The Preparation of Novel Microcapsules Based on Palmitic Acid Core and Waterborne Polyurethane/Silane Shell as Phase Change Materials for Thermal Energy Storage

摘要

In this study work, a novel form-stable microcapsule phase change material was synthesized for thermal energy storage based on palmtic acid (PA) as the core and silane modified waterborne polyurethane (WBPU/Si) as the shell. The polymeric shell was prepared by the reaction of polypropylene glycol, 2,2-bis(hydroxymethyl) propionic acid (DMPA) and 1,5-naphthalene diisocyanate (NDI) by incorporation of 3-aminopropyltriethoxysilane (APTS) via in situ polymerization method. In continue, a simple mixing of this aqueous dispersion of polyurethane with dispersion of PA in water using an anionic surfactant as a stabilizer, results in the self-assembly of WBPU onto the PA droplets by an electrostatic interaction, lead to the encapsulation of PA by PU to form a core-shell composite microcapsule. Fourier transform infrared spectroscopy was used to characterize the chemical structure, and the crystalline properties were analyzed by the X-ray diffraction. The morphology and particle distribution in the samples have been reported with scanning electron microscope imaging. Thermal properties of the prepared composites were estimated via thermogravimetric analysis and differential scanning calorimetry. The results show the successful preparation of the smooth and compact surface microcapsules with mean particle size of 200-400 mu m which have good thermal storage properties.