Phenylene Sulfide Sulfone Research Articles

Viscoelastic Behavior of the Crystallization of Poly (phenylene sulfide sulfone) from N-methylpyrrolidone Solutions

The isothermal crystallization of poly (phenylene sulfidesulfone) (PPSS) from N‐methylpyrrolidone (NMP) solutions has been monitored by a viscoelastic technique. We have observed four characteristic changes which occur with increasing time in 20 wt % solution at 24 °C; (i) a decrease in η*, (ii) a steep increase in G’, (iii) a slight decrease in η*, and (iv) an increase in η* and G’. These changes indicate the crystallization process from a nucleation to an aggregation. Further, the crystallization at several temperatures and of poly (ethylene terephthalate) (PET), poly (butylene terephthalate) (PBT) melts was measured similarly. It was found that the rate of crystallization of PPSS from NMP solutions is very slow, and its temperature dependence is very small.

The Major Developments of the Evolving Reverse Osmosis Membranes and Ultrafiltration Membranes

The current status of reverse osmosis and ultrafiltration membranes are reviewed with the view for the future. In the case of reverse osmosis (RO) membranes, as examples, new crosslinked aromatic polyamide membranes exhibited the superior separation performance with the sufficient water permeability, the high tolerance for oxidizing agents and chemicals. Ultrafiltration (UF) membrane based on poly(phenylene sulfide sulfone)(PPSS) also exibited the superior separation performance with the high solvent, heat and fouling resistance.