Structural Features of Celluloses of Different Origin

Abstract Parameters of supramolecular structure of celluloses isolated from various natural sources have been studied, such as type of crystalline allomorph, crystallinity and amorphicity degrees, interplanar distances and specific volume of crystalline unit cells, as well as sizes and area of specific surface of crystallites. It was found that in the sequence of various CIβ samples, from tunicate cellulose to celluloses of cotton, bast fibers (flax), wood and herbaceous plants, a gradual decrease in crystallinity degree and sizes of crystallites was observed, whereas the area of specific surface of crystallites, specific volume of crystalline unit cells and interplanar distance increased. Among CIα samples, the cellulose isolated from Valonia algae has the more ordered supramolecular structure than the isolated bacterial cellulose. Comparison of CIα and CIβ cellulose samples having the close crystallinity, lateral size of crystallites and area of specific surface showed that the CIα lattice is more distorted than CIβ lattice. It was found that independently on the type of crystalline allomorph; hydrophilic properties of isolated celluloses (sorption of water vapor and heat of wetting) are directly proportional to amorphicity degree, whereas specific gravity is directly proportional to crystallinity degree of celluloses. On the other hand, content of CII after alkalization of cellulose samples with 12% NaOH is inversely proportional to lateral size of crystallites.

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