Effect of matrix ductility on fatigue strength of unidirectional jute spun yarns impregnated with biodegradable plastics

Abstract

Natural fiber-reinforced composites are carbon-neutral materials that are anticipated for use as an alternative to glass fiber-reinforced plastics. This study investigated the effects of matrix ductility on the fatigue strength of unidirectional jute spun yarns impregnated with biodegradable plastics. Polylactic acid (PLA) and polybutylene succinate (PBS) were used for the matrix. PLA is brittle, but it is widely used as a matrix of green composites. Because PBS has much higher ductility than that of PLA, it can be expected to have higher fatigue strength when subjected to the same strain amplitude as PLA. Fatigue tests were conducted with maximum stress set to 40–90% of the tensile strength. The stress ratio was set as 0.1. Results show that the matrix ductility strongly affects the fatigue strength and the fatigue mechanism of the composite. A matrix with better ductility was effective to improve fatigue strength.

Keywords:

• jute spun yarn
• unidirectional reinforcement
• fatigue
• biodegradable plastics
• PLA
• PBS

Acknowledgments

We thank Prof Satoshi Kobayashi at Tokyo Metropolitan University for providing PBS pellets, and thank Mr Koji Iwata for providing experimental data of tensile tests of PBS specimens.