Influence of degree of substitution on thermal dynamic mechanical and physicochemical properties of cellulose acetate

Deacetylation of commercial cellulose acetate (CA) with initial 2.48 of substitution (DS) was studied by alkaline hydrolysis. Kinetic behavior of hydrolysis was studied and samples with different degree of substitutions were obtained as a function of reaction time. Spectrum of deacetylated CA has showed the disappearance of typical band of C=0 in 1750 cm(-1) in comparison to that of CA. Some very important parameters were obtained by techniques employed in samples characterization. For example, water temperature desorption (Td), Glass transition temperature (Tg) and fusion temperature (Tm) were obtained by DSC. Crystallinity index (CI) was obtained by XRD for all samples with different DS values. For comparative purposes, CA sample with DS 2.45 and sample with DS were analyzed by 2.29 DMA. These samples were soluble in acetone and in this way, films with good quality were obtained by casting. This small variation in DS causes significant changes in mechanical property. A decrease let DS of only 0.19 has caused an increase of over 120% in obtained storage modulus at 50 degrees C with CA DS 2.29.