UV stability of HMS-PP (High Melt Strength Polypropylene) obtained by radiation process

Abstract

HMS-PP in grains was synthesized by the gamma irradiation of PP under a crosslinking atmosphere of acetylene, followed by thermal treatment for radical recombination and thermal treatment for annihilation of the remaining radicals. The UV stability of the material was evaluated in reference to grains. Accelerated weathering test of HMS-PP samples were performed in artificial ultraviolet light and condensation chamber apparatus Comexim (C-UV type) in aging conditions of exposure for 120 hours and 240 hours. The results were compared to the deterioration caused by sunlight and dew under natural exposition. This work investigated changes in mechanical proprieties (elongation and rupture strength) behavior, Infrared Spectroscopy (FTIR), Optical Microscopy (MO), Scanning Electronic Microscopy (SEM) and Rheological properties of HMS-PP. The HMS-PP is more fragile than PP and undergoes predominately chain scission in aggressive environment degradation conditions.