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Abstract INTRODUCTION 1. Structure of ~~~~bers: A wood fiber cell consists of primary wall, secondary wall and the lumen or cell cavity. The fibers are cemented together by non-cellulosic material known as middle lamella(l). In higher plants, the primary wall in the form of a thin membrane is called cuticle. The secondary wall represents the bulk of cellulose substance paper, The fibers of cellulose may be regarded as a two-phase system consisting of the same chemical material which is arranged in two different types of physical aggregation, with a meso-amorphous portion as a region of transition. The cellulose chains in the crystalline region are arranged strictly parallel, less so in the meso-amorphous portion and more less in the amorphous region. The primary wall is though consistedmainly of amorphous non-cellulosic constituents. The major part of the crystalline cellulose exists in the secondary wall which is built up of fibrils. The ratio of crystalline to amorphous materials in cellulose fibers can be determined by:- 1. Chemical method such as the difference in the rate of acid hydrolysis and oxidation(Z). 2, Physical method such as x-ray analysis and density measurement. In general, the results obtained by chemical method show higher proportion of crystallinity than the physical method due to the crystallization which takes place during the treatment( |