Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing, 100029, China.
Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing, 100029, China.
Phys Chem Chem Phys. 2023 Feb 15;25(7):5602-5612. doi: 10.1039/d2cp04996a.
Carbon black has always played a pivotal role in reinforcing elastomers because it remarkably improves the mechanical properties. The reinforcing effect of carbon black is influenced by its grades, which mainly depend on the difference in the structure of the carbon black particles. Despite many traditional experiments on the performance of carbon black composites, there has been less emphasis on reinforcement mechanisms due to the challenges associated with unraveling the intermolecular interactions. In this paper, a coarse grained molecular dynamics simulation was employed to examine the relationship between the morphology of the carbon black particles and the mechanical properties of the elastomer nanocomposites. Specifically, three different morphological carbon black nanoparticle models, including the smooth particle model, rough particle model, and the rough ellipsoid model, were constructed first. We then focused on investigating the changes of the mechanical properties by systematically varying the filling fraction of the carbon black particles, and the strength of the interfacial interaction between the filler and the rubber. The results indicated that the surface roughness and the filler's shape had a significant impact on the mechanical properties of the filled rubber models. The mechanical enhancement effect of the rough ellipsoidal carbon black is around 50-400% higher than that of the smooth carbon black, and the stronger the interfacial interactions, the more pronounced the enhancement. In addition, the rough ellipsoid filled system has low hysteresis, low permanent deformation, and high fatigue resistance. In general, this work explores the strengthening mechanism of carbon black on the elastomer at the molecular level and generates new insight into the design and fabrication of novel reinforcing fillers.
炭黑在增强弹性体方面一直起着关键作用，因为它显著提高了机械性能。炭黑的增强效果受其等级的影响，这主要取决于炭黑颗粒结构的差异。尽管对炭黑复合材料的性能进行了许多传统实验，但由于难以揭示分子间相互作用，对增强机制的重视较少。在本文中，采用粗粒分子动力学模拟研究了炭黑颗粒的形态与弹性体纳米复合材料力学性能之间的关系。具体来说，首先构建了三种不同形态的炭黑纳米颗粒模型，包括光滑颗粒模型、粗糙颗粒模型和粗糙椭球模型。然后，我们通过系统地改变炭黑颗粒的填充分数和填料与橡胶之间的界面相互作用强度，重点研究了力学性能的变化。结果表明，表面粗糙度和填料形状对填充橡胶模型的力学性能有显著影响。粗糙椭球炭黑的机械增强效果比光滑炭黑高约 50-400%，界面相互作用越强，增强效果越明显。此外，粗糙椭球填充体系具有低滞后、低永久变形和高耐疲劳性。总的来说，这项工作从分子水平探索了炭黑对弹性体的增强机制，为新型增强填料的设计和制造提供了新的思路。
