Key Laboratory of Public Security Management Technology in Universities of Shandong, School of Intelligence Engineering, Shandong Management University, Jinan, Shandong, China.
School of Chemistry and Chemical Engineering, Qilu Normal University, Jinan, Shandong, China.
Sci Rep. 2024 May 11;14(1):10825. doi: 10.1038/s41598-024-61642-x.
This study developed a kind of PEG-crosslinked O-carboxymethyl chitosan (O-CMC-PEG) with various PEG content for food packaging. The crosslinking agent of isocyanate-terminated PEG was firstly synthesized by a simple condensation reaction between PEG and excess diisocyanate, then the crosslink between O-carboxymethyl chitosan (O-CMC) and crosslinking agent occurred under mild conditions to produce O-CMC-PEG with a crosslinked structure linked by urea bonds. FT-IR and H NMR techniques were utilized to confirm the chemical structures of the crosslinking agent and O-CMC-PEGs. Extensive research was conducted to investigate the impact of the PEG content (or crosslinking degree) on the physicochemical characteristics of the casted O-CMC-PEG films. The results illuminated that crosslinking and components compatibility could improve their tensile features and water vapor barrier performance, while high PEG content played the inverse effects due to the microphase separation between PEG and O-CMC segments. The in vitro degradation rate and water sensitivity primarily depended on the crosslinking degree in comparison with the PEG content. Furthermore, caused by the remaining -NH groups of O-CMC, the films demonstrated antibacterial activity against Escherichia coli and Staphylococcus aureus. When the PEG content was 6% (medium crosslinking degree), the prepared O-CMC-PEG film possessed optimal tensile features, high water resistance, appropriate degradation rate, low water vapor transmission rate and fine broad-spectrum antibacterial capacity, manifesting a great potential for application in food packaging to extend the shelf life.
本研究开发了一种具有不同聚乙二醇（PEG）含量的聚乙二醇交联 O-羧甲基壳聚糖（O-CMC-PEG），用于食品包装。首先通过聚乙二醇（PEG）与过量二异氰酸酯之间的简单缩合反应合成了末端为异氰酸酯的聚乙二醇交联剂，然后在温和条件下，O-羧甲基壳聚糖（O-CMC）与交联剂之间发生交联反应，生成通过脲键连接的具有交联结构的 O-CMC-PEG。傅里叶变换红外光谱（FT-IR）和核磁共振（1H NMR）技术用于确认交联剂和 O-CMC-PEG 的化学结构。研究了 PEG 含量（或交联度）对浇铸的 O-CMC-PEG 薄膜的物理化学特性的影响。结果表明，交联和组分相容性可以提高其拉伸性能和水蒸气阻隔性能，而高 PEG 含量由于 PEG 和 O-CMC 段之间的微相分离而产生相反的效果。体外降解率和水分敏感性主要取决于与 PEG 含量相比的交联度。此外，由于 O-CMC 中的-NH 基团的存在，薄膜对大肠杆菌和金黄色葡萄球菌表现出抗菌活性。当 PEG 含量为 6%（中等交联度）时，所制备的 O-CMC-PEG 薄膜具有最佳的拉伸性能、高耐水性、适当的降解率、低水蒸气透过率和良好的广谱抗菌能力，在食品包装中具有延长货架寿命的巨大应用潜力。
