Synthesis And Application Of Microencapsulated Phase Change Material Using Polyurea As Shell

Microencapsulated phase change materials is a new chemical materials whose phase change latent heat is used to store energy and release energy. The change of their phase or structural with different environment temperature may absorb and release energy automatically, thus they can control the environment temperature. So that they can be widely used in building energy saving, chemical energy saving, military engineering and plays an irreplaceable role.Microencapsulated phase change materials with a thick shell of2,4-toluenediisocyanate/triethylenetetramine,2,4-toluenediisocyanate(TDI)/tetraethy-lenepentamine,2,4-toluenediisocyanate/hexamethylendiamine, respectively, were prepared by the method of interfacial polymerization using buty stearate as core materials, Tween-80, span-80as emulsifiers in our research. The prepared phase change materials were characterized by Fourier Transmission Infrared Spectra (FT-IR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and grainsize analyzer. Meanwhile, corrosion protective and temperature control coatings were made up to use to storage tank and pipeline. In addition, the corrosion protective and temperature control effect of coatings were studied. The main research results were as follows:1. Technological conditions of core materials emulsifying were discussed. Latex prepared on deferent conditions was observed by light-microscope. As a result, the stability of the prepared latex is the best and the storage time of it is longest, when the dosages of emulsifier accounts for2g, the speed of agitator is4000r/min, the ratio of water and oil is7.5:1, the emulsifying time is10min, the emulsifying temperature is25℃.2. The preparation process of microencapsulated phase change materials was studied by bath experiments. As a result, the optimum condition of preparing phase change materials is that the ratio of core materials and shell materials is2:1, the reaction temperature and time is65℃and2h, respectively. The phase-transition temperature and the phase change latent heat of phase change materials prepared with2,4-toluene diisocyanate/hexamethylendiamine as shell materials is19.2℃and55.5J/g; The phase-transition temperature and the phase change latent heat of phase change materials prepared with2,4-toluenediisocyanate/triethylenetetr-amine as shell materials is21.1℃and63.77J/g; The phase-transition temperature and the phase change latent heat of phase change materials prepared with2,4-toluen ediisocyanate(TDI)/tetraethylenepentamine as shell materials is19.2℃and75J/g.3. The modification of phase change materials was researched by bath experiments. The phase change materials were modified by ethanediol to enhance the compactness and stability. The phase-transition temperature and the phase change latent heat of phase change materials modified by ethanediol is20.5℃and87.75J/g. The structure of phase change materials modified by ethanediol is the regular balls, the diameter of them rang from1to30μm and the average specific surface area is0.0099m2/g. the small average specific surface area indicate that the apillage of cachet is small and the phase change materials modified by ethanediol has good compactness.4. Temperature control coatings were made up using phase change materials modified by ethanediol as temperature control materials to use to storage tank and pipeline. In addition, the corrosion protective and temperature control effect of coatings were studied by using self-made analog device. As a result, compared with ordinary epoxy coatings, the temperature control property of this kind of coatings is better, its latent heat is65.5J/g, and its antistatic property is very good.