Synthesis and characterization of ABA triblock copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) as A blocks and tetramethyl bisphenol‐A polysulfone as B blocks

Abstract

Abstractα, β‐Bis(hydroxyphenol) tetramethyl bisphenol‐A polysulfone (PSUT) was synthesized by two different methods, one using a strong base, the other using a weak base. The bifunctional polysulfone containing tetramethyl bisphenol‐A chain ends was exploited as a model telechelic that can be used for the preparation of ABA triblock copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as A segments and PSUT as B segments. PSUT and PPO were incorporated into triblock copolymers by an oxidative coupling copolymerization of PSUT with 2,6‐dimethylphenol or by the redistribution of PPO in the presence of PSUT. The mechanism of block copolymerization is discussed. DSC studies indicate that short immiscible PPO and PSUT segments incorporated into a triblock copolymer do not exhibit phase separation. Polymer blends of the PPO–PSUT–PPO triblock copolymers with PPO homopolymer were analyzed by DSC. Both miscible and phase‐separated blends can be prepared depending on the molecular weight of both PPO homopolymer and of the PPO segment present in the triblock copolymer. Polymer blends of the PPO–PSUT–PPO triblock copolymer with PSUT were miscible at all compositions.