Abstract:

To investigate the impact of nano kaolin content on the thermal and mechanical properties of epoxy resin, a composite epoxy resin system was developed using epoxy resin as the matrix and curing agent, and the composite epoxy resin system was constructed with nano kaolin as filler in different dosage. The glass transition temperature, elastic modulus, shear modulus, Poisson's ratio and hardness of the composites were examined, and the free volume fraction and interaction energy were quantified. Additionally, the free volume fraction and interaction energy were computed. The findings revealed that under experimental conditions, a nano kaolin mass fraction of 10% resulted in the nano kaolin/epoxy resin composite exhibited optimal properties: a glass transition temperature of 120.06℃, a hardness rating of 6H, a Young's modulus of 6.655GPa, a shear modulus of 2.594GPa and a Poisson's ratio of 0.283. This content led to the best thermal stability and mechanical properties. Molecular dynamics simulations further indicated that when the composite's crosslinking degree reached 90%, the model displayed minimal energy fluctuations in equilibrium. The glass transition temperature and mechanical properties calculated under these conditions were the best at a nano kaolin mass fraction of 10%, aligning well with the experimental results. Nano kaolin, known for its exceptional thermodynamic properties, could effectively reduce the free volume fraction when incorporated appropriately. The favorable interfacial energy interaction between nano kaolin and epoxy resin was pivotal in enhancing the thermal and mechanical characteristics of kaolin/epoxy resin nanocomposites. This research offered a foundational theory for the microscopic investigation of epoxy nanocomposites.

Key words: nano kaolin, epoxy resin, glass transition temperature, mechanical properties, molecular dynamics simulation

摘要：

为了研究纳米高岭土的掺量对环氧树脂热性能和力学性能的影响，以环氧树脂为基体并配以固化剂，以不同掺量下的纳米高岭土为填料构建了复合环氧树脂体系，分别考察了复合材料的玻璃化转变温度、弹性模量、剪切模量、泊松比、硬度等指标并计算了自由体积分数和相互作用能。结果表明：实验条件下当纳米高岭土掺量（质量分数）为10%时，环氧复合材料的玻璃化转变温度达到最大值120.06℃、硬度达到最大值6H，杨氏模量为6.655GPa，剪切模量为2.594GPa，泊松比为0.283，热稳定性能和力学性能均达到了最佳。通过分子动力学模拟，当复合材料的交联度为90%时，模型在平衡状态下的能量波动较小并处于平衡状态，此状态下计算得到的玻璃化转变温度和力学性能在纳米高岭土掺量10%时为最优，与实验值基本吻合。纳米高岭土自身有着优异的热力学性质的同时，其适量掺入可有效降低自由体积分数，与环氧树脂之间良好的界面能相互作用对于提升高岭土/环氧树脂纳米复合材料的热稳定性能和力学性能有着十分重要的作用，为环氧纳米复合材料的微观角度研究提供了理论基础。

关键词: 纳米高岭土, 环氧树脂, 玻璃化转变温度, 力学性能, 分子动力学模拟