Development and Characterization of Cardanol Based Polymer Reinforced Fibre Bicomposites

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Volume 4 Issue 5
International Journal of Trend in Scientific Research and Development (IJTSRD) 
Volume 5 Issue 3, March-April 2021 Available Online: www.ijtsrd.com e-ISSN: 2456 – 6470 
 
@ IJTSRD     |     Unique Paper ID – IJTSRD40010      |     Volume – 5 | Issue – 3     |     March-April 2021 
Page 895 
Development and Characterization of Cardanol-Based 
Polymer Reinforced Fibre Bicomposites 
Iheoma Chigoziri Nwuzor1,2, Jeremiah Lekwuwa Chukwuneke2, 
Chinomso Macanthony Ewulonu1, Paul Chukwulozie Okolie2 
1Department of Polymer and Textile Engineering, 2Department of Mechanical Engineering, 
1,2Nnamdi Azikiwe University, Awka, Anambra State, Nigeria 
 
ABSTRACT 
The emerging quest for optimal use of naturally obtained resources through 
advanced technigues and products has escalated research and exploration of 
naturally oriented renewable materials. In present investigation, cardanol, 
obtained from cashew nut shell liquid (CNSL), was utilized as base material for 
a thermosetting polymer (TP) development. Furthermore, rice husks flour 
(RHF) was utilized as reinforcement for the TP. The fabricated biocomposite 
was characterized for microstructure, thermal behavior and biodegradability. 
Results from DSC and TG analysis revealed that the sample filled with 5 wt. % 
NaOH modified RHF demonstrated most superior thermal stability, and tensile 
strength. Moreover, results from FESEM revealed uniform dispersion, and 
bonding to polymer matrix. Enhanced biodegradability was realized from 
NaOH modified RHF filled biocomposite post 90 days of monitored soil tests. 
Therefore, the cardanol obtained TP and biocomposites demonstrated good 
prospects for application in the electronics, automotive and furniture industry. 
 
 
KEYWORD: Cardanol obtained plastic; thermoseeting polymer; bio-fiber; 
biodegradability; biocomposites 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
How to cite this paper: Iheoma Chigoziri 
Nwuzor 
| 
Jeremiah 
Lekwuwa 
Chukwuneke | Chinomso Macanthony 
Ewulonu | Paul Chukwulozie Okolie 
"Development and Characterization of 
Cardanol-Based Polymer Reinforced Fibre 
Bicomposites" 
Published 
in 
International Journal 
of Trend in Scientific 
Research 
and 
Development (ijtsrd), 
ISSN: 
2456-6470, 
Volume-5 | Issue-3, 
April 
2021, 
pp.895-904, 
URL: 
www.ijtsrd.com/papers/ijtsrd40010.pdf 
 
Copyright © 2021 by author (s) and 
International Journal of Trend in Scientific 
Research and Development Journal. This 
is an Open Access article distributed 
under the terms of 
the 
Creative 
Commons Attribution 
License 
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4.0) 
(http://creativecommons.org/licenses/by/4.0) 
1. INTRODUCTION 
The enmerging searches for optimal utilization of natural 
resources through advanced procedures and products has 
increased researches into new uses of natural renewable 
materials [1]. CNSL is a notable instance of a renewable 
resource commonly utilized in polymeric materials 
synthesis. CNSL is a thick liquid in the soft fleshy part of 
cashew nut (CN), obtained from cashew tree, or Anacardium 
occidentale L [2]. The major components obtained from 
CNSL include cardanol, cardol, anacardic acid and 2-
methylcardol which is a phenolic compound, composed of 
long side-chain substituted at the meta-position. A large 
number of polymeric materials with a wide variety of 
applicaions can be manufactured using these phenolic 
compounds. Application of CNSL in place of phenol is an 
excellent instance of effective usage of a synthetically 
derived material and byproduct utilization [3]. Technical 
CNSL (t-CNSL), a commercial type of CNSL, scarcely contains 
any anacardic acid. This is as a result of the occurrence of 
decarboxylation during processing, thereby converting 
anacardic acid to cardanol [4]. Cardanol is composed of 
compounds, having a variable number of unsaturations, 
occurring in the fifteenth carbon atom-chains, and situated 
on the hydroxyl group meta position [5]. Polymers, including 
polymeric materials synthesized from cardanol are well  
 
