Hyperbranched aromatic polyamides from 3,5-diaminobenzoic acid and G1 aromatic polyamide dendrons with terminal phenylethynylphthalimide groups were synthesized, and solubility and thermal properties of the resulting polymers were examined. Molecular weights of the resulting hyperbranched polyamides could be controlled by the copolymerization of 3,5-diaminobenzoic acid and m-phenylenediamine. All resulting polymers with imide groups were soluble in aprotic polar solvents such as DMAc and NMP. T_gs of the polymers having phenylethynyl groups cured at 370°C for 1h were not detected below 400°C by DSC. Thermal decomposition temperatures of the polymers with terminal imide groups were higher than those of terminal amino groups and benzamide groups. Furthermore, and the first generation (G1) polyamide dendrons having phenylethynyl groups and the additive polyimide “TriA-PI”, which was prepared from 2,3,3’,4’-biphenyltetracarboxylic anhydride, 4,4’-oxydianiline and 4-phenylethynylphthalic anhydride, were blended and cured. The blends had good processability and clear films were obtained. The blends of the additive polyamide dendrons exhibited higher T_g than that of TriA-PI. However, the elongation at break was decreased with the increase in the ratio of the polyamide dendrons.

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A series of urea derivatives were synthesized by reactions of amines and isocyanates and their acceleration effects on epoxy-dicyandiamide (DICY) curing system were studied. The focus of this study was the influence of substituents of the ureas on their acceleration effects, which clarified that the acceleration effects were almost independent on the isocyantederived part, but were strongly dependent on steric hinderance of the amine-derived part. The smaller steric hinderance of the amine-derived part was advantageous for the efficient acceleration of the curing system, implying that the ureas underwent thermal dissociation to give the corresponding amines, of which reactions with epoxide triggered the accelerated curing reactions. The noteworthy finding was the efficient acceleration by the ureas derived from cyclic amines, of which steric hinderance was smaller than the linear counterparts.

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Recently, phosphoric ester compounds have been used as non-halogen flame retardants for epoxy resins. This results in a problem that the phosphoric esters often inhibit the thermosetting of epoxy resins. In this study, to solve this problem, the thermosetting inhibition mechanism was clarified by ¹H-NMR and GC-MASS analysis of products obtained from the reaction of epoxy compound/imidazol/phosphoric ester. As a result, it was found that phosphoric ester was first decomposed by a trace amount of hydroxyl group to generate free hydroxyl groups. Then the free hydroxyl group reacts with epoxy compound to generate alcohol, which decomposes phosphoric ester again. In this way, thermosetting of epoxy resin is probably inhibited.

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Epoxy resins were synthesized using phenyl silsesquioxanes with three kinds of structures, double-decker (DDEP), cage (DDQEP) and ladder-like (PGSQ). The epoxy resins were thermally hardened by heat using tetraethylenepentamin as a curing agent. Thermal properties were measured by thermal gravimetric analysis and dynamic mechanical analysis. Mechanical properties were measured by tensile test. In these studies, we confirmed following points. (1) The thermal decomposition proceeded in two steps under an air atmosphere; the primary decomposition temperatures for all three samples were found at 270°C and the secondary decomposition temperatures were observed at 600°C. (2) The glass transition temperature (Tg) was determined by dynamic mechanical analysis as follows; DDQEP had the highest Tg (86°C), while PGSQ had the lowest Tg (67°C). The storage modulus was barely changed below and above Tg. (3) The order of fractural energy was DDEP>DDQEP>PGSQ, and DDEP gave 18 times larger energy than that of the PGSQ. Through these studies, correlations between silsesquioxanes structures and some properties (fractural strength, fractural energy and Tg) was found, although the decomposition temperature was independent of the structures.

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The wear-resistant polymer-based composites that have excellent mechanical properties have been increasingly required to satisfy the social needs of CO₂ reduction. We developed the wear-resistant composite composed of the heatresistant phenol-resin and some kinds of the effective filler for the lubrication and protection of the worn surface. The developed material showed the excellent limiting PV value and the wear-resistance slid against aluminum alloy and stainless steel. In order to clarify the wear-resistant mechanism, tribological measurement and observation of worn surfaces were carried out. As a result, we confirmed that the wear powder had formed the smooth wear-resistance-film on the worn surface.

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Paint is a product that contributes environmental protection with a variety of functions such as protecting materials, giving aesthetic worth, thermal barrier, less polluting and maintaining these functions over long periods by several micrometer-thick coating. At present, most of paints are thermosetting type and the choice of curing reaction type is one of the significant elementary technologies. From the standpoint of the recent environmental protection movement, the paint manufacturing industries must respond to the issues of emission control of VOC and greenhouse gas such as CO₂. As most of VOC and CO₂ from paint are released in the drying process of coating, the improvement of this process is essential. For reduction of VOC in the drying process, conversion of the paint from solvent-based to waterborne and powdery is necessary. Meanwhile, the reacting system which harden at low temperatures in a short time is needed for reducing of CO₂ . It is significant to choose the appropriate curing reaction to solve these issues. In this article, I will introduce two kinds of curing systems. One is used in waterborne and powdery coating and the other is ultraviolet curing system as a significant tool which harden at low temperatures in a short time.

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I will discuss here the regulation of molecular arrangement within the supramolecular film formed from an oligoleucine-containing amphiphile (Chart I). The oligoleucine-containing amphiphile possessing three and more consecutive leucinate residues initially formed a β-sheet structure, which stacked by a fastener-like action between the side chains of leucines (Leucine-fastener) within the different β-sheets (Fig. 3). The molecular arrangement was improved by hydraulic press of the xero-gel of MEE-Leu₆ Glu(OC₁₂)₂ (Fig. 8) or by warming the air-dried cast film of N⁺C₁₁-Leu₄ Glu(OC₁₂)₂ (Figs. 3, 9 and 10). The tensile stress of the hydraulic pressed film increased to ca. 2.5MPa, when a larger pressure was applied to form the pressed film (Fig. 8). Depending on the increase of the tensile stress, the absorbance of FT-IR bands increased (Fig. 11). On the other hand, the same increase of the FT-IR spectral intensity was observed, when the air-dried cast film was warmed (70°C) and then cooled (r. t. ). These results suggest that the mechanical processing or the thermal treatment should promote the mechanical strength of the supramolecular film of the oligoleucine-containing amphiphile. This is because a large pressure or a higher temperature brought about tight coupling between the nearest neighboring β-sheets of the oligoleucine derivatives.

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