Thermal stability and mechanical properties of epoxy resin/microcapsule composite phase change materials

Abstract

Studies and applications of microencapsulated phase change materials (MPCM) in asphalt mixtures have shown that these materials have great potential in reducing temperature-induced pavement defects, but the leakage of MPCM due to their poor temperature stability and mechanical properties seriously limits their application in asphalt pavements. To solve this problem, in this study, epoxy resin and MPCM were compounded to enhance the thermal stability and mechanical properties of MPCM. First, the secondary wrapping method and pouring method were used to composite microencapsulated phase change materials with epoxy resin, and the phase change enthalpy of the epoxy composite microencapsulated phase change materials (EMPCMs) was used to evaluate and optimize the compositing method. The results showed that EMPCMs should be prepared using the pouring method. Based on the pouring method, the effects of the epoxy resin type and content on the properties of EMPCMs were analyzed by thermogravimetric (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and heat treatment analyses. The results showed that epoxy resin could be combined with microencapsulated PCMs, thereby improving the thermal stability and mechanical properties of the composite PCMs; however, the wrapping effects of different types and contents of epoxy resin on the microcapsules were significantly different. When bisphenol A epoxy resin (EP3) was used and the content was 50 wt% of the EMPCMs, the enthalpy reached approximately 35 J/g after heat treatment, and the compressive strength and crush value of EMPCMs were 31.1 MPa and 8.6%, respectively, which meet the requirements for high-temperature mixing and transportation, as well as paving and rolling of the asphalt mixture.