captured in literature [6], and the theme of developing 
studies. Included as a CNSL component is cardanol, which is 
a lucrative alternative in synthesizing polymeric materials. 
This is as a result of the incentive of belonging to a mono-
replaced phenol, which minimizes the challenges of steric 
obstruction during polymerization reaction. Recently, great 
interests has been aroused in the formation of composite 
materials from polymer matrices filled with natural fibers 
[7]. Ecobenign materials formation, and a more purified 
production procedure, is essential to environmental 
preservation, and better living conditions for the next 
generation. Natural biofibers are biopolymers constituting of 
cellulose, hemicelluloses, and lignin, which individually 
enhance the composite mechanical strength [8,9]. The 
application of natural fibers as reinforcements offers 
minimal density, elevated porosity, effective tensile and 
impact strength to composite materials apart from increased 
fissuration control, and improved ductility at break [10-12]. 
Natural fibers offers benefits such as reduced cost, excellent 
solvents, and temperature resistance. Additionally, they 
undergo easy modification by chemicals, and are also non-
toxic, and non-abrasive [13, 14]. Lignocellulosic fibers such 
as coconut fibers [15], jute [16], sisal [17], and banana 
tree[18], have been versatily researched, and utilized in 
 
 
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reinforcing polymer matrices. Rice is a cereal grain utilized 
in producing hull fibers. Recently, corn, oats, wheat, rye and 
other cereal crops have been utilized in producing fibers and 
studied as reinforcement for composites [19–21]. Generally, 
lignocellulosic fibers exhibit hydrophilic tendencies, and 
hence, exhibit low compatibility with hydrophobic polymer 
matrices [7]. This deficiency results in poor adherence, 
which impacts negatively on effective transfer of tensions, 
thereby compromising the composites mechanical behavior 
[22,23]. Hence, a pretreatment is essential prior to using 
these fibers as fillers in polymer matrices. Alkaline 
modification is a renowned technique for fiber surface 
modification to enable improved adherence.  
Therefore, the motivation for this research is hinged on 
exploration of the novelty garnered from the development 
and characterization of a thermosetting polymer obtained 
from cardanol and filled using pristine and modified rice 
flour. This thermosetting polymer and biocompostes were 
studied via techniques including Thermogravimetry (TG), 
Differential Scanning Calorimetry (DSC), tensile testing, field 
emission scanning electron microscopy (FESEM) and 
biodegradative tests in simulated soil.  
2. Materials and methods  
2.1. Materials 
Rice husks was purchased from Abakaliki, Nigeria. Dynamic 
sodium hydroxide (NaOH - 97%), and a commercial sodium 
hypochlorite solution composed of 2.0 wt. % active chlorine 
in NaClO, were utilized in alkaline modification and 
bleaching of the fibers. The technical CNSL utilized in this 
study was obtained from fresh cashew-nut gathered from 
cashew plants (A. occidentale) of Abia state University, 
Uturu, Abia State, Nigeria. Anhydrous sodium sulfate (Na2SO4 
- 99%), hexane (C6H14 - 98.5%), methanol (CH3OH - 99.8%), 
ammonium hydroxide (NH4OH - 28-30% ), hydrochloric acid 
(HCl 
- 37%), 
formaldehyde 
(CH2O - 36.5-38%), 
diethylenetriamine (DETA, C4H13N3 - 99% - Sigma-Aldrich), 
toluene (C7H8 - 99.5%) were used devoid of any previous 
modification. Epoxy resin DGEBA (Bisphenol A diglycidyl 
ether) was commercially purchased. 
2.2. Alkaline treatment 
The rice husks fibers (RHF) were generally cleaned, and 
dried. The dried fibers were later ground in a grinding 
machine and later sieved using a sieving equipment of 150µ. 
Sodium hydroxide solutions of concentrations 5 wt. % and 
10 wt. % were used in treating RHF at 65 °C for 4 h. The 
fibers were subsequently washed with distillate water to 
remove excess NaOH until neutral pH was attained. The 
fibers were then further treated with sodium hypochlorite 
solution containing 1 wt. % of active chlorine at 65 °C for 1 h. 
Finally, mordified-RHF were cleansed with distillate water to 
eliminate excess NaClO, and dried in an aerated oven at 65 
°C.  
2.3. Cardanol extraction and polymer synthesis 
2.3.1. Cardanol extraction 
Cashew nut shell liquid (CNSL) was extracted from Cashew 
nut (CN) via soxhlet extraction method. CNSL was dissolved 
in methyl isobutyl ketone (MIBK), and calculated amounts of 
barium hydroxide was included with continuous stirring for 
10 minutes. The temperature was raised to 60oC and stirring 
was continued for 3 hrs to obtain anacardic acid. At the end 
of the reaction, the barium anacardate precipitated 
underwent filteration and washed with MIBK and dried for 2 
hrs. The filtrate obtained was subjected to subsequent 
isolation of cardol and cardanol. Barium anacardate was 
modified using distillate water and concentrated HCl at 
constant stirring at 200 rpm for 30 min. The resultant 
solution contained petroleum ether. The organic layering 
was washed with distillate water, dried using anhydrous 
sodium sulfate, and evaporated to dryness to get anacardic 
acid. The anacardic acid was decarboxylated to obtain tCNSL 
and subsequently isolated to obtain cardanol using 
hexane/ethyl acetate [24].  
2.3.2. Synthesis of thermosetting polymer  
Polymer synthesis was performed in a bench glass reactor 
containing a reflux-condenser, stirrer, and thermometer. The 
thermosetting polymer was synthesized via mixing of 
cardanol, and aqueous solution of formaldehyde, where 
NH4OH was used as catalyst. The combination was heated till 
80 °C for 4 h via magnetic stirring. Preparation of 
cardanol/formaldehyde in the molar ratio of 1:2 was 
undertaken in this synthesis.  
2.3.3. TP and biocomposites preparation 
In the preparation of the thermosetting polymer, di-
ethylene-triamine was utilized as a catalyst, while epoxy 
