Preparation And Characterization Of Microcapsule Containing Phase Change Materials For Functionally Thermal Fluid

The application of Microcapsule Containing Phase Change Materials (MCPCM) for Functional thermal fluid fields has received considerable attention in recent years due to their large storage capacity and isothermal nature of the storage process. In this thesis, the technics of microcapsule production by interfacial polymerization with paraffin as the phase change material was studied. The craft route and process were formulated. The best condition of emulsification, microencapsulation and the best ratio of core to wall of microcapsule were established. Also the surface condition and thermal characteristics of MCPCM synthesized by interfacial polymerization were dealt with.First, diisocyanate(IPDI) was dissolved in paraffin to form the oil phase. Then, the oil solution was dispersed in the aqueous phase with span60 and tween60 used as an emulsifier and formed a steady oil-in-water emulsion. When the tetraethylenepentamine(TEPA) solution is added into the emulsion, interfacial polymerization takes place at the interface of two phases, then tridimensional and reticulate polymer wall is produced, and the oil is enveloped in microcapsule.The surface condition and thermal characteristics of the microcapsules were investigated by means of phase-contrast microscope (PCM) , Scanning electron Microscopy(SEM), differential scanning calorimeter(DSC) and Thermogravimetric Analyzer(TGA) , respectively. The profiles of PCM and SEM attested for the narrow distribution of size, the spherical shape of the capsules,and a smooth external wall. Results obtained from a DSC showed that microcapsules have a thermal energy storage/release capacity of about 124.47 J/g, namely, which core materials content is about 92.4%. Results obtained from TGA indicated that microcapsules without core material can be suffered high temperature up to 247℃. The chemical structure of the polymer wall was studied by ~1HNMR. The experiments indicate that microcapsule productionby interfacial polymerization with paraffin as the phase change materials is feasible. In addition, this microencapsulation technics is convenient and simple without costly and complicated apparatus. Also the microcapsules showed wellcompact and anti-swelling property through other experiments. Hence, encapsulated paraffin wax shows a good potential as a thermal energy storage material.