SULFONATED POLYETHERIMIDE SEMIPERMEABLE MEMBRANE

摘要

PURPOSE:To obtain a hydrophilic semipermeable membrane having stable values of physical properties even in hot water and excellent organic solvent resistance, by using sulfonated polyetherimide which is a polymerized sulfone derivative represented by a specific formula. CONSTITUTION:By causing sulfonating agent such as chlorosulfonic acid to drip into a solution of polyetherimide represented by the formula, sulfonated polyetherimide having an ion-exchange capacity of 0.1-6 milli-equivalent/dry resin weight (g) is obtained. Said substance is dissolved uniformly in an excellent solvent such as dimethyl acetamide and a poor solvent such as tetraethylene glycol and vacuum defoaming is applied thereto to make a cast liquid. Said liquid is cast on a glass plate and immediately dipped in a coagulation bath such as water to form a membrane.