Preparation And Damping Properties Of Polyurethane/Montmorillonite Microcapsules

With the development of the urban economy,the vibration and noise induced by the mechanism is attended more and more which directly affects the quality of people's lives.Damping ratio is the main index representing the property of materials in reducing vibration where high damping materials come in.Microencapsulation is a technology that uses membranous materials to coat solids or liquids into micro particles which attracts most people's attention has been widely used in various fields recently.Microcapsules are introduced into substrate materials based on its structural and morphology characteristics to achieve the purpose of improving the damping property of materials effectively in this paper.This paper firstly uses polyurethane as the coating material,the simethicone as core materials to prepare microcapsules by the method of interfacial polymerization,and the effects of monomer ratio of polyurethane,dosage of simethicone and emulsifiers,stirring speed,temperature and time of reaction have been discussed to obtain the most favorable experimental conditions.The structure,morphology,thermo stability,barrier and damping performance of microcapsules has been systemic studied by the tests of FTIR,SEM,TG and other analysis,the results show that simethicone has been entrapped successfully with a coating rate of 23.16% in polyurethane microcapsules.At the same time,it has smooth surface,excellent sealing,average particle diameter of 50?m and a good thermal stability below 225?.The microcapsules are incorporated into the epoxy resin,and its damping capacity is improved effectively when the content of microcapsules is 5wt.% by Dynamic Thermal Analysis(DMA)as the maximum of loss factor(tan?)raises from 0.376 to 0.563.Montmorillonite(MMT)is introduced to the preparation of microcapsules to improve the barrier performance of coating materials.The structure,morphology,thermo stability,barrier and damping performance of microcapsules has been systemic studied by the tests of FTIR,SEM,TG and other analysis,the surface turns rougher,the size increases larger to 54?m because of the addition of montmorillonite,the barrier performance of microcapsules is improved as well.The damping capacity of composite materials of microcapsules and epoxy resin is improved effectively as the maximum of loss factor(tan?)raises from 0.563 to 0.713.In the range of 1~200Hz,the loss factor(tan?)of the microcapsules is 0.5~1 times higher than that of the substrate,which indicated that the damping capacity of the microcapsules was good at low frequency.