ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The evaluation of cellulose by 'U' value

V. Mašura

Slovak Academy of Sciences, Bratislava

Abstract: 'U' value expresses the polydispersity (heterogeneity) of cellulose and is dependent not only on the contents of low-mol. and high-mol. fractions but also on the av. degree of polymerization (DP) of the cellulose. Equal contents of low-mol. fractions in the cellulose with a higher av. DP increase the U value to a greater extent than in the cellulose with a lower av. DP. The U value of alkali celluloses from conventional sulfite pulps goes through a min. during aging at an av. DP 700 to 900. With further decrease of the DP by cleavage, the U value increases. Each type of pulp gives a characteristic U value of alkali cellulose during aging. The content of low-mol.-wt fractions of alkali cellulose after cleavage to the desired DP is dependent not only on the content in the original cellulose or on the content of α-cellulose, but also on other factors such as reactivity and accessibility.

Full paper in Portable Document Format: 159a668.pdf (in Slovak)

Chemical Papers 15 (9) 668–676 (1961)