自修复环氧树脂微胶囊合成及其反应机理

Synthesis and reaction mechanism of self-healing epoxy microcapsules

以环氧树脂作为囊芯材料,以三乙烯四胺为固化剂,采用界面聚合法制备一种在环氧树脂液滴表面形成交联结构环氧树脂囊壁包覆环氧树脂液芯的自修复微胶囊.设计L_9(3~4)正交试验,研究乳化剂用量、固化剂用量、固化温度及固化剂滴加速率对环氧树脂微胶囊囊芯含量和储存期的影响.采用扫描电镜和广角静态动态同步激光散射仪分别对微胶囊表面形貌、粒径大小及分布情况进行表征,采用傅里叶变换红外光谱和热失重分析仪分别研究环氧树脂微胶囊囊壁的反应机理及环氧树脂微胶囊热稳定性.实验表明,乳化剂和固化剂的质量分数均为1. 2%,固化剂滴加速率为1. 2 g/h,固化温度为50℃时,制得的微胶囊呈规则球形,表面致密性及分散性好、热稳定性佳;囊芯的质量分数为82. 3%,平均粒径为275. 3μm,这种环氧树脂微胶囊的化学稳定性较差,在室温放置12 d后囊芯的质量分数下降2. 0%.通过万能电子拉力机对质量分数为2. 0%的200～300μm微胶囊的环氧树脂复合材料进行损伤,经修复后测得修复率为67. 04%.

Self-healing epoxy resin microcapsules are prepared by interfacial polymerization,in which the core materials are epoxy resin,the wall materials are constructed with triethylenetetramine( TETA) and the epoxy resin.The orthogonal experiments L9( 34) are designed to investigate the influence of emulsifier dosage,hardener dosage,curing temperature and hardener adding rate on the core content and storage life of epoxy resin microcapsule. Scanning electron microscope and static dynamic wide angle laser light scattering instrument synchronization are used to characterize surface topography,particle size and distribution. Fourier transform infrared spectroscopy and thermogravimetric analyzer are used to study reaction mechanism of the microcapsule wall materials and thermal stability of the microcapsules,respectively. The results indicate that when the dosage of emulsifier is 1. 2%,the dosage of hardener is 1. 2%,the hardener droplets adding rate is 1. 2 g/h and the curing temperature is 50 ℃,the microcapsules prepared are spherical in shape with good surface compactness,dispersibility and thermal stability and the capsule core content is 82. 3% and the average particle size is 275. 3 μm. However,this type of epoxy resin microcapsule has relatively poor chemical stability. The core content decreases by 2. 0% after 12 d storedat room temperature. After epoxy resin composite doped with 2. 0% mass fraction of 200 ~ 300 μm microcapsules is damaged by the tensile testing machine,their repair rate is 67. 04%.