Abstract：
Polyvinyl alcohol (PVA) is a promising alternative to non-biodegradable flexible packaging materials, and nanocellulose is often used to enhance the properties of PVA films, but the composite films still have poor water resistance and barrier properties. To address this issue, iron ions (Fe3+) were introduced into PVA/cellulose nanofibrils (CNF) films, and Fe3+ formed coordination bonds with carboxyl and hydroxyl groups on the surface of CNF and PVA chains. Therefore, constructing a strong coordination crosslinking network within the film and improving the interfacial interaction between PVA and CNF. The water resistance, mechanical and barrier properties of the crosslinked films were significantly improved. Compared with the un-crosslinked film, the oxygen transmission rate (OTR) was decreased by up to 67 %, and the water swelling ratio was significantly reduced from 1085 % to 352 %. The tensile strength of the film with 1.5 wt% Fe3+ reached 41.93 MPa, which was 62 % higher than that of the un-crosslinked film. Furthermore, the composite film demonstrated good recyclability, almost recovering its original mechanical properties in two recycling tests. This simple and effective method for preparing water resistance and barrier films shows potential applications in flexible packaging areas.
摘要：
聚乙烯醇（PVA）是一种有前途的替代不可生物降解的软包装材料，纳米纤维素通常用于增强PVA薄膜的性能，但复合薄膜的耐水性和阻隔性能仍然较差。为了解决这个问题，将铁离子(Fe3+)引入PVA/纤维素纳米纤丝(CNF)薄膜中,Fe3+与CNF和PVA链表面的羧基和羟基形成配位键。因此,在膜内构建强配位交联网络，改善PVA与CNF之间的界面相互作用。耐水性,交联膜的机械性能和阻隔性能得到显著改善。与未交联的薄膜相比，氧气透过率(OTR)下降了67%，水溶胀率从1085%显著降低到352%。含1.5wt%Fe3+的薄膜的拉伸强度达到41.93MPa,比未交联膜高62%。此外，复合膜表现出良好的可回收性，在两次回收测试中几乎恢复了其原始机械性能。这种制备耐水性和阻隔膜的简单而有效的方法显示了在软包装领域的潜在应用。