resin was utilized as modifing agent. The use of aliphatic 
amines as catalysts enabled the production of materials 
under normal conditions of temperature and pressure, 
thereby facilitating their processing. The TP was prepared 
through blending of thermosetting polymer, epoxy resin and 
di-ethylene-triamine in the proportion of 0.95:1:0.15 (wt. 
%), respectively. The blend was then moved to a metallic 
mold of 180 mm height, 160 mm width and 5 mm thickness, 
with subsequent curing for 48 h, at room temperature in a 
dispenser, while post-curing occurred in the oven at 100 °C 
for 4 h. The mold releasing agent used was carnauba wax. 
The resin obtained from cardanol was utilized as the 
polymer matrix, while the biocomposites were prepared 
using modified and unmodified RHF fibers as reinforcement 
phase with matrix-fiber weight ratio of 85:15. The 
processing conditions used for the biocomposites were the 
same process utilized for thermosetting plastics. 
2.3.4. Cross-linking degree determination 
ASTM D2765 [25] gravimetric method was applied in 
ascertaining the degree of cross-linking (DoC). The TP 
specimens were weighed (Wi), and subsequently immersed 
in toluene for 24 h to extract the soluble content and 
determine the DoC. When immersion was finished, the 
specimens were dried at room temperature to constant 
weight and weighing repeated (Wd). The experimentation 
were performed thrice for the TP which underwent curing at 
room temperature for 48 h, in addition to the post-cured at 
60, 80, and 100 °C for 2 h. At the end of curing, another 
experiment was carried out, using a fixed temperature, while 
the DoC was measured at post-cure ranges of 30, 60, 120, 
180, 240, 300, and 360 min. The DoC was calculated using 
Equation 1. 
 (1) 
2.4. Characterization 
2.4.1. Thermogravimetry (TG) 
Perkin Elmer TG STA 6000 equipment was used in achieving 
TG under N2 atmosphere with a flow-rate of 50 ml/min, and 
10 °C/min heating-rate, within a temperature range of 30 
and 600 °C to analyze TP, and biocomposites thermal 
stability. Platinum-pan was utilized, while the weight of each 
specimen was about 5 mg. 
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2.4.2. Differential scanning calorimetry (DSC) 
A DSC Q-20 equipment (TA Instruments) was used in 
obtaining DSC curves under N2 atmosphere at a flow rate of 
50 ml/min, and heating-rate of 10 °C/min, within 
temperature range of 30 °C and 400 °C used in studying the 
DOC, and investigate TP and biocomposites heat capacity 
variation with temperature. A hermetic aluminum-pan was 
utilized, while the weight of each specimen was about 2.5 
mg. 
2.4.3. Tensile testing 
ASTM D638 [26], and ASTM D3039 [27] were applied in 
conducting the tensile tests on the specimen. A DL 
10000/700 tensile machine with test speed of 5 mm/min, 
and a load-cell of 100 kN was used in performing the tensile 
test on the materials. Sample dimensions of height 175 mm, 
width 25 mm, and thickness of 5 mm thick were used for the 
testing. Five samples were used in testing each material, 
while the mean value was calculated.  
2.4.4. Field emission scanning eletron microscopy 
(FESEM) 
For FESEM analysis, the materials were coated with a mild 
layering of metallic gold in a sputter-coater Q-150R-ES. A 
Shimadzu-SSX-550 electron microscope was utilized in 
achieving micrographs from the fractured surface of the 
samples after tensile testing at an acceleration voltage of 15 
kV. 
2.4.5. Biodegradability analysis 
The specimens for biodegradation analysis were subjected to 
prepared soil analysis. They were initially weighed, and 
buried at about ambient temperature. A combination in 
(wt/wt) of loamy-silt (23%), cow manure (23%), sand 
(23%), and distilled water (31%) were used in preparing the 
soil. For about 90 days, biodegradative activity was closely 
monitored through measurement of changes in mass of the 
buried samples. After this period, the buried samples were 
exhumed, and distilled water utilized in drying them at room 
temperature, until there was zero weight changes, after 
which the materials were weighed. Subsequently, the 
samples were re-buried. These investigation were conducted 
four times. 
2.4.6. Fourier transform infrared spectroscopy (FT-IR) 
A BOMEM - MB 100 spectrometer (4000 to 400 cm -1) was 
used in recording the FTIR spectra of the specimens. 
3. Results and Discussion 
The physicochemical characterization of raw cashew nut 
shell liquid (CNSL) and cardanol were determined using 
international standard methods. Technical CNSL composed 
majorly of cardanol and cardol. Proximate analysis showed 
that cardanol contained 0.1% moisture, 4.9mgKOH/g acid 
value, 37.22mg/100g iodine value, 0.92kg/m3 density, 
1.12g/cm3 specific gravity and insignificant refractive index 
of 0.0001m/s. The cardanol maintained all the major 
components of an oil after preparation. The peroxide value 
of the cardanol was observed to be higher than that of raw 
CNSL. There was an observed decrease in specific gravity 
with the cardanol which may be attributed to the elimination 
of hydrogen bond during decarboxylation and isolation. This 
decrease in specific gravity enhances bulk properties 
without adverse effect on the material properties. 
Rice husk flour was modified using already established 
techniques [28, 29]. Generally, chemical modification 
involved the use of equal concentration of NaClO (1 wt. %). 
Hence, in this report, increasing concentration of NaOH, (5 
and 10 wt. %), was discussed. Thermosetting polymer and 
biocomposites filled with untreated rice husks flour (URHF) 
and those filled with modified rice husks fiber (MRHF) 
treated using 5 and 10 wt. % NaOH were designated as TP, 
URHF, MRHF5, and MRHF10, respectively. It is vital to 
investigate 
the degree of 
cross-linking 
(DoC) of 
thermosetting materials because it is directly related to the 
behavior of the end product. Figure 1 reveals TP DoC results 
obtained via gravimetric method. 
 
