Patent ID: 7176247

Claim:
A water-insoluble interpenetrating polymer network comprising: a first polymer derived from a monomer having the general structure where R 1 is independently in each occurrence H, C 1 –C 4 alkyl, C 1 –C 4 hydroxy alkyl, Cl or Br; Z is a nullity, O, C(O)NR 3 or C(O); R 2 is independently in each occurrence H, C 1 –C 4 alkyl, C 1 –C 4 hydroxy alkyl, C 0 –C 4 SO 3 M or C 0 –C 4 PO 2 H 2 ; R 3 is H, C 1 –C 4 alkyl, C 1 –C 4 hydroxy alkyl, where M is H, Li, Na, K, Zn, Mg, Ca, Ba, Sr, Cs and Al; n is an integer from 1 to 5, inclusive, with the proviso that adjacent carbon atoms lack sulfonic and/or phosphonic acid groups and at least one sulfonic acid or phosphonic acid group is present in the structure; a second monomer copolymerized with said monomer to impart water insolubility to said first polymer; and a second polymer polymerized independently of said first polymer and interpenetrating said first polymer wherein said second polymer is more permeable to water than methanol.