Particularly preferred solvents and plasticizing agents are those derived from graft copolymers of ethylene oxide and oligomers of poly(dimethyl siloxane) of general formula X, as described in U.S. Pat. No. 5,362,493, ##STR5## wherein o is an integer equal to or greater than 1; p is an integer equal to or greater than 0 and less than about 30; and, the ratio t/s is equal to or greater than 0.