AbstractA thermoplastic elastomeric blend was introduced based on high-density polyethylene and styrene-butadiene rubber (SBR). The morphology of the blend system was found to change from two-phase to co-continuous, depending on the polyethylene (PE) concentration. The thermo-mechanical measurements showed that, at the PE concentrations, which seemed to have a co-continuous morphology, the SBR inclusions were very fine. The fineness of the SBR domains resulted in a 20° depression of the glass transition temperature (Tg) of the SBR phase. This was attributed to the smooth interfaces at which the SBR chain sensed a higher free volume as compared with that in bulk SBR. A model correlating thin polymer thickness to the Tg of the confined polymer in the films was employed to correlate SBR domain size to the experimental Tg measured. The adjusting parameters A=129 and δ=1.45 were successfully used to fit the experimental data.
Effect of the morphology of two phase polymer blends on glass transition temperature