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). 2021 Mar 17;13(6):927. doi: 10.3390/polym13060927.
Hemicellulose is a kind of biopolymer with abundant resources and excellent biodegradability. Owing to its large number of polar hydroxyls, hemicellulose has a good barrier performance to nonpolar oxygen, making this biopolymer promising as food packaging material. Hydrophilic hydroxyls also make the polymer prone to water absorption, resulting in less satisfied strength especially under humid conditions. Thus, preparation of hemicellulose film with enhanced oxygen and water vapor barrier ability, as well as mechanical strength is still sought after. Herein, sodium trimetaphosphate (STMP) was used as esterification agent to form a crosslinked structure with hemicellulose through esterification reaction to render improved barrier performance by reducing the distance between molecular chains. The thus modified hemicellulose film achieved an oxygen permeability and water vapor permeability of 3.72 cm × μm × m × d × kPa and 2.85 × 10 × g × m × s × Pa, respectively, at the lowest esterification agent addition of 10%. The crosslinked structure also brought good mechanical and thermal properties, with the tensile strength reaching 30 MPa, which is 118% higher than that of the hemicellulose film. Preliminary test of its application in apple preservation showed that the barrier film obtained can effectively slow down the oxidation and dehydration of apples, showing the prospect of application in the field of food packaging.
半纤维素是一种资源丰富且具有优异生物降解性的生物聚合物。由于其大量的极性羟基，半纤维素对非极性氧气具有良好的阻隔性能，这使得这种生物聚合物有望成为食品包装材料。亲水性羟基也使该聚合物易于吸水，导致其强度不太令人满意，尤其是在潮湿条件下。因此，制备具有增强的氧气和水蒸气阻隔能力以及机械强度的半纤维素膜仍然备受关注。在此，三聚磷酸钠（STMP）用作酯化剂，通过酯化反应与半纤维素形成交联结构，以通过减小分子链之间的距离来提高阻隔性能。在酯化剂最低添加量为10%时，如此改性的半纤维素膜的氧气透过率和水蒸气透过率分别达到3.72 cm×μm×m×d×kPa和2.85×10×g×m×s×Pa。交联结构还带来了良好的机械和热性能，拉伸强度达到30 MPa，比半纤维素膜高118%。其在苹果保鲜中的应用初步测试表明，所得的阻隔膜可以有效地减缓苹果的氧化和脱水，显示出在食品包装领域的应用前景。
