Physical properties of microporous membranes prepared by hydrolyzing cellulose/soy protein blends

Abstract

Microporous membranes (CS1- n) were prepared by blending cellulose and soy protein isolate (SPI) in 6 wt.% NaOH/5 wt.% thiourea aqueous solution. The membranes CS1- n were hydrolyzed with 5 wt.% NaOH aqueous solution to obtain membranes CS2- n. The structure and properties of the membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), the flow rate method, and tensile testing. The blend membranes CS1- n exhibited mesh structure woven by SPI and cellulose, and the membranes CS2- n possess microporous structure as a result of the removal of SPI during the NaOH-hydrolysis process. The apparent pore size (2 r e) measured with SEM, the mean pore size (2 r f) obtained by the flow rate method, and the water ultrafiltration rate (UFR) of the CS1- n and CS2- n membranes increased with an increase in SPI content, and are higher than those of the pure cellulose membrane and previous membranes. The values of 2 r f (47.7–77.2 nm) and UFR (28–53.5 mL h −1 m −2 mmHg −1) of the microporous membranes CS2- n are higher than those of the corresponding membranes CS1- n, because of removing of most of SPI by NaOH-treatment. The microporous membranes also kept high tensile strength in both dry and wet states. In addition, the membranes CS2- n containing a small amount of SPI are suitable for the culture of Vero cells. Therefore, the membranes could be used as candidates for application in separation technology and biomedical fields.