The effect of a polypyrrole coating on the thermal stability of microporous polyethylene membranes

Microporous polyethylene (PE) membranes were coated on both sides with a polypyrrole (PPy) overlayer. PPy was deposited also on the walls of pores. Thermodeformation measurements indicate that the hard framework produced by rigid-chain PPy controls the mechanical properties of composite membranes. FTIR spectroscopy was used to detect oxidative processes in both polymer components above 200 degreesC. Elemental analysis showed that the nitrogen content remains at high level, even after the treatment of membranes in air at 300 degreesC, indicating that the decomposition involved mainly PE while PPy was much more stable. The changes in surface relief after annealing were assessed with electron microscopy. No oxidative processes were identified in the FTIR spectra of composites after annealing in vacuum, even after treatment at 300 degreesC. (C) 2002 Elsevier Science Ltd. All rights reserved.