The effect of nanosize alumina (Al2O3) concentration on the morphology and mechanical properties of microfibrillar composites obtained by processing the thermodynamically incompatible polypropylene/ copolyamide (PP/CPA) blend was studied. It was established that composite monofilaments exhibited a selfreinforcing effect due to the in situ formation of PP fibrils (microfibers) in the CPA matrix. The tensile strength and the initial elastic modulus of the filaments studied depended on their structure and correlated with dimensional characteristics of the disperse phase component. It is shown that the introduction of Al2O3 nanoparticles in an amount of (0.1-3.0) wt.% allows one to adjust the structure formation process of the dispersed phase component to obtain composites with a thin homogeneous morphology. The maximum performance was achieved for filaments formed from a composition containing 1.0 wt.% alumina. In this case, microfibers were the predominant type of structure, and their diameters were minimum. The increasing ability of the jets of nanofilled melts of PP/CPA blends to the longitudinal deformation was due to the formation of a more perfect microfibrillar structure during extrusion. This makes it possible to obtain filaments from such blends on already existing extrusion equipment.

中文翻译：

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氧化铝纳米粒子对微原纤复合材料结构和力学性能的影响

研究了纳米氧化铝 (Al2O3) 浓度对通过加工热力学不相容的聚丙烯/共聚酰胺 (PP/CPA) 共混物获得的微纤维复合材料的形态和机械性能的影响。已确定复合单丝由于在 CPA 基质中原位形成 PP 原纤维（微纤维）而表现出自增强作用。所研究的长丝的拉伸强度和初始弹性模量取决于它们的结构并与分散相组分的尺寸特征相关。结果表明，以（0.1-3.0）wt.% 的量引入 Al2O3 纳米粒子可以调整分散相组分的结构形成过程，以获得具有薄均匀形态的复合材料。对于由包含 1.0 重量％氧化铝的组合物形成的长丝，实现了最大性能。在这种情况下，微纤维是主要的结构类型，它们的直径最小。PP/CPA 共混物的纳米填充熔体射流纵向变形能力的增加是由于在挤出过程中形成了更完美的微纤维结构。这使得可以在现有的挤出设备上从这种共混物获得长丝。