Polymer composite of rigid and flexible molecules: Blend systems of poly(p‐phenylene terephthalamide) and ABS resin

Homogeneous coagulant of poly( p ‐phenylene terephthalamide) (PPTA) and ABS resin was obtained by pouring the dimethylsulfoxide solution of N ‐sodium PPTA and ABS into acidic water. Transmission electron microscopic observation proved that PPTA was dispersed in the matrix in a form of microfibril with a diameter of 10–30 nm. The T g of the resin component in ABS shifted to higher temperatures with increasing fraction of PPTA. Stress‐strain behavior of the polymer composite showed increased tensile modulus and strength with addition of PPTA. The transition temperature from brittle to ductile fracture, however, shifted to higher temperature resulting in lower extensibility. Incorporation of the block copolymer of PPTA and polybutadiene into ABS improved the ultimate extensibility, i.e., increased toughness was provided compared with the simple composite systems of ABS and PPTA microfibrils. Scanning electron microscopic observation showed that the polymer composite made with the block copolymer generated many crazes upon deformation, while the composite with PPTA homopolymer fractured without remarkable craze formation. Thus, a new type of thermoplastic with improved mechanical properties was obtained by use of PPTA block copolymer as compatibilizer.