PROCESS TO PREPARE CROSSLINKABLE TRIFLUOROSTYRENE POLYMERS AND MEMBRANES
Described herein is a trifluorostyrene compound that can be used as a monomer to form crosslinkable polymers, and their use as polymer electrolyte membranes.
1 . A compound of Formula IV:
wherein Rf′ is a linear or branched perfluoroalkylene group, optionally containing oxygen or chlorine; T is S, SO, or SO 2 ; n is 1; and X is Br or Cl.
2 . The compound of claim 1 wherein Rf′ is selected from the group consisting of (CF 2 ) r wherein r=1 to 20, (CF 2 CF 2 ) r OCF 2 CF 2 wherein r=1 to 6, and (CF 2 CF(CF 3 )O) r CF 2 CF 2 wherein r=1 to 8.
3 . The compound of claim 2 wherein Rf′ is (CF 2 ) r wherein r=1 to 4.
4 . The compound of claim 1 wherein X is Br.
5 . The compound of claim 1 wherein n is 1 and T is S or SO 2 .
6 . The compound of claim 1 wherein Formula IV is Formula IVa:
7 . A copolymer prepared from the compound of claim 1 .
8 . The copolymer of claim 7 comprising repeat units of Formula (I) and Formula (II):
wherein Rf and Rf′ are independently a linear or branched perfluoroalkylene group, optionally containing oxygen or chlorine; T is independently S, SO, or SO 2 ; n is 0 or 1 in Formula I; n is 1 in Formula II; X is Br or Cl; and Q is F, Br, Cl, or OM wherein M is a univalent cation.
9 . The copolymer of claim 8 wherein (II) is present at 0.01 to 0.10 mole % and (I) is present at 0.99 to 0.90 mole %.
10 . The copolymer of claim 8 wherein Rf and Rf′ are independently selected from the group consisting of (CF 2 ) r wherein r=1 to 20, (CF 2 CF 2 ) r OCF 2 CF 2 wherein r=1 to 6, and (CF 2 CF(CF 3 )O) r CF 2 CF 2 wherein r=1 to 8.
11 . The copolymer of claim 10 wherein Rf and Rf′ are selected from the group consisting of (CF 2 ) r wherein r=1 to 4.
12 . The copolymer of claim 8 wherein Q is F and X is Br.
13 . The copolymer of claim 8 wherein M is H.
14 . The copolymer of claim 8 wherein the copolymer is crosslinked.
15 . The copolymer of claim 8 additionally comprising repeat units of the Formula (VII):
16 . The copolymer of claim 15 wherein (VII) is present at less than 10 mole %.
17 . The copolymer of claim 8 wherein n is 1 in both Formula I and Formula II, and T is S or SO 2 .
18 . The copolymer of claim 8 comprising repeat units (Ia) and (IIa):
19 . A membrane comprising the copolymer of claim 8 .
20 . The membrane of claim 19 wherein Rf and Rf′ are independently selected from the group consisting of (CF 2 ) r wherein r=1 to 20, (CF 2 CF 2 ) r OCF 2 CF 2 wherein r=1 to 6, and (CF 2 CF(CF 3 )O) r CF 2 CF 2 wherein r=1 to 8.
21 . An electrochemical cell comprising the membrane of claim 19 .
22 . The electrochemical cell of claim 21 that is a fuel cell.