*Corr. Author’s Address: Middle Technical University, Technical Engineering College-Baghdad, Iraq, balsam.college@yahoo.com 377
Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384 Received for review: 2021-11-05
© 2022 The Authors. CC BY 4.0 Int. Licensee: SV-JME Received revised form: 2022-03-27
DOI:10.5545/sv-jme.2021.7471 Original Scientific Paper Accepted for publication: 2022-04-20
Effect of Immersion Media for Polyester Composite Reinforced 
with Chicken Feathers on Creep Behaviour
Abed, B.H. – Battawi, A.A. – Khuder, A.W.H.
Balsam H. Abed* – Ali A. Battawi – Abdul Wahab H. Khuder
Middle Technical University, Technical Engineering College-Baghdad, Iraq
The use of composite materials has expanded in industrial applications around the world, reinforcing composites with waste materials like 
chicken feather is one of the effective ways to solve environmental concerns compared to traditional methods, as it is considered one of the 
renewable and inexpensive methods, in addition to its presence in abundance. The main added feature of composite materials over classic 
materials are the light weight. This paper investigates the effect of immersion media for a polyester composite reinforced with chicken feather 
fillers to enhance the creep characteristic. The composite was manufactured using a hand-layup process. The samples were produced by 
varying the weight ratios of fibre loading (0 %, 0.2 %, 0.4 %, 0.6 %, and 0.8 %) and immersed in three different media (KCl (salt media), 
NaOH (alkali media) and HNO
3
 (acid media)). The creep samples were tested according to ASTM standards. The results show that chicken 
feather-reinforced composites immersed in various media have probable applications because of their superior mechanical properties over 
non-reinforced composites.
Keywords: immersed, chicken feather, polyester composite, creep behaviour, reinforcement
Highlights
• 	 In this study, three different media were used to immerse polyester composites 
• 	 When compared to standard methods, reinforcing composites with waste materials such as chicken feathers is one of the most 
effective approaches to address environmental concerns. 
• 	 This study looked at the effect of creep behaviour on a polyester composite reinforced with chicken feather; there are few 
investigations on this type of test exist in comparison to when compared to the other mechanical properties.
0  INTRODUCTION
Due to disposal and pollution, chicken feather 
fibres have a prevalent concern. This has a severe 
influence on the environment; however, current study 
reveals that chicken feather waste may be used as 
reinforcement instead of being burned [1]. However, 
industries are primarily concentrating on the notion 
of sustainable manufacturing, which involves limiting 
the use of non-renewable resources and implementing 
environmentally friendly material processes, such as 
waste recycling and reuse. Composite materials are 
manufactured for this purpose, and substantial study is 
being out by researchers in many regions of the world. 
[2] and [3]. Chicken feathers comprise 91 % protein 
(keratin), 8 % water and 1 % lipids [4].
Several attempts had been made throughout 
the past decades to evaluate the potential of chicken 
feathers as reinforcements in applications of 
composite materials. Abed et al. [5] investigate the 
creep behaviour of an epoxy composite reinforced 
with Yttrium Oxide Powder at different weight ratios. 
Each volume ratio was subjected to five loads at a 
steady temperature. The creep behaviour of epoxy 
composite was studied using both experimental and 
computational methods. 
Šafarič et al. [6] evaluated the use of wood 
waste with poultry feather waste to produce natural 
insulating fibreboard composite. The fibreboard 
composite was set using various amounts of poultry 
feather waste (20 % to 70 %) and wood waste, 
resembling mixed wood remains or wood shavings. 
The thermal and mechanical properties were studied, 
along with their biodegrading abilities. Oladele et al. 
[7] utilized brown chicken feather fibres to reinforce 
polyethylene as a substitution for synthetic fibres to 
improve mechanical properties of polyethylene, using 
varying ratios of fibre (2 wt.%, 4 wt.%, 6 wt.%, 8 
wt.% and 10 wt.%) with the polyethylene matrix. 
The flexural modulus and tensile properties for each 
ratio were studied. In addition, scanning electron 
microscopy (SEM) and X-ray diffraction (XRD) were 
performed.  
Abed and Battawi [8] investigated the creep 
behaviour of polystyrene composites reinforced with 
natural fibre at various weight fractions, constant 
loads, and temperatures. Hand layup technique was 
used to build the manufacturing setup for composite 
materials. Maxwell techniques were utilized to derive 
the stress and modulus of elasticity from the strain 
time curve using curve-fitting methods.
Reddy et al. [9] showed that chicken feathers 
could be used as a matrix to build total biodegradable 

Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384
378 Abed, B.H. – Battawi, A.A. – Khuder, A.W.H.
composites with properties comparable to those of 
polypropylene composites, even using jute fibre 
reinforcements. Using feathers as a matrix allows for 
100 % biodegradable composites containing feathers 
or other bio-polymers as reinforcement at a low cost. 
Amieva et al. [10] explored extrusion-processed 
chicken feathers for making recycled polypropylene 
compounds. The specimen density and thermal, 
morphological, and thermo-mechanical properties 
were assessed. The density of the composite material 
was lower than that of the non-recycled material. 
When compared to polypropylene compounds, the 
transition temperature of the composite materials 
remained unchanged. 
The influence of creep behaviour on polyester 
composite reinforced with chicken feather was the 
subject of this research. In comparison to the rest of 
the mechanical properties, there are few studies on 
this type of test.
1  EXPERIMENTAL
1.1  Preparation of Fillers
The chicken feathers were gathered from poultry 
production units. They were first cleaned with ethanol, 
then washed five times with tap water and exposed 
to the sun for two days until they dried entirely. The 
dried chicken feathers were trimmed with scissors 
to separate the avian fibres (barbs) from the quill 
(rachis) portion of the feathers, as shown in Fig. 1. 
The average size of 1 cm was considered for chicken 
feather samples.
Fig. 1.  Dried feathers
1.2 Sample Fabrication
Polystyrene (Ps) granules were dissolved by adding 
chloroform and mixing with a magnetic stirrer. 
Liquid polyester (Up) was prepared separately and 
added to the Ps mixture at a 92:8 ratio of polyester 
to polystyrene and stirred for 3 h [8]. Thereafter, an 
appropriate hardener (K-6) was added to the solution 
in the recommended proportion (10:1) and stirred for 
15 min. A rubber mould was initially gently washed, 
and liberated from moisture and dust. A thin layer of 
wax was then added along with its base plate to the 
inner walls of the rubber mould for quick removal of 
the cast after drying. Previously prepared avian fibres 
(dried chicken feathers) were laid longitudinally inside 
the mould with weight ratios (0 %, 0.2 %, 0.4 %, 0.6 
%, and 0.8 %). The Up-Ps resin mixture was then 
poured over them using a hand lay-up method. Care 
was taken to prevent air bubble formation. Samples 
were kept in the mould for 18 h and subsequently 
placed in an oven at 55 °C for 3 h to rid the moisture.
1.3  Immersion Media
In the present work, samples were immersed in 
different media, as salt media (KCl), alkali media 
(NaOH), and acid media (HNO₃), as shown in Fig. 2, 
at a rate of 5 % for 4 h. The samples were then washed 
with tap water and left to dry. Fig. 3 illustrates a creep 
sample of Up-Ps reinforced with different weight 
ratios of chicken feathers and immersed in the three 
media.
Fig. 2.  Samples immersed in different media
1.4  Testing
The creep characteristics of the Up-Ps composites 
were estimated by creep testing. The tests were 
conducted according to ASTM D2990 [8] at a constant 
temperature of 21 °C using the creep testing machine 
model WP600, as shown in Fig. 4. A total of 45 creep 
tests were performed for all volume ratios (0 %, 0.2 

Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384
379 Effect of Immersion Media for Polyester Composite Reinforced with Chicken Feathers on Creep Behaviour
%, 0.4 %, 0.6 %, and 0.8 %). Each ratio was tested 
three times to obtain an average. The load was applied 
for 1 hour, then removed, and readings were taken 
continuously for another hour.
Fig. 3.  Creep sample of Ps-Up reinforced
Fig. 4.  Creep testing machine (WP600) with chicken feathers
2  RESULTS AND DISCUSSION
A creep test was used to determine the mechanical 
properties (strain, stress, and modulus of elasticity) 
of the polyester composites reinforced with chicken 
feathers at 0.2 wt.%, 0.4 wt.%, 0.6 wt.%, and 0.8 
wt.% and immersed in the three different media (salt, 
alkali, acid) at 26 °C atmospheric temperature. All 
the samples successfully carried the equivalent load 
for 1 hour. For the estimation, three samples were 
examined for mechanical properties, and the values 
were averaged.
Curve-fitting techniques, as shown in Fig. 5, 
were used for the extraction of stress and modulus 
of elasticity)from the strain-time curve using the 
Maxwell method (spring and dashpot in series) [11].
 


