Diene rubber is regarded as internal olefinic multiallyl monomers linked allyl groups (-CH=CR-CH₂- : R = H or CH₃) with methylene units (-CH₂-) and thus, liquid diene rubbers such as liquid polybutadiene rubber (LBR) and liquid polyisoprene rubber (LIR) as nonconjugated polyene oligomers are called as “internal olefinic multivinyl crosslinkers”. So this work is concerned with the free-radical crosslinking copolymerizations of (meth) acrylic monomers with LBR and LIR in order to examine the role of “internal olefinic multivinyl crosslinker” as an extension of our continuing studies concerned with the mechanistic discussion of network formation in the free-radical crosslinking polymerization and copolymerization of multivinyl monomers. The present discussion was focused on the elucidation of the competitive occurrence of both addition reaction to internal double bonds and abstraction reaction of allylic hydrogens in LBR and LIR by growing polymer radical.

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The polyaddition reaction of 1, 3, 5-trisglycidyloxybenzene (TGOB) with 3, 3-bis (4-carboxylphenyloxymethyl) oxetane (CPOMO), methacrylic acid (MAA), and 3-carboxyl-3-ethyloxetane (CEO) was carried out in the presence of tetrabutylammonium bromide (TBAB) as a catalyst at 90°C for 18 h to give the hybrid hyperbranched polymer (HBP-OX-MA-CA) (M_n's = 5200, M_w/M_n=2.21) with terminal oxetanyl, methacryloyl, and carboxyl groups in 80 % yield. Certain curing reactions of HBP-OX-MA-CA were performed in the film state using appropriate photo-acid generator, photo-radical initiator, or tetraphenylphosphonium iodide (TPPI) as a catalyst to give the corresponding cured films. The thermal properties of resulting cured films were examined, and it was found that hybrid cured film by photo-initiated radical polymerization + photo-initiated cationic polymerization + thermal reaction of oxetane groups with carboxyl groups showed higher T_g than the other cured films by each reaction such as photo-initiated radical polymerization, photo-initiated cationic polymerization, and thermal reaction of oxetane groups with carboxyl groups.

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Dimeric acid polyamides (PA) were synthesized by the reaction of dimeric acid with m-xylylenediamine or diethylenetriamine. PA were added to a diallyl phthalate resin (DAP) to a concentration of 0.026mo1 to improve the adhesive properties. These blends were cured with dicumyl peroxide. The T-peel adhesive strength of the modified diallyl phthalate resin was markedly improved compared with that of diallyl phthalate resin. By modification with PA, the T-peel adhesive strength to copper increased up to about 2.0 times that of the diallyl phthalate resin. It is thought that the reason for this result is that flexibility was given to the adhesive layer by modifying PA concluding the dimeric acid unit. Moreover, it was revealed from FTIR analysis that adhesive strength to copper was improved because amide groups of PA were concentrated in the interface of copper substrate. Dynamic viscoelastic behavior and SEM showed that the diallyl phthalate resin modified with PA formed phase separated structure.

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Three kinds of orgno-bentonite (MMT) were prepared from sodium montmorillonite and dimethylstearyl-benzylammonium chloride (DMSB). DMSB31-MMT was prepared from equimolar amount of sodium montmorillonite and DMSB. The gallery expansion of the MMT was 19.2Å. DMSB31-MMT-Me0H was prepared with expansion of DMSB31-MMT by methanol. The gallery expansion of the MMT was 36.0Å. DMSB52-MMT was prepared from sodium montmorillonite and excess amount of DMSB. The gallery expansion of the MMT was 38.4Å. Phenolic rein-layered silicate nanocomposites were prepared from conventional phenol novolac, hexamethylenetetramine and these MMTs by hot-roll kneading. Phenolic resin was intercalateed between layers of these MMTs, especially DMSB31-MMT-Me0H and DMSB52-MMT were finely dispersed in phenolic matrix. The gallery expansion of these MMTs was 38-45Å. Flexural strength, flexural strain and tensile strength of phenolic/DMSB31-MMT nanocomposites were inferior to those of others. The main reason was considered that a part of MMT was aggregated in phenolic matrix and the dimension of the aggregation became a few micron meter. Phenolic/DMSB52-MMT nanocomposites had the best mechanical properties, which may be associated to the following reasons : DMSB52-MMT was finely dispersed in phenolic matrix and excess amount of DMSB between layered MMTs acted as plasticizer.

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The anisotropy of the dielectric property of polymer materials was measured at GHz bands using cylindrical cavity resonators. We could measure the dielectric anisotropy for the glass epoxy boards with multi-layers. We also measured the dielectric anisotropy of some polymer materials at 5GHz by this method. Epoxy sheet and polytetrafluoroethylene (PTFE) were found to be isotropic materials, whereas polyimide films were anisotropic materials, and their anisotropy increased as the thickness of the films decreased. A more precise design in new device development may be realized by considering the anisotropy of materials.

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Novel alkoxysilane-terminated polyurethanes (silylated polyurethanes) were synthesized from isocyanateterminated polyurethane and silane endcappers having alkoxysilyl group. The silane endcappers were also synthesized by the conjugate reaction of 3-aminopropyltrialkoxysilane with acrylate monomers. The viscosities of the obtained silylated polyurethanes were lower than that of silylated polyurethane derived from untreated 3-aminopropyltrialkoxysilane. The silylated polyurethanes were evaluated by the curing speeds and the bond strengths to four adherends. Shorter alkyl groups of starting acrylate monomers led to higher curing speed. The tensile shear bond strength and adherence depended on trialkoxysilane end-capping ratio. The effects of BF₃-monoethylamine complex (BF₃-MEA) and dibutyltin dimethoxide (DBTDM) on the curing speeds and thermal stabilities were examined. BF3-MEA was significantly superior to DBTDM in terms of both the catalytic effect to cure the silylated polyurethanes and the thermal stability of cured silylated polyurethanes. The obtained silylated polyurethanes are useful as base polymers of environmentally-friendly moisture-curable adhesives, and BF₃-MEA is an effective curing catalyst for the silylated polyurethanes.

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We have recently developed a novel type of gel called the slide-ring gel or topological gel that is different from physical and chemical gels by using the supramolecular architecture with topological characteristics. In this gel, polymer chains with bulky end groups exhibit neither covalently cross-links as in chemical gels nor attractive interactions as in physical gels but are topologically interlocked by figure-of-eight cross-links. Hence, these cross-links can pass along the polymer chains freely to equalize the tension of the threading polymer chains similarly to pulleys; this is called the pulley effect. The slide-ring material is a new cross-linking concept for the polymer network as well as a real example of a slip-link model or sliding gel, which was previously considered only theoretically. In this report, we review recent researches on progress in the cross-linking of polymeric materials together with the synthesis, structure, and mechanical properties of the slide-ring gels. This concept of the slide-ring material can be applied to not only gels but also to a wide variety of polymeric materials without solvents.

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