wherein each R1 is an organic group containing a straight or branched alkyl or alkenyl group optionally subsituted with up to 3 phenyl groups and optionally interrupted by up to 4 structures selected from the group consisting of ##STR7## and mixtures thereof, and which contains from about 8 to 22 carbon atoms, and which may additionally contain up to 20 ethoxy groups, m is a number from one to thr