Shao Hui, Zhao Yuelong, Sun Hui, Yang Biao, Fan Baomin, Zhang Huijuan, Weng Yunxuan
College of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China.
Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics, Beijing Technology and Business University, Beijing 100048, China.
Polymers (Basel). 2020 Sep 25;12(10):2199. doi: 10.3390/polym12102199.
Hemicellulose with good biodegradability and low oxygen permeability shows great potential in food packaging. However, its strong hydrophilicity leads to its poor moisture resistance, which hinders its wider application. In this paper, a near-hydrophobic hemicellulose was obtained by using single-step synthesis from poplar powder via etherification modification with epoxy chloropropane. This proposed approach has the advantage of avoiding the destruction of hemicellulose structure by secondary alkali-hydrolysis, which was what usually occurred in traditional etherification procedures. The feasibility of using epoxy chloropropane as an alkylation reagent to etherify hemicellulose was confirmed, and the reaction mechanism was elucidated. Contact angle test, thermogravimetric analysis, oxygen transmittance test, and infrared spectrum analysis showed that the barrier property and thermal stability of etherified hemicellulose films have been significantly improved. At an epoxy chloropropane/wood powder ratio (volume/weight) of 2/3 (mL/g), the epoxy hemicellulose films contained the most epoxy groups and displayed the best performance, i.e., tensile strength of 14.6 MPa, surface contact angle of 71.7° and oxygen transmission coefficient of 1.9 (cm·µm)/(m·d·kPa), showing great promise as barrier film in food-packaging.
具有良好生物降解性和低透氧性的半纤维素在食品包装中显示出巨大潜力。然而，其较强的亲水性导致其防潮性较差，这阻碍了其更广泛的应用。本文通过用环氧氯丙烷进行醚化改性，从杨木粉一步合成得到了一种近疏水性半纤维素。该方法的优点是避免了传统醚化过程中通常发生的二次碱水解对半纤维素结构的破坏。证实了使用环氧氯丙烷作为烷基化试剂醚化半纤维素的可行性，并阐明了反应机理。接触角测试、热重分析、透氧率测试和红外光谱分析表明，醚化半纤维素膜的阻隔性能和热稳定性得到了显著提高。在环氧氯丙烷/木粉比（体积/重量）为2/3（mL/g）时，环氧半纤维素膜含有的环氧基团最多，表现出最佳性能，即拉伸强度为14.6 MPa，表面接触角为71.7°，氧气透过系数为1.9（cm·µm）/（m·d·kPa），作为食品包装中的阻隔膜显示出巨大潜力。
