Graft copolymers and process for their preparation

A graft copolymer from a polymer having a hydroxyl-containing backbone (HCB) having the structure R.sup.1 (OH).sub.n wherein n represents an integer in the range from 1 to about 400, wherein from 1 to about 200 are pendant OH groups, the remaining groups, if any, being terminal, and, an oxirane monomer, said graft copolymer having the structure

• R.sup.1 [O[A--.sub.a --H].sub.b (III)
• wherein, R.sup.1 represents the residue of said HCB;
• A represents a single ring-openable oxirane monomer selected from the group consisting of (i) an aliphatic or aromatic glycidyl ether having the structure ##STR7## wherein R.sup.2 and R.sup.3 is each independently selected from the group consisting of hydrogen, alkyl having from 1 to about 40 carbon atoms, haloalkyl, alkenyl having from 2 to about 40 carbon atoms, haloalkenyl, alkoxyalkyl having from 1 to about 40 carbon atoms, aryl(Ar) or substituted aryl(Ar-Q), wherein Q is selected from the group consisting of alkyl, haloalkyl each having from 1 to about 10 carbon atoms, alkenyl and haloalkenyl each having from 2 to about 10 carbon atoms;
• and, (ii) a haloalkyl epoxide having the structure ##STR8## wherein X is a halogen atom and R.sup.4 and R.sup.5 is each independently selected from the group consisting of hydrogen and alkyl having from 1 to about 4 carbon atoms;
• so that the molecular weight of the resulting graft copolymer is directly proportional to the amount of monomer converted;
• and,
• a represents an integer in the range from about 1 to about 100;
• b represents an integer in the range from 1 to about 400;
• so that the molecular weight of each grafting chain of said graft copolymer is in the range from about 100 to about 10,000, and the molecular weight of the overall graft copolymer is in the range from about 2000 to about 500,000.