Effect of degree of acetylation on mechanical properties of cellulose acetate films.
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Pour samples of cellulose acetates having degrees of combined acetic acid between 50.8 - 55.8% were fractionated to obtain sharp fractions or approximately the same degree ot polymerization.
About 2000 grams starting material of each sample of cellulose acetate were needed to obtain approximately 50 grams or sharp fraction ror testing the mechanical properties of their films.
Fractionation of the cellulose acetate was from an acetone-water mixture, by addition of n-heptane to precipitate a certain traction. After a series ot refractionations, a sharp traction of each ot the four cellulose acetates was obtained. These fractions had different degrees of acetylation but approximately the same degrees of polymerization. These fractions were then dissolved in acetone and cast into films which were conditioned for three days and their mechanical properties were determined in an attempt to determine the effect of degree of acetylation on the mechanical properties.It was found that the degrees of acetylation of the various sharp tractions ot cellulose acetates had no appreciable effect on the mechanical properties of their films. It was concluded that the degrees of polymerization of the various fractions were so high that the effect of the degree or acetylation on the mechanical properties could not be detected.
- Doctoral Dissertations