Surface/interface plays an important role for adhesive, laminates, composites, and so on. In this study, surface deformation of rubber was compared with bulk deformation using a scanning electron microscope and an atomic force microscope. The silica reinforced rubber showed inhomogeneous surface deformation, however, the deformation of oriented poly (ethylene terephthalate) filament was found to obey affine deformation. In addition, change of O₂ plasma modified surface properties of elastomer under tensile deformation was evaluated using a contact angle, X-ray photo-electron spectroscopy. The contact angle of the elastomer increased under stretching, which is brought by the decrease of functional groups density on the elastomer surface. On the contrary, when the elastomer was plasma treated under deformation followed by recovery, the high water wettability was kept even after stretching. This PsPR (Pre-stretch followed by Plasma treatment in situ under stretching, then allowed to Recover) process was proposed as a new surface treatment method of rubber. Finally, X-ray computed tomographic image around interphase was shown to investigate adhesion mechanism. Through these studies, relationship between rubber deformation and surface/interface was investigated.

Strong adhesion between rubber and steel cords is essential for tires, pressure resistant hose, conveyor belt and so on to exhibit a good performance. Therefore, many studies have been carried out to clarify the adhesion mechanism between rubber and steel cords. It has been recognized that the rubber/brass plated cord interface is composed of some layers, such as cupper sulfide, zinc oxide and zinc sulfide. Although photoelectron spectroscopy (PES) is often used to observe such adhesive interfaces, it is difficult to expose the strongly adhered layers.
In this report, two studies which examine buried interfaces of rubber/brass systems are introduced. One is a study applied synchrotron PES to analyze the formation process of the adhesive interlayer during vulcanization by using so-called a filter-paper method. At least five sulfur- containing species are identified in the adhesive interlayer including CuS and Cu_xS (x≃2). Formation of Cu_xS (x≃2) in the adhesive layer is observed at the very beginning of vulcanization. Then Cu_xS (x≃2) chemically changes to CuS due to a presence of excess sulfur. The other is a study applied HAXPES (Hard X-ray Photoelectron Spectroscopy) to directly observe the buried interfaces. Excess sulfur is observed in the model of the exposed interface prepared by the filter-paper method in comparison with an actual rubber/brass interface.

Adhesion is one of the most important technologies for modern technology. However, it is not easy to elucidate the adhesion mechanism because of the multiplicity of influencing factors and also the difficulties in analyzing the interface. Therefore, it is important to set purpose and hypothesis in analysis of adhesion. The analysis is for verifying the hypothesis. For adhesion analysis, surface and interface analysis are the main functions. For example, contact angle, spectroscopic analysis such as XPS, TOF-SIMS, FTIR-ATR and others are generally used. Depth profiling is usually used in the interface analysis, but various ingenious measures such as GSP are required to obtain necessary information. It is important to visualize the true nature by contrasting with such various ideas, utilization of multiple methods, and adhesion behavior.

Molding and welding conditions have a significant influence on the mechanical properties of the thermoplastic welding products. In this paper, we described our investigation of the relationship between the interfacial structure and the mechanical strength of them. Especially, we focused on the weld line of polyamide and the welded interface of poly (phenylene sulfide). Using the N-ARC method (the original photo based observation method) and imaging infrared, the traces of the molten polymer flow and the higher-order structure were analyzed. These results showed that the weld line and the welded interface became the fatal defects for their mechanical properties.

In Denso, the resin (engineering plastic) of automobile parts has been focused as the lightweighting in oreder to protect global environment now. One of the problems in the lightweighting of engineering plastic PBT, had improvement of the adhesive strength. To solve the problem, we analized the PBT surface in the nano-meter molecular size by SAICAS, SVM and GIXD in SPring-8. As the result, we found that the cause of low adhesive strength of PBT is WBL (Weak Boundary Layer) after annealing. As the measurement of PBT adhesive strength improvement we developed a plasma surface treatment etc. based on the mechanism and adopted this technology in automobile resin parts and contributed to the lightweighting/ reliability improvement of the automobile.

Recently, it is increasing that double-shot molding technology using some engineering plastics is required particularly for molding parts such as sensors and connectors in automobile and electronics fields.
There are two major constraints in conventional double molding technology: (1) difference in melting temperature or softening temperature between primary and secondary materials, and (2) compatibility between primary and secondary materials. These limitations are obstacles to adopt double shot molding technology for joining molding parts with similar materials or dissimilar materials.
Joining mechanism of conventional double shot molding is fusing primary material by heat transfer and shear from secondary material flow. By changing from the fusion joining mechanism to use of a physical anchor, we thought it would be possible to overcome the aforementioned constraints and join between even if dissimilar materials.
As a result, we developed a technique that adopted laser etching on surface of primary material to remove resin and expose the glass fibers which then acts as an anchor for the secondary molding material. We named this process AKI-Lock^®(Advanced Knitting Integrated Lock)and introduce its various features.