Potential of oil palm empty fruit bunch (OPEFB) and sugarcane bagasse fibers for thermal insulation application–a review

In Malaysia, the majority of household electricity (45%) is consumed by air conditioning. Such high energy consumption is mainly caused by inefficient insulating materials with poor thermal performance. Hence, the selection of a thermal wall insulator with low thermal conductivity is vital to reduce the energy consumption. Utilizing agro waste based thermal insulation materials has become an efficient and economical method for energy efficient building. In this review, the standards required for an efficient thermal insulator have been addressed. Moreover, thermal, acoustic, physical and mechanical performance of oil palm empty fruit bunch fiber (OPEFB) and sugarcane bagasse fiber and their composites are described in detail. Optimal fiber loading and different surface modifications were reported to enhance the thermal performance, acoustic, physical and mechanical performance of composites. From the observations, it has been concluded that agro waste based OPEFB and bagasse fibers can act as an efficient thermal insulator, which will significantly reduce the excess utilization of energy and thus the costs

Characterization of hybrid oil palm empty fruit bunch/woven kenaf fabric-reinforced epoxy composites

In this research, the physical, mechanical and morphological properties of oil palm empty fruit bunch (EFB) mat/woven kenaf fabric-reinforced epoxy composites have been investigated. The oil palm EFB/woven kenaf fabrics were varied, with weight ratios of 50/0 (T1), 35/15 (T2), 25/25 (T3), 15/35 (T4) and 0/50 (T5). The composites were fabricated using a simple hand lay-up technique followed by hot pressing. The result obtained shows that an increase in kenaf fiber content exhibited higher tensile and flexural properties. On the other hand, the opposite trend was observed in the impact strength of hybrid composites, where an increase in kenaf fiber content reduced the impact strength. This can be corroborated with the physical properties analysis, where a higher void content, water absorption and thickness swelling were observed for pure oil palm EFB (T1) composites compared to other samples. The scanning electron microscopy analysis results clearly show the different failure modes of the tensile fractured samples. Statistical analysis was performed using one-way ANOVA and shows significant differences between the obtained results

Thermal degradation and viscoelastic properties of Kevlar/Cocos nucifera sheath reinforced epoxy hybrid composites

The aim of this research work is to develop high performance structural composites using Kevlar 29 (K) and Cocos nucifera sheath (CNS). The Kevlar and CNS laminates were fabricated by using hand lay-up method followed by hot pressing. The weight ratios of Kevlar/CNS are as follows 100/0 (S1), 75/25(S2), 50/50 (S3), 25/75 (S4), 0/100(S5). Thermal and viscoelastic properties of laminated composites were investigated as a function of temperature using thermogravimetric (TGA) and dynamic mechanical analyzer (DMA). The obtained results revealed that the thermal stability, char residue of S2 laminate was higher compared S3, S4 and S5 laminates. Moreover, S2 laminates showed comparable thermal stability with Kevlar/epoxy composites (S1). Differential scanning calorimetry (DSC) results revealed that hybrid composite (S2) offers a virtuous resistance or stability towards heat in the epoxy composites. Viscoelastic analysis results showed that the storage modulus (E’) and loss modulus (E”) of S2 composites were higher among the laminates due to improved interfacial interactions and effective stress transfer rate. Moreover, the damping of hybrid laminates (S2) almost closer to Kevlar/epoxy laminates (S1). Hence, it was observed that hybrid Kevlar/CNS composites (S2) can be efficiently utilized for advanced structural applications where rigidity, thermal stability along with renewability are prime requirements

Effect of Cyrtostachys renda fiber loading on the mechanical, morphology, and flammability properties of multi-walled carbon nanotubes/phenolic bio-composites

