Development and characterization of self-reinforced poly(propylene) composites:: carded mat reinforcement

Self-reinforced poly(propylene) (PP) composites were produced by film-stacking using carded mats of alpha-isotactic PP fibers and films of beta-isotactic PP. Composite sheets were produced at various consolidation temperatures (T = 150-170 degrees C) and constant holding time (t = 2 min). In a test series the holding time was varied (t = 2-20 min) by keeping the consolidation temperature constant. The consolidation degree of the sheets was studied on polished sections by light microscopy and quantified by density and peel test results. Specimens cut of the sheets were subjected to in-plane static tensile and out-of-plane dynamic impact (instrumented falling weight impact, IFWI) tests. It was established that the best indicators for the consolidation degree are the density, tensile strength and specific perforation impact energy and between them linear correlations exists. Increasing the density of the composites resulted in increased tensile strength (due to lower void content and better fiber/matrix adhesion) and reduced perforation impact energy (due to hindered delamination between the constituent layers). Copyright (c) 2006 John Wiley & Sons, Ltd.