PREPARATION AND PROPERTIES OF CELLULOSE B ENZOATE

Cellulose benzoates with degrees of substitution between 2.8 and 2.9 w ere synthesized in a one-step reaction of cellulose with benzoyl chlor ide in prescence of pyridine as base. Their molecular weights were in the range 140 000 - 100 000; the glass transition temperature and the melting temperature were 155 and 274-degrees-C, respectively. The este rs are readily soluble in organic solvents such as N,N-dimethyl formam ide, chloroform and dichloromethane and show good thermal resistance u p to 250-degrees-C. Because of the brittle character of cellulose benz oate, plasticizer (diethyl phthalate) must be added for the fabricatio n of films and workable, moulded parts. As shown by stress-strain and impact measurements, the hard and brittle character is retained for pl asticizer contents up to 20 wt.-%.