Abstract: Provided herein are compounds of the formula: in which n is an integer equal to or greater than 1; m is an integer equal to or greater than 1; R2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R1, R3, and R4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched, wherein at least one of R1, R2, R3, or R4 is sulfurized or epoxidized. Also provided are compositions containing the compounds and methods of making both the compounds and compositions thereof.