We have developed and commercialized novel biomass-based diisocyanate 1,5-pentamthylenediisocyanate, STABiO^TM PDI^TM (PDI) and the polyisocyanate hardener under the concept of high performance and sustainable isocyanate. PDI and its polyisocyanate hardener prepared from biomass resource show high curability with alcohol to produce high performance polyurethane compared to petrochemical 1,6-hexamethylenediisocyanate (HDI), and the polyisocyanate hardener based polyurethane. This paper describes the properties of PDI, the polyisocyanate hardener and polyurethanes.

Hydrogels were prepared by UV irradiation to aqueous solutions of poly(sodium acrylate) with different polymerization degrees in the presence of a radical initiator. When potassium persulfate or ammonium persulfate was used as an initiator, gels were efficiently produced. The effects of the polymerization degree and the concentration of the polymer, the type and concentration of the initiators, and the UV irradiation time on the gel fraction and the swelling ratio of the produced gel were clarified. The storage modulus (G'), loss modulus (G"), and complex viscosity (|η*|) of the isolated gels were determined by rheological measurement. The relation of the swelling ratio and cross-linking density of the gels and the rheological properties as well as the radical reaction mechanism for gel formation were discussed. Furthermore, hydrogels with a cross-linked structure inclined in the depth direction were synthesized by controlling the absorption energy of irradiated UV light.

Liquid crystalline (LC) epoxy resin containing rigid mesogenic units (DGETAM) was prepared by curing with the binary mixed curing agent with different chemical structures, m-phenylenediamine (m-PDA) and 4, 4’-bis (4-aminobenzoyloxy) dodecane (12BAB). We determined the optimal composition ratio in binary mixed curing agent in order to form highly ordered network structure during the crosslinking reaction. The analysis of LC phase structure reveals that the DGETAM/m-PDA/12BAB_20 mol% system forms larger size of LC domain structure with highly ordered smectic phase. In the laser flash method, the value of thermal conductivity in DGETAM/m-PDA/12BAB_20 mol% system(0.31 W/(m･K)) is slightly higher compared to those of the other systems(0.27－0.30 (W/(m･K))). However, the thermal conductive map which was drawn by the periodic heating radiation-temperature measuring method showed a clear distribution of thermal conductivity in the cured resin. These results suggest that the effective phonon conductivity may be suppressed by the presence of locally low thermal conductive regions in DGETAM/m-PDA/12BAB_20 mol% system.

Cyanate ester is recognized as one of the most important high-performance thermosetting materials used in the electrical & electronic and the composite materials fields. In order to understand the overall picture of cyanate ester as a type of epoxy resin curing agent, the chemical structures and the CAS registration numbers are investigated and classified for various types of cyanate esters including commercially available ones. There are no stoichiometric ratios in the curing reaction of epoxy resin and cyanate ester, because the self-polymerization of cyanate ester is included in the several curing reactions between them. Curing- and cured-properties of epoxy resin/cyanate ester systems are reviewed focusing on the composition dependences for a dozen of key properties such as the curing behavior, the glass transition temperature, the tensile & flexural properties, the impact strength, the thermal expansion, the thermal stability, the water absorption, and the dielectric properties. Some comments are also added on the optimal formulations.

Materials such as polymer, ceramics, and metal can be well bonded by molecular bonding technology. We use a molecular bonding agent with the functional groups which are active to the surfaces of the adherent materials (polymer, ceramics, or metal) to bond the different materials by chemical bonding. The chemical bonding is strong enough so that we no longer have to roughen the surfaces of the adherents to increase the surface area and the bonding strength as when applying a conventional process. Namely, achieving a strong enough bonding strength between different materials with a flat boundary is possible.