Ahmad Jamekhorshid

The continuous increase in the level of greenhouse gas emissions is the main reason for trying to use different renewable energy sources more effectively. One of the thermal energy storage techniques is the use of flexible phase change materials. Flexible phase change materials are a new class of materials that can tolerate specific deformations and have significant potential for use in a wide range of everyday applications. In the present project, using the melt mixing method, a flexible phase change material in which paraffin is used as a phase change material, an elastomeric copolymer called styrene-ethylene-butylene-styrene triblock copolymer (SEBS) used as a flexible state stabilizer for this material, and HDPE has been used as a support material. The purpose of this research is to provide a solution to improve the flexibility and shape stability of the phase change material with no leakage of the phase change material to the surrounding environment. To check the amount of paraffin leakage, the samples were subjected to several cooling-heating cycles and the amount of paraffin leakage from the samples was measured. Also, the samples were examined and evaluated using DSC, TGA, XRD and DMTA analyses. In these analyses, the melting enthalpy and crystallization enthalpy values along with the melting and crystallization temperatures of the samples, the degradation temperature of the blended samples and pure samples, their crystal structure to examine the uniform dispersion of paraffin in the samples, as well as their elastic and viscous behavior were investigated. The results obtained in this research showed that among the prepared samples, the sample that contains 80% paraffin, 10% SEBS and 10% HDPE has the lowest amount of paraffin leakage of less than 2% after 10 cycles and shows an acceptable level of flexibility. The enthalpy of melting and crystallization for this sample was 75.5 and 60.5 J/g, respectively. With the increase of flexibility in the samples, the