dc.description.abstract |
Poly(p-phenylene sulfide), PPS and related polymers such as poly(p-phenylene sulfide sulfone), PPSS and poly(p-phenylene sulfide ketone), PPSK were prepared from sodium sulfide (SS) and three different comonomers p-dichlorobenzene (DCB), 4-chlorophenylsulfone (CPS), and 4,4'-dichlorobenzophenone (DCBP), respectively, employing N-methyl pyrrolidinone (NMP) as solvent under high temperature (250 similar to 290 degrees C) and pressure (120 similar to 180 psi). The molecular weight of polymers were determined by high temperature (210 degrees C) GPC with 1-chloronaphthalene as eluent against polystyrene standards. The thermal transition temperatures and thermal stability of polymers, were studied by DSC and TGA. PPS showed maximum yield at 250 degrees C of reaction temperature, whereas PPSS and PPSK which have electron-withdrawing groups gave maximum yield at 200 degrees C. As for the stoichiometry of comonomers, PPS exhibited highest yield of 83% in the range of [SS]/[DCB] = 0.75/1 similar to 1.25/1. The yield of PPSK and especially PPSS were highly sensitive to stoichiometric ratio of [SS]/[DCBP] and [SS]/[CPS] decreased sharply. As for the content water as additive in the reaction mixture, PPS and PPSK showed maximum yield at [H2O]/[Na2S]=9/1. PPSS could nor be obtained under [H2O]/[Na2S]=4.5/1, but the maximum yield was shown at [H2O]/[Na2S]=13.5/1. From the DSC study, PPS and PPSK were crystalline materials with T-m=279 and T-m=344 degrees C, respectively. PPSS was amorphous material with only T-g being detected at 210 degrees C |
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