Papapetros Konstantinos, Mathioudakis Georgios N, Vroulias Dionysios, Koutroumanis Nikolaos, Voyiatzis George A, Andrikopoulos Konstantinos S
Foundation for Research and Technology-Hellas (FORTH), Institute of Chemical Engineering Science (ICE-HT), Stadiou Street, 265 04 Patras, Greece.
Department of Chemical Engineering, University of Patras, 265 04 Patras, Greece.
Polymers (Basel). 2025 Jul 10;17(14):1911. doi: 10.3390/polym17141911.
Bio-nanocomposites based on poly (vinyl alcohol) (PVA) and cellulosic nanostructures are favorable for active food packaging applications. The current study systematically investigates the mechanical properties, gas permeation, and swelling parameters of PVA composites with cellulose nanocrystals (CNC) or nano lignocellulose (NLC) fibers. Alterations in these macroscopic properties, which are critical for food packaging applications, are correlated with structural information at the molecular level. Strong interactions between the fillers and polymer host matrix were observed, while the PVA crystallinity exhibited a maximum at 1% loading. Finally, the orientation of the PVA nanocrystals in the uniaxially stretched samples was found to depend non-monotonically on the CNC loading and draw ratio. Concerning the macroscopic properties of the composites, the swelling properties were reduced for the D1 food simulant, while for water, a considerable decrease was observed only when high NLC loadings were involved. Furthermore, although the water vapor transmission rates are roughly similar for all samples, the CO, N, and O gas permeabilities are low, exhibiting further decrease in the 1% and 1-5% loading for CNC and NLC composites, respectively. The mechanical properties were considerably altered as a consequence of the good dispersion of the filler, increased crystallinity of the polymer matrix, and morphology of the filler. Thus, up to ~50%/170% enhancement of the Young's modulus and up to 20%/50% enhancement of the tensile strength are observed for the CNC/NLC composites. Interestingly, the elongation at break is also increased by ~20% for CNC composites, while it is reduced by ~40% for the NLC composites, signifying the favorable/unfavorable interactions of cellulose/lignin with the matrix.
基于聚乙烯醇（PVA）和纤维素纳米结构的生物纳米复合材料有利于活性食品包装应用。当前的研究系统地研究了含有纤维素纳米晶体（CNC）或纳米木质纤维素（NLC）纤维的PVA复合材料的机械性能、气体渗透性和溶胀参数。这些对于食品包装应用至关重要的宏观性能的变化与分子水平的结构信息相关。观察到填料与聚合物主体基质之间有强烈的相互作用，而PVA结晶度在1%负载量时呈现最大值。最后，发现单轴拉伸样品中PVA纳米晶体的取向非单调地取决于CNC负载量和拉伸比。关于复合材料的宏观性能，D1食品模拟物的溶胀性能降低，而对于水，仅当涉及高NLC负载量时才观察到显著下降。此外，尽管所有样品的水蒸气透过率大致相似，但CO、N和O气体渗透率较低，分别在CNC和NLC复合材料的1%和1 - 5%负载量时进一步降低。由于填料的良好分散、聚合物基体结晶度的提高以及填料的形态，机械性能发生了显著变化。因此，对于CNC/NLC复合材料，观察到杨氏模量提高了约50%/170%，拉伸强度提高了约20%/50%。有趣的是，CNC复合材料的断裂伸长率也提高了约20%，而NLC复合材料的断裂伸长率降低了约40%，这表明纤维素/木质素与基体之间存在有利/不利的相互作用。
