Abstract
Recently, green composites (GC) using natural fibers and biodegradable resin have been developed and investigated, aiming at contribution to preservation and improvement of the global environment. However, in composites using biodegradable resin as matrix, it is considered that the degradation by hydrolysis might be selectively accelerated at the interface. In the present study, we aim to clarify the local hydrolysis behavior at interface in fiber reinforced plastics using biodegradable resin as matrix. Here, we prepared a new type of GC model specimen, where the inside interfacial debonding can be observed directly, using a glass rod (GR) as fiber and polybutylene succinate adipate (PBSA) as matrix. In-situ observation of the internal interfacial debonding behavior was carried out during tensile tests of GC model specimens after immersion into water within the range of 3 weeks of immersion time, where the tensile strength of PBSA matrix itself was not degraded. In addition, experimental results were discussed combined with a simple finite element analysis. As a result, it was demonstrated that the hydrolytic degradation speed of interface was much higher than that of matrix resin. It was considered that water molecules diffused in the free volume of resin and locally accumulated at the interface between fibers and resin, resulting in the acceleration of hydrolysis at the interface.
