Ai Ling Pang

The Effects of Kenaf Loadings and 3-aminopropyltriethoxysilane (APTES) Coupling Agent on Mechanical Properties of Polypropylene/Waste Tire Dust/Kenaf (Pp/WTD/KNF) Composites

The mechanical properties of polypropylene (PP)/waste tire dust (WTD)/kenaf (KNF) composites with and without 3-aminopropyltriethoxysilane (APTES) coupling agent were investigated. The composites were prepared using a Thermo Haake Polydrive internal mixer, where different KNF loading (0, 5, 10, 15, 20 phr) were used. The results revealed that the tensile modulus increased with increasing KNF loading but tensile strength and elongation at break were found decreased. Composites with APTES give higher tensile strength and modulus but lower elongation at break than composites without APTES. The presence of APTES enhanced the interfacial adhesion between PP/WTD matrices and KNF which result in higher tensile strength and modulus of the composites. These findings were supported by the morphological study of the tensile fractured surfaces of the composites.

Eco-friendly coupling agent-treated kenaf/linear low-density polyethylene/poly (vinyl alcohol) composites

Untreated kenaf (KNF) and eco-friendly coupling agent (EFCA)-treated kenaf were used as filler to prepare natural fiber-reinforced polymer composites (NFPCs) using linear low-density polyethylene (LLDPE) and poly(vinyl alcohol) (PVOH) as polymer matrices. The composites containing various loadings of untreated and EFCA-treated KNF (0, 10, 20, and 40 phr) were melt-blended in an internal mixer. The effect of treatment on the behavior of processing torque, mechanical properties, morphology, functional groups, water absorption, and thermal stability of KNF/LLDPE/PVOH composites were investigated. The results revealed that EFCA-treated KNF composites exhibited higher equilibrium torque, indicating that the viscosity of molten composites increased in the presence of EFCA. The tensile strength and tensile modulus of KNF/LLDPE/PVOH composites were improved with the addition of EFCA-treated KNF attributed to the enhancement of the interfacial adhesion between KNF and LLDPE/PVOH matrices, as confirmed by field-emission scanning electron microscopy. Fourier transform infrared spectroscopy indicated the presence of ester bond in EFCA-treated KNF composites. Furthermore, EFCA-treated KNF composites possessed a lower water absorption and greater thermal stability as compared to untreated KNF composites. Therefore, EFCA could be suggested as an effective coupling agent to enhance the performance of KNF/LLDPE/PVOH composites.

Degradation of linear low-density polyethylene/poly(vinyl alcohol)/kenaf composites

The interest of this study was to examine various kenaf (KNF) loadings and burial time, and their effects on degradability behavior of linear low-density polyethylene/poly(vinyl alcohol)/kenaf (LLDPE/PVOH/KNF) composites in soil. The LLDPE/PVOH/KNF composites with various KNF loadings were melt-mixed in a Thermo Haake internal mixer. The composites were buried in soil and their extent of degradability was assessed by tensile properties, morphological study, and weight loss and crystallinity measurements of the degraded composites. Fourier transform infrared spectroscopy was utilized to monitor the changes in chemical structure of the composites before and after degradation in soil. The results showed that with increase in KNF loading, the tensile modulus increased; meanwhile, the tensile strength and elongation-at-break of the degraded composites were dropped. Tensile properties of the degraded composites were decreased with prolonging soil burial time. The formation of cracks and pores was observed in field emission scanning electron microscope micrographs. By measuring the weight loss in LLDPE/PVOH/KNF composite samples before and after the soil burial testing and differential scanning calorimetry measurements, it was found that the weight loss and crystallinity of the composites increased with soil burial time. The degradation of the composites was confirmed by the formation of a strong absorption band assigned to carbonyl groups.

The Effect of Fiber Surface Treatment on the Water Absorption and Morphological Properties of Linear Low Density Polyethylene/Poly(Vinyl Alcohol)/Kenaf Composites

The effect of untreated and treated (chromium sulfate and sodium bicarbonate) kenaf (KNF) on the water uptake and morphological properties of linear low density polyethylene/poly(vinyl alcohol)/kenaf (LLDPE/PVOH/KNF) composites was studied. The composites were prepared by using an internal mixer (Haake Polydrive) at 150 °C and 50 rpm for 10 min. The results showed that the untreated composites tend to absorb greater amount of water compared to the treated composites. This shows that the chromium sulfate and sodium bicarbonate treatment on KNF had improved the interfacial adhesion between KNF and LLDPE/PVOH matrices. Consequently, the capability of water absorption by the treated composites was reduced. Scanning electron microscope (SEM) result shows that lesser traces of filler pull-out and better filler-matrix interfacial adhesion were observed in the tensile fractured surfaces of treated composites.

Linear Low Density Polyethylene/Poly(Vinyl Alcohol)/Kenaf (LLDPE/PVA/KNF) Composites: Effect of 3-(Trimethoxysilyl)Propyl Methacrylate as Silane Coupling Agent on Tensile and Morphological Properties

The tensile properties and morphological studies of linear low density polyethylene (LLDPE)/poly (vinyl alcohol) (PVA)/kenaf (KNF) composites with and without 3-(trimethoxysilyl) propyl methacrylate (silane coupling agent) were investigated. The composites with different KNF loading (10, 20, 30, 40 phr) were prepared using a Thermo Haake Polydrive internal mixer at 150°C and 50 rpm for 10 min. The results indicated that composites with 3-(trimethoxysilyl) propyl methacrylate gives higher tensile strength and modulus but lower elongation at break than composites without. The presence of 3-(trimethoxysilyl) propyl methacrylate found to enhance the interfacial adhesion between LLDPE/PVA matrix and KNF fiber. Morphological studies on tensile fractured surfaces showed good adhesion between LLDPE/PVA matrix and KNF, and better dispersion of KNF for the composites with 3-(trimethoxysilyl) propyl methacrylate.