Effect of glass fiber and maleated ethylene-propylene rubber content on the impact fracture parameters of nylon 6

The impact fracture parameters of blends of nylon 6 and maleated ethylene-p ropylene rubber (EPR-g-MA) reinforced with glass fibers as a function of gl ass fiber and EPR-g-MA content were examined. Both the linear elastic fract ure mechanics (LEFM) model and a modified essential work of fracture (EWF) model were used to analyze the data. It was found that the addition of EPR- g-MA to unreinforced nylon 6 increased the EWF parameters u(o) and u(d) def ined by U/A = u(o) + u(d)l, where U/A is the total fracture energy per unit area and I is the ligament length. Beyond a critical rubber content, which coincided with the ductile-to-brittle transition, there was a large increa se in u(d) When glass fiber reinforcement was used without rubber toughenin g, the EWF model was unable to model the observed fracture response. On the other hand, the LEFM model adequately described the fracture behavior, and it was found that the critical strain energy release rate, G(IC), increase d with increasing glass fiber content. When both glass fiber reinforcement and rubber toughening were used, the u(o) increased with increasing EPR-g-M A or glass fiber content; whereas, u(d) increased with increasing ERR-g-MA content or decreasing glass fiber content. (C) 2001 Elsevier Science Ltd. A ll rights reserved.