石蜡/碱改性硅藻土/膨胀石墨复合相变储热材料的制备及性能

通过碱处理，优化了硅藻土(DIA)的孔隙结构，提高了孔隙率，增加了石蜡(paraffin)负载量。通过直接浸渍法制备了新型性状稳定的石蜡/碱改性DIA/膨胀石墨(EG-alDIAP)复合材料，并研究了其结构与性能的关系。结果表明，复合相变材料的石蜡负载量从47.4%提高到了61.1%，进而提高了复合材料的储热性能；向改性DIA中添加膨胀石墨(EG)提高了复合材料的传热能力，添加质量分数10%EG时导热系数提高了113%(从0.276 W·m^-1·K^-1提高到了0.589 W·m^-1·K^-1)。随着EG含量的升高，复合相变材料的相变潜热有所增加，但化学相容性、稳定性等无明显变化。含 10%EG的石蜡/碱改性 DIA复合材料具有可靠的储能性能、良好的温度调节性能和蓄放热能力。

Preparation and performance of paraffin/alkali modified diatomite/expanded graphite composite phase change thermal storage material

Through alkali treatment, the pore structure of diatomite (DIA) was optimized, the porosity was increased, and the paraffin loading was increased. A novel paraffin/alkali-modified DIA/expanded graphite (EG-alDIAP) composite with stable properties was prepared by direct impregnation method. The relationship between structure and properties of the material was studied. The results showed that the paraffin loading of the composite phase change material increased from 47.4% to 61.1%, thereby improving the heat storage performance of the composite material. The addition of expanded graphite (EG) to the modified diatomite improved the heat transfer capacity of the composite material. The addition of mass fraction of 10% EG increased the thermal conductivity by 113% (from 0.276 to 0.589 W·m^-1·K^-1). With the increase of EG content, the latent heat of the composite phase change material increased slightly, but the chemical compatibility and stability did not change significantly. The paraffin/alkali-modi-fied DIA composite containing 10% expanded graphite had reliable energy storage, good temperature regulation performance and heat storage and release capacity.