酸性低共熔溶剂预处理制备含木质素的纤维素纳米纤丝及其复合膜的研究

Study on Preparation of Lignin-containing Cellulose Nanofibril with Acidic Deep Eutectic Solvents and Its Composite Film

关键词:  低共熔溶剂  预处理  含木质素的纤维素纳米纤丝  聚乙烯醇

Key Words:deep eutectic solvent  pretreatment  lignin-containing cellulose nanofibril  polyvinyl alcohol

摘要:采用酸性低共熔溶剂（deep eutectic solvent，DES）预处理并结合高压均质法制备了含木质素的纤维素纳米纤丝（lignin-containing cellulose nanofibril，LCNF），并与聚乙烯醇（PVA）共混制备了LCNF/PVA复合膜，探讨了2种酸性DES预处理的效果，分析比较了LCNF的特性及LCNF/PVA复合膜的性能。结果表明，乳酸-氯化胆碱（LC）和乙酸-氯化胆碱（AC）对半纤维素的提取率均达到78%以上，其中LC预处理后用乙醇洗涤的处理方式对木质素的提取率高达61.2%；DES预处理后，乙醇洗涤有利于木质素的分离；利用LC制备的纤维素纳米纤丝（LC-E-LCNF）的直径为50~100 nm；相较于纯PVA膜，LCNF/PVA复合膜的疏水性明显提高，应力提升至70.3 MPa，紫外屏蔽性接近100%，且具有良好的热稳定性和雾度，以及一定的保鲜性能，该复合膜有望应用于食品包装领域。

Abstract:Lignin-containing cellulose nanofibril （LCNF） was prepared by acidic deep eutectic solvent （DES） pretreatment combined with high pressure homogenization， and was co-blended with polyvinyl alcohol （PVA） to form LCNF/PVA composite film. The effects of two acidic DES pretreatments were investigated， the properties of LCNF were compared and analyzed， the performance of the LCNF/PVA composite film was discussed. The results showed that the extractions of hemicellulose by lactic acid-choline chloride （LC） and acetic acid-choline chloride （AC） both were more than 78%， and the lignin extraction was as high as 61.2% after LC pretreatment with ethanol washing. After DES pretreatment， ethanol washing was beneficial to separation of lignin. The diameter of cellulose nanofilament prepared by LC （LC-E-LCNF） was 50~100 nm. Compared with pure PVA film， the hydrophobicity of LCNF/PVA composite film was significantly improved， and its stress was raised to 70.3 MPa， and its UV blocking ability was approximately 100%. It had good thermal stability and haze， as well as certain freshness preservation performance， which was expected to be used in the food packaging field.