Green chemistry in the production of cellulose acetate: the use of a new low-cost, highly available waste product

This study aimed to investigate the potential of Eucalyptus bark for the production of cellulose acetate, as well as to assess the impact of reaction time on the synthesis of these materials. The bark was subjected to purification and acetylation processes, followed by chemical and thermal characterization of the resulting acetates. The results revealed remarkable efficiency in the production of cellulose acetate from Eucalyptus bark, with physicochemical properties comparable to those of previous studies with different cellulose precursors. In more detail, the chemical analysis of the bark showed a high holocellulose content of ~ 68%, while the lignin content was low ~ 19%. This favorable chemical composition suggests significant potential for the production of cellulose acetate. In addition, the results of the Fourier transform infrared analysis revealed that the reaction time had a direct influence on the degree of substitution of the hydroxyl groups of the cellulose. Thermogravimetric (TG) analysis of the acetates produced revealed interesting patterns of thermal stability. The acetate produced over 4 h (ACE4) showed around 8% greater thermal stability up to 200 °C compared to the other groups. However, this profile was inverted after approximately 250 °C, with a marked loss of mass. From 250 °C onwards, the ACE8 group proved to be the most stable, maintaining this characteristic until complete degradation. These results suggest a relationship between the reaction time and the thermal stability of the acetates produced. In short, the findings of this study highlight the promising potential of Eucalyptus bark as a sustainable source for the production of cellulose acetate with various industrial applications.