Study On Preparation Of Amine Curing Agent Microcapsules And Application As Self-healing Materials

Polymeric materials are widely used in many fields such as construction,transportation,aerospace,electronics and so on because of their excellent performance.During long-term use,it will inevitably appear micro-cracks in the materials and the micro-cracks which are hard to find by eyes will damage the integrity and strength of the material.It is a challenging subject for repairing the microcracks inside the material,so in this paper,the preparation of amine curing agent microcapsules and its application as self-healing materials were studied.In this paper,self-healing curing agent microcapsules were respectively synthesized with amine curing agent(1618)as core material,urea-formaldehyde resin and melamine formaldehyde as shell material,respectively.The effects of some reaction parametrers such as different preparation method,the mass ratio of core marerials to wall materials,the kind and amount of emulsifier,pH of reaction system and rotation speed on the properties of microcapsules were studied.Simultaneously,the morphology of microcapsules was characterized with optical microscope(OM)and scaning electron microscope(SEM).The structure,thermal stability and mechanical property of microcapsules are evaluated using fourier transform infrared(FTIR),thermogravimetric analysis(TGA)and almighty stretcher.The results revealed that optimum technology parameter of urea-formaldehyde resin microcapsule was: interfacial polymerization as preparation method,the core-wall ration of 0.8,SDBS as emulsifier and the amount of SDBS 1.3% for the core,the pH of 2~3and the rotation speed of 500 r/min.The optimum technology parameter of melamine formaldehyde resin microcapsule was: interfacial polymerization as preparation method,the core-wall ration of 1,GA as emulsifier and the amount of GA 2% for the core,the pH of4~5 and the rotation speed of 500 r/min.The results showed melamine formaldehyde resin microcapsule had better dispersibility,good thermostability and good mechanical property.At the same time,silicane coupling agent was applied to modify the surface of melamine formaldehyde resin microcapsules prepared under optimum conditions and the effect of the kind and amount of coupling agent on the properties of microcapsules was investigated.The results indicated that when the coupling agent was KBM7803 and the WKBM7803%=2%,the modified microcapsules had good dispersibility,thermal stability and mechanical properties.The results of SEM showed that when the modified microcapsules were added to the epoxy resin matrix and the matrix material was scratched,the microcapsules were broken and showed self-healing performance.