无机水合盐相变陶粒的制备与性能

Preparation and Properties of Phase Change Ceramisite Loaded with Inorganic Salt Hydrate

采用无机水合盐Ca Cl_2·6H_2O(CCH)作为相变材料,通过真空吸附法制备黏土陶粒负载CCH的相变陶粒,研究了陶粒负载CCH对其液–固相变过冷度的影响以及表面封闭处理对水泥基复合相变材料性能的影响。结果表明,与吸附有机相变材料正癸酸相比,陶粒对CCH的吸附量明显增大,有效减小CCH液–固相变过冷度;采用水泥和聚乙二醇(PEG)对相变陶粒进行包覆,无法实现有效的表面封闭处理:前者在空气中暴露3 d后,表面出现露珠;后者在空气中暴露1个月后,表面出现膨胀性霜状物,使相变陶粒发生破坏。通过进一步吸附正癸酸和油性涂料进行表面处理的相变陶粒,应用于水泥基材料,可有效降低水泥水化放热温升。但采用正癸酸处理时,存在液态正癸酸渗出现象;采用油性涂料处理,则可有效防止液态相变材料渗出。

Phase change ceramisite （PCC） was prepared by vacuum adsorption method using inorganic CaCl2·6H2O （CCH） as phase change material. Effect of loading in ceramsite on super–cooling of CCH during liquid–solid phase change process as well as effect of surface–sealing treatment of PCC on properties of the cement–based composite phase change material were investigated. The results showed that the amount of CCH adsorbed in ceramsite was significantly higher than that of capric acid （CA）, and the supercooling degree of CCH during liquid–solid phase change was greatly reduced after being loaded in ceramisite. By simple clading with cement and PEG, the salt hydrate cannot be effectively sealed within ceramisite. The dewdrops appeared on the surface after exposed in the air for 3 d for claded with cement, and expansive cream–like substance was found on the surface after exposed in the air for one month for claded with PEG, leading to a destruction of PCC. After further loaded with capric acid or oily paint, incorporation of both PCC in cement–based materials can effectively lower the temperature rise during hydration. However, the hardened composite showed leakage of CA for the former case whereas no leakage appeared for the ceramisite coated by using oily paint.