This work presents scientific approaches to the formation of quality criteria for finely dispersed cellulose powder in relation to medical purposes. Actual research methods (a laser analyzer for determining the fractional composition by particle size, a scanning electron microscope) have revealed the structural and morphological features of microcrystalline cellulose (MCC) obtained from medical bandage waste in comparison with fine cellulose powder from high-viscosity cotton cellulose. The quality and yield of the target product depends, judging by the literature, on the composition of the original fiber and the conditions of acid hydrolysis. It has been experimentally established that the size of the obtained crystallites of microcrystalline cellulose is determined not only by the duration of hydrolysis, temperature and acid concentration, but also by the nature of cellulose (cotton, wood), modification of the source material. The formation of agglomerates as a result of coarsening of microcrystalline cellulose particles is a side effect that significantly degrades the quality of the product as a whole. In this work, to reduce this effect, the subsequent mechanical disintegration of hydrolyzed cellulose and ultrasonic treatment of the material are carried out in order to obtain particles with a size of 10-150 μm and a high degree of crystallinity. A microphotograph of the MCC surface (made from a defibre material based on waste medical bandages) indicates severe destruction of the fibrillar structure along the surface of the particles. This is due to the fact that MCC was obtained hydrolytically in an aqueous environment to the “maximum” degree of polymerization. In this case, individual elements of the fibrillar structure of the fibers (amorphous layers), which play the role of ligaments between the fibrils, are destroyed. It is shown, the investigated sample is not inferior to the sample of RETTENMAIER brand 101 (Germany) at in terms of purity, structural and morphological properties.
Валишина et al. (Sun,) studied this question.