This research focuses on evaluating the effect of Cyrtostachys renda (CR) fiber and the impact of adding multi-walled carbon nanotubes (MWCNT) on the morphological, physical, mechanical, and flammability properties of phenolic composites. MWCNT were supplemented with phenolic resin through a dry dispersion ball milling method. Composites were fabricated by incorporating CR fiber in 0.5 wt.% MWCNT-phenolic matrix by hot pressing. Nevertheless, the void content, higher water absorption, and thickness swelling increased with fiber loading to the MWCNT/phenolic composites. The presence of MWCNT in phenolic enhanced the tensile, flexural, and impact strength by as much as 18%, 8%, and 8%, respectively, compared to pristine phenolic. The addition of CR fiber, however, strengthened MWCNT-phenolic composites, improving the tensile, flexural, and impact strength by as much as 16%, 16%, and 266%, respectively, for 50 wt.% loading of CR fiber. The CR fiber may adhere properly to the matrix, indicating that there is a strong interface between fiber and MWCNT-phenolic resin. UL-94 horizontal and limiting oxygen index (LOI) results indicated that all composite materials are in the category of self-extinguishing. Based on the technique for order preference by similarity to the ideal solution (TOPSIS) technique, 50 wt.% CR fiber-reinforced MWCNT-phenolic composite was chosen as the optimal composite for mechanical and flammability properties. This bio-based eco-friendly composite has the potential to be used as an aircraft interior component

Void content, tensile, vibration and acoustic properties of kenaf/bamboo fiber reinforced epoxy hybrid composites

This study aims to investigate the void content, tensile, vibration and acoustic properties of kenaf/bamboo fiber reinforced epoxy hybrid composites. The composites were made using the hand lay-up method. The weight ratios of kenaf/bamboo were 30:70, 50:50 and 70:30. Further, kenaf and bamboo composites were fabricated for the purpose of comparison. The hybridization of woven kenaf/bamboo reduced the void content. The void contents of hybrid composites were almost similar. An enhancement in elongation at break, tensile strength and modulus of hybrid composites was observed until a kenaf/bamboo ratio of 50:50. Kenaf/bamboo (50:50) hybrid composite displays the highest elongation at break, tensile strength and modulus compared to the other hybrid composites which are 2.42 mm, 55.18 MPa and 5.15 GPa, respectively. On the other hand, the highest natural frequency and damping factors were observed for Bamboo/Kenaf (30:70) hybrid composites. The sound absorption coefficient of composites were measured in two conditions: without air gap and with air gap (10, 20, 30 mm). The sound absorption coefficient for testing without air gap was less than 0.5. Introducing an air gap improved the sound absorption coefficient of all composites. Hence, hybrid kenaf/bamboo composites exhibited less void content, as well as improved tensile, vibration and acoustic properties

Characterization of Hybrid Oil Palm Empty Fruit Bunch/Woven Kenaf Fabric-Reinforced Epoxy Composites

In this research, the physical, mechanical and morphological properties of oil palm empty fruit bunch (EFB) mat/woven kenaf fabric-reinforced epoxy composites have been investigated. The oil palm EFB/woven kenaf fabrics were varied, with weight ratios of 50/0 (T1), 35/15 (T2), 25/25 (T3), 15/35 (T4) and 0/50 (T5). The composites were fabricated using a simple hand lay-up technique followed by hot pressing. The result obtained shows that an increase in kenaf fiber content exhibited higher tensile and flexural properties. On the other hand, the opposite trend was observed in the impact strength of hybrid composites, where an increase in kenaf fiber content reduced the impact strength. This can be corroborated with the physical properties analysis, where a higher void content, water absorption and thickness swelling were observed for pure oil palm EFB (T1) composites compared to other samples. The scanning electron microscopy analysis results clearly show the different failure modes of the tensile fractured samples. Statistical analysis was performed using one-way ANOVA and shows significant differences between the obtained results

Improved mechanical and moisture-resistant properties of woven hybrid epoxy composites by graphene nanoplatelets (GNP)

