| abstract |
The molecular weight of linear and non-linear poly(arylene sulfide) PAS is increased by reprecipitation. The reprecipitation is accomplished by heating PAS to its dispersion temperature in a mixture of polar organic solvent, water, and alkali metal carboxylate until the PAS is dispersed in the mixture. Water is then added to cause a phase separation, then the total mixture is slowly cooled and a PAS of increased molecular weight is recovered. PAS slime, a waste product of some polymerization processes, can also be reprecipitated, as above, to recover useful particulate PAS that would normally be discarded. |