Interfacial Adhesion between an Amorphous Polymer (Polystyrene) and a Semi-crystalline Polymer (Polyamidenylon 6)

摘要

We present an investigation of the interfacial reinforcement between a flexible amorphous polymer (polystyrene, PS) and a semi-crystalline polymer (a polyamide, Ny6). Poly(styrene-co-maleic anhydride) was used as a compatibilizer. The fracture toughness was measured using an asymmetric double cantilever beam test (ADCB). The adhesion strength increased with bonding time, passed a peak value, and then reached a plateau for each temperature series higher than 190 deg C. The fracture toughness also increased with the bonding temperature, passed a peak around 200 deg C, and then decreased with higher bonding temperature. This behavior appears more explicitly for an amorphous polymer/semi-crystalline pair than for a semi-crystalline polymer pair. The variation in the fracture toughness with annealing time and temperature could be plausibly explained by the occurrence of two different failure mechanisms: adhesive failure at the interface at early times and when the annealing temperature is low, and cohesive failure between chains at the interface and the bulk side of PS at later times and at high annealing temperatures due to decreased chain entanglements. No matter whether the polymers were amorphous or semi-crystalline, a change between these two failure mechanisms was generally observed in most polymer interfaces as long as the molecular weights of both polymers were large enough.