Abstract
Molecular motion of poly(propylene) (PP) composites with short glass fiber was analysed by dynamic viscoelastic measurement. The effect of glass fiber content on molecular motion of PP and the interaction between PP and glass fiber were discussed. Two types of 2wt% ethylene block-copolymerized PP, maleic anhydride treated PP and non-treated PP, were used as matrix resin. The maleic anhydride treated PP showed reinforced effect on mechanical properties remarkably. Four tan δ peaks, α'-, α-, β- and γ-relaxations from high temperature side were observed for PP and PP composites in the temperature range from -70°C to 170°C at 1Hz. α'-, β-, and γ-relaxations were assigned to melting, glass transition of PP and main chain motion of ethylen-propylene unit, respectively, in relation to transition temperature and activation energy. α-relaxation of PP was caused by relaxation in crystal, however, α-relaxation of glass fiber reinforced PP contained α1-relaxation which was observed independently at 0.02Hz. α1-relaxation was caused by molecular motion of amorphous region surrounding glass fibers in relation to frequency dependency of tan δ peak temperature and activation energy.
