Synthesis of PPS by copolymerization and two-stage polymerization and their thermal properties

Abstract

For the purpose of increasing molecular weight of poly (phenylene sulfide), PPS, copolymerization method and two-stage polymerization method were investigated. The thermal properties and molecular weight of copolymers and homopolymers were determined by DSC thermal analyzer and high temperature (210 degrees C) GPC with 1-chloronaphthalene as eluent, respectively. Copolymers were prepared by the reaction of Na2S . 9H(2)O (SS) with p-dichlorobenzene (p-DCB) and m-dichlorobenzene (m-DCB) or 1,2,4-trichlorobenzene (TCB) in N-methyl-2-pyrrolidinone (NMP) solvent at 250 degrees C. In case of the PPS copolymers synthesized by the reaction of m-DCB/p-DCB/SS, molecular weight, T-g's, and T-m's were lower than those of PPS homopolymer. On the other hand, the T-g's of copolymer synthesized by the reaction of TCB/p-DCB/SS increased with increasing amount of TCB comonomer and the use of minor amount (2 mole%) of TCB comonomer gave higher molecular weight polymer than PPS homopolymer. Two-stage polymerization of PPS reported Kureha company and a simplified direct two-stage polymerization were compared with one-stage polymerization of PPS with increased reaction time or m-DCB and TCB copolymerization. It was found that PPS homopolymer by the simplified two-stage polymerization method gave higher molecular weight PPS sample than those by the one-stage polymerization with increased reaction time or copolymerizations