Figure 1 DoC at varying ranges of post-curing temperature of the materials 
TP is represented by 0 °C, and underwent curing for 48 h at ambient temperature devoid of any after-curing procedure. Thus, 
the material demonstrated degree of cross-linking of 95% ± 0.2 after the curing process. Apart from undergoing curing for 48h 
at ambient temperature, TP specimen also underwent post-curing for 2 h at increasing temperatures of 60, 80, and 100 °C 
where the degrees of crosslinking were 98 ± 0.9, 98 ± 0.7, and 99.5% ± 0.4, respectively. Additionally, temperatures of over 100 
°C were also used in further testing, however material deformation were observed. Hence, post-curing temperature was fixed 
at 100 °C, and demonstrated the highest degree of cross-linking at the investigated time duration. However, the DoC was 
studied for varying time ranges, as shown in Figure 2 below. 
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Figure 2 DoC at increasing ranges of material post-curing temperature. 
The degree of cross-linking to post-cure time ranges of 30, 60, 120, 180, 240, 300, and 360 min were 96 ± 0.4, 98±0.1, 97±0.2, 
98.06 ± 0.3, 99.5 ± 0.1, 98.1 ± 0.2, and 99.9% ± 1, respectively. The DoC increased with increasing temperature and no 
significant changes were observed from 240 minutes. 
Investigative results reveal that the condition of curing and post-curing of TP were situated at 48 h at room temperature in the 
distribution hood and 4 h at 100 °C in the oven, respectively. Same conditions were also attributed to biocomposites, while the 
curing time of 48 h in the distribution hood was to enhance total release of the catalyst used (DETA). The results from the 
degree of cross-linking were confirmed via DSC. This is a major technique used in studying curing of TP materials. Figure 3 
represents DSC curve obtained from the curing procedure of TP.  
 
