The function of resin components, such as methylene donors, methylene acceptors and silica, was investigated in the adhesion of styrene-butadiene rubber (SBR) to zinc during curing with an HRH adhesion system. Adhesion strength was increased with an increase in the ability of polymerization of the donor and acceptor compounds in the adhesion of SBR to zinc. Both the methylene donor (e. g., hexamethylenetetramine) and the methylene acceptor (e. g., resorcinol) migrated to the interface between Zn and SBR during curing reaction. In this case, adhesion strength was generated by forming a reinforcement layer of resin at the interface. The layer is produced by reaction of the methylene acceptor and the donor. In the SBR compound, polymerization of the acceptors and the donors is delayed by the presence of silica, therefore the acceptor and donor are able to migrate to the interface. The resin layer at Zn/SBR interface works not only as a reinforcement layer but also as a binder which connects SBR molecules with zinc. Resorcinol reacted with PbO and then C₆H₄O₃Pb₂ was formed. The C₆H₄O₃Pb₂ migrated to the interface. This result suggested that the resorcinol acts as carrier as well as a methylene acceptor.

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Inhomogeneous structure in natural rubber (NR) vulcanizate was examined by ¹H pulsed NMR. The spin-spin relaxation times (T₂) under various extension ratios (α) were measured by the Hahn echo method and the solid echo method. The decay curves of NRs were resolved into three T₂ components, T_2SS, T_2HS, and T_2HL, which were respectively arising from the strain-induced crystalline chains, the network chains, and the more mobile chains that were less affected by crosslinks or entanglements. T_2HS and T_2HL decreased with increasing α. However, T_2HL leveled off at α beyond 4 while T_2HS kept decrease. The decrease in T_2HL with α was more rapid than that of T_2HS until T_2HL became constant. This indicates that the deformation of the more mobile chains was larger than that of the network chains. The increase in the fraction of T_2SS component with increasing α was observed in the region of α that T_2HL were almost unchanged. It was suggested that the strain-induced crystallization is closely related with the more mobile chains.

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The behavior of polymer and filler in stretched rubber has been studied. Using SPM (scanning probe microscopy) and TEM (transmission electron microscopy), it was found that rubber disobeys the assumption of “affine deformation” in nano-scale. The result of ESR (electron spin resonance) study suggests that chain scission of polymer under stretching occurs mainly at the interface between polymer and filler. From solid-state ¹³C NMR (nuclear magnetic resonance) study of elongated natural rubber, it was found that the elongation decreased the mobility of the polymer chains and that almost all polymer chains were oriented uniaxially. The polymer/filler interfaces were investigated using EFTEM (energy-filtering transmission electron microscopy). The distribution of a silane coupling agent around silica in cured rubber can be visualized by elemental maps of silicon and sulfur. The interfaces between zinc oxide particles and the rubber matrix were also investigated, which show the adsorption of sulfur compounds on the zinc oxide surface. We observed ZnS nanoparticles distributed in rubber matrix for the first time by EFTEM and HAADF-STEM (high-angle annular dark field scanning transmission electron microscopy). This fact indicates that cross-linked rubber have inhomogeneous network structures that may influence the properties. The nanostructures in rubber have been revealed through direct nanoscopic observation.

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The bicycle tire for the truck race has been improved to be much lighter than the tire of general bicycle. The bicycle tire for the race is used with a high pressure of 10 atm. Since the best speed of the truck race is 80km per hour, much contrivance has been conducted to the tire for the truck race. For example, NR (natural rubber) latex is used as a raw tube material, since the tear strength of NR is strong, in order to reduce the risk to burst. Therefore, there is small impact of the puncture, so the accident in which rider falls down from the bicycle is suppressed. For the adhesion of rim and tire, the rubber cement made by CR (chloroprene rubber) is used. The rubber cement has the work as cushion material of the stress which is added to the tire from various directions.

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Recent advances in precise synthesis of macromolecules with specially designed architectures will be reviewed in this paper. Such designed macromolecules include graft copolymers, comb-like polymers, cyclic polymers, regular and asymmetric star-branched polymers, and a variety of hyperbranched polymers with complexed structures as well as block copolymers and chain-end-functionalized polymers synthesized by living (anionic) polymerization. Their architectures are well defined in branching, position, and shape and chain structures are precisely controlled in molecular weights and molecular weight distributions. Recently, new macromolecules with more complex branched architectures have been further synthesized along with rapid progress of living anionic polymerization and new development of living polymerization systems with different mechanisms. These are star-branched polymers with many arms and multi-components, highly dense comb-like polymers having one polymer segment in each unit, star-linear block polymers, comb-like graft and star polymers, dendritic hyperbranched polymers. A particular example is a seventhgeneration well-defined dendrimer-like star-branched polymer having a M_n of 2000000 and comprised of 508 polymer segments and 512 end-functionalities. They are characteristic and quite different from linear polymers in physical property and behavior in solution, melt, and solid state. Furthermore, their different segments are segregated and self-organized at molecular level to form novel nano-scale supra-structures and molecular assemblies.

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When international exhibitions faced difficulties, the EXPO 2005 was succeeded in showing the continuous significance and a new model for international exhibitions or world fares. In order to emphasize and deepen the EXPO's theme “Nature's Wisdom” toward solving global problems and to stir citizens to action, a variety of experimental projects were conducted from four viewpoints: application of cutting-edge technologies; adoption of new social systems; participation by NGOs and citizens; sharing of diverse cultures and values. These experiments were deeply interconnected and served as a model for sustainable society. The EXPO 2005, which had a major impact on the mindset and behavior of over 22 million visitors, particularly young people, earned an international reputation as a “leading project” of the United Nations Decade of Education for Sustainable Development from 2005 to 2014, which was proposed during the World Summit on Sustainable Development held in Johannesburg, South Africa, and adopted by the UN General Assembly in 2002. As a part of international exhibition movement, the EXPO 2005 is communicating its concepts and achievements at every opportunity in the international arena in order to realize the aim of contributing to the solution of global issues.

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