Thermal Storage Property of Polyethylene Glycol Type Acrylic Polymer

Abstract

Conventional latent heat storage materials such as water and paraffin require sealed structures because the phase change between melting and solidification occurs. On the other hand, the polymer having a crystalline structure in the side chains does not liquefy even above the melting point, and can be used without sealed structures. In this study, we focused on polyethylene glycol (PEG) acrylate having high thermal storage density, and evaluated how to control the melting point and heat of fusion(ΔH_m) of the acrylic polymer which had PEG structure in side chain. The samples were made as polymer sheets from PEG monoacrylate (PEGMA) and PEG diacrylate (PEGDA). It was found that there is a positive correlation between their heat storage properties and average molecular weights calculated from mix ratio of PEGMA and PEGDA of different molecular weight. It was also found that the melting point of the copolymer was in the temperature region between the upper and lower limits of PEGMA or PEGDA homopolymer. In addition, it was found that the ΔH_m increased with increasing of PEGMA content, while modulus of elasticity the polymer sheet decreased beyond their melting points.