Figure 3 DSC curve of TP curing procedure. 
The curing procedure revealed a large exothermic reaction at 88 °C and total heat of 93 J/g at 136 °C ascribed to dehydration.  
From the result, all the samples demonstrated a change in behavior about 60 °C. This change was ascribed to glass transition 
temperature (Tg), determined using the technique presented in ASTM D3418 [30]. This is similar to the result obtained in a 
recent study involving biocomposites fabricated using a matrix synthesized from cardanol and filled using natural fibers. Here, 
Tg of the samples was depicted around 56 °C [31]. 
Results emanating from DSC revealed that zero exothermic interaction occurred as regards the residual heat released from the 
TP or any of the biocomposites. It revealed that the curing parameters used for the TP were also good for the biocomposites, 
enabling full conversion and subsequently, total curing of all samples. The samples DSC curing results confirmed the results 
obtained from DoC experiments as shown in Figure 4. A brief endothermic activity was observed at 200, 180, and 175 °C for 
MRHF10, and MRHF5, and URHF respectively. 
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Figure 4 DSC curves of samples 
This event was attributed to dehydration. This trend was not observed in TP because of its hydrophobicity. However, 
significant endothermic activities were observed at 350, 285, 300, and 325 °C ascribed to the degradation of TP, URHF, MRHF5, 
and MRHF10 respectively. Moreover, results demonstrate that TP is slightly more thermally stable when compared with the 
biocomposites. However, chemical modification improved the biocomposites thermal stability, especially MRHF10. This 
occurred because chemical modification significantly eliminated the lignin and hemicellulose and initiated degradation at lower 
temperatures. The chemical modification removed waxes on the surface, thereby enhancing improved bonding between 
biocomposite interface. Hence, the more improved the interaction between fiber and matrix, the more elevated the initial 
thermal degradation temperature. Here, the fiber-matrix interface is a two-dimensional line between the surfaces of fiber and 
matrix [31]. Fiber/ matrix interface enables control of composite properties as fiber/ matrix interactions take place at the 
interface. These interactions are posted to occur via surface energies and secondary bonding between the fiber and the matrix, 
as the fibers act as heat-sink during curing of TP, via endothermic cross-linking reaction. This is posited to create a thin three-
dimensional interfacial region encompassing the fiber, and exhibiting properties different from the TP. Additionally, the 
interfacial region is created as a result of special adsorption of the TP at the fiber surface, resulting in a region of higher or 
lower cross-linking TP, from interpretation of DoC results. From the DSC results, the interphase is the transcrystallinity region 
on the surface of the fiber developed during cooling [31]. This is also notable in FESEM and TEM images. 
Thermogravimetry (TG), was used in studying materials weight changes relative to temperature. Figure 5 shows the TG and 
DTG (Differential Thermogravimetry) curves of the TP and biocomposites. 
 
