Institute of Polymer Science and Technology (ICTP-CSIC) , Juan de la Cierva 3, 28006 Madrid, Spain.
ACS Appl Mater Interfaces. 2014 Jun 25;6(12):9822-34. doi: 10.1021/am502261e. Epub 2014 Jun 3.
Biodegradable nanocomposites were prepared by adding ZnO nanoparticles to bacterial polyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) via solution casting technique. The morphology, thermal, mechanical, antibacterial, barrier, and migration properties of the nanocomposites were analyzed. The nanoparticles were uniformly dispersed within PHBV without the aid of coupling agents, and acted effectively as nucleating agents, raising the crystallization temperature and the level of crystallinity of the matrix while decreasing its crystallite size. A gradual rise in thermal stability was found with increasing ZnO loading, since the nanofillers hinder the diffusion of volatiles generated during the decomposition process. The nanocomposites displayed superior stiffness, strength, toughness, and glass transition temperature, whereas they displayed reduced water uptake and oxygen and water vapor permeability compared to the neat biopolymer, related to the strong matrix-nanofiller interfacial adhesion attained via hydrogen bonding interactions. At an optimal concentration of 4.0 wt % ZnO, the tensile strength and Young's and storage moduli showed a maximum that coincided with the highest crystallinity and the best barrier properties. PHBV/ZnO films showed antibacterial activity against human pathogen bacteria, and the effect on Escherichia coli was stronger than on Staphylococcus aureus. The overall migration levels of the nanocomposites in both nonpolar and polar simulants dropped upon increasing nanoparticle content, and were well below the limits required by the current normative for food packaging materials. These sustainable nanomaterials with antimicrobial function are very promising to be used as containers for beverage and food products as well as for disposable applications like cutlery or overwrap films.
采用溶液浇铸法将氧化锌纳米粒子添加到细菌聚酯聚（3-羟基丁酸-co-3-羟基戊酸）（PHBV）中制备可生物降解的纳米复合材料。分析了纳米复合材料的形态、热学、力学、抗菌、阻隔和迁移性能。纳米粒子在没有偶联剂的帮助下均匀分散在 PHBV 中，并且有效地作为成核剂，提高了基体的结晶温度和结晶度水平，同时减小了其晶粒尺寸。随着 ZnO 负载量的增加，发现热稳定性逐渐提高，因为纳米填料阻碍了在分解过程中产生的挥发性物质的扩散。与纯生物聚合物相比，纳米复合材料表现出更高的刚性、强度、韧性和玻璃化转变温度，同时表现出更低的吸水率以及氧气和水蒸气透过率，这与通过氢键相互作用获得的强基质-纳米填料界面附着力有关。在 4.0wt% ZnO 的最佳浓度下，拉伸强度、杨氏模量和储能模量表现出最大值，这与最高结晶度和最佳阻隔性能相一致。PHBV/ZnO 薄膜对人体病原体细菌表现出抗菌活性，对大肠杆菌的作用强于金黄色葡萄球菌。随着纳米粒子含量的增加，非极性和极性模拟物中纳米复合材料的整体迁移水平下降，远低于当前食品包装材料标准要求的限制。这些具有抗菌功能的可持续纳米材料非常有希望用作饮料和食品容器，以及一次性应用，如餐具或外包装薄膜。
