Study On The Synthesis And Technology Of Microcapsules As Self-healing Coatings

As one of the means to prevent metal corrosion, coated with anti-corrosion painting on metal surface is very effectively. However, due to the environmental factors, the mechanical properties of the anti-corrosion coatings will be result in microcracks finally,even stripped with the metal surface. As a new research project, the concept of self-healing coatings was proposed, and the key to self-healing coatings is the synthsis of microcapsules.In this article, two types of Self-healing microcapsules were synthesized by different means. The process of in situ polymerization, the poly urea-formaldehyde resin epoxy(PUF- epoxy) microcapsules were synthesized successfully with epoxy resin E-51 and T-8810 as core material and urea-formaldehyde resin as wall material. Another, the cationic photoinitiator microcapsules were prepared from isophorone diisocyanate(IPDI, as shell monomer) and cationic photoinitiator(PI6992,as core material)in the catalyst. By talking reaction parameters of the system, such as type and amount of emulsifier, emulsification speed, the ratio of core /wall, acidification time, p H, the optimum process of the two methods were obtained finally. Once more, the properties of microcapsules for example morphology of microcapsules, the particle size distribution,the average diameter, chemical structure and thermal properties were characterized by Field emission scanning electron microscope(FE-SEM),optical microscopy(OM), Fourier transform infrared spectroscopy(FT-IR), thermal gravimetric analysis(TGA) and other analytical instruments.The results of experimental show that two self-healing microcapsules were synthesized successfully. The PUF- epoxy microcapsules were of smooth surface, better dispersion and excellent thermal stability in the condition of SDBS of 1%,core / shall ratio is1: 1,the ratio E-51 / T-8810 of 2: 1, stirring rate of 600 rpm, acidification time of 40-60 min, the reaction time of 2.5h. As the same to that, the optimal process of photoinitiator agent microcapsules was: core/shell material ratio of 1: 3, the rotation speed of 8000 rpm, betaine of 1%,the reaction time of 2h. And the as-prepared microcapsules were good at dispersion, uniform particle size distribution, and high thermal stability.