Internal Activation of Thermoplastic Polypropylene GFRTP Composite by Homogeneous Low Energy Electron Beam Irradiation (HLEBI) of the Interlayered Glass Fiber Chopped Strand Mats (GF-CSM) Prior to Assembly

A new process of internal activation of glass fiber reinforced thermoplastic polymer (GFRTP) of Polypropylene (PP) was achieved by homogeneous low energy electron beam irradiation (HLEBI) to the interlayered glass fiber chopped strand mats (GF-CSM) prior to assembly. Panels were fabricated by hot-press consisting of 5 HELBI-treated GF-CSMs between 6 untreated PP sheets. HLEBI improved the Charpy impact value (a(uc)) of the internally activated GFRTP. HLEBI from 0.22 to 0.86 MGy mostly improved the a(uc) at each accumulative probability of fracture (P-f). Based on the 3-parameter Weibull equation, the a(uc) value was defined as the statistically lowest impact value, a(s) estimated as the a(uc) at P-f = zero. The highest a(s) values at more than 87 kJ/m(2) were found for GFRTP irradiated at 0.65 MGy which appears to be at or near the optimum HLEBI dose. Strengthening the adhesion force at the extremely broad surface area of the fibers increased interfacial friction force to prevent fiber pull out, fiber/matrix debonding and crack generation in the hard to adhere PP matrix GFRTP, resulting in increasing aue of GFRTP with glass fiber surface-activated by HLEBI.