Effects of Grafted PP Addition on Flexural Properties and Water Absorption Degradation of Glass Beads Filled PP Composites

An attempt was made to improve the interfacial adhesion between glass beads and polypropylene (PP) matrix by the introduction of graft-modified PP. Two types of modified PP's, which were grafted by different amount of maleic anhydride, were used. The grafted PP was added to PP matrix up to 30 wt%, then 30 wt% of glass beads were filled to make the composite specimen. Flexural properties, the water absorption behavior under the immersion in 80°C water, and the degradation of flexural properties of the composites by water absorption were investigated. Results obtained are as follows : (1) Flexural modulus and strength of the composite exhibit maximum values when 5 wt% of the grafted PP is added to PP. (2) When 3 wt% or 5 wt% of the grafted PP is added to PP, the water absorption of the composite decreases and the degradation by the water absorption is suppressed. (3) The grafted PP by less amount of maleic anhydride is more effective to improve the flexural properties.