Polyethyl methacrylate (PEMA)/fatty acids blends as novel phase change materials for thermal energy storage

This study deals with the preparation and characterization of polyethyl methacrylate/fatty acid blends as a novel form-stable phase change material for latent heat thermal energy storage applications. In the blends, fatty acids act as a phase change material when polyethyl methacrylate is operated as a supporting material. The fatty acids could be retained by 50 wt% into polyethyl methacrylate without melted phase change material seepage from the blends. Therefore, these blends are called form stable composite phase change materials and they have utility advantage without encapsulation in passive latent heat thermal energy storage applications. The prepared fatty acid/polyethyl methacrylate blends (50/50 w/w%) as form-stable phase change material was characterized using optic microscopy and Fourier transform infrared spectroscopy methods and the results showed that the polyethyl methacrylate was physically and chemically compatible with the fatty acids. Thermal properties and thermal stabilities of the form-stable phase change materials were measured using differential scanning calorimetry. Differential scanning calorimetry results indicated that the melting temperatures and latent heats of the prepared phase change materials are in the range of 30.67-61.09°C and 86.93-107.75 J/g, respectively. The thermal cycling test, including 5,000 cycling processes, was conducted to determine the thermal reliability of the synthesized form-stable phase change materials, and it is found that phase change materials were thermally and chemically stable after thermal cycling. On the basis of all the results, it was concluded that form stable polyethyl methacrylate/fatty acids composite phase change materials had important potential for practical latent heat thermal energy storage applications, such as under floor space heating of buildings and passive solar space heating of buildings by using wallboard, plasterboard, or floors impregnated with a form stable phase change material.