Physical chemistry of native cellulose

Abstract

AbstractThe knowledge of the physical chemical properties of cellulose and the laws of their alteration during the growth of natural filaments is very important for scientifically increasing the production of natural cellulose filaments. While dealing with cotton growing we have been continuously performing the physical chemical investigation of natural cellulose. The results obtained may be summarized as follows. Cellulose appears in the cotton tissue together with the flower and pod and not several days after blossoming, as is the general opinion to be encountered in the literature. The synthesis of cellulose in cotton is at first very slow, showing an acceleration by the 15th day after bloom with a subsequent slow‐down again and complete cessation approximately on the 40th day after bloom. Thus the characteristic curve of cellulose accumulation in cotton has an S‐shaped form. The natural cellulose of an early age has a very low degree of polymerization which later, by the 25th to 30th day after bloom, shows an abrupt increase and remains almost stable. The filament then almost completely consists of α‐cellulose. The kinetics of the polymerization and accumulation of cellulose is connected with the ripening period of cotton under investigation and makes it possible to predict the time of the ripening of pods. Early cellulose is very porous, it easily hydrolyzes, and has a higher sorption capacity and heat of solution than the cellulose of a mature age. However, the tightness of packing of the natural cellulose evaluated in terms of water sorption and heat of solution in water, reaches its maximum in the vegetation period, i.e., approximately on the 40th day of the maturation of filaments. The gradual increase in tightness of cellulose packing and its drop after 40 days can be accounted for if we consider the possibility of synthesis in all layers of the secondary wall of the filament, i. e., throughout the tissue of cellulose and not only in the channel of the filament. The main physicochemical and technological properties of cellulose bodies are the functions of the tightness of molecular packing of cellulose. The tightness of packing may vaccilate within a very broad range depending on the conditions of biosynthesis or processing.