Preparation of Phase Change Hydrogels with Highly Thermal Conductivity and Their Temperature Responsiveness
Conventional phase change hydrogels for temperature monitoring face problems such as slow response time,poor mechanical properties,poor electrical conductivity,and low enthalpy of phase change.Therefore,in this paper,xanthan gum and polyvinyl alcohol were used as main raw material to emulsify paraffin wax by using the activity of multifunctional groups and dispersion of xanthan gum molecules,and combine the ionic conductivity and high thermal conductivity of Zn2+and nano-alumina to prepare a double network cross-linked xanthan gum/paraffin wax/polyvinyl alcohol/boric acid/zinc ion/nano-alumina(XPPB-Zn2+-Al2O3)phase change hydrogel with high enthalpy,high thermal conductivity,high electrical conductivity and strong mechanical properties.The SEM images show that the phase change particles are uniformly embedded in the microstructure of the hydrogel;the mechanical test results show that the double cross-linked network gives excellent mechanical properties to the phase change hydrogel,and the tensile strength reaches(0.38±0.01)MPa;the DSC resulst show that the phase change enthalpy of the hydrogel is as high as(180.98±3.12)J/g.In addition,the phase change hydrogel exhibits a high thermal conductivity,and its thermal conductivity reaches(0.558±0.035)W/(m·K)and a resistance temperature coefficient of 1.23％℃-1,showing a good temperature cycling stability in the range of 25～60 ℃.The results indicate that the high-performance phase change hydrogel prepared in this paper has good application prospects in the field of temperature monitoring.
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