Date palm fiber (DPF) and kenaf fiber were reinforced in epoxy having various fiber loading 40%, 50%, and 60% by weight. These hybrid samples were manufactured by hot press technique and then characterized for tensile, impact, and morphological behavior to evaluate the ratio of fibers in the hybrid composites; the addition of kenaf improved the tensile properties, Scanning Electron Microscopy (SEM) revealed the interfacial bonding of fiber/matrix, and dispersion and void content in composites. Impact test studies reflected the effect of natural fiber with epoxy, level of stress transfer from matrix to reinforced material, and reinforced material’s role in absorbing the impacts. It showed that 50% of DPF had the best shock-absorbing capacity. The obtained results indicated that 30% DPF in hybrid composite showed improved tensile properties and homogeneous distribution of fiber without void content; however, 50% DPF loading in hybrid composites had the best impact properties.
The limited resources of petroleum-based polymers and increasing cost due to limited supply of crude oil is an issue for the synthetic polymers industries. These synthetic polymers also affect the environment negatively, due to their non-degradable characteristics. A study on the production of synthetic polymers in 2015 found that 8300 million metric tonnes polymers such as resin, fiber and additives have been produced for various applications by only eight big industrial sectors [
Many fibers are extracted from plants such as bast, core, seeds, leaves, fruits etc. However, some plants give specific type of fibers such as jute core and bast fiber, leaf fiber from pineapple [
Natural fibers have been used for engineering purposes from long ago such as cotton fibers for insulation foam, and wood fiber reinforced phenolic composites for clutch disk [
Among the thermoset polymers, epoxy is one of the versatile and established resins with epoxide groups and very promising for the polymeric structure consisting of two atoms of carbon and one atom of oxygen [
Basic studies on DPF are investigated to predict properties of thermoset and thermoplastic composites such as single tensile properties, chemical compositions, morphological studies, anatomical structure, and thermal properties [
DPF may be used with other fiber to improve the mechanical strength and compatibility within the matrix. Kenaf fiber is an industrial crop, known for its good mechanical properties when it is reinforced in the polymer matrices. This fiber has attracted the researchers due to its high performance in polymer composites [
By using hybridization technique, composites’ properties such as mechanical, thermal, physical and moisture absorption can be designed and enhanced by better fiber/matrix bonding [
Many other studies have investigated the hybridization effect of the physical, thermal and mechanical properties of the composites [
In this study, DPF and kenaf fibers reinforced epoxy composites are developed using hand lay-up process to derive the benefits of both the reinforcing fibers in improving the tensile properties and impact resistance. SEM studies employed to analyze fiber/matrix bonding in the composites.
The epoxy resin was used as a matrix and hardener (Jointmine 905–3S) purchased from Tazdiq Engineering Sdn. Bhd., Malaysia. Date palm fibers were extracted from date palm trees in Saudi Arabia and imported to Malaysia. The chemical composition of DPF was studied and mentioned in previous research [
In this study, DPF and kenaf are the reinforcement material used for the fabrication of DPF/K/Epoxy hybrid composites. In these hybrid composites, the matrix content is fixed at 50%, and natural fibers are also fixed at 50%. But, there are 2 types are fibers, so the ratio of fiber in composites was varied. There were three compositions of fibers, shown in
Hybrid composites | Total fiber percent in fiber is 50% | Epoxy Resin (wt. % of composite) | |
---|---|---|---|
Date Palm Fiber (wt. % of fiber) | Kenaf Fiber (wt. % of fiber) | ||
3DPF7K | 30 | 70 | 50 |
1DPF1K | 50 | 50 | 50 |
7DPF3K | 70 | 30 | 50 |
The samples were cut as per ASTM standard D3039 in size of 120 mm × 20 mm × 3 mm [
The fracture cross-section of spent tensile test specimens were examined under optical and scanning electron microscopes. Scanning Electron Microscope (SEM) Model HITACHI S-3400N was used for the microscopic structure. For sample preparation, it needs to be coated with gold then placed in SEM machine at the distance of 6.2 mm from the lens, and emission current was 58 μA and the acceleration voltage of 5.0 kV. SEM helps to examine the morphology and fibers and voids.
All samples were cut and prepared according to ASTM D256 into 6 replica of dimension 70 mm × 15 mm × 8 mm, then conditioned at 22°C with the humidity of 50% for 48 h before the testing operated. For impact test, Izod Impact machine Zwick/Roell HIT5OP was used.
The tensile properties of kenaf and DPF reinforced hybrid composites have been illustrated in
It is observed that 1DP1K and 7DP3K values are very close to each other composites. However, among all composites, it is observed that a higher ratio of kenaf fiber enhanced the mechanical properties. The reinforced materials decide the thermal, mechanical and physical properties of a hybrid composite [
In
In
The impact-resistant properties of DPF reinforced composites showed better than other fibers due to the anatomical structure of DPF. This DPF is hollow from the center, which helps to absorb impact and stabilize the structure of fiber and composites [
As we know from the literature kenaf has better interfacial bonding than the DPF, and the impact properties matrix transfers the stress to the reinforced fibers to absorb the energy. Still, if interfacial bonding is weak, it hinders the transfer of stress, resulting in lower impact strength. In 7DP3K, the bonding is weak; due to this impact, strength is weak. In another case, strong interfacial bonding provide better interfacial bonding [
This research investigated the mechanical and morphological properties of kenaf and DPF reinforced epoxy hybrid composites and confirmed that kenaf fibers loading improves the tensile properties of the DPF/Epoxy composites. It also shows that composites with DPF 30% display better mechanical properties as compared with other composites. The morphology of both fibers has huge differences such as density, anatomy, and chemical constituents, so the ratio is essential to optimize and found 30% DPF is the best fiber loading used to hybridize with kenaf fiber to fabricate hybrid composites. In SEM, 3DP7K did not show the void content and agglomeration of fibers; however, other fiber loading revealed the untouched matrix, which means fibers were agglomerated and there were void contents. The Impact properties of 1DP1K showed the highest shock absorbing composites which revealed that DPF worked as impact-resistant efficiently, the 7DP3K did not work well it may be due to the weaker interfacial bonding of the fiber and matrix of the composites, and 3DP7K showed lower impact strength despite better interfacial strength, is lower DPF content in composites. This composite can be used as a false wall, sound absorbing wall and false ceiling.