Most preferably, R1 is a linear or branched alkyl group having from about 16 to about 22 carbon atoms and R4 is methyl, R2 in each of the x (R2O) groups is ethylene, R3 is hydrogen, and x is an average number from about 1 to about 5, or R1 is a linear or branched alkyl group having from about 8 to about 15 carbon atoms and R4 is methyl, R2 in each of the x (R2O) groups is ethylene, R3 is hydrogen,