Kelnar Ivan, Kaprálková Ludmila, Němeček Pavel, Dybal Jiří, Abdel-Rahman Rasha M, Vyroubalová Michaela, Nevoralová Martina, Abdel-Mohsen A M
Institute of Macromolecular Chemistry, Czech Academy of Sciences, 162 00 Prague, Czech Republic.
Polymers (Basel). 2023 Jul 17;15(14):3071. doi: 10.3390/polym15143071.
The multiple roles of organic nanofillers in biodegradable nanocomposites (NC) with a blend-based matrix is not yet fully understood. This work highlights combination of reinforcing and structure-directing effects of chitin nanowhiskers (CNW) with different degrees of deacetylation (DA), i.e., content of primary or secondary amines on their surface, in the nanocomposite with the PCL/PLA 1:1 matrix. Of importance is the fact that aminolysis with CNW leading to chain scission of both polyesters, especially of PLA, is practically independent of DA. DA also does not influence thermal stability. At the same time, the more marked chain scission/CNW grafting for PLA in comparison to PCL, causing changes in rheological parameters of components and related structural alterations, has crucial effects on mechanical properties in systems with a bicontinuous structure. Favourable combinations of multiple effects of CNW leads to enhanced mechanical performance at low 1% content only, whereas negative effects of structural changes, particularly of changed continuity, may eliminate the reinforcing effects of CNW at higher contents. The explanation of both synergistic and antagonistic effects of structures formed is based on the correspondence of experimental results with respective basic model calculations.
有机纳米填料在具有共混基基体的可生物降解纳米复合材料（NC）中的多重作用尚未得到充分理解。这项工作突出了不同脱乙酰度（DA）的几丁质纳米晶须（CNW），即其表面伯胺或仲胺的含量，在与聚己内酯/聚乳酸1:1基体的纳米复合材料中的增强和结构导向作用的结合。重要的是，CNW的氨解导致两种聚酯尤其是聚乳酸的断链，实际上与DA无关。DA也不影响热稳定性。同时，与聚己内酯相比，聚乳酸更明显的断链/CNW接枝，导致组分流变参数的变化和相关的结构改变，对具有双连续结构的体系的力学性能有至关重要的影响。CNW多重效应的有利组合仅在低含量1%时导致机械性能增强，而结构变化尤其是连续性改变的负面影响可能在较高含量时消除CNW的增强作用。对所形成结构的协同和拮抗效应的解释基于实验结果与相应基本模型计算的对应关系。
