Cellulose porosity improves its dissolution by facilitating solvent diffusion

Abstract

This paper reports on the effect of improved porous characteristics of cellulose on its solubility in DMAc/LiCl. The use of freeze-drying (FD) treatment led to higher surface area and void fraction of volume for high-molecular-weight (HMW) cotton cellulose (DP~5000). Improvement in porous characteristics of cellulose did not change the chemical and crystalline structures of cellulose, as compared to hot-drying (HD) treatment. However, significant improvement in the dissolution of FD-HMW cellulose in DMAc/LiCl was observed under relatively low temperature (80 °C). The relationship between the solubility and the porous characteristics of cellulose was discussed using Stokes-Einstein Equation and effective diffusion coefficient equation. It was concluded that the increase in the diffusion coefficient of the solvent and the improvement in the porous characteristics of cellulose played key roles to enhance the diffusion rate of the solvent through the cellulose molecular network.

Keywords: Cellulose dissolution; Porous characteristics; Solvent diffusivity.