液相法制备低取代羟乙基纤维素及其结构和性能研究

Preparation of HEC with low MS by liquid phase method and its structure and property

低取代羟乙基纤维素(HEC)具有成纤潜力,但是目前采用的气固相制备方法不佳,采用液相法制备了HEC,运用正交试验考察了碱化温度、碱化时间、碱化浓度、醚化温度对HEC溶解性的影响,同时通过气相色谱、X射线衍射、核磁碳谱和偏光显微镜对优化工艺下产物的结构和性能进行表征。结果表明:当碱化温度为20℃,碱化时间为1h,碱化浓度为20%,醚化温度为70℃时为相对最优的制备工艺条件。纤维素经过微弱的醚化改性,羟乙基基团取代了纤维素上的部分羟基基团,制备出具有碱溶性的低摩尔取代度(MS)的HEC,且随着醚化程度的加深,HEC结晶度下降,溶解性能逐渐改善,但HEC膜的力学性能有所下降。

Hydroxyethyl cellulose(HEC)with low molar substitution(MS)shows potential in producing regenerating fibers,but currently the gas-solid phase method used for preparing HEC is not so desired.Another liquid phase method was adopted,and the orthogonal experiment was used to investigate the influences of the alkalization temperature,alkalization time,concentration of NaOH solution on alkalization and etherification temperature on the HEC solubility,respectively.The results showed that when the alkalization temperature was 20℃,the reaction time was 1h,the concentration of alkalization was 20wt%,and the etherification temperature was 70℃,the optimal conditions were obtained.Meanwhile,the structure and properties of the products were characterized by gas chromatography,XRD,^(13)C-NMR and polarizing microscope.It was shown that partial hydroxyl groups on cellulose were successfully replaced by hydroxyethyl groups,and the resultant HEC with low MS was easily soluble in alkali solution.With the increasing of MS,the crystallinity of HEC decreased,and the solubility of HEC gradually improved,but the mechanical properties of HEC film decreased.