Influence of polymerization conditions on the molecular structure stability and physical behavior of poly(phenylene sulfide sulfone) homopolymers

The influence of polymerization conditions on the nucleophilic substitution step polymerization of high molecular weight poly(phenylene sulfide sulfon e) (PPSS) has been studied and optimized with respect to molecular weight f or the system 4,4'-dichlorodiphenylsulfone, sodium sulfide, NMP/water/sodiu m acetate. Reactions at about 200 degrees C for 3 h were observed to produc e the highest molecular weight. Longer reaction times and/or higher tempera ture degrade the molecular weight, probably because of base-catalyzed react ions on the activated backbone. These polymeric materials are amorphous wit h T-g values up to 222 degrees C. However, the systems show some ordering i n the presence of organic liquids, and this allows for an unexpectedly high degree of solvent resistance for molded films. The materials also show a h igh refractive index of 1.69 and cone calorimetry showed the PPSS system to have very good fire resistance. (C) 2000 Elsevier Science Ltd. All rights reserved.