Study On The Crystallization Behavior Of Cellulose Spherulites

Due to the shortage of resources and serious pollution,natural polymer,which are green and environmentally friendly,are widely used in chemical and material industries.Cellulose,as the most abundant natural polymer,has many excellent properties.The study of cellulose crystallization has a guiding significance for the preparation of cellulose materials,and promotes the development of polymer crystallography.Cellulose spherulites are successfully prepared using cellulose/ILs system,of which the mechanism is further discussed:ILs absorb water when they are isothermal in the air.With the diffusion of water in the sample,the solubility of ILs to cellulose decreases,and the cellulose precipitates from ILs.The cellulose chain is reformed with hydrogen bonds,forming a bundle-like whisker,which eventually grows into spherulites.The crystallization behavior of cellulose spherulites was studied by controlling different crystallization conditions.We further explored the effects of crystallization temperature,dissolution conditions and crystallization humidity on the growth of spherulites.The growth of spherulites is controlled by the humidity gradient produced by large glass sheets.The structure of cellulose spherulite was studied at last.T_g and T_m of cellulose and its spherulites were measured by DSC.The crystal form and crystallinity were characterized by FTIR and WAXD,and the long period was measured by SAXS.The spherulites were heated in situ to study their thermal behavior and redissolution behavior.The internal structure and crystal twisting of spherulites were characterized by POM and SEM.