Siloxanes and Silicones, di-Me, Bu group- and 3-[(2-methyl-1-oxo-2-propen-1-yl)oxy]propyl group-terminated; Siloxanes, di-Me, Bu group- and 3-[(2-methyl-1-oxo-2-propenyl)oxy]propyl group-terminated, di-Me, Bu group- and 3-[(2-methyl-1-oxo-2-propenyl)oxy]propyl group-terminated