Effect of the Consolidation Degree on the Fracture and Failure Behavior of Self-Reinforced Polypropylene Composites as Assessed by Acoustic Emission

In this work, the fracture and failure behavior of self-reinforced polypropylene composites (SRPPC) was studied. As reinforcement woven fabric, whereas as matrix materials alpha and beta crystal forms of isotactic polypropylene (PP) homopolymer and random PP copolymer (with ethylene) were used. Composite sheets were produced by a film-stacking method and compression molded for constant holding time and at constant pressure but at different processing temperatures to obtain SRPPC sheets with different consolidation quality. The failure behavior of tensile specimens was assessed by the acoustic emission (AE) technique and the typical failure behavior was deduced for the differently consolidated composites. Both the number of AE events and the shape of the cumulative AE events versus deformation curve depend on the adhesion between phases. Correlations between the dominant failure mechanisms and AE events amplitude for model specimens were established which can be used to monitor the damage growth process in SRPPCs. POLYM. ENG. SCI., 50:2106-2113, 2010. (C) 2010 Society of Plastics Engineers