| Phase change wax is a kind of solid-liquid ester phase change material with high enthalpy,stability and no supercooling.The microencapsulation technology can effectively prevent the melt leakage of phase change wax and improve its thermal recycling efficiency.Compared with organic wall materials,inorganic wall materials have good chemical stability,thermal stability and thermal conductivity,and there is no problem of formaldehyde release.Therefore,this paper takes ester phase change wax as the core material,and silica which has a wide source and low price as the wall material,in order to prepare the environment-friendly SiO2/phase change wax microcapsules with excellent thermal conductivity and high enthalpy,and corresponding textiles with temperature regulation and heat storage functionsThe research work of this thesis mainly includes four parts:(1)The microcapsules of SiO2/phase change wax were prepared by sol-gel method with tetraethyl orthosilicate as the silicon source and ester phase change wax as the core material.The preparation process of SiO2/phase change wax microcapsules was optimized by adjusting the factors such as the type and dosage of emulsifier,the rate and time of emulsification,the ratio of water to ethanol and the ratio of core to wall;(2)The microcapsules of SiO2/phase change wax were prepared by chemical precipitation method with sodium silicate as the silicon source and ester phase change wax as the core material.The preparation process of SiO2/phase change wax microcapsules was optimized by adjusting the factors such as the ratio and dosage of compound emulsifier,concentration of hydrochloric acid,reaction temperature and the ratio of core to wall;(3)Application of scanning electron microscopy,differential scanning calorimeter,Fourier infrared spectrometer,thermal constant analyzer,thermogravimetric analyzer,temperature recorder to test and characterize the apparent morphology,enthalpy value,chemical composition,thermal conductivity,thermal stability and thermal insulation performance of SiO2/phase change wax microcapsules;(4)Adopt the coating technology to prepare the temperature-regulating and heat-storing polyester fabric,and optimize the process conditions such as the type and dosage of the coating agent,the dosage of the phase change wax microcapsule,the viscosity of the coating slurry and the thickness of the coating,and characterize the temperature-regulating and heat-storing coating polyester fabric’s appearance,thermal properties,hand,breathability,temperature regulation and washing fastnessThe results show that:(1)The optimized process of SiO2/phase change wax microcapsules with TEOS as silicon source was as follows:CTAB was selected as emulsifier,the dosage of emulsifier was 1.2 wt%of water mass,the emulsification rate was 10000 r/min,the emulsification time was 20 min,the ratio of water to ethanol was 1.4:1,and the ratio of core to wall was 2.0:1.The prepared SiO2/phase change wax microcapsules were spherical,with particle size was concentrated in 150～250 nm,the melting enthalpy was 116.94 J/g,the crystallization enthalpy was 113.73 J/g,the coating rate was 88.31%,and the thermal conductivity was 0.3205 W/m·K;(2)The optimized process of SiO2/phase change wax microcapsules with Na2SiO3·9H2O as silicon source was as follows:compound emulsifier OP-10/CTAB ratio was 1:1.5,the dosage of compound emulsifier was 1.2 wt%of the total mass of water phase,the hydrochloric acid concentration was 0.95 mol/L,the reaction temperature was 45℃,and the core-wall ratio was 2.4:1.The prepared SiO2/phase change wax microcapsules had good sphericity,the particle size was concentrated in 200～300 nm,the melting enthalpy was 123.65 J/g,the crystallization enthalpy was 119.74 J/g,the coating rate was 88.19%,and the thermal conductivity was 0.3389 W/m·K;(3)The optimized coating process of SiO2/phase change wax microcapsules on polyester fabric was as follows:the mass concentration of SiO2/phase change wax microcapsules emulsion was 45.0 wt%,the dosage of waterborne polyacrylate was 30.0 wt%of the mass of the microcapsule emulsion,the viscosity of the coating slurry was controlled at 11.62 Pa·s,and the coating thickness was 60 μm.The prepared temperature-regulating and heat-storing coating polyester fabric had a melting enthalpy of 23.04 J/g and a crystallization enthalpy of 19.91 J/g,which had good heat storage and temperature regulation performance,although the hand feeling and gas permeability were decreased,it had good water resistance. |
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