Microcapsules with thermal, mechanical, and chemical stability from polystyrene waste to contain phase change materials

Abstract

Phase change materials (PCM) are compounds which at specific temperature suffer a reversible phase transition, being solid-liquid the most used. These materials are widely used for thermal energy storage (TES), which is a potential method to combat the increase of energy consumption for thermal conditioning. Microencapsulation of PCM is a powerful technique to preserve it and avoid possible leakage. This research aims to address the environmental issues caused by plastic waste by developing sustainable recycled microencapsulated phase change materials (r-MPCM). A solvent evaporation method was used to microencapsulate a commercial PCM within a polystyrene (PS) waste as shell. Microcapsules with different core/shell (c/s) mass ratios were produced to be thermal, chemical, and mechanical evaluated. The characterization of r-MPCM produced was conducted using several techniques such as scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and atomic force microscope (AFM). SEM images confirm that r-MPCM were successfully produced, with spherical shape, and were thermal and chemical resistant for the evaluated conditions. The data obtained from DSC demonstrates that the sample with higher TES performance was r-MPCM with 3:1 c/s mass ratio, with a latent heat of 63.7 J·g⁻¹.