(I) R3 O(R2 O)c (R'O)b (CH2)a SiR2 (OSiR2)y (CH2)a (OR')b (OR2)c OR3 wherein each R is a substituted or unsubstituted hydrocarbon radical, R' is --CH2 CH2 --, R2 is R' or ##STR1## R3 is hydrogen or a substituted or unsubstituted hydrocarbon radical, a is a positive integer, b plus c, either of which may be zero, equal from about 1 to about 50, inclusive, and y is a positive int