More preferably, R1, R3, R4 and R5 are independently hydrogen or a linear or branched alkyl group having from about 1 to about 18 carbon atoms or ???(R6O)xR7, R2 is a linear or branched alkylene group having from about 1 to about 6 carbon atoms, R6 in each of the x (R6O) and y (R6O) groups is independently ethylene or propylene, R7 is hydrogen, or a linear or branched alkyl group having from 1 to