Composite Phase Change Materials With Both Heat Dissipation And Heat Preservation And Their Applications In Human Heat Management

The need for heat dissipation and insulation has now penetrated into all aspects of people’s lives,including human body temperature regulation,building warmth,animal husbandry warmth,special operations,etc.At present,the research on individual heat dissipation and insulation systems at home and abroad has been very in-depth,but there are few studies involving the simultaneous realization of heat dissipation and insulation functions.Therefore,sodium carbonate decahydrate Na₂CO₃·10H₂O)and disodium hydrogen phosphate dodecahydrate（Na₂HPO₄·12H₂O）were used as raw materials and sodium silicate nonahydrate（Na₂SiO₃·9H₂O）was used as nucleating agent to prepare a composite phase change material with low supercooling,suitable temperature to change,high enthalpy value and good stability.Based on the composite phase change material,the design,preparation and testing of heat insulation clothing were completed.The main contents of this study are as follows:（1）Na₂CO₃·10H₂O-Na₂HPO₄·12H₂O binary phase change materials were prepared by melt blending.The phase transition temperature of the binary phase change material is about 26.3℃,the phase change enthalpy value is 91.2 k J/kg,and the subcooling degree is 1.8℃.Then,SEM and XRD characterization proved that only physical interaction occurred between the two types of hydrated salts.Finally,1%Na₂SiO₃·9H₂O was added to the binary phase change material to obtain the composite phase change material with the lowest subcooling,the best repeatability,the most stability and high enthalpy.The phase transition temperature of the composite phase change material was 25.86℃,the phase change enthalpy value was 91 k J/kg,and the subcooling degree was 0.3℃.（2）The structure of the heat dissipation and insulation suit was preliminarily designed.In order to enhance the heat dissipation effect during the design,it is necessary to add a layer of heat dissipation film on the basis of the composite phase change material to enhance the heat dissipation capacity,and realize the intelligent adjustment function of heat preservation and heat dissipation by adding multiple heat dissipation and insulation modules to the clothes.In order to find high-performance heat dissipation films,three kinds of heat dissipation films were prepared by color paste method,namely acrylic heat dissipation film,improved acrylic heat dissipation film and PVDF heat dissipation film,and microscopic observation and heat dissipation performance test were carried out on the heat dissipation film.Through the heat dissipation test results,it was determined that the film with the strongest heat dissipation capacity was PVDF heat dissipation film,which can reduce the temperature of 25.2℃ under high-intensity simulated sunlight for ten minutes.（3）The heat dissipation vest is prepared and tested for heat dissipation and thermal insulation performance.The experimental results show that compared with the ordinary vest,the prepared thermal insulation vest can reduce the temperature by 4℃ in a warm environment of 30℃,and increase the temperature by 5.1℃ in a cold environment of 0℃.