FUNCTIONAL MATERIALS FROM WASTE PAPER. III. COMPARATIVE STUDY OF MORPHOLOGY OF POWDER CELLULOSES AND CELLULOSE HYDROGELS

Abstract

The morphology of hydrogels regenerated from solutions of waste paper and cardboard in DMAс/LiCl was studied for the first time in comparison with the morphology of pristine samples and powder celluloses isolated from waste paper. Two sets consisted every of them from 4 samples, pristine waste paper or cardboard, powder cellulose, swollen hydrogel and freeze-dried hydrogel, were examined with a SEM. As revealed by SEM, the freeze-dried hydrogels are porous systems with a variety of through pores in a wide range of sizes. The number, shape, and size of pores, as well as their availability, differed markedly. The pore sizes in freeze-dried hydrogels obtained from the waste paper are mostly ranged at 30-50 nm. The smallest pores in the waste cardboard are 30-40 nm in size, the largest ones are up to 4 μm. According to the results of the study, these samples will have satisfactory sorption properties but, due to the different morphology of the porous system, the availability of each sample is likely to vary significantly.