双环戊二烯微胶囊自修复对环氧复合材料拉伸和疲劳性能的影响

Effect of Self-Healing by Dicyclopentadiene Microcapsules on Tensile and Fatigue Properties of Epoxy Composites.

作者信息

Pandey Abhishek, Sharma Atul Kumar, Shukla Dharmendra Kumar, Pandey Kailash Narayan

机构信息

Mechanical Engineering Department, Motilal Nehru National Institute of Technology Allahabad, Prayagraj 211004, India.

Mechanical Engineering Department, ABES Engineering College, Ghaziabad 201009, India.

出版信息

Materials (Basel). 2023 Jul 24;16(14):5191. doi: 10.3390/ma16145191.

DOI:10.3390/ma16145191

PMID:37512465

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10384437/

Abstract

Microcapsules of urea-formaldehyde (UF) containing dicyclopentadiene (DCPD) were synthesized by the in situ polymerization technique for self-healing of epoxy. The dispersion of microcapsules in the epoxy matrix was achieved using ultrasonication. Composites of epoxy, having 0.5, 1.0, 1.5, and 2.0 wt.% of microcapsules capable of self-healing, were prepared. The shape and size of the microcapsules were determined by field emission electron microscopy. Spherical capsules of DCPD, with an average diameter of 172 nm, were obtained. Investigation of tensile properties indicated a decrease in the tensile modulus with an increase in wt.% of microcapsules. There was a reduction of 22%, 27%, 39%, and 30% in the elastic modulus of composites for 0.5, 1.0, 1.5, and 2.0 wt.% of microcapsules, respectively. Tensile strength was found to increase with an increase in wt.% of microcapsules. The tensile strength of the composites increased by 33%, 20%, 8%, and 21% for 0.5, 1.0, 1.5, and 2.0 wt.% of microcapsules, respectively, in comparison with that of neat epoxy. The fatigue life of composites was investigated by conducting uniaxial tension-tension fatigue tests at constant stress amplitudes of 20, 25, 30, and 35 MPa, at a constant stress ratio (R = 0.1) and a frequency of 3 Hz. The fatigue life of composites increased with an increase in wt.% of microcapsules in comparison with that of neat epoxy. It was found that the fatigue life of the composites decreased with 1.5 and 2.0 wt.% of microcapsules in comparison with composites with 0.5 and 1.0 wt.% of microcapsules. The fracture surfaces of the tested samples were examined with the help of scanning electron microscopy (SEM) to understand the various mechanisms responsible for the change in modulus, strength, failure strain, and fatigue life of composites.

摘要

通过原位聚合法合成了含有二环戊二烯（DCPD）的脲醛（UF）微胶囊，用于环氧树脂的自修复。使用超声处理使微胶囊在环氧树脂基体中分散。制备了含有0.5%、1.0%、1.5%和2.0%（重量）可自修复微胶囊的环氧复合材料。通过场发射电子显微镜确定微胶囊的形状和尺寸。获得了平均直径为172nm的DCPD球形胶囊。拉伸性能研究表明，随着微胶囊重量百分比的增加，拉伸模量降低。对于含有0.5%、1.0%、1.5%和2.0%（重量）微胶囊的复合材料，其弹性模量分别降低了22%、27%、39%和30%。发现拉伸强度随着微胶囊重量百分比的增加而增加。与纯环氧树脂相比，含有0.5%、1.0%、1.5%和2.0%（重量）微胶囊的复合材料的拉伸强度分别提高了33%、20%、8%和21%。通过在20、25、30和35MPa的恒定应力幅值下进行单轴拉伸-拉伸疲劳试验，在恒定应力比（R = 0.1）和3Hz频率下研究复合材料的疲劳寿命。与纯环氧树脂相比，复合材料的疲劳寿命随着微胶囊重量百分比的增加而增加。发现与含有0.5%和1.0%（重量）微胶囊的复合材料相比，含有1.5%和2.0%（重量）微胶囊的复合材料的疲劳寿命降低。借助扫描电子显微镜（SEM）检查测试样品的断裂表面，以了解导致复合材料模量、强度、破坏应变和疲劳寿命变化的各种机制。