PROCESSING AND MECHANICAL PROPERTIES OF BIODEGRADABLE COMPOSITES

Continuous natural fiber reinforced thermoplastic materials are expected to replace inorganic fiber reinforced thermosetting materials. However, natural fiber itself has low strength and in the process of fabricating the composite, it is difficult to impregnate the thermoplastic resin into reinforcement fiber because of the high melt viscosity. In our previous studies, it has been clarified that a spun natural yarn had high strength. Moreover intermediate material, which allows highly impregnation during molding, can be obtained for fabricating continuous fiber reinforced thermoplastic composite by aligning resin fiber alongside reinforcing fiber with braiding technique. This intermediate material has been called “Micro-braided-yarn”. In this investigation, completely naturally-derived micro-braided-yarn was fabricated by using thermoplastic biodegradable resin fiber (PLA) as the resin fiber and jute spun yarn as the reinforcement. Using jute spun yarn/PLA micro-braided-yarn, continuous natural fiber reinforced biodegradable resin composite plates were molded by hot press molding with various molding conditions. Observation of impregnation state and evaluation of mechanical properties were performed, and consequently, the relationship between the molding conditions and the mechanical properties of jute spun yarn/PLA composite was clarified. In addition, it is well known that the interfacial properties between natural fiber and resin is low, therefore, surface treatment on jute fibers was performed by using shellac resin (a natural surfactant) to improve the interfacial properties of jute fiber. Furthermore, jute spun yarn/PLA Micro-braided yarn textile was fabricated by using weaving techniques.