Figure 5. TG and DTG curves of TP, URHF, MRHF5, and MRHF10 
TG curves in Figure 5 shows a minor loss in weight from ambient temperature to 180 °C of 2.8, 2.9, and 3.9% for URHF, MRHF5 
and MRHF10, respectively. This trend relates to water loss, and was not observed in TP due to its hydrophobicity, as also 
confirmed in DSC curves. The biocomposites water content increased with increasing concentration of NaOH. This happened 
because alkaline modification exposed the fiber’s hydroxyl groups, which escalated its hydrophobic behavior. A study has 
revealed that alkaline modification of fiber escalated moisture uptake [32]. DTG curves revealed two stages of weight loss. 
Initially, thermal stability of TP, MRHF10, MRHF5, and URHF were maintained, with maximum temperature peak at about 495 
and 400, 490 and 395, 450 and 360, 430 and 359 °C, respectively. This trend occurred due to lignin, hemicellulose, and 
cellulose decomposition [33-35]. In addition to degradation of polymer matrix soft segments. At the second stage, deterioration 
was attributed to carbonaceous residues degradation. At the end of both stages, TP, MRHF10, MRHF5, and URHF showed 16, 
18, 15, and 14 % residues, respectively. Both TG and DTG data confirm the DSC results. The mechanical behavior of the 
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biocomposites revealed dependance on synergy between the reinforcing agent and the matrix as shown in Figures 6 and 7. 
Figure 6 (a) depicts the tensile strength, while 6(b) depicts the Young’s Modulus. Figure 7 (a) represents the breaking load, 
while 7 (b) depicts the deformation behavior of the samples.  
 
Figure 6 (a) Tensile strength (b) Young’s modulus of samples. 
 
Figure 7 (a) Breaking load (b) Deformation behavior of samples. 
Overall, the mechanical behavior depicts an increasing trend respectively. From the Figures, all the specimens were 
investigated to ascertain the effect of RHF as reinforcement, in addition to the effects of chemical modification on 
biocomposites mechanical behavior. Significant variations were observed. Tensile strength values of URHF, MRHF5, and 
MRHF10 increased by 99, 91, and 150% respectively, in comparison to TP. Also, values of the Young modulus and breaking load 
of URHF, MRHF5 and MRHF10 were increased by 129 and 120, 125 and 106, 140 and 150 % respectively, in comparison with 
TP. All the biocomposites samples exhibited higher mechanical behavior, in comparison with TP, especially MRHF 10. This is 
because, lignocellulosic fibers can be effective reinforcement for polymeric matrices. These results demonstrate that RHFs 
modified with 10 wt. % NaOH exhibited improved interaction with polymer matrix, enabling greater stiffness, improved 
tension distribution and therefore, a higher tensile tests results. Both DSC and TG data also corroborated these results. 
FESEM and TEM were used in obtaining micrographs from fractured surface of samples to enable investigation of the 
microstructure and interaction between polymer matrix and RHFs. FESEM and TEM of TP and biocomposites are shown in 
Figures 8 and 9 respectively. 
 
Figure 8 FESEM of samples 
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Figure 9 TEM of samples 
 The images revealed crevices on TP fractured surface (Figure 8a). This may be ascribed to exothermic curing, air inclusion or 
water availability. The surface of URHF (Figure 8b) and MRHF5 (Figure 8c) revealed bonding fracture, demonstrated by 
interfacial de-adherance between fiber and matrix as a result of reduced interaction and inferior adhesion. However, on the 
surface of MRHF 10 (Figure 8d), no voids or debonding were observed, implying effective compatibility between RHF and 
matrix, resulting in enhanced tension distribution. The fractured area dwells more on debonding in URHF, and improved 
adherence and greater flattened fracture in MRHF 10 at macroscopic level as revealed in Figure 8d. These are cofirmed by TEM 
images (9a, b, c, and d) respectively. It is well established that pre-modification can initiate improved adherence between 
matrix and fiber [36, 37]. Hence, micrographic and photographic results revealed that alkaline modification enabled improved 
interface between RHF and cardanol thermosetting polymer, especially MRHF 10. These results demonstrate agreement with 
DSC, TG, and Tensile tests results  
Nowadays, there is increasing demand for ecobenign and more durable materials. Results of TP and biocomposites behavior in 
simulated soil after 90 days are shown in Figure 10. 
 
