| As China is the world’s most populous country, Chinese People need to consume a largeamount of temperature-sensitive goods every day, such as perishable agricultural commodities,low temperature milk, blood, vaccines, etc., which will inevitably require large quantities ofcold chain logistics. Electricity refrigeration or mechanical refrigeration is usually used fortemperature-sensitive goods during the cold chain transport. So phase change energy storagehas been gaining more and more attention in today’s world which highlights power cuts,energy issues. Phase change energy storage is a high-tech which has the advantage of highenergy storage density, energy output and temperature stability, etc. based on phase changematerial. Phase change material is described what can utilize a large number of thermalenergy that absorb or release during its change of state for energy storage. Different PCM hasdifferent phase transition temperature and latent heat. The wide temperature range makes iteasy to meet a variety of applications. But there also exist some problems, such as largechange in phase transition volume, easy to leak, sub cooling, phase separation, corrosion, etc.Prepareing phase change material microencapsulated is an effective way to solve theseproblems.Firstly, a low temperature microencapsulated phase change material was prepared byin-situ polymerization with n-tetradecane as the core materials, polymethyl methacrylate(PMMA) which was prepared by radical polymerization of methyl methacrylate (MMA)monomer as the raw material for the wall and azobisisobutyronitrile (AIBN) as the initiator.The influence of different types of emulsifiers for preparing microcapsules was alsoresearched. The obtained phase-change microcapsules were characterized by scanningelectron microscopy (SEM), laser particle size analyzer, and differential scanning calorimeter(DSC), thermal gravimetric analysis (TG), etc. The results show that: OP-10/SDBS (40/60) isthe optimum in the analysis of three emulsifiers. The microencapsulated phase changematerial prepared under this condition has a phase transition temperature of6.22℃, latentheat150.1J/g, average particle size about171.8μm, which must be used below thetemperature137.21℃.Secondly, based on n-tetradecane microencapsulated phase change material formulationpreferred, the binary composite core microencapsulated phase change material were preparedby in-situ polymerization with binary combination phase change material Dodecanol/Decanol (50/50) as the core materials, polymethyl methacrylate (PMMA) which was preparedby radical polymerization of methyl methacrylate (MMA) monomer as the raw material forthe wall and azobisisobutyronitrile (AIBN) as the initiator. The influence of different types ofemulsifiers for preparing microcapsules was also researched. The obtained phase-changemicrocapsules were characterized by scanning electron microscopy (SEM), laser particle sizeanalyzer, and differential scanning calorimeter (DSC), thermal gravimetric analysis (TG), etc.The results show that: OP-10/SDBS (40/60) is the optimum in the analysis of threeemulsifiers. The microencapsulated phase change material prepared under this condition has amain phase transition temperature of7.85℃, latent heat105.8J/g, average particle size about 180.3μm, which must be used below the temperature177.16℃.Lastly, application of the preferably prepared n-tetradecane microencapsulated phasechange material in the temperature controlled packaging was discussed. The results showedthat: after saved at the same conditions for12h, the incubator temperatures of theexperimental group were lower than the control group at any one time; compared with thecontrol group, pH and viscosity decreases of the experimental group yogurt were lower. Thisshows that to some extent, microencapsulated phase change has an important role in themaintenance of low temperature milk quality and the assurance of its commercial value,which will have broad application prospects in the field of temperature controlled packaging. |
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