LAUSR

Abstract Acrylic based microcapsules containing octadecane as a phase change material (PCM) were prepared via suspension polymerization, using different types of initiator and/or polymerization temperature. Benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN) and Trigonox 23 (TRIG) were used as thermal initiators in a range of temperatures from 40 °C to 80 °C. A comprehensive characterization of microcapsules was undertaken, regarding their chemical composition (by infrared spectroscopy), morphology (by scanning electronic microscopy (SEM)), particle size distribution (by laser diffraction) and thermal properties (by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). The experimental results show that the studied reaction parameters influenced the monomer conversion profiles while their impact on the microcapsules properties was not quite relevant. The microcapsules exhibited mean particle sizes around 12 μm, melting enthalpies of approximately 175 J/g, PCM content about 70% and were thermally stable up to 170 °C, the temperature corresponding to 5% of weight measured by TGA. This study confirmed that octadecane can be successfully encapsulated via a suspension polymerization technique, exhibiting a well-defined core/shell structure. Moreover, employing TRIG as initiator enables the use of a reaction temperature as low as 40 °C. The acrylic shell microcapsules with encapsulated octadecane show a good potential to be incorporated in textile substrates in order to produce thermo-regulating textiles.