Synthesis of celulose acetates by six different methods

Cellulose acetate is synthesized by two different methods; solution acetylation and fibrous acetylation. Having been the most used method for production of cellulose acetate, the acetic acid method is carried out in four steps: activation, acetylation, precipitation and washing steps. The chemicals used in activation and acetylation stages, however, cause products with high free acidity. Also, polymerisation degrees of cellulose and cellulose acetate were decreased because of the high acidity in acetylation medium. In this thesis, to diminish the problems arising from acetic acid process, cellulose acetates were synthesized by six different methods: Acetic acid method (control), Ethyl acetate method, Ethyl lactate method, Zinc chloride or Potassium acetate catalyzed acetylation and transesterification by vinyl acetate in DMSO/TBAF. Then, synthesized cellulose acetates were characterized by standard test methods and used in the production of cellulose acetate films too. Ethyl acetate and lactate processes, which were not found in the literature before, were developed within the scope of this study. Free acidity amount of cellulose acetatate produced by acetic acid method was 15%; while the amount of free acidity was diminished by ethyl acetate method and ethyl lactate to 10% and 6.5% respectively. In the room temperature and with 1% amount of catalyst, cellulose acetate (DS: 2.32) was synthesized by ethyl acetate method. On the other hand, the texture of cellulose acetate film produced from ethyl acetate method was less brittle that those of acetic acid method.