Thermosetting polymer materials, especially epoxy resin, are developed as matrix resin in carbon fiber reinforced plastic expected to be used for aircraft and other transportation equipment structural materials. We are trying to clarify the relationship between molecular structure and basic physical, thermal and mechanical properties of resin. Additionally, we believe that predicting resin's properties by molecular dynamics simulation will lead to the promotion of material development. Comparing with the results of actual curing experiments, we consider the simulation results of estimating various properties of epoxy resin. As a result of simulation analysis, it was clarified that the average distribution of free volume changes as the curing reaction progresses, and the possibility as a data analysis method to capture the heterogeneity of thermosetting resins at the molecular level was suggested.

Electrically conductive and low viscosity epoxy blends containing small amount of silver (Ag) fillers, were researched. In specific, diglycidyl ethers of bisphenol-F (DGEBF) / dicyclopentenyl oxyethyl methacrylate (DPOMA) mixtures were polymerized in curing process to be formulated as the matrix resins for the electrically conductive polymer composites. The DGEBF/40wt%DPOMA polymer blends formed co-continuous phase structures in the cured composites.Scanning electron microscopy revealed that the Ag fillers were selectively localized in the methacrylate polymer-rich phases of the blends. The selective placement of the Ag fillers in the continuous phase with a relatively small volume fraction increased the continuity of the Ag fillers. As the results, the Ag filler content in the DGEBF/DPOMA/Ag composites was reduced by 30vol% in order to achieve the same electrical conductivity as that in the DGEBF/Ag composites. The mechanism of the selective placement of Ag fillers was discussed in terms of the affinity among epoxy, methacrylic resin and Ag fillers, measuring their Hansen solubility parameter (HSP).

There is an epoxy resin having an ether ether ketone (EEK) structure as one measure for improving the heat resistance of the epoxy resin. A bisphenol compound having an EEK unit was obtained by the reaction of hydroquinone and 4,4'-difluorobenzophenone, and then an epoxidation reaction was performed to synthesize an epoxy resin having an EEK unit (DGEEK). As a result of evaluating the physical properties of the cured product obtained from DGEEK and phenol novolac, the glass transition temperature (T_g) was 149℃, which was 22℃ higher than that of bisphenol A type epoxy resin (DGBPA). Further, the 10wt% weight loss temperature (Td₁₀) was 406℃, confirming high thermal stability. Furthermore, the char yield at 700℃ was 35.0wt%, which was more than double the value of the cured product from DGBPA.

Photo curing is used in fields related to electronics where heat treatment is not possible. Anionic UV curing using a photobase generating reaction has attracted attention because it does not corrode metals, but only a few articles have mentioned anionic UV curing materials have been reported. This is probably due to relatively low quantum yields for photobase generation and weaker basicity of photogenerated bases, leading to low photosensitivity of anionic UV curing materials. We report here novel photobase generators to release organic strong bases with high quantum yields and a novel concept of base proliferation to improve the photosensitivity of the anionic UV curing. The concept involves the basecatalyzed decomposition of an organic compound termed a base amplifier which produces a newborn base molecule, leading to its autocatalytic decomposition. The addition of base amplifiers to the anionic UV curing materials resulted in the marked improvement of photosensitivity because the number of photogenerated base molecules increases markedly as a result of the base proliferation reaction of the doped base amplifier.