Study of the effect of regrinding on the cumulative damage to the mechanical properties of fiber-reinforced nylon 66

Abstract

An experimental study of the tensile strength of nylon 66 regrind, with and without short-fiber reinforcement, is reported. For nylon 66 without reinforcement, a uniform increase in tensile strength has been observed with increasing number of moldings. This is due to a further condensation reaction which occurs during molding. For short fiber-reinforced nylon 66 composite, the tensile strength decreases with increasing number of moldings, which is attributed to the cumulative breakage of fiber length through mechanical working. A model based on fiber length analysis is proposed, and the semiempirical equation can be used to predict experimental results and balance cost–end use properties.