Figure 10 TP and biocomposites behavior in simulated soil post 90 days 
 Initially, increased weight notable in TP, URHF, and MRHF5 were ascribed to water absorption or ad-sorption by samples, 
which demonstrated resistance to hydrolysis [38], in comparison with MRHF 10. TP demonstrated the highest water inclusion 
due to inherent voids as observed by FESEM. Observable increase in material weight was ascribed to development of micro-
organisms involved in polymer degradation. Also, during the 90 day duration of analysis, a weight loss of 10 ± 0.5, 41 ± 0.2, 65 ± 
0.3 and 66% ± 0.3% were observed in TP, URHF, MRHF5, and MRHF 10, respectively. Research has shown that polymers 
undergo biological degradation via oxidation and hydrolysis. Hence, initial stage of aging in simulated-soil is equivalent to 
abiotic phase, were macromolecules undergo hydrolyzation and formation of smaller molecules such as monomers and 
oligomers [39]. A study has demonstrated that lignin protects the fiber from activities of micro-organisms. Hence, it becomes 
feasible to imply that alkaline modification was responsible for the highest weight reduction observed in MRHF5, and MRHF10, 
due to lig-nin elimination, which caused the modified fibers and their biocomposites to become more prone to biodegradation. 
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The FTIR spectra of cardanol revealed the presence of notable functional groups. Akynes bend (C–H bending) was observed at 
693 cm-1 with a doublet at 823 cm-1. The ester group (C–O stretch) was identified at 909 cm-1, 1156 cm-1, and 1207 cm-1. The 
presence of aromatic amines (C-N stretch) was confirmed at 3318 cm-1. The peaks corresponding to the presence of alkenes (–
C=C–stretch) was confirmed at 1453 cm-1 with a doublet at 3012 cm-1. The alkanes (C–H stretch) group was identified at 2855 
cm-1 - 2926 cm-1 with CH2 symmetric stretch. A lower peak observed on the aliphatic C-H stretching in CH3 which was identified 
at 1362 cm-1 was reported [40]. 
The FTIR spectra of specimens are elucidated in Figure 11. 
 
Figure 11 FTIR spectra of the specimen 
 
4. Conclusions 
This study investigated efficient usage of cardanol as basis 
for the development of a TP matrix filled RHF biocomposite. 
Combined curing at room temperature and post-curing were 
simultaneously conducted to elevated handling duration, 
with enhanced matrix-polymer interaction, in addition to 
optimal degree of cross linking and complete curing. 
Gravimetric technique utilized in determining TP DoC 
revealed that DETA has capability of giving room 
temperature DoC thereby presenting a good alternative as a 
polymer system indexing tool, especially as a result of its 
inexpesiveness and efficient performance. However, results 
from DSC affirmed complete conversion of groups linked in 
the crosslinking, while also demonstrating that curing and 
post-curing parameters applied to the TP and biocomposites 
were appropriate. DSC curves revealed a Tg around 60 °C of 
the TP and biocomposites, implying that the RHF did not 
impact on Tg. Despite the TP exhibiting superior thermal 
stability when compared with biocomposites, RHF seemed a 
viable reinforcement, as demonstrated by the high 
enhancement in mechanical behavior of the biocomposites. 
Results emanating from DSC and TG revealed that MRHF10 
exhibited the highest thermal stability. The most superior 
tensile behavior was exhibited by MRHF10, and ascribed to 
good inclusion, distribution and adherence to the polymer 
matrix, as demonstrated by FESEM. The presence of 
modified 
fiber 
enabled 
improved 
biocomposites 
biodegradability behavior as demonstrated after after 90 
days in simulated-soil. Thus, the present paper offers vital 
information, while exposing a set of experimental results on 
the synthesis, and characterization of a cardarnol obtained 
TP and RHF biocomposites using a cheap mode of 
fabrication. The materials demonstrate good potential for 
applications in several sectors such as electronics, furniture, 
articles, and automobile industries. 
CRediT authorship contribution statement 
Iheoma C. Nwuzor: Conceptualization, Methodology, Formal 
analysis, Writing - review & editing, Funding acquisition. 
Jeremiah L. Chukwuneke: Validation, Formal analysis. 
Chinomso M. Ewulonu: Investigation, Writing - original 
draft. Paul C. Okolie: Supervision. 
Acknowledgement 
This work was supported by Nnamdi Azikiwe University, 
through Tertiary Education Trust Fund (TETfund), 
Institution Based Research grant (IBR). Years 2012–2014 
Merged TETFUND Research Projects (RP) Intervention 
Funds 8th Batch. 
Conflict of interests 
The Authors report no conflict of interests. 
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