Poly(urea-formaldehyde) microcapsules containing commercial paraffin: in situ polymerization study
Microcapsules containing Rubitherm® RT-42 paraffin wax (core) and a poly(urea-formaldehyde) shell were prepared by an in situ polymerization. The influence of prepolymerization/polymerization time, the reaction temperature, and the monomers/phase change material (PCM) mass ratio on the encapsulation process and the physical properties of the resulting microcapsules was studied. The morphology, chemical composition, and particle size distribution of the microcapsules were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). It was found that the structure of the generated poly(urea-formaldehyde) microcapsules strongly depended on the reaction time. The content of encapsulated Rubitherm® RT-42 increased with increasing reaction temperature until a limit, ranging the optimum reaction temperature from 60 to 70 °C. Finally, it was found that the optimal monomers/PCM mass ratio was 0.8. The poly(urea-formaldehyde) microcapsules obtained containing the RT-42 paraffin can be used as thermal energy storage systems.
KeywordsIn situ polymerization Microcapsules Poly(urea-formaldehyde) Phase change materials
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Conflict of interest
The authors declare that they have no conflict of interest.
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