The effect of surface coating and fibre loading on thermo-mechanical properties of recycled polyethylene terephthalate (RPET)/epoxy-coated kenaf fibre composites
“…The results are validated by our previous finding where there was a slight decrease in impact strength upon addition of fillers at a constant processing temperature of 200°C. 20 Similar observation was reported by Talib et al with composites of short leather fibre reinforced unsaturated polyester composites. 30 Figure 5.Effect of processing temperature on the flexural strength of ABS, coated and uncoated leather waste short fibres filled ABS composites.…”
Section: Resultssupporting
confidence: 83%
“…Other researchers have reported various significant improvements in mechanical properties with epoxy coated fibre filled engineering composites. 4,20,21,23 They concluded that flexible or diluted epoxy resin is considered useful for surface modification in enhancing the mechanical properties of natural fibre filled engineering thermoplastic polymer composites.…”
Section: Resultsmentioning
confidence: 99%
“…These include natural kenaf fibres/high temperature engineering polyethylene terephthalate (PET) who pre-coated the fibres used in the preparation of their composites to improve the thermal resistance. 20,21 Furthermore, Saliu et al 22 incorporated epoxy coated-sodium hydroxide treated kenaf fibres into thermoplastics Acrylonitrile butadiene styrene (ABS) at processing temperature of 230°C and dynamically cured epoxy at high temperature (80°C) in order to prevent degradation. However, the researchers found that an optimum level of mechanical properties were obtained with epoxy coated fillers and concluded that epoxy coated bast kenaf fibre can be incorporated into higher temperature engineering thermoplastic ABS without degradation of the fibres.…”
The effect of varying processing temperatures (200, 220 and 240°C) on the thermal and mechanical properties of uncoated and epoxy-coated chrome-tanned leather wastes-ABS composites has been studied. The results obtained showed that the mechanical properties of the composites decreased as the processing temperature increased. Epoxy-coated leather wastes fibre-ABS (CLWABS) composite yielded better mechanical properties compared to the uncoated leather wastes-ABS composite (LWABS). These results were obtained at an optimized processing temperature of 200°C. Furthermore, the results were confirmed by the field emission scanning electron microscopy (FESEM) studies. The differential scanning calorimetry (DSC) studies revealed that the epoxy-coated leather wastes fibres (CLW) showed higher onset and melting temperatures of 131.8 and 179.35°C than the uncoated leather wastes fibres (LW) with glass transition (Tg) and melting (Tm) temperatures of 128.2 and 169.4°C, respectively. When the LW and CLW fibres were mixed with Acrylonitrile butadiene styrene (ABS), the Tg and Tm of CLWABS composite were found to be 94.9 and 269.8°C, respectively, higher than the LWABS composite with Tg and Tm of 89.1 and 261.6°C, respectively. Thus, this study has demonstrated that utilization of epoxy-coated chrome-tanned leather wastes fibres as fillers in the design of ABS-based composites will help a great deal in addressing the problem of solid waste pollutants in our environment.
“…The results are validated by our previous finding where there was a slight decrease in impact strength upon addition of fillers at a constant processing temperature of 200°C. 20 Similar observation was reported by Talib et al with composites of short leather fibre reinforced unsaturated polyester composites. 30 Figure 5.Effect of processing temperature on the flexural strength of ABS, coated and uncoated leather waste short fibres filled ABS composites.…”
Section: Resultssupporting
confidence: 83%
“…Other researchers have reported various significant improvements in mechanical properties with epoxy coated fibre filled engineering composites. 4,20,21,23 They concluded that flexible or diluted epoxy resin is considered useful for surface modification in enhancing the mechanical properties of natural fibre filled engineering thermoplastic polymer composites.…”
Section: Resultsmentioning
confidence: 99%
“…These include natural kenaf fibres/high temperature engineering polyethylene terephthalate (PET) who pre-coated the fibres used in the preparation of their composites to improve the thermal resistance. 20,21 Furthermore, Saliu et al 22 incorporated epoxy coated-sodium hydroxide treated kenaf fibres into thermoplastics Acrylonitrile butadiene styrene (ABS) at processing temperature of 230°C and dynamically cured epoxy at high temperature (80°C) in order to prevent degradation. However, the researchers found that an optimum level of mechanical properties were obtained with epoxy coated fillers and concluded that epoxy coated bast kenaf fibre can be incorporated into higher temperature engineering thermoplastic ABS without degradation of the fibres.…”
The effect of varying processing temperatures (200, 220 and 240°C) on the thermal and mechanical properties of uncoated and epoxy-coated chrome-tanned leather wastes-ABS composites has been studied. The results obtained showed that the mechanical properties of the composites decreased as the processing temperature increased. Epoxy-coated leather wastes fibre-ABS (CLWABS) composite yielded better mechanical properties compared to the uncoated leather wastes-ABS composite (LWABS). These results were obtained at an optimized processing temperature of 200°C. Furthermore, the results were confirmed by the field emission scanning electron microscopy (FESEM) studies. The differential scanning calorimetry (DSC) studies revealed that the epoxy-coated leather wastes fibres (CLW) showed higher onset and melting temperatures of 131.8 and 179.35°C than the uncoated leather wastes fibres (LW) with glass transition (Tg) and melting (Tm) temperatures of 128.2 and 169.4°C, respectively. When the LW and CLW fibres were mixed with Acrylonitrile butadiene styrene (ABS), the Tg and Tm of CLWABS composite were found to be 94.9 and 269.8°C, respectively, higher than the LWABS composite with Tg and Tm of 89.1 and 261.6°C, respectively. Thus, this study has demonstrated that utilization of epoxy-coated chrome-tanned leather wastes fibres as fillers in the design of ABS-based composites will help a great deal in addressing the problem of solid waste pollutants in our environment.
