Changes in the chemical composition and the structure of cellulose and lignin in elm wood exposed to various forms of arsenic

Abstract

Cellulose is the main component of plant cell walls and ranks very high in terms of its contents in the plant world. Wood contains approx. 40–45% cellulose (Rowell et al. 2005 ), while cellulose content in cotton may be as high as 95% (Prosiński 1984 ). It is a natural chain polymer composed of d -glucopyranose residues that are bound by β-(1 → 4)-glucosidic bonds (Rowell et al. 2005 ; Fengel and Wegener 1989 ). Cellulose chains in various materials differ in their lengths. The number of d -glucopyranose constitutional units in the chain defines the degree of polymerisation (DP). In turn, the ratio of crystalline areas to amorphous areas in the structure of a given fibre is defined as crystallinity of cellulose. The degree of polymerization and cellulose crystallinity (CrI) are some of the most useful characteristics of renewable and biodegradable materials, because they play an important role in their physical, mechanical, and chemical properties. Knowledge on the degree of polymerisation is of great importance for the assessment of strength of a given fibre. DP of native cellulose varies depending on plant material, ranging from 9000 to 10,000, and possibly may be as high as 15,000 (Pettersen 1984 ).