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Halogen‐Free Polyarylphosphonates and Polyelectrolyte Membranes for PEMFC by Nickel‐Catalyzed Phosphonylation with Silylated Phosphates
Author(s) -
Bock Thorsten,
Mülhaupt Rolf,
Möhwald Helmut
Publication year - 2006
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200600601
Subject(s) - polyelectrolyte , membrane , polysulfone , catalysis , polymer chemistry , chemistry , polymer , ether , trimethylsilyl , chemical modification , materials science , organic chemistry , biochemistry
Summary: The nickel‐catalyzed arylphosphonylation with tris(trimethylsilyl) phosphite (TMSP) is applied to brominated high‐performance (HP) polymers in weakly coordinating high temperature solvents. At elevated temperatures, this affords halogen‐free, soluble, phosphonic acid‐functionalized polyelectrolytes and an unprecedented control of the degree of phosphonylation (ds P ). Brominated polysulfone (PSU) of various degrees of bromination (ds Br ) has been phosphonylated with TMSP in diphenyl ether at 200 °C in the presence of 1–10 mol‐% NiCl 2 . Upon methanolysis, arylphosphonic PSU with ds P up to 223 mol‐% is obtained in near quantitative bromine conversion. Catalyst residues are readily removed during methanolysis. This very versatile two‐step process affords soluble arylphosphonic polymers for casting tough membrane films. In contrast to sulfonated PSU, the arylphosphonic PSU membranes exhibit improved thermal and chemical stabilities, combined with far lower water swelling in accordance with the demands of polyelectrolyte membrane fuel cell (PEMFC) applications.Mass swelling (sw M ) in water of sulfonated (A–C) and phosphonylated PSU (D).