Naranjo-Adorno Eduardo, Castrejón-González Edgar O, Alvarado Juan F J, Díaz-Ovalle Christian O, Rico-Ramírez Vicente
Departamento de Ingeniería Química, Tecnológico Nacional de México en Celaya, Av. Antonio García Cubas 600 Pte, Celaya, Guanajuato, México.
Departamento de Ingenierías, Tecnológico Nacional de México/I.T. Roque, Km 8.0 Carretera Celaya-Juventino Rosas, Celaya, Guanajuato, 38124, México.
J Mol Model. 2025 May 30;31(6):176. doi: 10.1007/s00894-025-06403-x.
Polyethylene (PE) and polylactic acid (PLA) are two of the most widely used polymers. It is known that their mechanical properties, such as hardness, are poor. In order to enhance the mechanical properties of those polymers, reinforcements have to be incorporated. Carbon nanotubes (CNTs) have proven to be an excellent choice for reinforcement. However, due to the π-π interactions, the nanotubes tend to agglomerate. One of the strategies to avoid agglomerations is chemical functionalization. The 3-amino-propyl tri-ethoxy silane (APTES) is a suitable option for functionalization. In this work, three different polymeric configurations were analyzed to verify their effect on hardness: linear, hyperbranched, and star-like. Further, the configuration with the highest hardness was reinforced with functionalized CNTs with APTES groups. Results indicate that a linear configuration, both of PE and PLA, generates greater hardness due to better structural arrangement. The percentage of functionalization of CNTs that generates a better interaction with PLA is 3%, which corresponds to five anchored groups. The addition of CNTs increases the hardness 14 times with respect to that of PLA without reinforcement.
Molecular models were built and visualized using MedeA and OVITO software programs. All simulations were run using the LAMMPS software. The force fields utilized were PCFF for polyethylene and COMPASS for PLA and carbon nanotubes. A van der Waals model was used to consider the non-bonding interactions between the indenter and substrate. An NVT ensemble was used to construct the substrates, and the indentation procedure involved iterative cycles of minimization and displacement of the indenter.
聚乙烯（PE）和聚乳酸（PLA）是两种应用最为广泛的聚合物。众所周知，它们的机械性能，如硬度较差。为了提高这些聚合物的机械性能，必须加入增强材料。碳纳米管（CNT）已被证明是一种出色的增强材料选择。然而，由于π-π相互作用，纳米管容易团聚。避免团聚的策略之一是化学功能化。3-氨基丙基三乙氧基硅烷（APTES）是一种合适的功能化选择。在这项工作中，分析了三种不同的聚合物构型以验证它们对硬度的影响：线性、超支化和星型。此外，用带有APTES基团的功能化碳纳米管增强硬度最高的构型。结果表明，PE和PLA的线性构型由于更好的结构排列而产生更大的硬度。与PLA产生更好相互作用的碳纳米管功能化百分比为3%，对应五个锚定基团。相对于未增强的PLA，碳纳米管的加入使硬度提高了14倍。
使用MedeA和OVITO软件程序构建并可视化分子模型。所有模拟均使用LAMMPS软件运行。所使用的力场，对于聚乙烯是PCFF，对于PLA和碳纳米管是COMPASS。使用范德华模型来考虑压头与基底之间的非键相互作用。使用NVT系综构建基底，压痕过程涉及压头最小化和位移的迭代循环。
