Preparation and properties of phosphorylated and crosslinked poly(vinyl alcohol)/bisphenol A–epoxy resin membranes for fuel cell applications

Abstract

To overcome the strong dependence of the conductivity on the relative humidity and the lower thermal stability at high temperature of perfluorosulfonate polymers and the leaching-out problem of phosphoric acid doped membranes, a series of phosphorylated and crosslinked poly(vinyl alcohol) (PVA)/bisphenol A-epoxy resin [diglycidyl ether of bisphenol A (DGEBA)] membranes were prepared. The membrane properties were characterized by Fourier transform infrared spectra, solubility, thermogravimetric analysis, water uptake, swelling ratio, ion-exchange capacity (IEC), small-angle X-ray scattering, and proton conductivity measurements. The results show that the crosslinked PVA/DGEBA membrane had a higher thermal stability (T d ! 250 C) than the pure PVA membrane (T d ! 220 C) and that the phosphorylated and crosslinked PVA/DGEBA membranes (IEC ¼ 5.54 mmol/g) with a low volume swelling ratio (7.21%) could achieve a maximum proton conductivity of 2.51 Â 10 À3 S/cm at a temperature as high as 150 C in anhydrous conditions V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: [3071][3072][3073][3074][3075][3076][3077][3078][3079] 2011

Fabrication of Porous Polyimide Membrane with Through‐Hole via Multiple Solvent Displacement Method

“…Table 2 summarized the comparison of thermal properties of the fabricated PI membranes from this study (type K and J) and other kinds of porous membranes. It is worth nothing that both types of fabricated PI membranes (type K and J) Air Permeability (Gurley value; s/100 cc) [28] Solubility Parameter [27] exhibit a higher decomposition temperature and the remaining weight at 800 °C than the porous membranes fabricated from poly(vinyl alcohol), [29] polyvinylidene fluoride, [30] and cellulose acetate. [31] Therefore, these fabricated PI membranes possessed high thermal properties and excellent thermal stability at high temperatures, compared to other kinds of materials which had already been used as a microfiltration (MF) or ultrafiltration (UF).…”

“…To complete imidization, the temperature was kept stable at 300 °C for 30 min. [32] Then, the desired porous PI membrane was Poly(vinyl alcohol) [29] 220-300 15 (at 500 °C) Polyvinylidene fluoride [30] 460-480 25 (at 800 °C)…”

Tribological properties of PBO fabric composites modified by poly (vinyl alcohol)

“…In Figure , in both air‐300°C and Ar‐300°C conditions [Figure (a, b)], there are mainly C, O, and P elements on the fabric surface. In the presence of H 3 PO 4 , crosslinking and dehydration reaction of PVA leads to form a network polymer containing P–O–C structure . The crosslinked polymer coated on the fabric surface enhanced significantly the surface energy of fabric.…”

“…In air‐500°C and Ar‐500°C conditions [Figure (c, d)], the crosslinked PVA could be decomposed and carbonized . The P–O bonds were broken and the –OH of PVA was dehydrated, and the P elements were eliminated by the heat treatment and subsequent washing process. Thus the P elements fail to be detected in the fabric modified at Air‐500°C and Ar‐500°C, and the content of C element increases from 66% to 80%.…”

Phosphorylated Poly(vinyl alcohol) Electrospun Mats for Protective Equipment Applications

“…In the first instance, partially phosphorylated PVA attracted special attention in research and industry communities due to its improved non-flammability, ability to form complexes with metals, and possibility to produce anionic polyelectrolyte hydrogels or cation exchange resins [ 23 , 24 ]. Currently, partially phosphorylated PVA is being investigated for potential biomedical applications [ 25 ].…”