Ion exchange membranes (IEMs) were prepared by preirradiation induced grafting of styrene with or without divinylbenzene (DVB) into crosslinked polytetrafluoroethylene (RX-PTFE) films and successively sulfonated by chlorosulfonic acid. The effects of the DVB concentration and solvent on the kinetic of the graft polymerization were studied. The ion exchange capacity (IEC) values of the prepared membranes ranging from 1.5 to 2.8 mequiv/g were obtained. The degree of swelling increased with the increase in the degree of grafting, while higher crosslinking density of both the RX-PTFE matrices and the grafts suppressed the degree of swelling. The chemical stabilities of the IEMs were tested by recording the weight of the membranes being soaked in hot H 2O2 solutions. The weight-time curves of the prepared membranes showed one-step quick decrease due to the decomposition of the poly(styrene-sulfonic acid) (PSSA) grafts. Higher crosslinking density in both the RX-PTFE matrices and the grafts improved the chemical stability of the IEMs. The ionic conductivity of the IEMs increases with the increase in the IEC values. The IEMs with IEC values higher than 2.2 mequiv/g hold the higher ionic conductivity than that of Nafion® 112 membrane.
- Crosslinked polytetra-fluoroethylene
- Ion exchange membrane
- Pre-irradiation induced graft polymerization
ASJC Scopus subject areas
- Polymers and Plastics