Preparation and properties of poly (vinyl chloride) epoxidized natural rubber kenaf core powder composites

Loading...
Thumbnail Image
Date
2016-03-01
Authors
Rohani Abdul Majid
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
An increase in the use of natural fibre-reinforced polymer composites has attracted attention towards a greener environment, and at the same time has reduced the production cost for synthetic fibres. On the other hand, researchers, in their efforts to produce a flexible thermoplastic through the incorporation of elastomeric materials, have also shown a positive trend towards improving certain properties of the polymers. Efforts are currently underway to produce polyvinyl chloride (PVC), epoxidized natural rubber (ENR) and kenaf core powder (KCP) composites. In this study, the effects of KCP loading, compatibilizers, dynamic vulcanization and filler chemical treatment on the tensile, morphological, water absorption and swelling, thermo-oxidative ageing, and thermal properties of a composite were investigated. Firstly, the PVC/ENR/KCP, containing 0 to 20 phr of KCP, was prepared using the melt blending and compression moulding methods. The addition of KCP into the PVC/ENR matrix resulted in a decrease in tensile strength and an elongation at break. The Young’s modulus was observed to increase due to the addition of rigid KCP into the PVC/ENR matrix. The reduction in tensile strength was due to low interfacial adhesion between the filler and the matrix, leading to lower stress transfer. Secondly, the effect of maleic anhydride as a compatibilizer on the properties of the PVC/ENR/KCP composite was studied. Two types of MA compatibilizer were used. It was found that PE-g-MA and PVC-g-MA compatibilizers elevated the tensile strength and elongation at break. The PVC-g-MA compatibilized composites exhibited higher tensile properties compared to the PE-g-MA compatibilized composites. The thermo-oxidative ageing of the PVC/ENR/KCP with PVC-g-MA showed better resistance due to the enhancement in the interfacial adhesion as compared to the PE-g-MA. Later, the incorporation of cross-linking or dynamic vulcanization showed an outstanding improvement in tensile properties. Dynamic vulcanization using a semi-efficient sulphur system improved the matrix-matrix interaction with the sulphur cross-linking bond. It was also observed that thermooxidative ageing improved with dynamic vulcanization. Next, filler treatments were incorporated. The benzoyl chloride treatment improved the tensile strength, Young’s modulus and elongation of the PVC/ENR/KCP composite. The benzoyl chloride treatment was also observed to have improved the water absorption properties due to the enhancement of interfacial adhesion. Unfortunately, there was a reduction in the thermo-oxidative ageing properties as early as after 3 days of exposure. For the sodium dodecyl sulphate-treated composite, there was a slight increase in the tensile strength and an outstanding increase in the elongation at break. Unlike the benzoyl chloride-treated composite, the Young’s modulus for the sodium dodecyl sulphatetreated composite showed a lower value compared to the untreated composite. The same observation as that of the benzoyl chloride-treated composite was recorded for the thermo-oxidative ageing properties. The results indicated that there was a reduction as early as after 3 days of exposure.
Description
Keywords
Citation