Covalently crosslinked water-absorbent graft copolymer

An covalently crosslinked water-absorbent graft copolymer comprising the copolymerization reaction product of one or more water soluble base monomers A and water soluble or water dispersible macromer C, and optionally one or more B monomers copolymerized with said A monomer, wherein said base monomer A consists of a vinyl monomer capable of forming a hydrophilic polymer and having a Tg<20.degree. C., said optional monomer B being different from monomer A and capable of forming a hydrophilic or hydrophobic polymer, and said C macromer forming polymeric sidechains on said graft copolymer and defined by the formula X--(Y).sub.p --Z--R, wherein X is a moiety copolymerizable with monomers A and B or capable of attachment to copolymerized monomers A and B, Y is a divalent linking group, Z is a water-soluble or water-dispersible homo- or copolymeric moiety, R is a terminal group, and p is 0 or 1, with the provisos that when said C macromer is present in an amount of at least 45 percent by weight, then at least 5 percent by weight of a B monomer having a Tg of >20.degree. C. is present, and when said C macromer is present in an amount of 35 percent by weight or less, then at least 5 percent by weight of a B monomer having a Tg of <0.degree. C. is present, and wherein any B monomer present, if hydrophobic, is present in an amount up to 25 percent by weight, each said amounts being based on the total weight of the components A, B and C.