Effect of crosslinkers on the preparation and properties of ETFE‐based radiation‐grafted polymer electrolyte membranes

Abstract

This study concerns a comparative study of three crosslinkers, divinylbenzene (DVB), 1,2-bis(p,p-vinylphenyl)ethane (BVPE), and triallyl cyanurate (TAC) crosslinked poly(ethylene-co-tetrafluoroethylene) (ETFE)-based radiation-grafted membranes, which were prepared by radiation grafting of p-methylstyrene onto ETFE films and subsequent sulfonation. The effect of the different types and contents of the crosslinkers on the grafting and sulfonation, and the properties such as water uptake, proton conductivity, and thermal/chemical stability of the resulting polymer electrolyte membranes were investigated in detail. Introducing crosslink structure into the radiation-grafted membranes leads to a decrease in proton conductivity due to the decrease in water uptake. The thermal stability of the crosslinked radiation-grafted membranes is also somewhat lower than that of the noncrosslinked one. However, the crosslinked radiation-grafted membranes show significantly higher chemical stability characterized in the 3% H 2 O 2 at 50°C. Among the three crosslinkers, the DVB shows a most pronounced efficiency on the crosslinking of the radiationgrafted membranes, while the TAC has no significant influence; the BVPE is a mild and effective crosslinker, showing the moderate influence between the DVB and TAC crosslinkers.

Suitability of some fluoropolymers used as base films for preparation of polymer electrolyte fuel cell membranes

“…In a three-necked flask, 94 ml of styrene (Wako) and 6 ml of DVB (Wako, 55% mixture of isomers, 45% of ethylvinylbenzene) were added and then deaerated by nitrogen bubbling. Therefore, the volume concentration of the DVB crosslinker in the monomer solution is about 3 vol.%, which showed the highest reaction rate for the grafting of styrene into ETFE films in our previous study [29]. After 30 min, the monomer solution was heated to 60 • C and the preirradiated films were added for grafting.…”

Novel hybrid polymer electrolyte membranes prepared by a silane-cross-linking technique for direct methanol fuel cells

“…However, ionic cross-linking loses its effect at elevated temperatures. Chemical cross-linking by covalent bonding not only provides membranes with excellent thermal and mechanical stability, but also retains the characteristics of being cross-linked even at high temperatures [19][20][21][22].…”

Hydrocarbon proton-conductive membranes prepared by radiation-grafting of styrenesulfonate onto aromatic polyamide films

“…This method has advantages such as low preparation costs, easy and controllable introduction of graft chains and applicability with various polymer films. In our previous reports, we developed proton-conductive membranes by radiation-grafting of styrene to fluoropolymer films and subsequent sulfonation [20][21][22][23][24][25][26]. After the sulfonation, the fluoropolymer base films remained their excellent properties in the proton-conductive membranes.…”