STRUCTURE OF CARBOXYMETHYLCELLULOSE DURING GRANULATION AND CHEMICAL CROSS-LINKING

The work is devoted to the investigation of granulation methods on the chemical cross-linking of carboxymethylcellulose (CMC), physico-chemical properties and structure of the resulted products. It was shown that, in the course of chemical cross-linking of CMC by CH2O, DMEM, DMDEM, the reagents activity decreases in the series : CH2O > DMEM > DMDEM. Cellulose reaction activity depends on granulation methods ; the other conditions being equal, it is arranged as follows : sublimation > pulverisation > emulsification. The different reaction activity of CMC depends on the structure formed in the course of its granulation. The differences in structure, more prominent on the macro as well as on the micro-level, are manifested during emulsificating and pulverisation processes, the transition solution polymer taking place at room temperature followed by formation of amorphous granulars with unhomogeneous surface and tightened edges at the cost of capillar contractions forces. Under on freezing, the CMC-solution is separated as a glass-like polymer and as a crystalline solution, the latter being removed on sublimation. It leads to more porous granulated CMC with rounded forms, even edges and developed inner surface, which provides high reaction, activity. Chemical cross-linking of granulated CMC changes the picture of its interaction with H2O in H- and Na-forms. The swelling degree of CMC cross-linked samples depends on the cross-links number, on their nature and degree of neutralisation. Increasing the quantity of linked CH2O from 0.11 to 1.96 % leads to changes of CMC swelling from 11000 to 850 %, respectively. It was shown that the relief surface, loose structure, the presence of high quality of pores, fractures and holies in the inner and external regions of samples with different degrees of cross-linking. determines the effective sorption activity of granulated CMC and the ways of its use in medical practice as a sorbent for purulent wounds.