Surface glass transition of miscible amorphous polymers blends

Abstract

The surface glass transition temperature (Tgsurface) of the bulk samples of miscible blends formed of amorphous polystyrene (PS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) has been characterised in terms of an adhesion approach we proposed recently. Tgsurface has been measured as the temperature transition “occurrence of autoadhesion–nonoccurrence of autoadhesion” by employing a lap-shear joint mechanical testing method. The effect of the reduction in Tgsurface with respect to the glass transition temperature of the bulk (Tgbulk), which had been observed earlier in pure homopolymers, has been found to exist in the blends of PS with PPO as well. The values of this effect for the blends have been compared with those for pure homopolymers, and the differences found have been discussed.