Flexural properties of sawdust-reinforced epoxy composites post-cured in microwaves

Abstract

Epoxy resin was filled with sawdust to optimize the flexural properties of the composite for structural applications. In order to reduce costs, it will be necessary to fill as much sawdust as possible subject to maintaining sufficient strength of the composites in civil and structural applications. This project varies the percentage by weight of the sawdust in the composites. The sawdust particles were sieved into three different sizes, which were <425 µm, 425–600 µm and 600–1180 µm, respectively. Palm oil was also added to the composites of epoxy resin and sawdust as a plasticizer to improve the flexibility of the composites. After casting the composites to the moulds, they were cured at ambient conditions for 24 h. They were then post-cured in a conventional oven or microwave irradiation and subjected to flexural tests. It was found that the best percentage of sawdust, with particle size of <425 µm, and of palm oil, by weight that can be added to epoxy resin to give an optimum flexural modulus and flexural strength, as well as cost was 15% and 5%, respectively. The contribution of the study was that if flexural modulus was the most important factor to be considered in the applications of the composites, sawdust is a suitable filler. However, if the most sought after properties were the flexural strength then sawdust is not a suitable filler.