A polyol having a substituent of formula (I) attached via a carbon-carbon single bond to a saturated carbon atom in a fatty acid hydrocarbyl group; wherein R1 and R2 are esterified residues of aliphatic or cycloaliphatic diols; and from 0 to 15 wt % of esterified residues of at least one C4-C12 anhydride, C4-C12 diacid or C4-C12 lactone, not including units of formula (I) attached to a fatty acid hydrocarbyl group.