High performance self-reinforced polypropylene composites

Highly oriented polypropylene fiber reinforced random PP copolymer composites were produced by film-stacking method. The reinforcing fibers were carded and needle punched and the film-stacked packages were compression molded at different processing temperatures (T= 150...170 degrees C and holding times (t=90...600 s). For characterization of the consolidation of the composite sheets interlaminar strength was determined and further the polished sections were studied by light microscopy. Static tensile and dynamic impact (instrumented failing weight impact - IFWI) tests were performed on the specimens cut from the sheets. It was established that the best properties can be achieved when the processing conditions are 165 degrees C and 90s. Increasing temperature and improving consolidation reduced perforation impact energy owning to better fiber/matrix adhesion and the smaller extent of delamination between the film-stacked layers.