SynopsisXylylene diisocyanate (XDI) has both characteristics of an aromatic and an aliphatic polyisocyanate. Polyisocyante adduct was adopted for hardener of coatings. It is particularly interesting that the reactivity of XDI adduct with alcohol is higher than that of toluene diisocyanate (TDI) adduct. In addition, polyurethane coating that prepared from XDI adduct shows excellent stain resistance and metal adhesion compared to those of hexamethylene diisocyanate (HDI) Biuret. XDI adduct is the specialty polyisocyanate with high reactivity, polarity and refractive index, so it can be applied to various uses including coating, adhesive, sealant, elastomer and plastic lens.

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SynopsisBrittleness at raised temperature of novel organic inorganic hybrid material derived from cubic silsesquioxane as nano building block was improved while keeping high transparency as well as UV exposure durability. It is clarifi ed that brittleness of the hybrid material is attributed to low cross-linking density of the cured hybrid material due to rearrangement of vinyl group to lower functionality position during its cross-linking reaction. In order to improve the brittleness of the hybrid material, the chemical structure without the rearrangement of vinyl group is estimated by computational simulation.The material having estimated structure is then synthesized and the increase in cross linking density in the cured material was confirmed. Thus, tough, transparent, and UV durable hybrid material is demonstrated. This work also deals with improvement of molding process ability of the hybrid material. Hence potential of the hybrid to be used in optical device application is increased.

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SynopsisThe conventional thermosetting resins have low thermal conductivities because of phonon scattering in their amorphous structures. Therefore, it is important to improve the thermal conductivity by suppressing phonon scattering, such as controlling the high-order structures or increasing the crosslink densities. In this paper, we investigated the correlation between three thermophysical parameters and the thermal conductivity, and the effectiveness of the high order structure and crosslink density. As a result, it was found that the thermal conductivity is correlated with and controlled by the thermal diffusivity. Then, the effects on the thermal conductivity of the high-order structures and the crosslink densities were investigated. The results revealed that the thermal conductivities of the resins having the mesogen groups were 1.5－4times higher than those of conventional ones with same crosslink densities. Additionally, higher thermal conductivity was obtained from higher domain-area ratio of high-order structures. In contrast, the increase in the thermal conductivities of the conventional resins by the crosslink density was slight, suggesting that to enhance the thermal conductivity, the formation of the highly ordered structure by mesogen is much more effective than the crosslink density.

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SynopsisWe investigated the properties of the cured films prepared from various inorganic materials dispersed in solvent soluble imide resins containing carboxyl group at the end of the epoxy resins. It turned out that layered type inorganic materials are more effective. The thermal properties of the epoxy resin curable films, which were obtained from nanocomposites synthesized by solvent soluble imide resin in the presence of organoclay via an intercalation technique, have dramatically improved as compared with conventional solvent soluble imide resin.

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SynopsisTo further improve the characteristics of phenolic resins and the moldings, it is necessary to design the cross-linking structure. Currently, analysis of the structure and properties of the cured phenolic resin is not progressing much, because they are insoluble in solvents and not melt. In this study, we investigated cross-linking structure of cured phenolic resins by ¹³C-MAS method of solid-state NMR and evaluated mechanical properties of them. As a result, intermediate structure was increased with increasing hardener and was converted into methylene bridge by the post-cure. In addition, T_g of cured phenolic resin was increased with increasing the amount of intermediate structure and methylene bridge.

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High-molecular weight phenol novolak resins (RN) and o-cresol novolak resins (oCR) were prepared in organic solvent. The molecular structure was determined by ¹H and ¹³C NMR measurements. It was found that RN was a branched polymer and a microgel formation was observed, arising from intramolecular reaction (cyclization). The dilute solution properties of acetylated RN (Ac-RN) and acetylated oCR (Ac-oCR) were determined to elucidate the nature of highmolecular weight phenolic resins. The intrinsic viscosity [η] of Ac-RN and Ac-oCR was determined in good solvent and θ-solvent. The exponent values in MHS Eq. for Ac-RN were 0.24 in good solvent and 0.23 in θ-solvent, respectivity. AcRN behaved as a branched polymer. On the other hand, the exponent values in MHS Eq. for Ac-oCR were 0.43 in good solvent and 0.28 in θ-solvent, respectively. Each value was much smaller than that for polystyrene, which is a typical linear polymer. However, the values of expansion factor _η³= [η]/[η]_θ for Ac-oCR in THF were equal to those for polystyrene in toluene, indicating that Ac-oCR showed the excluded volume effect and behaved like a linear polymer in good solvent. We concluded that Ac-oCR with higher molecular weight showed linear polymeric properties such as polystyrene in solution. The properties of high-molecular weight phenolic resins will depend on the main chain structure composed from phenolic ring and methylene linkages.

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SynopsisIn order to achieve the cascade-type fl ow of lignocellulosic components as functional materials in human life, a novel conversion system has been developed and a new type of structure-controllable lignin-based polymers (lignophenols) has originally been designed. The originally designed process includes the phase-separative reaction system composed of phenol derivatives and concentrated acid. Through this process, native lignins are converted quantitatively to a new type of ligninbased polymer (lignophenols) composed mainly of 1,1-bis(aryl)propane type units. The selective grafting of monomeric phenol derivatives to C1-positions of propane units leads to the formation of new phenylpropane units between grafted phenolic units and lignin propane units, resulting in a dramatic change of the original lignin functions. The characteristic units in lignophenols, 1,1-bis(aryl) propane-2-O-aryl ethers, can be used as switching devices for the structural control. The separated carbohydrates include water-soluble monomers, oligomers,and polymers. These are easily converted to valuable chemicals such as alcohols, lactic acid, furfural, xylitol, etc. In order to create sustainable human society without petroleum, aliphatic and aromatic types of industrial raw materials must be derived from biomaterials (lignocellulosics). A new sustainable industrial network initiated from forests is designed.

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[in Japanese]

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