Development of woven fabric reinforced all-polypropylene composites with beta nucleated homo- and copolymer matrices

In the present work self-reinforced polypropylene composites (SRPPC) were developed and investigated. As reinforcement a fabric, woven from highly stretched split PP yarns, whereas as matrix materials alpha and beta crystal forms of isotactic PP homopolymer and random copolymer (with ethylene) were selected and used. The composite sheets were produced by film-stacking method and compression moulded at different processing temperatures keeping the holding time and pressure constant. The quality of the composite sheets was assessed by optical microscopy, density and peel-strength measurements. The SRPPC specimens were subjected to static tensile and flexural, and dynamic falling weight impact tests and the related results were analyzed as a function of processing temperature and polymorphic composition. Based on the results the optimum processing temperature was determined and found by 20-25 degrees C above the related matrix melting temperature. It was established that the P-modified PP homopolymer based one-component SRPPCs possessed similar attractive mechanical properties as the intensively studied alpha-random PP copolymer based two-component ones. (C) 2009 Elsevier Ltd. All rights reserved.