B. Gupta et al., THERMAL-STABILITY OF PROTON-EXCHANGE MEMBRANES PREPARED BY GRAFTING OF STYRENE INTO PRE-IRRADIATED FEP FILMS AND THE EFFECT OF CROSS-LINKING, Die Angewandte makromolekulare Chemie, 256, 1998, pp. 81-84
The thermal stability of crosslinked ion exchange membranes, prepared
by pre-irradiation grafting of styrene into FEP films in the presence
of divinylbenzene (DVB) as a crosslinker and subsequent sulfonation of
the grafted films, was investigated by thermogravimetry. The formatio
n of different fragments with increasing temperature was monitored by
FTIR. Pre-irradiation leads to destabilization of the FEP backbone, sh
owing both earlier depolymerization and substantial redistribution of
monomer formation between the two main degradation steps. The presence
of DVB had clear effects on the thermal degradation pattern of the su
lfonated graft copolymer membrane. Desulfonation occurred at a lower t
emperature whereas dearomatization was observed to shift to higher tem
peratures.