Reprocessing Effects on the Properties of a Hybrid Nylon 6,6-Composite Reinforced with Short Glass and Carbon Fibers

Abstract

A hybrid nylon 6,6 short glass/carbon fiber composite has been studied. The effect of reprocessing on the microstructure and mechanical properties was evaluated for injection-molded products. Fiber size distribution, molecular weight of matrix, thermal transitions, Young modulus and impact strength are among the properties evaluated during nine reprocessing cycles by injection molding. For the first five injection cycles an increase in tensile strength, Young modulus and impact strength are observed whereas molecular weight and average fibers-size are decreased. Reprocessing after 5 cycles led to a decrease in mechanical properties. SEM images show that the matrix first recovers from its fractures (up to 5 cycles) and after that, fractures again accompanied by an increased fiber pull-out.