Preparation Of Alkali Soluble HEC Solution And Study On The Spinning Characterties

Cellulose is considered as the most abundant renewable biopolymer with excellent biocompatiblity and biodegradability in nature. It can be used to prepare various useful cellulose products, and can be derivatized to prepare cellulose derivative, and replace oil resources partly. Cellulose molecules have many hydroxyls, which can form complex inter- and intra- molecular hydrogen bonds. So cellulose cannot be dissolved in common solvents and cannot be melt, which limits its applications. However, the traditional viseose process has its own shortcomings such as, toxic gas (CS2,H2S) and heavy metals. These disadvantages are challenging researchers to dedicate themselves exploring new process producing cellulose and its derivatives. In this thesis, we studied the preparation of Hydroxy Ethyl Cellulose (HEC) solution and spinning characterties..HEC, product of the etherification between cellulose and ethylene oxide, could be divided into water soluble and alkali soluble two types according to different mole degrees of substitution (MS). HEC with low degree MS does not dissolve in water but can dissolve in diluted alkali solution. This alkali soluble HEC has a good process ability of making fibers, and is promising to be another vital cellulose fiber.In this paper, the preparation of alkali soluble HEC with gas-solid reaction route, as well as the HEC fiber spinning were studied. First, good etherification degree and alkali-soluble HEC could be prepared at 40℃when weight ratio of EO/alkali cellulose was 0.20. HEC can be dissolved more easily in 8wt% NaOH aqueous solution below 0℃for 6-8h. After that, static rheological behavior and dynamic rheological behavior of HEC/NaOH solution were respectively studied by falling-sphere viscosimeter and plate rheometres.The dynamic viscous character under different temperature, different concentration and different angular frequency were studied. The results showed that HEC/NaOH solution was a shear-thinning non-Newtonian fluid. The dynamic viscosity of the HEC solution increased nonlinearly with the increase of the HEC mass fraction. The viscosity of the solution was not sensitive to the change of testing angular frequency and temperature because of the semirigid chain of HEC molecular.