Abstract

The preparation of commodity polymers that can undergo self-healing of scratched surfaces is still quite challenging without involving complicated synthetic processes and high cost of healing agents. In the research described here, we prepared a self-healing acrylic acid-functionalized metallocene polyethylene elastomer (mPE-g-AA) nanocomposite with the addition of arginine to form supramolecular hydrogen bonding. Thermal characterization, mechanical properties, shape memory effect, and self-healing properties were investigated. The addition of mutilwall carbon nanotubes (MWCNTs) effectively increased the tensile properties of the modified mPE. The acrylic acid-modified mPE greatly improved its shape recovery ratio, up to 94.2 ± 4.7%, and maintained a high shape fixing ratio (91.6 ± 1.3%) due to the hydrogen bonding acting as physical crosslinks. Overall, all modified mPE samples showed good shape memory performance. Besides the conventional thermal heating to heal the scratched surface cracks, MWCNTs were incorporated to permit healing the surface cracks through near-infrared radiation (NIR). However, the MWCNTs-filled samples under the thermal healing process unexpectedly resulted in the crack widths increasing, perhaps due to the effect of the MWCNTs with high recovery stress pushing outward on both sides of the crack during heating. Interestingly, the synergistic approach of combining thermal healing and NIR was found to be the most effective in improving the healing efficiency of the mPE-g-AA-Arg/MWCNTs, close to 50% within a short time, in comparison with the existing literature with required healing times of 60 min to have a self-healing efficiency of 45% for mPE modified with maleic anhydride and 3-amino-1,2,4-triazole. To the best of the authors’ knowledge, no work has been reported on the preparation of self-healing thermoplastic elastomer nanocomposites through this approach so far.

摘要

在不涉及复杂的合成过程和高成本的修复剂的情况下，制备可以对划痕表面进行自修复的商品聚合物仍然非常具有挑战性。在这里描述的研究中，我们制备了一种自修复丙烯酸官能化茂金属聚乙烯弹性体 (mPE-g-AA) 纳米复合材料，并添加了精氨酸以形成超分子氢键。研究了热表征、机械性能、形状记忆效应和自愈性能。添加多壁碳纳米管 (MWCNTs) 有效地提高了改性 mPE 的拉伸性能。丙烯酸改性的 mPE 大大提高了其形状恢复率，高达 94.2 ± 4.7%，并且由于氢键作为物理交联，保持了较高的形状固定率 (91.6 ± 1.3%)。总体而言，所有改性 mPE 样品均显示出良好的形状记忆性能。除了传统的热加热来修复划伤的表面裂缝外，还加入了多壁碳纳米管以允许通过近红外辐射 (NIR) 修复表面裂缝。然而，在热愈合过程中填充多壁碳纳米管的样品出乎意料地导致裂纹宽度增加，这可能是由于高恢复应力的多壁碳纳米管在加热过程中向裂纹两侧向外推的影响。有趣的是，发现结合热愈合和 NIR 的协同方法在提高 mPE-g-AA-Arg/MWCNTs 的愈合效率方面最有效，在短时间内接近 50%，与现有文献相比，用马来酸酐和 3-氨基-1,2,4-三唑改性的 mPE 所需的愈合时间为 60 分钟，自愈效率为 45%。据作者所知，到目前为止，还没有关于通过这种方法制备自修复热塑性弹性体纳米复合材料的报道。