Abstract: In this paper, ionic liquid of 1-(2-hydroxylethyl)-3-ethyl imidazolium chloride([HeEIM]Cl) was synthesized, and the chemical structure of [HeEIM]Cl was confirmed by FTIR and ¹H NMR. The influence of NaOH, microwave and high-pressure on crystallinity, degree of polymerization(DP), solubility of cotton fibre were studied. The effects of different temperatures on dissolution rate of cotton fibre and DP for the regenerated cellulose were investigated on the conditions of microwave heating and traditional heating respectively. The chemical structure, change of crystallinity, thermostability and appearance of the regenerated cellulose were analyzed by FTIR, XRD, TGA and SEM respectively. The results show that the ionic liquid exhibited a good ability of dissolution for cotton fibre, and during the dissolution and coagulation processes of the celloluse, no chemical reaction occurred. The solubility was the best when the cotton fibre was pretreated with 30%(mass fraction) NaOH on the high pressure condition. The solubility by microwave heating was far superior to traditional heating method, and with the dissolution temperatures elevation, the dissolution rate increased gradually. The crystallinity of the regenerated cellulose was lower than that of original cellulose, the DP of the regenerated cellulose declined and thermostability dropped.

Key words: Ionic liquid, Cotton fibre, Dissolution rate, Degree of polymerization(DP), Regenerated cellulose