Rheolocical Properties Of Bacterial Cellulose And Stady On The First Coagulation Bath Of Wet Spinning Process For High Strength Fiber

Bacterial cellulose as a new type of biological fiber has high purity, high strength, high modulus, good biocompatibility and degradability which other cellulose do not have the excellent performance, so it’s become the hot topics in the study of domestic and foreign scholars. But using bacterial cellulose prepare fiber has not been reported, for the preparation of the excellent performance of biological bacteria cellulose fiber, this paper selected the lithium chloride/dimethylacetamide solvent system as the solvent, with dimethyl acetamide/water mixed precipitant by wet spinning process preparation of the bacterial cellulose fiber.In this paper, we has done a lot of work before the preparation of biological bacteria cellulose fiber. We studied the lithium chloride/dimethylacetamide solvent dissolving, including the Solid content, molecular weight and LiCl content, temperature and time. The results show that:the dissolving capacity decreases with the increase of solid content, the most content is5%;The greater the molecular weight is, the dissolving ability is worse; The best content of LiCl is8%, too high or too low will reduce the solvent capacity; The higher the temperature is, the better dissolving ability is, but if the temperature is too high, it can lead to the degradation of cellulose; The longer the time is, the better ability is to dissolve.Using rotational rheometer to investigate the Theological properties of bacterial cellulose LiC1/DMAc solution,investigate the influence of shear rate、 solid content and molecular weight temperature to the solution apparent viscosity, calculate the solution nonnewtonian index n at different solid content and molecular weight, calculate the structural viscosity index of solution, investigate the influence of solid content to elastic modulus and viscous modulus. The results show that the solution apparent viscosity of bacterial cellulose decreases with the increasing of shear rate, increases with the increasing of solid content, increases with the increasing molecular weight, decreases with the increasing temperature; Non Newtonian index n decreases with the increase of solid content nonnewtonian index n decreases with the increase of solid content, with increases with the increase of molecular weight and increase solid content, non-newtonian behavior increase, the molecular weight increased non-newtonian behavior; Solution of solid content, the higher the greater the structural viscosity index, spinning the harder; Modulus G ’energy consumption and energy storage modulus G’ increase with the increase of solid content. For the preparation of high quality high performance of biological bacteria cellulose fiber, this paper explores the process conditions on the primary coagulation bath, the influence of the structure and the properties of the nascent fibers for two or three coagulation bath and the final fiber preparation of big down the good foundation. Results showed that the nascent state biological bacteria cellulose fiber diameter decreases with increasing concentration of coagulation bath, with the increasing of coagulation bath temperature and decreases with increasing of coagulation bath time, apparent negative draft increases with coagulation bath; Intensity increases with the concentration of coagulation, while decreases with the increasing of coagulation bath temperature, along with the increasing of coagulation bath time, along with the augment of coagulation bath apparent negative draft first increases then decreases50%and negative draft is the largest. Crystallinity increases with concentration of coagulation bath, while decreases with the increasing of coagulation bath temperature, along with the increasing of coagulation bath time, decreases with increasing of coagulation bath apparent negative draft.