Study of thermal energy storing beeswax microcapsules by in situ polymerization method

Abstract

Bioproduct beeswax has good potential to serve as Phase Change Material (PCM) for thermal energy storage applications. But leakage problems during the thermal transition process of beeswax demand for its encapsulation. This study demonstrates the use of resorcinol modified phenol-formaldehyde shell for beeswax microencapsulation. The optimum values of process parameters for microencapsulation were determined with the help of the Taguchi orthogonal array. Taguchi method helps to minimize experimental formulation numbers for determining optimum values of process parameters. The optimum values for control parameters core to shell ratio, surfactant concentration and agitation speed were 1:1, 3% and 800 rpm respectively. The microencapsulation process carried out with optimum parameter values yielded microencapsulated PCM. FTIR, DSC and particle size analysis confirmed microencapsulation of beeswax with resorcinol modified phenol-formaldehyde shell. Microcapsules had high melting enthalpy of 148.93 J/g with the peak phase transition temperature of 57.86 oC. Morphological analysis with SEM and optical microscope reported spherical geometry of beeswax microcapsules. Heat transfer profile of microcapsules captured with thermal imaging camera reciprocated with DSC results. The prepared thermal energy storing microcapsules will enhance the performance of building materials, solar devices, electronic systems and packaging materials.