Yawen Huang

Characterization of Poly(Vinyl Alcohol) Membranes Cross-Linked by Aldehyde-Substituting Cyclotriphosphazene

A new type of cross-linker, based on cyclotriphosphazene with six aldehyde groups, was used for the cross-linking of poly(vinyl alcohol) membranes. FTIR-ATR analysis indicated that cyclophosphazene reacted with poly(vinyl alcohol) by forming C–O–C bonds. TGA and DTG analysis showed that cross-linking improved the thermal stability. The swelling degree and pervaporation properties of cross-linked PVA membranes were also characterized. With increasing cross-linker concentration, swelling degrees and flux decrease while separation factors increase. Compared with PVA membranes cross-linked by glutaraldehyde, PVA membranes cross-linked by cyclophosphazene exhibited better selectivity and permeation rate.

Novel cross-linkable polyphosphazene with o-acetyl phenoxide as the pendant group

Abstract A new polyphosphazene which bears o-acetylphenoxide group [NP(o- C6H4-COCH3)]n, PAOP was synthesized. PAOP can be efficiently thermally crosslinked at mild condition using p-phthalaldehyde as cross-linker and sodium hydroxide as catalyst both in solution and solid reaction. It was found that solid reaction gives more products with carbon-carbon double bond. The suggested process of cross-linking reaction was described based on the progress of small molecular reaction. Influence factors of cross-linking reaction including water and temperature were also discussed and it was concluded that water prevents crosslinking and higher temperature causes higher percent conversion. The photochemical reaction of cross-linked PAOP was simply studied using UV and it was demonstrated that carbon-carbon double bond decayed under UV irradiation and more complicated products were obtained.