Effects of coagulation bath temperature on structure and performance of poly (vinyl butyral) hollow fiber membranes via thermally induced phase separation

Abstract

Poly (vinyl butyral) (PVB) hollow fiber membranes were fabricated via thermally induced phase separation (TIPS). The effects of coagulation bath temperature (CBT) on the structure and performance of membranes were investigated in detail. The morphologies of the membranes were studied by scanning electron microscopy (SEM), the performances of water permeability, rejection, breaking strength and elongation were measured, respectively. The results indicate that all the membranes have the asymmetric morphology and the thickness of the skin layer decreases and the pore size of the outer layer increases with the increase of CBT. The permeability of membranes prepared at air gap 1.0 cm and take-up speed 0.253 m/s increases from 1.047×10−7 to 5.909×10−7 m3/(m2·s·kPa) with the CBT increasing from 20 °C to 40 °C, and sharply increases to 35.226×10−7 m3/(m2·s·kPa) once the CBT arrives at 50 °C. While the carbonic ink rejections have no significant decrease, totally exceed 98%, but that of acid-maleic acid copolymer greatly decreases with the increase of CBT. Both the breaking strength and elongation decrease with the increase of CBT.