Abstract：
The aim of this work was to evaluate the influence of halloysite clay nanoparticles - unmodified (Hal) and organically modified (mHal) - and oregano essential oil (OEO), used as an antimicrobial agent in active packaging, on the biodegradation behavior of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) films. Five samples were prepared by melt mixing using 3 wt% clay, and 8 wt% and 10.4 wt% OEO. PHBV compositions containing OEO presented the highest rate of biodegradation, achieving 46% of mass loss after aging for 12 weeks in simulated soil. The addition of clay nanoparticles reduced the polymer\'s biodegradation to 32%. The compositions containing OEO showed a rough and layered surface with visible cracks, indicating degradation occurring through layer-by-layer erosion from the surface. This degradation was confirmed by the chemical changes on the surface of all samples, with a slight decrease in molar masses. The composition containing 8 wt% OEO presented an increase in the crystallization degree as a result of the preferential consumption of amorphous phase, whereas for the compositions containing clay nanoparticles, both crystalline and amorphous regions were degraded at similar rates. Therefore, the combination of additives allows the biodegradation process of PHBV to be controlled for use in the production of active packaging.
摘要：
这项工作的目的是评估埃洛石粘土纳米颗粒-未改性（Hal）和有机改性（mHal）-和牛至精油（OEO）的影响，用作活性包装中的抗菌剂，聚(羟基丁酸酯-羟基戊酸酯共聚物)(PHBV)薄膜的生物降解行为。使用3重量%的粘土通过熔融混合制备五个样品，和8重量%和10.4重量%的OEO。含有OEO的PHBV组合物呈现最高的生物降解速率，在模拟土壤中老化12周后达到46%的质量损失。粘土纳米颗粒的添加将聚合物的生物降解降低到32%。含有OEO的组合物显示出粗糙和分层的表面，具有可见的裂纹，表明通过从表面逐层侵蚀发生的降解。所有样品表面的化学变化证实了这种降解，摩尔质量略有下降。由于非晶相的优先消耗，含有8重量％OEO的组合物的结晶度增加，而对于含有粘土纳米颗粒的组合物，结晶区和无定形区都以相似的速率降解。因此,添加剂的组合允许控制PHBV的生物降解过程以用于生产活性包装。
