SECONDARY RELAXATIONS IN A MISCIBLE POLYMER SYSTEM - POLY(HYDROXY ETHER OF BISPHENOL-A) POLY(EPSILON-CAPROLACTONE) BLENDS

Dynamic mechanical measurements have been used to study the alpha- and beta-relaxation in blends of Phenoxy (PH) and poly(epsilon-caprolacto ne (PCL). Single glass transition temperatures between those of the or iginal polymers are obtained. The crystallinity causes a significant i nfluence on the T-g values, giving rise to a positive deviation from t he T-g data obtained from DSC measurements. Regarding the beta-relaxat ion, it is observed that the two polymers relax independently of each other in the blend, although the shift of the Phenoxy beta-relaxation to lower temperatures as PCL concentration increases is a symptom of t he influence of this polymer on the secondary relaxation of Phenoxy. W e discuss this influence by comparing the Phenoxy beta-relaxations of PH/PCL blends with those of acetylated Phenoxy, PH/PEO blends, and ant iplasticized Phenoxy and analyzing the effect of hydrogen-bonding inte ractions in the rotation of the hydroxy ether groups of Phenoxy.