Research On Microencapsulation Technology Of Perfluorohexanone Fire Extinguishing Agent

With the continuous development of China’s national economy,power consumption and electrical equipment will continue to increase.In the context of the increasingly severe situation of electrical fires,sufficient attention and prevention of the society must be aroused.For fires caused by electrical distribution cabinets,there are no effective targeted protection measures and no effective fire extinguishing products in the current fire management.In order to effectively alleviate this problem,this article intends to microencapsulate the perfluorohexanone fire extinguishing agent and explore the technological ways to prepare perfluorohexanone microencapsulation,so as to lay the technical foundation for the development of practical perfluorohexanone microcapsule products.In this paper,considering many factors,the embedding rate,particle size and distribution and the compactness of microcapsule shell were proposed as the three key indicators to evaluate the quality of perfluorohexanone microcapsule,and simple and efficient test methods were found respectively,and a set of performance evaluation system suitable for perfluorohexanone microcapsule was established to support the research of perfluorohexanone microcapsule technology.In this paper,linear polyurethane microcapsules with perfluorohexanone as the core material were prepared by interfacial polymerization using isophorone diisocyanate(IPDI)and diethylenetriamine(DETA)as monomers.At the same time,the surface morphology,chemical structure,thermal stability,particle size distribution and compactness of the microcapsules were studied and analyzed by optical microscope,infrared spectroscopy(FTIR),thermogravimetric analyzer(TGA)and laser particle size analyzer.The results showed that the uniform and stable emulsification of perfluorohexanone and monomers was achieved by using suitable and efficient compound fluorocarbon surfactant and exploring the influencing factors of the stability of microcapsules;The results of infrared analysis showed that the core material perfluorohexanone was successfully coated into the polyurethane shell,which was further verified by thermogravimetric analysis;The optical microscope images of emulsion droplets show that when the emulsification speed is 2000 rpm and the emulsification time is 10 min,the emulsification effect is excellent,the dispersion is uniform and the particle size is uniform;The optimum ratio of IPDI and deta was 3:8 by infrared spectrum analysis;Through thermogravimetric analysis,it was found that the increase of emulsifying speed and emulsifier dosage could improve the thermal stability and coating rate of microcapsules,but it should not be too large.The optimal emulsifying speed was 2000 rpm and emulsifier dosage was 0.3g.In addition,it is found that the method of fractional heating is better;Through particle size analysis,it was found that with the increase of emulsification speed,the particle size decreased significantly,and the distribution was more uniform.Moreover,when the ratio of water to oil is 6:1,the particle size distribution of microcapsules is uniform and the average particle size is small;Through the analysis of immersion resistance,it is found that the microcapsules with better immersion resistance can be obtained by using smaller core-wall ratio.At the same time,it was found that the linear shell microcapsules had poor immersion resistance,could not protect the core material,and could not meet the needs of practical application.In order to solve the problem of poor immersion resistance of linear shell microcapsules,two methods were proposed.One is to add polyol cross-linking agent to form a network shell microcapsule,and the other is to add PPG2000 to form a polyurea /polyurethane composite structure microcapsule.The prepared microcapsules were analyzed by infrared spectroscopy,thermogravimetry and immersion resistance.Infrared results showed that the microcapsules with reticular shell were successfully formed;The results of thermogravimetry showed that increasing the amount of pentaerythritol could improve the heat resistance temperature and embedding rate of microcapsules,and the optimal amount of pentaerythritol was 0.1g;The immersion resistance analysis showed that the microcapsules with reticular shell and polyurea / polyurethane composite structure greatly improved the immersion resistance and effectively protected the core material.