Qingsong Lian,Yan Li,Asim A. S. Sayyed,Jue Cheng,Junying Zhang
Designing novel phase change materials (PCMs) is of vital importance in achieving the sustainable development of energy. Here, we facilely prepare a series of novel multiple solid–solid PCMs (SSPCMs, EPPa-X systems) by blending paraffin, epoxy resin with crystalline side chains (D18), and poly(propylene oxide)diamine together followed by a one-pot curing process. Strong intermolecular forces between paraffin and D18 (based on their good compatibility) and a reliable three-dimensional (3-D) cross-linking network of epoxy resin form a unique encapsulation mechanism, which provides the EPPa-X SSPCMs with excellent shape-stable properties and superior thermal stability (remain stable below 180 °C) without sacrificing too much latent heat of paraffin (only 1.6% latent heat loss). Due to the combination of two melting processes at 36 and 60 °C derived from D18 and paraffin, respectively, the latent heat of the EPPa-50 system is high, up to 152.6 J/g. Besides, the supercooling extent of D18 decreased from 13.6 to 10.5 °C with the addition of paraffin due to the heterogeneous nucleation effect. The novel EPPa-X SSPCMs possess tremendous potential for a wide range of applications due to their facile preparation, low cost, high reliability, and excellent phase change properties, while the unique encapsulation mechanism may open a new door for preparing other novel types of PCMs.
In this article, waste phoenix leaf biochar was introduced into three most used organic phase change materials (PCMs) to prepare shape-stable composite PCMs by the vacuum impregnation method. The encapsulation capacity and encapsulation efficiency of steam activated biochar for paraffin, stearic acid, and polyethylene glycol were 59.28% and 49.14%, 63.03% and 57.62%, 71.38% and 46.84%, respectively, which was related to the mechanisms of biochar encapsulated organic PCMs. The dominant mechanisms of biochar encapsulated organic PCMs are summarized as pore-filling, hydrogen-bonding, hydrophobic interaction between biochar and PCMs, and other potential mechanisms. Influence degree η was introduced to illustrate the effect of biochar on organic PCMs, 16.56%, 8.72%, and 35.75% for steam activated biochar on paraffin, stearic acid, and polyethylene glycol. In addition, compared with original PCMs, the thermal conductivity of biochar-based composite PCMs first decreased and then increased with the increase of biochar pyrolysis temperature. Moreover, biochar-based composite PCMs had better thermal stability, concerned with the dominant mechanisms of biochar encapsulated organic PCMs. Therefore, biochar-based composite PCMs proposed in this study expand the application of biochar and organic PCMs in thermal energy storage , building energy conservation , solar energy utilization, and battery thermal management system .
危险品化学品经营许可证（带存储）