CELLULOSE ESTERIFICATION WITH FATTY-ACIDS AND ACETIC-ANHYDRIDE IN LITHIUM-CHLORIDE N,N-DIMETHYLACETAMIDE MEDIUM

Homogeneous esterification of cellulose with saturated fatty acids (n- octanoic to n-octadecanoic) was accomplished with acetic anhydride co- reactant in lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) medium. Cellulose mixed triesters (CMT) were obtained after 5 h at 130 degree s C with an average of 2.2 acetyl groups and 0.8 fatty substituents pe r anhydroglucose unit. A mixed acetic-fatty anhydride, formed in situ, accounts for the grafting of the fatty moiety. The purified products were characterized and compared to the analogous cellulose simple fatt y triesters (CST) that were synthesized from fatty acid chlorides in p yridine medium. Dynamic contact angle with water, glass transition, an d storage moduli were correlated with the length of the fatty substitu ents. The CMT proved to be highly hydrophobic and more mechanically re sistant than the CST.