Exploring Torlon/P84 co-polyamide-imide blended hollow fibers and their chemical cross-linking modifications for pervaporation dehydration of isopropanol

A research study has been conducted to fabricate and chemically modify Torlon® 4000T and Torlon/P84 co-polyamide-imide blended hollow fibers as new materials for the dehydration of isopropanol (IPA). It has been found that Torlon/P84 blends are miscible, as confirmed through the single glass transition temperatures (Tgs) detected by differential scanning calorimetry (DSC). Both pure and blended hollow fibers fabricated from the dry-jet wet-spinning process do not show sufficient resistance to suppress water and IPA induced swelling, whereas cross-linked pure Torlon hollow fibers show only marginal improvement. However, the Torlon/P84 blended fibers display enhanced separation performance after chemical cross-linking modification with the aid of p-xylenediamine. It is believed that the p-xylenediamine induced cross-linking reactions result in greater chain packing and the reduction of free volume. The highest separation factor obtained was 185 ± 8 for the 85/15 wt.% IPA/H2O feed solution and the total permeation flux obtained was 1000 ± 45 g/m2 h.