An epoxy resin having a stilbene structure (DGTMS) was synthesized, and the physical properties of the cured polymer using phenol novolac as a hardener were compared with the biphenyl type epoxy resin (DGTBP) and the bisphenol F type epoxy resin (DGTBF). The glass transition temperature of the cured polymer of DGTMS is 169℃, which is 15℃ and27℃ higher than those of the cured DGTBF, and of the cured DGTBP, respectirely. In addition, the char yields of the cured products of DGTMS and of DGTBP at 700℃ are 24.9 wt%, and 19.9 wt%, respectirely, which indicates a higher thermal stability of the DGTMS cured product.

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.

Development of refractive-indices change materials enables application to optical switching devices. However, there are not so many reports concerning the refractive-indices change materials. In order to promote the practical use of optical switching materials, it has been important to increase the values of refractive-indices changes. Recently, the change in the refractive index might reach the practical level. It was also proved that the refractive-indices changes accurately not only by UV-irradiation but also by heating and cooling. Furthermore, the quick response of the change in the refractive-indices and its durability will be the subject of future study.