Solvent-free synthesis and properties of carboxymethyl starch fatty acid ester derivatives

Abstract

AbstractWater-soluble, partially hydrophobized polysaccharides have become attractive due to their potential to act as polymeric surfactants. From carboxymethyl starch (CMS), water-soluble polymeric surfactants were prepared by esterification using two unconvential methods based on (A) a reaction with mixed anhydrides and (B) with methyl laureate (MELA) and methyl esters of the fatty acid complex of rape seed oil (MERO) under ‘solvent-free’ conditions. The obtained CMS derivatives were characterized by structural, surface-active and surfactant performance properties. Esterification using method B was successful in contrast to method A which yielded derivatives with a very low extent of esterification. Although the derivatives reduced the surface tension moderately, they exhibited remarkable emulsifying properties. The performance tests indicated good washing power and antiredeposition efficiency. The results suggest that suitable polymeric surfactants can be prepared by the unconventional esterification method B using both acylation agents. The preparations might substitute the expensive and invasive industrially applied conventional methods.