The thermally latent polymeric hardener 1 a-d consisting of hemiacetal ester moiety in the polymer back bone was designed, and examined on its thermally latent ability with complex 3 and/or 5 as the crosslinking system of glycidyl phenyl ether (2) and/or 3-ethyl-3-phenoxymethyl oxetane (4). Further, the compound 1 a-d thermally acted as a cross-linker of bisphenol A diglycidyl ether (8) and/or 1, 4-bis {[(3-ethyl-3-oxetanyl)methoxy] methyl} benzene (9). The storage stability of these systems was evaluated in the presence of Lewis acidic complex 3 and/or 5, in which any curing reaction was not observed during 2 months at room temperature.

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Rapidly curable films having high hydrophobicities and solvent-proof abilities were prepared from polyamines and copolymers from methacrylate monomers with long-alkyl chains and cyclic structures for crosslinking. The thermal treatments of the films at 150 °C for 20 or 50 seconds gave the corresponding cured films. The reaction efficiency order of the cross-linkable moieties was as follows : five-membered dithiocarbonate>five-membered carbonate>epoxy. Under the optimized conditions, the curing proceeded as rapidly as the thermal treatment for 20 seconds, and the cross-linked film could be obtained almost quantitatively.

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Multi-block copolymers composed of poly (N-phenylmaleimide-alt-styrene) and flexible segments such as polydimethylsiloxane or polyoxyethylene were prepared by copolymerization of N-phenylmaleimide and styrene with macromolecular azo-initiators containing polydimethylsiloxane or polyoxyethylene segments, and used for the modification of high performance epoxy resin, which is a mixture of N,N, N', N'-tetraglycidyldiaminodiphenylmethane, dicyclopentadienyl-type epoxy resin, naphthalene-type epoxy resin and bisphenol-A diglycidyl ether, cured with 4, 4' -diaminodiphenyl sulfone. The fracture toughness (K_IC) and flexural strength of the modified resin were strongly dependent on both the molecular weight (M_w) and structure (composition) of the modifier, while the modulus and glass transition temperature of the modified resin were maintained in this modification system. The addition of 5 phr of poly [poly (N-phenylmaleimide-alt-styrene) -block-polydimethylsiloxane] (PMSZ) having low M_w (157,000) and high dimethylsiloxane (VPS) content (40 mol%), or high M_w (664,000) and low VPS content (11 mol%) brought about increases (ca. 70%) in K_IC of the modified resin without large loss of flexural strength, compared with the control resin. The addition of 12-15 phr of poly [poly (N-phenylmaleimide-alt-styrene) -block-polyoxyethylene] (PMSE : M_w, 300,000, oxyethylene content 35mol%) resulted in the largely increased K_IC (210%) with rather large loss of flexural strength. PMSE was more effective for toughening of the epoxy matrix resin compared with corresponding PMSZ (M_w 371,000, VPS content 30 mol%) or poly (N-phenylmaleimide-alt-styrene) (PMS : M_w 397,000) without flexible segments. It was concluded that this is due to the high compatibility of polyoxyethylene segments in PMSE with the matrix resin. These modified resins with high K_IC had the co-continuous-phase morphology. The toughening mechanism was discussed in terms of the morphological and dynamic viscoelastic behaviors of the modified epoxy resin system.

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Fiber Reinforced Plastics, FRP, applied for bath units and pleasure boats, are very difficult to be recycled. Then, most of them are landfilled today. To accomplish the Horizontal Recycling Technology for FRP, Sub-critical Water Hydrolysis were examined. Reaction temperature at 360°C, only 20wt% of the total thermo-setting polyester resin existed in the reaction liquid as reusable matters due to pyrolysis of styrene bridges. To suppress the pyrolysis, the reaction was conducted at 230°C, which the pyrolysis of styrene bridges was believed to occur. As a result of measuring the concentration of glycol and fumaric-acid in the reaction liquid, 71 wt% of initial glycol and 22wt% of initial fumaric-acid were existed. In addition, solid were extracted in thereaction liquid and its weight corresponded 75wt% of initial total thermo-setting polyester resin. The molecular-structure study of the solid was conducted and determined that the solid was styrene-fumaric acid copolymer. It was suggested that it is usable as a raw material for a functionsl polymer. The result showed that 96wt% of initial total thermosetting polyester resin existed as reusable matters in the reaction liquid.

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The purpose of this study is to improve the several properties of composites consisting of a phenolic, fly ash, and sodium or calcium type artificial Zeolite (Na-Ze or Ca-Ze). And it also includes the improvement in the flowability of molding compounds. The molding compounds were prepared from a phenol novolac, a curing agent, and several fillers. The flowability of the compounds containing fly ash and artificial Zeolite as a filler, mentioned above, was superior to that of the compounds containing glass fiber (GF), calcium carbonate (CaCO₃), or talc as a filler. The phenolic composites were prepared from the above molding compounds by transfer molding. The phenolic composite containing Ca-Ze had most superior heat resistance, electrical insulation, and flexural strength, though in the lastly listed property it ranked next to the GF-filled composite. The linear expansion coefficient of the composite containing Ca-Ze was as low as almost isotropic. The reasons of obtaining these excellent properties were thought to be as follows : 1) Ca-Ze could finely be dispersed in the phenolic resin to bring good impregnation. 2) The surface chemical and physical interaction between the resin and Ca-Ze was higher than that between the resin and the other fillers.

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Polymerization of one-component epoxy resins by imines as water-initiated latent hardeners can progress through two reactions which are hydrolysis of imines and the reaction of epoxide with amines released from the imines. This one-component system has been inappropriate for practical use because of slower curing. In these reactions, the hydrolysis reaction of imines is commonly very slow, resulting in rate-determining step of curing.
It is most important, therefore to develop new imines showing faster hydrolysis. Several imines were synthesized and their hydrolysis rates were investigated. Imines with lower electron density on the C=N carbon werw found to have faster hydrolysis rates. Especially, one-component epoxy resins with imines synthesized from diethyl ketone and aliphatic amines showed faster curing rates than those with common imines. These epoxy resins showed good adhesive strength and durability as same as two-component epoxy resins. The one-component epoxy resin system with the novel diethyl ketoen-based imines was clarified to be appropriate for practical use.

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