Inducing a network structure of rubber phase: an effective approach to toughen polymer without sacrificing stiffness

Abstract

One drawback of rubber/elastomer-toughened polymer is that the improved toughness is accompanied with a loss in stiffness. Interestingly, we find herein that, by combination of 15 phr elastomer component, chlorinated polyethylene (CPE), and a rigid component, poly(acrylonitrile-styrene-acrylic) (ASA), the impact toughness of a poly(vinyl chloride) (PVC)/α-methylstyrene-acrylonitrile copolymer (α-MSAN) (70/30) blend was considerably increased from 15.0 kJ m⁻² to 60.0 kJ m⁻² without sacrificing stiffness; while CPE or ASA alone did not effectively toughen the PVC/α-MSAN (70/30) blend. The reason for the improvement is due to the induced network structure consisting of ASA (the inner/encapsulated part) and CPE (the outer part). The network structure is attributed to the selective interaction between ASA and CPE, the enhanced elasticity of the ASA-localized CPE phase, and the change in viscosity ratio between the ASA-localized CPE phase and the PVC/α-MSAN phase. This work provides a facile method to overcome the shortcomings of rubber-toughened polymer, which involves inducing a network structure by controlling thermodynamic and kinetic factors.