| abstract |
Method for avoiding network defects due to unwanted secondary reactions during the polymerization in water-swellable hydrophilic polymers which contain polymers prepared by free radical (co)polymerization of one or more hydrophilic monomers of the formula I <IMAGE> wherein R1 is hydrogen, methyl or ethyl, R2 is the group -COOR4, the sulphonyl group, the phosphonyl group, the phosphonyl group-esterified by (C1-C4)-alkanol or a group of the formula <IMAGE> R3 is hydrogen, methyl, ethyl or the carboxyl group, R4 is hydrogen, amino or hydroxy-(C1-C4)-alkyl and R5 is the sulphonyl group, the phosphonyl group or the carboxyl group, or grafting (co)polymerization of one or more hydrophilic monomers of the formula I onto a grafting base, using a free radical initiator which forms three or more free radical sites per molecule. |