Microencapsulation of Butyl Stearate as Phase Change Material by Melamine Formaldehyde Shell for Thermal Energy Storage

Abstract

Butyl stearate as a phase change material was microencapsulated within melamine-formaldehyde resin using emulsion polymerization. Morphology and thermal specification of produced microcapsules were studied by Fourier transform infrared spectroscopy, FT-IR, scanning electron microscopy, SEM, and Differential scanning calorimetry analysis, DSC. FT-IR spectra validated the existence of the butyl stearate in the core of microcapsules. SEM graphs showed that melamine formaldehyde polymer without core was spherical and almost uniform with an approximate size of 2µm and microcapsules of butyl stearate in melamine formaldehyde shell were also spherical with the average diameter of 4µm. DSC results showed that microencapsulation reduced the latent heat of melting and freezing of butyl stearate and increased melting point. The performance of the produced microcapsules was obtained 36.64%. Moreover, the efficiency of energy storage by the microcapsules was obtained about 40%. It was observed that the rate of thermal energy conservation was high during the phase change process of microcapsule core and it was reduces after completion of the melting process.

Keywords

• butyl stearate
• formaldehyde
• melamine
• microencapsulation
• phase change materials