wherein R1 and R4 are independently hydrogen, or a linear or branched alkyl group having from 1 to about 30 carbon atoms and at least one of R1 and R4 is an alkyl group, R2 in each of the x (R2O) groups is independently C2???C4 alkylene, R3 is hydrogen, or a linear or branched alkyl group having from 1 to about 4 carbon atoms, and x is an average number from 1 to about 60; or