Preparation And Properties Of Carbon Nano Tube Composite Phase Change Microcapsule

In recent years, phase change material （PCM） becomes the research hotspot of energy useand materials science all over the world. Phase change microcapsule takes advantage of phasetransition to achieve energy absorption, storage or release. However, phase changemicrocapsules have some limitations, such as low encapsulation efficiency, low therrmalconductivity, high level of super-cooling, mono-function, low thermal stability and etc. Inorder to overcome these shortbacks and improve performance, we have prepared nanocomposite phase change microcapsules by doping carbon nano tube （CNT） into themicrocapsule structure successfully.The carbon nano tube composite phase change microcapsule, with hexadecane bromide ascore and melamine-formaldehyde as shell, were prepared by in situ polymerization. Themorphology of microcapsules was characterized by using scanning electron microscopy（SEM）, the physical and chemical properties and thermal properties were characterized byusing infra-red spectroscopy （FTIR）, X-Ray Diffraction and Scattering （XRD）,thermogravimetry/derivative thermogravimetry （TG/DTG）, and Differential scanningcalorimetry （DSC）, data were analyzed by modern statistical software of SPSS16.0andMinitab15. Fabrics were coated with CNT composite phase change microcapsule Slurry. Thewearability and temperature regulation performance of the coated fabrics were evaluated.The test results of carbon nano tube composite phase change microcapsule have shown thatthese microcapsules are spherical with an average particle size2⁴μm. The influence ofdifferent processing parameters, such as doping amount of CNT, molar ratio of melamine andformaldehyde were analyzed. The results show that increasing amount of CNT can increasecomprehensive thermal stability temperature from427.2℃to481.1℃, while, encapsulationefficiency was decreased from75.37%to62.22%, super-cooling was decreased from9.77℃to6.84℃. The addition of CNT does not have an impact on crystal structure of the phasechange microcapsules.The test results of the coated fabrics show that some membrane materials were detected onthe surface of yarns, the coating thickness is about0.02⁰.03mm. Weight addition of coatedthe fabrics is between31%and32%. The breaking strength is significantly increased from855N to1100¹200N. Air permeability of the fabrics was61L m^-2 s^-1or so. Temperaturebuffering ability of these coated fabrics was studied by putting fabrics into a chamber where a sharp temperature fluctuated in a range of^-18℃⁵0℃and50℃^<sup>-18℃, fabricshave shown a1.5minutes temperature buffering ability around of the melting point ofbromo-hexadecane.