Microbial degradation of a vulcanized natural rubber material treated by a wood decay fungus, Trichaptum abietinum TUES-023 was observed by X-ray μCT with non-destructive 1.25 μm resolution. After treatment with T. abieti num for 172 days at 25 °C in a static condition, the rubber surface distorted and the inside structure became porous due to elution of a filler, calcium carbonate from the rubber. The structural change was observed from subsurface to 328 μm depth in the rubber. In this study, we demonstrate that X-ray μCT have an advantage as a tool to monitor structure of rubber inside without addition of physical damage to the rubber materials.

Tires perform vital functions that keep drivers safe and comfortable on a contact patch about the size of the palm of a hand. Keeping proper tire inflation and maintaining safe tread depth are extremely essential to prevent tire failure and to reduce down-time of operation related to the tires.

Recently tires are having a new function as an interface to connect between human, vehicles and various information of transportation in addition to the conventional ones. Drivers can grasp real-time information of tires through Tire Pressure Monitoring System (TPMS) and also developed is another technology that can classify road conditions in actual time by using accelerometer attached inside tires. This is an example to use tires as a kind of sensors to catch outer circumstances.

Rolling resistance of tire has been continuously improved for many years, and reducing CO₂ emission through whole life cycle of tires is also an important subject for mobility to be more sustainable.

The solution technology surrounding tires such as mine and aviation were already deployed to optimize total tire maintenance and operation.

Furthermore, some recent technologies in line with “CASE” trends that tire manufacturers may face are also discussed in this review.

Recently, polymer thin films for use in flexible devices such as semiconductor block copolymers consisting of fully aromatic rigid polymer and rubbery polymer have attracted much attention. Thus, rubbery materials are increasingly being used not only in the amorphous bulk state, but also as ordered thin films (films less than 500 nm in thickness). Additionally, rubber materials are often used as composite materials with inorganic fillers, and thin films on the inorganic substrates are suitable model system for structural evaluation near the interface because of the significantly larger specific area than the bulk material. With this background, precise and rapid methods to evaluate the structures of thin films (periodic order, molecular chain orientation, etc.) are increasingly demanded. In this paper, infrared p-polarized multiple-angle incidence resolved spectroscopy (pMAIRS), and combined methods of pMAIRS with conventional grazing incidence wide-angle X-ray scattering (GI-WAXS) and spectroscopic ellipsometry (SE) methods are introduced for analyses on the hierarchical ordered structure of polymer thin films (crystal, liquid crystal glass, oriented and unoriented amorphous, and their mixed complex structures).

Continuing to the previous report, we discuss on the synthesis of cyclic polymers based on the “rotaxane protocol”. Although the synthesis of pure cyclic polymer is a tough challenge, recent advances on this subject have gradually overcome the problems associated with it: we have succeeded in synthesizing pure cyclic polymers through the ring-expansion of the small cyclic structure to cyclic polymer using the concept of “linear to cyclic polymer topological transformation”caused by the high structural flexibility or component mobility of rotaxane. In the light of a limited number of cyclic vinyl polymers, cyclic poly(methyl acrylate) was prepared by transforming [1]polyrotaxane-type linear poly(methyl acrylate) to cyclic poly(methyl acrylate) by moving the wheel component of [1]polyrotaxane from one terminal to other terminal by the action of macromolecular rotaxane switch. High-yielding synthesis of cyclic polymer was achieved by the spontaneous dimerization to Janus-shaped rotaxane derived from an ammonium moiety-containing crown ether, of which axle components have hydroxy terminals. The introduction of two polymer chains to the two hydroxy terminals for the synthesis of linear polymer was followed by the movement of the wheel components from the center to the axle terminal by using the rotaxane switch, to eventually yield cyclic polymer. The process of the cyclic polymer formation requires no diluted concentration condition, and therefore 7.3 g of pure cyclic polymer was obtained from a 50 mL reaction flask, suggesting that the present protocol provides the reliable useful synthetic method of cyclic polymer.

A synchrotron radiation experiment and a large-scale simulation are indispensable for development new functional rubber materials in recent years. In this series of lectures, I will try to explain about an analysis of structure of filled rubber vulcanizates by cooperation of a synchrotron radiation experiment and a large-scale simulation. In this fourth article, I will discuss coarse-grained molecular dynamics (CGMD) simulations of hydrogenated styrene butadiene rubber (SBR) which shows very high strength. Since the high strength of hydrogenated SBR is thought to be due to the increment of entanglement density with hydrogenation, we have added angle potential to Kremer-Grest model in order to control entanglement density. We conducted CGMD simulations of hydrogenated SBR with this model. The stress-strain curves and the tanδ master curves by simulation reproduced experimental data. Then we conclude that the increment of entanglement density plays an important roll in mechanical properties of hydrogenated SBR.