纤维素在离子液体水溶液中的溶胀与溶解行为的研究

以含水的离子液体1-丁基-3-甲基咪唑氯盐([BMIM]C)l为溶剂,研究了纤维素在其中的溶胀和溶解行为。通过偏光显微镜观察发现,[BMIM]Cl水溶液中的含水率对纤维素浆粕的溶胀与溶解行为有着重要的影响,主要表现为三种状态:当[BMIM]Cl中含水率小于1%时,浆粕纤维横向被迅速切断并快速溶解,没有发现明显的溶胀现象;当[BMIM]Cl中含水率在2%～5%时,浆粕纤维发生了非常明显的非均相溶胀,但并不溶解;而当[BMIM]Cl中含水率进一步增大到6%～20%时,浆粕纤维不再发生明显的溶胀现象。此外,研究结果还表明,当[BMIM]Cl中含水率在2%～5%时,溶胀温度和[BMIM]Cl中的含水率对于纤维素的溶胀有很大影响,随着温度升高,浆粕纤维的溶胀速度增大,达到最大溶胀比所需要的时间缩短;而随着[BMIM]Cl中含水率的提高,浆粕纤维在[BMIM]Cl水溶液中达到的最大溶胀比减小。

Swelling and Dissolution of Cellulose Pulp in Aqueous Ionic Liquids

The swelling and dissolution of cellulose pulp in [BMIM]Cl （1-butyl-3-methylimidazolium chloride） containing different contents of water were studied respectively. The results showed that there existed three ranges of water content in aqueous ionic liquids which influenced the swelling and dissolution of cellulose pulp. When water content was below 1%, the pulp dissolved in the ionic liquids very quickly and no swelling phenomena were observed. When water content was in the range of 2 %-5 % in the aqueous ionic liquids, the cellulose pulp exhibited an apparently and heterogeneous swelling, whereas the pulp couldn＇t be dissolved. With more water content in ionic liquids （6 %-20 %）, no swelling and dissolving phenomena were observed on the pulp. It was also found when the water content in ionic liquids was in the range of 2 %-5 %, the swelling of cellulose pulp was greatly influenced by temperature and water content in ionic liquids. With increasing of temperature, the swelling rate of pulp was increased, whereas the time to reach the maximum swelling ratio decreased. In addition, the maximum swelling of cellulose pulp would decrease when the water content was increased in the ionic liquids.