“…The silane treatment removed hemicellulose, and lignin, with other pectin contents and improved the hydrophilic characteristics of the fibers, while on the other hand, surface coating of the silane-treated fibers with diluted thermoset epoxy resin at various concentrations improved the thermal degradation and stability of the fibers. These results substantiate previous findings 18–20 The present research has established that the fiber degradation and stability of coated fibers also improved with increasing epoxy coating concentration. 1:4 ESKF with the highest degradation temperature is considered the optimum concentration.…”
Section: Thermal Propertiessupporting
confidence: 93%
“…From the DSC results, RPET showed some similarities in comparison to virgin PET having glass transition temperatures ( T g ) of 80.8°C and 73.8°C, and melting peaks temperatures ( T m ) of 249.3°C and 248.5°C respectively, an indication that the recycling process was efficient, void of contamination and the basis composites were processed at a temperature of 240°C. 20 The extrusion temperature (240°C) has no adverse effect on the thermal phases for RPET and the constituent composites as they have maintained balanced thermal stability values within 240°C.…”
The effect of different concentrations of epoxy surface coating treatment on the thermal and mechanical properties of kenaf fiber reinforced recycled poly (ethylene terephthalate) (RPET) composites was studied. Silane-treated kenaf fibers (SKF) were epoxy-coated with optimized coating concentrations (in the ratios of 1:4, 1:5, and 1:6 epoxy to acetone solutions) to improve the thermal degradation/decomposition resistance and interfacial bonding with RPET matrix. The different epoxy coated-silane treated kenaf fibers 1:4 ESKF, 1:5 ESKF, and 1:6 ESKF were compounded with RPET at an optimized temperature of 240°C, and their constituents’ composites KF/RPET, 1:4 ESKF/RPET, 1:5 ESKF/RPET, and 1:6 ESKF/RPET were subjected to thermal, mechanical and microstructural investigation. The obtained results showed some remarkable effects of epoxy concentrations on the chemical and surface structures of the treated fibers. Thermal properties of both ESKF and ESKF/RPET composites were more stable and improved with different concentrations of epoxy treatment compared to the untreated counterparts. 1:4 ESKF and 1:5 ESKF were the most thermally stable with onset degradation and DTG decomposition temperatures of 331.6°C and 381.7°C, and 324.0°C and 388.7°C respectively. Mechanical properties of the epoxy-coated composites were higher and further improved with epoxy concentrations and fiber loadings compared to uncoated composites. Hence, the epoxy concentration of 1:4 gave the maximum tensile and impact properties, and at 10 wt. % fiber loading within the lower loading regions, followed by 1:5 with outstanding flexural properties. The coated-treated composites showed strong fiber/matrix bonding with no evidence of fiber decomposition compared to the untreated composites with poor fiber/matrix interaction. The current research findings are original and valid for improving the thermal degradation resistance and stability of natural fibers, and the mechanical properties of natural fiber reinforced engineering thermoplastic composites. The epoxy coated – silane-treated textile kenaf fibers reinforced with recycled PET composites have the potentials to be utilized in high-temperature industrial and engineering applications.
Phenolic resin (PR)‐based composites are the main materials used in thermal protection system (TPS) at present. However, the low graphitization degree of the char layer formed by PR easily leads to cracks and other defects. In this study, carbon/phenolic composites were modified by mesophase pitch (MP) to improve the structural strength, fracture toughness and crack propagation resistance. The ablation rate was significantly decreased after MP modification compared with the blank sample. With the increase of MP, the size of cracks and char blocks on the ablation center of the composites were reduced, and the surface was flat and dense. The Interlaminar shear strength (ILSS) of carbonized composites (5 wt% MP) were 9.79 MPa, and the flexural strength was 121.5 MPa, which improved 62.9% and 40.8% relative to the pure sample. The flexural strength of 5 wt% MP‐reinforced carbon/phenolic composites reached 525.6 MPa, which was 26.9% higher than that of pure carbon/phenolic composites, mainly due to the particle reinforcement effect of MP distributed between carbon fibers. The above results show that the carbon/phenolic composites modified by MP has great application prospects in the field of aircraft thermal protection.
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