This research investigated the effect of adding different wt.% (0, 0.25, 0.50, and 0.75) of GNP (graphene nanoplatelets) to improve the mechanical and moisture resistant properties of Kevlar (K)/cocos nucifera sheath (CS)/epoxy hybrid composites. The laminates were fabricated with different K/CS weight ratios such as 100/0 (S1), 75/25 (S2), 50/50 (S3), 25/75 (S4), and 0/100 (S5). The results revealed that the addition of GNP improved the tensile, flexural, and impact properties of laminated composites. However, the optimal wt.% of GNP varies with different laminates. A moisture diffusion analysis showed that the laminates with a 0.25 wt.% of GNP content efficiently hindered water uptake by closing all the unoccupied pores inside the laminate. Morphological investigations (SEM and FE-SEM (Field Emission Scanning Electron Microscope)) proved that the addition of GNP improved the interfacial adhesion and dispersion. Structural (XRD and FTIR) analyses reveals that at 0.25 wt.% of GNP, all the hybrid composites showed a better crystallinity index and the functional groups presents in the GNP can form strong interactions with the fibers and matrix. A statistical analysis was performed using One-way ANOVA, and it corroborates that the mechanical properties of different laminates showed a statistically significant difference. Hence, these GNP-modified epoxy hybrid composites can be efficiently utilized in load-bearing structures

Enhanced thermal and dynamic mechanical properties of synthetic/natural hybrid composites with graphene nanoplateletes

The aim of the present research work is to enhance the thermal and dynamic mechanical properties of Kevlar/Cocos nucifera sheath (CS)/epoxy composites with graphene nano platelets (GNP). Laminates were fabricated through the hand lay-up method followed by hot pressing. GNP at different wt.% (0.25, 0.5, and 0.75) were incorporated with epoxy resin through ultra-sonication. Kevlar/CS composites with different weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) were fabricated while maintaining a fiber/matrix weight ratio at 45/55. Thermal degradation and viscoelastic properties were evaluated using thermogravimetric analysys (TGA), differential scanning calorimetric (DSC) analysis, and a dynamic mechanical analyser (DMA). The obtained results revealed that Kevlar/CS (25/75) hybrid composites at 0.75 wt.% of GNP exhibited similar thermal stability compared to Kevlar/epoxy (100/0) composites at 0 wt.% of GNP. It has been corroborated with DSC observation that GNP act as a thermal barrier. However, DMA results showed that the Kevlar/CS (50/50) hybrid composites at 0.75 wt.% of GNP exhibited almost equal viscoelastic properties compared to Kevlar/epoxy (100/0) composites at 0 wt.% GNP due to effective crosslinking, which improves the stress transfer rate. Hence, this research proved that Kevlar can be efficiently (50%) replaced with CS at an optimal GNP loading for structural applications

Characterization of New Cellulosic Cyrtostachys renda and Ptychosperma macarthurii Fibers from Landscaping Plants

Cyrtostachys renda (CR) and Ptychosperma macarthurii (PM) fibers, as new cellulosic fibers were studied. The objective of this research is to evaluate the fibers from stem, leaf stalk, and frond of these two plants as reinforcement in the polymer composites. The density, chemical composition, functional group, crystallinity index, and thermal stability were studied for CR and PM fibers. From the analysis, the density and thermal stability of both leaf stalk fibers are found almost similar. The highest crystallinity index (55.67%) of the leaf stalk of CR was attributed to the highest cellulosic content (38.99%) and the functional group (C-H stretching). From the results, the optimized properties were found for the leaf stalk of CR fiber. The tensile strength, interfacial shear strength (IFSS), morphology of the leaf stalk of CR were explored. The ultimate tensile strength, Young modulus, and IFSS of the leaf stalk of CR is 51.82 ± 9.41 MPa, 0.69 ± 0.18 GPa, and 3.27 ± 0.5 MPa, respectively. The Scanning Electron Microscopy observation revealed that the leaf stalk fiber of CR possesses anti-microbial properties which has been corroborated through the presence of silica bodies over the fiber surface. Hence, the leaf stalk of CR acts as a potential reinforcement in the polymeric composites for lightweight applications