EFFECTS OF THE MULTIPHASE NATURE IN ABS AND RELATED SYSTEMS ON THERMAL OXIDATIVE-DEGRADATION AND STABILIZATION

Multiphase polymer blends contain compositionally distinct polymeric domains which can differ significantly in oxidative stability. Because the solubility parameters of the polymeric components will also differ, stabilizer concentrations in each phase may not be equal. This morphological aspect to the oxidation process was investigated by examining the behavior of the phase components in ABS. It is shown that the effects of rubber phase level on the oxidation process can be interpreted in terms of stabilizer partitioning. Data utilizing microscopy techniques to assess stabilizer concentrations in the rubber and thermoplastic phases in ABS and related model rubber systems are presented. Partitioning behavior is shown to depend on both additive and polymer composition and correlate to calculated solubility parameters.