m satisfy 0.5<n/(n+m)???1, Y is a hydrogen atom or is a group selected from a monovalent hydrocarbyl group that contains no more than 20 carbon atoms and that does not contain an aliphatically unsaturated bond, an acyl group that contains no more than 20 carbon atoms and that does not contain an aliphatically unsaturated bond, and a glycidyl group, p is an integer from 1 to 6, X is a divalent gro