() , te
t


0
1
1
 (1)
 


1
0
1
 , (2)
 


1
0

tan
, (3)
 



  tan, ,



tS
L
L
1
where (4)
 Et
t
tt
()
()
()
, 






11
1
 (5)
 




() . tt 
11
 (6)
Fig. 5.  Maxwell method (spring and dashpot in series)
2.1  Immersion in Salt Medium
Fig. 6 demonstrates creep behaviour (strain vs time) 
in KCl. The composite with 0.6 wt.% chicken feathers 
performed better than the other weight fractions in the 
salt medium, which yielded an 86.2 % enhancement 
in strain compared with pure polyester. All the 
reinforced composites showed a decrease in strain 
compared to the non-reinforced composite. The 0.4 
wt.% chicken feather composite had the least strain 
among the reinforced composites, resulting in 47.6 % 
when compared to pure polyester. The deformation 
was seen to develop in three distinct stages: elastic, 
yielding, and a plastic deformation zone. 
The stress vs time graphs for all reinforcements 
in salt media are shown in Fig. 7. The composite with 
0.2 wt.% of chicken feathers achieved the highest 
percentage of stress (100.05 % stress improvement 
over pure polyester) in the salt media compared with 
other weight fractions. The composite with 0.4 wt.% 
achieved only 99.998 %, the lowest percentage of the 

Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384
380 Abed, B.H. – Battawi, A.A. – Khuder, A.W.H.
weight fractions, which indicates that immersing in 
KCl enhance the creep behaviour of the composites.
Fig. 6.  Strain behaviour of polyester reinforced with different 
weight fraction of chicken feather immersed in KCl media
Fig. 7.  Stress vs time for polyester reinforced by different chicken 
feather weight fraction immersed in KCl media
Fig. 8 represents the modulus of elasticity with 
time in the salt medium. The results revealed that the 
0.2 wt.% chicken feather composite performed better 
than the other weight fractions in the salt medium, 
which yielded a 2.422 % enhancement in elasticity as 
compared with pure polyester. The 0.4 wt.% sample 
achieved the smallest improvement of 1.138 %. These 
findings imply that a fibre content of 0.2 wt.% is the 
ideal weight fraction for improving the property.
Fig. 8.  Modulus of elasticity for polyester reinforced by different 
weight fraction of chicken feather immersed in KCl media
2.2 Immersion in Alkali Medium (NaOH)
The strain vs time graphs for all reinforcements in the 
alkali medium are shown in Fig. 9. The composite 
with 0.4 wt.% of chicken feathers exhibited a higher 
percentage of strain in the alkali medium compared 
with other weight fractions and yielded a 75 % 
enhancement in the strain as compared with pure 
polyester. The composite with 0.8 wt.% achieved only 
43.12 %, which was the smallest percentage.
Fig. 9.  Strain vs time for polyester reinforced by different weight 
fraction of chicken feather immersed in NaOH media
Fig. 10 demonstrates stress vs time graphs for 
all reinforcements in the alkali medium. The results 

Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384
381 Effect of Immersion Media for Polyester Composite Reinforced with Chicken Feathers on Creep Behaviour
revealed that the 0.4 wt.% chicken feather composite 
had a better result than the other weight fractions, 
achieving 100.06 % stress improvement compared 
with pure polyester. The 0.2 wt.% sample achieved 
only 100.30 %, the lowest percentage of the weight 
fractions.
Fig. 10.  Stress vs time for polyester reinforced by different weight 
fraction of chicken feather immersed in NaOH media
Fig. 11.  Modulus of elasticity vs time for polyester reinforced  
by different weight fraction of chicken feather immersed  
in NaOH media
The modulus of elasticity vs time graphs for 
all reinforcements in the alkali medium are shown 
in Fig. (11). The composite with 0.8 wt.% had a 
higher percentage of modulus of elasticity in the 
alkali medium compared with other weight fractions, 
recording a 2.32 % improvement in modulus of 
elasticity as compared with pure polyester. The 0.2 
wt.% chicken feather composite had the lowest 
modulus of elasticity (1.42 %) as compared to pure 
polyester.
2.3  Immersion in Acidic Medium (HNO
3
)
Fig. 12 shows that strain vs time graphs for all 
reinforcements in the acidic medium. The results 
showed 0.2 wt.% chicken feather composite had 
a better strain than the other weight fractions in the 
acidic medium, yielding 112.5 % strain improvement 
compared with pure polyester. The 0.8 wt.% chicken 
feather composite had the lowest strain enhancement 
among the other samples, as it improved strain by 
(36.7 %) when compared to pure polyester. Because 
delamination increased after being submerged in 
acidic medium, the effect of acidic media on creep 
strain is relatively mild.
Fig. 12.  Strain vs time for polyester reinforced by different weight 
fraction of chicken feather immersed in HNO
3
 media
The stress vs time graphs for all reinforcements 
in the acidic medium are shown in Fig. 13. The results 
showed that 0.4 wt.% chicken feather composite 
outperformed the other weight fractions in the acidic 
medium, resulting in a 100.001 % enhancement 
in stress compared with pure polyester. The 0.8 
wt.% achieved only 99.81 %, with was the smallest 
percentage among the weight fractions.
Fig. 14 depicts the modulus of elasticity vs time 
graphs for all reinforcements in acidic media. The 
0.8 wt.% sample had a higher percentage increase 
of modulus of elasticity in the acidic medium than 

Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384
382 Abed, B.H. – Battawi, A.A. – Khuder, A.W.H.
the other weight fractions, which was 2.719 % when 
compared to pure polyester. The 0.2 wt.% only 
achieved 0.88 %, the smallest percentage among the 
weight fractions.
Fig. 13.  Stress vs time for polyester reinforced by different  
chicken feather weight fraction immersed in HNO
3
 media
Fig. 14.  Modulus of elasticity for polyester reinforced by different 
weight fraction of chicken feather immersed in HNO
3
 media
Fig. 15 clearly shows the comparison between 
the three different media (salt, alkali, and acid) on 
the percentage rate of creep strain. Of note, the strain 
decreases with increasing weight fraction of chicken 
feathers, which indicates the matrix’s engagement 
with the filler was satisfactory. In addition, the 
percentage rates of creep stress in the three different 
media are compared in Fig. 16. The stress increased 
gradually with the increase of weight fractions of 
chicken feathers. Therefore, using chicken feathers 
as a reinforcement material might have slowed the 
crack’s progression and allowed the load to be held. 
Finally, Fig. 17 represents the comparison of the 
percentage rate of creep modulus of elasticity in the 
three media (salt, alkali, and acidic), showing that the 
modulus of elasticity increased with increasing weight 
fraction of chicken feathers.
Fig. 15.  A comparative study for the effect of KCl, NaOH, and 
HNO
3
 media on the percentage rate of creep strain
Fig. 16.  A comparative study for the effect of KCl, NaOH, and 
HNO
3
 media on the percentage rate of creep stress
3  CONCLUSION
The study was conducted to develop materials for 
engineering applications using poultry wastes that are 

Strojniški vestnik - Journal of Mechanical Engineering 68(2022)6, 377-384
383 Effect of Immersion Media for Polyester Composite Reinforced with Chicken Feathers on Creep Behaviour
produced daily around the world. These composites, 
which are manufactured at a low cost and have 
superior properties, may be useful in light structural 
and other engineering applications. In the present 
study, a polyester composite was reinforced with 
chicken feathers at different weight fractions using 
the hand lay-up technique. The results demonstrated 
that chicken feather-reinforced composites immersed 
in various media have probable applications because 
of their superior mechanical properties over immersed 
for reinforced and non-reinforced composites.
Fig. 17.  A comparative study for the effect of KCl, NaOH, and HNO
3 
media on the percentage rate of creep modulus of elasticity
Polyester composites reinforced with 0.2 wt.% 
chicken feathers and immersed in the acidic medium 
had better strain enhancements compared with those 
immersed in other media and compared with pure 
polyester and Acidic media have minimal influence on 
the bonding between the fibres and Up. However, the 
composite of 0.4 wt.% of chicken feather immersed 
in the alkali medium showed maximum stress 
improvement over pure polyester compared with 
other immersed media. The salt medium improved the 
modulus of elasticity for the polyester composite at 0.8 
wt.% of chicken feathers the most compared with pure 
polyester and the samples in other immersed media. 
A literature review revealed that low weight fractions 
of chicken feather content have resulted in improved 
mechanical properties of polyester composite in 
various media. Natural resources have been re-used in 
a variety of industries as a way of disposal. As a result, 
the necessity of recycling composites in general and 
employing them in new applications is emphasized in 
this study.
4  NOMENCLATURES
σ
0
 initial stress [MPa]
σ(t) stress at any time [MPa]
δ
1
 spring constant [MPa]
ε
1
 Maxwell element, [-]
η
1
 dashpot constant, [MPa·s]
E(t) creep modulus in function of time, [MPa]
ε(t) strain in function of time, [-]
t time, [s]
β tan
–1
 Maxwell element [s]
ε
–
 the slope of Eq. (4) at (t  = t
1
) [1/s]
L gauge length [mm]
e Euler’s number (2.7)
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