ACETYLATION OF DMSO - PF SOLUTIONS OF CELLULOSE

Three different techniques for esterifying solutions of cellulose dissolved in mixtures of dimethyl sulfoxide (DMSO) and paraformaldehyde (PF) were evaluated and are described. The evaluation and development of suitable synthetic procedures and the characteristics of the resulting acetylated cellulose are reported. Glacial acetic acid (glacial HOAc), acetyl chloride (AcCl), and acetic anhydride (Ac//2O) were compared as acetylating agents for solutions of cellulose in DMSO:PF, and it was demonstrated that mixtures of pyridine (Py) and Ac//2O rapidly acetylated the cellulose to yield beige to amber acetone-soluble cellulose acetates which were partially oxidized. These thermoplastic resins exhibited softening points between 80 and 110 degree C and thermal stabilities (in nitrogen atmospheres) similar to those of native celluloses (350 to 375 degree C). Degree of acetyl substitution (DS) values ranged from 0 to 2. 0 as a function of acetylation time.