Bansal Suneev Anil, Singh Amrinder Pal, Singh Sukhbir, Kumar Suresh
Department of Mechanical Engineering, Bharat Institute of Engineering and Technology, Mangalpally, Ibrahimpatnam, Hyderabad501510, Telangana, India.
Department of Mechanical Engineering, MAIT, Maharaja Agrasen University, Himachal Pradesh174103, India.
Langmuir. 2023 Jan 11. doi: 10.1021/acs.langmuir.2c02723.
Epoxies, their derivatives, and composites, due to superior specific strength, are preferred for many potential applications in the field of automobiles, aircraft, bonding of structures, protective coatings, water filtration, etc. As structural members in automobiles and aircraft, the epoxy-based components are exposed to various static/dynamic mechanical loading conditions during their service life. The interfacial interactions, between the matrix and reinforcement, greatly affect the final properties of the composites. The present study demonstrates that the solvent used for the preparation of the composite can also contribute toward interfacial interactions. Present research systematically finds out a suitable solvent (acetone) and reinforcement type [multi-walled carbon nanotube (CNT)] for epoxy [bisphenol-A (BPA)] nanocomposites. Dynamic and static strengths of the as-prepared epoxy-CNT nanocomposites were carefully investigated. Well dispersed CNTs in acetone were mixed with an ester of BPA under constant magnetic stirring conditions. Samples of tablet shape were prepared for testing static and dynamic performance of the composite using a nano-indentation technique. Considerable enhancement by 55 and 22% in the static elastic modulus and hardness of BPA-CNT composites, respectively, was observed (compared with that of pristine BPA). The storage modulus and tan-delta of the nanocomposites were also improved by 14 and 46%, respectively. Improved static and dynamic performance, reported in this work, significantly enhances the scope of utilization of BPA-CNT-based nanocomposites under severe static and dynamic loading conditions simultaneously. Static and dynamical analysis of CNT-reinforced epoxy provides more realistic understanding of the mechanical performance of the nanocomposite. Density functional theory (using QuantumATK software) simulations were performed to investigate and identify the alterations in the atomic morphology of CNTs during interfacial interaction with the acetone molecule and epoxy matrix. The calculations predicted that CNTs with mild defects as compared to pristine CNTs were better suited for synthesis of the nanocomposite and also assisted in a homogeneous distribution of CNTs in BPA without aggregation (with acetone as the solvent). Furthermore, structural changes in CNTs after treatment with BPA and the curing agent and the role of defects are studied in detail.
环氧树脂及其衍生物和复合材料，由于具有优异的比强度，在汽车、飞机、结构粘结、防护涂层、水过滤等领域的许多潜在应用中更受青睐。作为汽车和飞机的结构部件，环氧基组件在其使用寿命期间会受到各种静态/动态机械载荷条件的影响。基体与增强材料之间的界面相互作用极大地影响复合材料的最终性能。本研究表明，用于制备复合材料的溶剂也有助于界面相互作用。目前的研究系统地找出了一种适合环氧树脂[双酚A（BPA）]纳米复合材料的溶剂（丙酮）和增强材料类型[多壁碳纳米管（CNT）]。对制备的环氧-CNT纳米复合材料的动态和静态强度进行了仔细研究。在恒定磁力搅拌条件下，将丙酮中分散良好的CNT与双酚A的酯混合。制备了片状样品，使用纳米压痕技术测试复合材料的静态和动态性能。观察到双酚A-CNT复合材料的静态弹性模量和硬度分别比原始双酚A显著提高了55%和22%。纳米复合材料的储能模量和损耗角正切也分别提高了14%和46%。本工作中报道的静态和动态性能的改善显著扩大了双酚A-CNT基纳米复合材料在同时承受严苛静态和动态载荷条件下的应用范围。对CNT增强环氧树脂的静态和动态分析能更真实地了解纳米复合材料的力学性能。进行了密度泛函理论（使用QuantumATK软件）模拟，以研究和识别CNT在与丙酮分子和环氧基体发生界面相互作用时原子形态的变化。计算预测，与原始CNT相比具有轻微缺陷的CNT更适合用于合成纳米复合材料，并且有助于CNT在双酚A中均匀分布而不聚集（以丙酮为溶剂）。此外，还详细研究了用双酚A和固化剂处理后CNT的结构变化以及缺陷的作用。
