is methyl, and R???6 is an alkyl group having from 8 to 12 carbon atoms; (iv) CH2???C(COOR???7)CH2COOR???8, wherein R???7 and R???8 are independently an alkyl group having from 8 to 12 carbon atoms; (v) CH3CH???CHCOOR???9, and R???9 is an alkyl group having from 8 to 12 carbon atoms; (vi) R???10C6H4CR???11???CHR???11, and R???10 and R???11 are independently methyl; and (vii) R???12CH???CHR???13, w