微胶囊含量对狄尔斯-阿尔德室温自修复热固性材料的影响。

Effect of Microcapsule Content on Diels-Alder Room Temperature Self-Healing Thermosets.

作者信息

Santos Sadella C, La Scala John J, Palmese Giuseppe R

机构信息

Department of Chemical & Biological Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.

Army Research Laboratory, 4600 Deer Creek Loop, Aberdeen Proving Grounds, MD 21005-5096, USA.

出版信息

Polymers (Basel). 2020 Dec 21;12(12):3064. doi: 10.3390/polym12123064.

DOI:10.3390/polym12123064

PMID:33371328

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7767355/

Abstract

A furan functionalized epoxy-amine thermoset with an embedded microcapsule healing system that utilizes reversible Diels-Alder healing chemistry was used to investigate the influence of microcapsule loading on healing efficiency. A urea-formaldehyde encapsulation technique was used to create capsules with an average diameter of 150 µm that were filled with a reactive solution of bismaleimide in phenyl acetate. It was found that optimum healing of the thermoset occurred at 10 wt% microcapsule content for the compositions investigated. The diffusion of solvent through the crack interface and within fractured samples was investigated using analytical diffusion models. The decrease in healing efficiency at higher microcapsule loading was attributed partially to solvent-induced plasticization at the interface. The diffusion analysis also showed that the 10% optimum microcapsule concentration occurs for systems with the same interfacial solvent concentration. This suggests that additional physical and chemical phenomena are also responsible for the observed optimum. Such phenomena could include a reduction in surface area available for healing and the saturation of interfacial furan moieties by reaction with increasing amounts of maleimide. Both would result from increased microcapsule loading.

摘要

一种具有嵌入式微胶囊修复系统的呋喃功能化环氧-胺热固性材料，该系统利用可逆的狄尔斯-阿尔德修复化学原理，用于研究微胶囊负载量对修复效率的影响。采用脲醛包封技术制备了平均直径为150 µm的胶囊，这些胶囊填充有双马来酰亚胺在乙酸苯酯中的反应溶液。研究发现，在所研究的组合物中，当微胶囊含量为10 wt%时，热固性材料实现了最佳修复效果。使用分析扩散模型研究了溶剂通过裂纹界面和在断裂样品内部的扩散情况。微胶囊负载量较高时修复效率的降低部分归因于界面处溶剂诱导的增塑作用。扩散分析还表明，对于具有相同界面溶剂浓度的体系，最佳微胶囊浓度为10%。这表明其他物理和化学现象也导致了观察到的最佳效果。这些现象可能包括可用于修复的表面积减少以及随着马来酰亚胺含量增加，界面呋喃部分因反应而饱和。两者都将由微胶囊负载量增加导致。