N-octadecane/poly (boron-urethane) microcapsulated phase exchange materials with thermal energy storage feature

Microcapsule applications are one of the fields of study that are increasing in importance. In this context, microcapsules, which have found a field of study from industry to health sector, have gained a wider usage area through the encapsulation of phase change materials (PCMs) with latent heat storage feature. Polyurethanes (PU) are preferred in microcapsule production due to their physical strength and ability to form spherical wall material. In this study, PU shell material was synthesized using 3 different diisocyanates and thermal behavior and morphological properties of the shells were developed by adding boron. While n-octadecane with its high thermal energy storage property was used as the core material, dibutyltindilaurate (DBTDL) was used as the catalyst, Tween 20 with a high hydrophilic-lipophilic balance (HLB) value was used as the surfactant and cyclohexanone was used as the solvent. Interfacial polymerization method was used in the polymerization reaction and the studies were carried out under room conditions. Surface image (SEM) and particle size distribution (PSD) analysis were used as morphological structure. Spectroscopy analysis (FT-IR) was used for the characterization and thermal gravimetric (TG) analysis, bomb calorimetric analysis, combustion test and differential scanning calorimetry (DSC) analysis were used to investigate the thermal behavior of the synthesized capsules. In the study, microcapsules with PU shell and n-octadecane core obtained by adding boron, and a total of 9 different PU shell microcapsule samples with and without n-octadecane core obtained by using EG were compared considering their surface morphology and thermal behavior. As a result of the analysis, positive developments were observed in the thermal behavior of the boron added PU shells, while positive developments were also observed in the surface morphology. The PSD range of the boron doped microcapsules obtained was 39.4-56.2 µm and the melting enthalpies were in the range of 75.4-94.3 Jg-1. Among the microcapsules synthesized under the same conditions, the best results in terms of morphological and thermal behavior were obtained in TDI/bor microcapsule