Grafting poly(phenylene oxide) with poly(vinylphosphonic acid) for fuel cell membranes

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Abstract

Densely phosphonated electrolyte membranes were prepared from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) grafted with poly(vinylphosphonic acid) (PVPA) side chains. In the first step, PPO was lithiated in solution at room temperature by adding n-butyllithium to form an anionic macroinitiatior. Next, diethyl vinylphosphonate (DEVP) was anionically polymerized from the lithiated sites at -78 °C. This protocol gave good control over the density of the grafting sites and the copolymer composition. Films of copolymers containing between 35 and 74 wt% poly(diethyl vinylphosphonate) were first cast from solution, and subsequently fully hydrolyzed to produce transparent flexible proton conducting membranes of PPO-graft-PVPA containing up to 6 mmol phosphonic acid groups per gram dry copolymer. Thermogravimetric analysis showed anhydride formation at increasing temperatures above 100 °C with no copolymer degradation occurring until nearly 400 °C under air. Fully hydrated membranes reached proton conductivities above 1 mS/cm at -20 °C and 80 mS/cm at 120 °C.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Sciences

Keywords

  • poly(vinylphosphonic acid), anionic graft polymerizations, polyelectrolytes, grafting, poly(phenylene oxide), polymer electrolyte membrane fuel cells, ionomers
Original languageEnglish
Pages (from-to)739-746
JournalPolymer Chemistry
Volume1
Issue number5
Publication statusPublished - 2010
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Polymer and Materials Chemistry (LTH) (011001041)