Reactive compatibilization of blends of poly(2,6-dimethyl-1,4-phenylene ether) and poly(butylene terephthalate)

This paper deals with the development of a compatibilized polymer blend bas ed on poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and poly(butylene tereph talate) (PBT). Blending of PET with PPE, with PET as the continuous phase, could yield materials which are mutually incompatible, and the phase morpho logies obtained during blending of these polymers are generally unstable. W hen PPE is functionalized selectively, in situ compatibilization during pro cessing is feasible. Due to the formation of segmented copolymers, which ac t as compatibilizing agents, stabilization of the morphology obtained durin g blending is feasible. Different types of reactive PPE polymers were inves tigated, e.g. PPE with hydroxyalkyl, carboxylic acid, methyl ester, amino a nd t-BOC protected amino endgroups. These groups are positioned either in t he middle of the chain or as the endgroup. All these reactive PPE polymers result in better compatibilization after mixing with PET versus unfunctiona lized PPE. PPEs with carboxylic acid endgroups proved to be the most effici ently compatibilized with PET, for the PET type employed in this study. Pro moters, which catalyze or take part in the coupling between PET and/or func tionalized PPEs, such as triphenyl phosphite (TPP), sodium stearate, titani um (IV) isopropoxide and epoxy resins, were used in order to improve compat ibilization of the PPE/PBT blends. The use of these promoters proved to giv e synergetic compatibilization in combination with functionalized PPEs. (C) 2001 Elsevier Science Ltd. All rights reserved.