Local Glass Transition Temperature T_g(z) Profile in Polystyrene next to Polybutadiene with and without Plasticization Effects

摘要

Rubber toughening of glassy polystyrene (PS) has been manufactured commercially for decades as high impact polystyrene, where rubbery polybutadiene (PB) inclusions are added to modify the PS matrix response to deformation and impact. In this study, measurements of the local glass transition temperature T_g(z) of PS next to PB rubber are presented, expanding the previous data to a polymer with a much lower Tg value (PB T_g~(bulk) = -96 °C). After accounting for a small molecule additive present in the commercial PB sample that would otherwise migrate over to the PS domain causing plasticization, it is found that the T_g(z) profile in PS next to PB is consistent with previous results. It is also demonstrated that these broad and asymmetric experimentally observed T_g(z) profiles are not caused by the migration of low molecular weight chains across the interface by comparing samples made with two different poly(n-butyl methacrylate) molecular weights.