	50% σfm(Mpa)	60% σfm(Mpa)
Polyamide fiber	199,51	125,03	110,66
Polyester fiber	205,24	148,87	111,29
Acrylic fiber	194,60	138,44	110,98

Figure 4. Inter
laminar shear strength (ILSS) graphics of composite materials

 

Table 6. and Figure 5. demonsrate impact strength obtained by the izod
impact test of all the composite samples. It has been observed that in all 3
types of fibers used in this study, the increase in the amount of fiber also
increases the impact strength. Maximum impact strength was observed in
composite specimens reinforced 60% polyamide, polyester and acrylic fiber.

In all composite specimens, the material with the highest impact
resistance is composite material with 60% polyamide fiber reinforcement.

Table
6. Impact test results of composite materials

Materials	40% (Kj/m²)	50% (Kj/m²)	60% (Kj/m²)
Polyamide fiber	280,33	302,50	320,75
Polyester fiber	84,75	145,50	174,25
Acrylic fiber	44,50	108	158,75

Figure 5. Izod
impact strength graphics of composite materials

 

4. CONCLUSION

Compared to
the mechanical properties of composite specimens, composite specimens
reinforced polyester fiber have the maximum tensile strength, flexural strength
and interlaminar shear strength. The polyamide fiber reinforced composite
specimen in all samples has the highest impact strength.

In applications where tensile strength, flexural strength and
interlaminar shear strength are mentioned, polyester fiber reinforced composite
material can be successfully used. It is clear that polyamide fiber reinforced
composites will be successful in many composite applications where tensile,
flexural and ILSS strengths are not important at first but impact strength is
important.

Composite materials produced with acrylic fiber reinforcement at low
ratios may also be preferred where tensile, flexural and interlaminar shear
strength is a concern.

 

Anahtar Kelimeler

Polyester Fiber, Acrylic Fiber, Polyamide Fiber, Araldite Resin, Composite Materials

Kaynakça

• 5. REFERENCES
• [1] G. Başer, Production of Fiber Reinforced Thermoplastic Composites, Ph. D. Thesis, İstanbul Technical University, İstanbul (2012)
• [2] S. Kerakra, S. Bouhelal, M. Ponçot, Study of Na-Montmorillonite–Polyamide Fiber/Polypropylene Hybrid Composite Prepared by Reactive Melt Mixing, International Journal of Polymer Science, 1-12 (2017)
• [3] A. Miravete, 3-D Textile Reinforcements in Composite Materials, Woodhead Publishing Ltd., Spain (1999)
• [4] J. F. Shackelford, W. Alexander, Materials Science and Engineering Handbook, CRC Press LLC., New York (2001)
• [5] D. D. L. Chung, Carbon Fiber Composites, First Edition, Butterworth-Heinemann (2012)
• [6] M. Çakır, İ. Kartal, Y. Boztoprak, H. Demirer, B. Aktaş, Poliamid Esaslı Kord Bezi Takviyeli Polyester Matrisli Kompozit Malzemenin Mekanik Özelliklerinin İncelenmesi, 9. Uluslararası Kırılma Konferansı, İstanbul, Türkiye (2011)
• [7] M. Çakır, İ. Kartal, H. Demirer, Ş. Taşyürek, Akrilik Elyaf Takviyeli Polyester Kompozitlerin Mekanik Özelliklerinin İncelenmesi, 6th International Advanced Technologies Symposium (IATS’11), 16-18 May, Elazığ, Turkey (2011)
• [8] K. Song, Y. Zhang, J. Meng, E. C. Green, N. Tajaddod, H. Li, M. L. Minus; Structural Polymer-Based Carbon Nanotube Composite Fibers: Understanding the Processing–Structure–Performance Relationship; Materials, 6, 2543-2577, (2013)
• [9] Rodriguez, F.; Cohen, C.; Ober, C.K.; Archer, L.A. Principles of Polymer Systems, 5th ed.; Taylor & Francis: London, UK, (2003)
• [10] V. K. Kothari, Polyesters and Polyamides, A volume in Woodhead Publishing Series in Textiles, 419–440, (2008)
• [11] J. Militký, M. Venkataraman, R. Mishra, Handbook of Properties of Textile and Technical Fibres (Second Edition), A volume in The Textile Institute Book Series, Pages 367–419, (2018)
• [12] T. Bashir, M. Skrifvars, N.K. Persson, High-Strength Electrically Conductive Fibers: Functionalization of Polyamide, Aramid and Polyester Fibers With PEDOT Polymer, Polymer Advanced Technologies, 29:310–318 (2018)
• [13] K. Gotoh, S. Yoshitaka, Improvement of Soil Release from Polyester Fabric with Atmospheric Pressure Plasma Jet, Textile Research Journal 83(15) 1606–1614 (2013)
• [14] P. Delhaes, Fibers And Composites, Taylor & Francis Inc, London (2003)
• [15] V.B. Gupta,V.K. Kothari, Manufactured Fibre Technology, Chapman And Hall (1997)