Alternative Method of Crosslinking Poly(vinyl alcohol) for Hydrophilic Pervaporation Membrane Formation: Free Radical Initiation with Potassium Persulfate

摘要

Pervaporation with hydrophilic polymer membranes for ethanol dehydration is a promising alternative to conventional methods such as dehydration with molecular sieves. Poly(vinyl alcohol) (PVA) is the benchmark solvent dehydration membrane material. Standard methods of crosslinking PVA involve the use of di-aldehydes or di-acids, such as glutaraldehyde (GA), and thermal curing. The bonds formed during traditional PVA crosslinking typically include hemi-acetals, ethers, and esters, which are hydrolytically unstable, limiting the operating temperature and water concentration ranges of the resulting membranes. In order to minimize membrane area for pervaporation systems or to operate in vapor permeation mode, high temperature operation is necessary.