| Microcapsules with excellent properties such as lower toxicity, controlled release and improve the stability of materials etc., which have been widely applied in some field, such as food, medicine, cosmetics, agriculture etc.. Research of intelligence microcapsules are used in material field have become a hot spot with the development of microencapsulation technology. Urea-formaldehyde resin compared other microcapsules has excellent wear resistance, high thermal stability and high strength, which often used as wall of microcapsule. The method of preparation and properties of urea-formaldehyde resin microcapsules are studied on its application in composite material, and have great significance.In this paper, two kinds of microcapsules were synthesized by in-situ polymerization with urea-formaldehyde resin as shell material, and E-44 epoxy resin and tetrachloroethylene as the core material respectively. The optimum reaction conditions such as the kind and concentration of emulsifier, core-wall ration, p H, rotation speed and reaction temperature of microencapsulation were studied in detail, and the synthesized microcapsule has excellent performance. The morphology and formation process of microcasule by using metallographic microscope, the surface morphology and wall thickness were examined by scanning electron microscopy(SEM), it was proved the chemical composition of microcapsule by fourier transform infrared spectrometer(FTIR), the thermal temperature zone was studied by thermogravimetric analyzer(TGA). The results indicated that the optimum process parameters of epoxy resin microcapsule were included that SDBS of 0.7% as emulsifier, and the core-wall ration of 1.2 : 1, and the p H of 3.0, and the rotation speed of 1200 r/min, the reaction temperature of 70℃. The epoxy resin microcapsule was synthesized, with rough surface, round shape, uniform distribution of particle size and the average diameter of about 160 μm and the wall thickness of about 2.1 μm, the microcapsules filled with epoxy resin had the content of epoxy resin was 62%, and the results of FTIR indicated that epoxy resin microcapsule can be synthesized successfully,and the TGA results indicated that epoxy resin microcapsule exhibit a good chemical stability below 248℃. The optimum process parameters of tetrachloroethylene microcapsule were synthesized which in the conditions of GA of 0.1% and SDBS of 0.1% as compound emulsifier, and the core-wall ration of 2.0 : 1, and the p H of 3.0, and the rotation speed of 400 r/min, the reaction temperature of 60℃, the microcapsules filled with tetrachloroethylene had the content of tetrachloroethylene was 86% and the average diameter of about 196 μm. Compared with the epoxy resin microcapsule, tetrachloroethylene microcapsule surface was more smooth, the cyst wall was thinner, and the better of dispersion.At the same time, composite materials were prepared with epoxy resin and microcapsules, and its friction and wear properties were analysed. The results indicated that the friction coefficient of composite materials which contain epoxy resin microcapsules became unstable and no obvious regulation, and the wear resistance of composite materials have no reproducibility; On the contrary, tetrachloroethylene microcapsules could effectively reduce the friction coefficient and the worn amount of epoxy resin through the lubricative role of oli. When the content of tetrachloroethylene microcapsule came up to 10%, the average friction coefficient of 0.252 was obtained, and the wear volume was reduced by about 68%. The worn mechanism was transformed from adherent and grain worn to fatigue worn with the improving addition of tetrachloroethylene microcapsule. |
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