Abstract
Phosphonic acid functional polymers are currently of interest because of their high proton conductivity in humidified and anhydrous systems. In addition, heterocyclic compounds are used in anhydrous proton conducting polymer membranes. In that study, a new copolymer based on 1-vinyl-1,2,4-triazole (VTri) and diisopropyl-p-vinylbenzyl phosphonate (VBP) was synthesized, and their thermal, chemical, and proton conducting properties were investigated. The copolymers were synthesized by free radical copolymerization of the corresponding monomers at several monomer feed ratios to obtain P(VTri-co-VBP) copolymers. The copolymer samples were then hydrolyzed to produce poly(vinyl triazole-co-vinyl phosphonic acid) copolymers. The composition of the copolymers was determined by elemental analysis. The copolymerization and hydrolysis reactions were verified by Fourier transform infrared spectroscopy and ion exchange capacity measurements. Thermogravimetry analysis indicates that the copolymers are thermally stable up to 300 degrees C. In order to increase the proton conductivity, the copolymers were doped with H3PO4 at several stoichometric ratios. The proton conductivity increases with triazole and phosphoric acid content. In the absence of humidity, the copolymer electrolyte, P(VTri-co-VBPA)1:0.5 X=2, showed a proton conductivity of 0.005S/cm at 150 degrees C. Copyright (c) 2013 John Wiley & Sons, Ltd.