Formation of pervaporation membranes from polyphosphazenes having hydrophilic and hydrophobic pendant groups: Synthesis and characterization

Abstract

A series of new polyphosphazene polymers were synthesized using three different pendant groups with the goal of probing structure–function relationships between pendant group substitution and polymer swelling/water flux through thin dense films. Formation of polymers with relative degrees of hydrophilicity was probed by varying the stoichiometry of the pendant groups attached to the phosphazene backbone: p‐methoxyphenol, 2‐(2‐methoxyethoxy)ethanol, and o‐allylphenol. The polymers in this study were characterized using NMR, thermal methods, and dilute solution light‐scattering techniques. These techniques revealed that the polymers were amorphous high polymers (Mw = 105–107) with varying ratios of pendant groups as determined by integration of the 1H‐ and 31P‐NMR spectra. Thin dense film membranes were solution‐cast with azo‐bis(cyclohexane)carbonitrile included in the matrix and crosslinked using thermal initiation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 422–431, 2001

Functional Polymeric Materials Based on Main‐Group Elements

“…First described by Stokes at the end of the 19th century and later reinvestigated and popularized by Allcock in the 1960s, polyphosphazenes have emerged as one of the most widely studied classes of inorganic polymers due to their biocompatibility, biodegradability, chain flexibility, and easy chemical tunability. This very unique set of properties has prompted a vast array of applications, principally as biomaterials, but also as components of solar cell and battery electrolytes, gas‐separation membranes, and elastomers . Comprehensive Reviews have already covered the rich synthetic versatility, which spans several decades of dedicated research .…”

Mixed substituent ether‐containing polyphosphazene/poly(bis‐phenoxyphosphazene) blends as membranes for CO2 separation from N2

“…Further manipulation of the phosphazene backbone can be accomplished through a blended pendant group strategy 14,19–21 . Small amounts of other pendant groups can be added that serve to hinder backbone motions, thus raising T g slightly, but also stiffening the backbone enough to give the materials dimensional stability.…”

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

“…The side groups attached to phosphorus atom provide an inherent diversity of physical and chemical properties [1][2][3][4][5][6][7][8][9][10][11][12]. As a result, polyphosphazenes have been studied as material for different types of application, including pervaporation membrane [1,2], gas separation membrane [3][4][5], proton exchange membrane [6,7], nonlinear optical material [8,9] and biosensor [10,11]. Generally, majority membranes for pervaporation based on polyphosphazenes are cross-linked membranes due to the improved chemical and physical stability [1,13].…”