Modification of mechanical properties of poly (methyl methacrylate) used for denture base material by using bamboo fiber

Abstract

The aim of this research is to study the mechanical effect of bamboo fiber as reinforcing material in poly (methyl methacrylate) (PMMA) used as denture base material. The composites with various fiber contents (0 to 20-wt %) were studied to find the trend of mechanical-property change, such as, flexural strength at break, flexural modulus, impact strength and compressive strength. In order to improve the interfacial adhesion between fiber and matrix, Gamma-methacryloxypropyltrimethoxysilane coupling agent (γ-MPS) was used. Comparative study of the bamboo fiber / PMMA composites with and without the coupling agent were carried out. Furthermore, the effect of aspect ratio of the bamboo fiber was also studied. It was found that the addition of more than 5-wt % of fiber tended to increase the flexural modulus at break at least 20 %, and compressive strength over 10%, but decrease the flexural strength at least 10 %. At 5-wt % loading, the bamboo fiber / PMMA composites with γ-MPS provided 10 % increase of compressive strength compared with the composite without coupling agent, 220 % increase of impact strength compared with PMMA without reinforcement, and 10 % decrease of the flexural strength compared with the composite without coupling agent. The composites with 126.5 aspect-ratio fiber had 15 % higher flexural strength than the ones with 79.7 aspect-ratio fiber. Morphology of the composites was observed by Scanning Electron Microscope (SEM). It was revealed that the composites with coupling agent had better adhesion between the interfacial surface than those without coupling agent had.