Oliver-Ortega Helena, Vandemoortele Victor, Bala Alba, Julian Fernando, Méndez José Alberto, Espinach Francesc Xavier
Group LEPAMAP-PRODIS, Department of Chemical Engineering, University of Girona, c. M. Aurèlia Capmany, 61, 17003 Girona, Spain.
KU LEUVEN, Gebroeders de Smetstraat 1, 9000 Gent, Belgium.
Polymers (Basel). 2021 Aug 16;13(16):2741. doi: 10.3390/polym13162741.
One of the most promising expectations in the design of new materials for food packaging is focused on the development of biodegradable systems with improved barrier character. In this sense PLA reinforced with nanoclay is a potential alternative to the use of conventional oil-derivative polymers due to the synergetic effect of the biodegradable character of PLA and the barrier-induced effect derived from the dispersion of nanoparticles. In this work, composite materials based on PLA and reinforced with bentonite nanoparticles (up to 4% /) (NC) have been prepared to produce films with improved barrier character against water vapor transportation. Additionally, the biodegradable character of the composites depending on the crystallinity of the polymer and percentage of NC have been evaluated in the presence of an enzymatic active medium (proteinase K). Finally, a study of the capacity to film production of the composites has been performed to determine the viability of the proposals. The dispersion of the nanoparticles induced a tortuous pathway of water vapor crossing, reducing this diffusion by more than 22%. Moreover, the nanoclays materials were in all the cases acceptable for food packing in terms of migration. A migration lower than 1 mg/m was obtained in all the materials. Nonetheless, the presence of the nanoclays in decreased biodegradable capacity was observed. The time was enlarged to more than 15 days for the maximum content (4% /). On the other hand, the incorporation of NC does not avoid the processability of the material to obtain film-shaped processed materials.
食品包装新材料设计中最有前景的期望之一集中在开发具有改进阻隔性能的可生物降解体系。从这个意义上讲，由于聚乳酸（PLA）的生物可降解特性与纳米颗粒分散产生的阻隔诱导效应的协同作用，用纳米粘土增强的PLA是使用传统石油衍生聚合物的潜在替代品。在这项工作中，制备了基于PLA并用膨润土纳米颗粒（最高4%/）增强的复合材料（NC），以生产具有改进的水蒸气传输阻隔性能的薄膜。此外，在酶活性介质（蛋白酶K）存在的情况下，评估了复合材料的生物可降解特性，该特性取决于聚合物的结晶度和NC的百分比。最后，对复合材料的成膜能力进行了研究，以确定这些方案是否可行。纳米颗粒的分散导致水蒸气穿越的曲折路径，使这种扩散减少了22%以上。此外，就迁移而言，纳米粘土材料在所有情况下都可用于食品包装。在所有材料中均获得了低于1毫克/平方米的迁移量。然而，观察到纳米粘土的存在降低了生物可降解能力。对于最大含量（4%/）而言，时间延长至超过15天。另一方面，加入NC并不影响材料获得薄膜状加工材料的可加工性。
