Adhesives are used in all aspects of life and have contributed to industrial development in terms of processing and operating costs, such as labor saving and weight reduction. In recent years, it has become desirable to have applications that can promote the reuse and recycling of the adhered by easily releasing the adhesion, thus contributing to resource saving. Such adhesives which can be easily separated are called“dismantlable adhesives” and are the subject of intensive research. Among them, dismantling adhesives that use light as a trigger means have been studied intensively. Because they can be irradiated without contact and with high spatial and temporal resolution, and be easily homogenized, enlarged, and curved. Dismantling adhesives based on photochemical reactions use irreversible photoreactions and photochromism. In this review, we describe several recent examples of photodisassembly adhesives and also photoinduced exfoliation of liquid crystalline polymeric composites.

Polypropylene （PP）-based composites have been used in a wide range of applications due to light weight, chemical resistance and excellent molding processability. However, the interface between PP and an inorganic filler is not generally well-controlled, resulting in that the mechanical properties have been not so improved as desired. The objective of this study is to examine the effect of addition of a functionalized polymer, maleic anhydride grafted polypropylene （PP-g-MA）, on the tensile properties for PP composites in which silica or alumina particles （SiO2 or Al2O3） are mixed as a filler. Scanning electron microscopy in conjunction with thermogravimetric analysis revealed that the interaction of PP-g-MA was stronger with Al2O3 than with SiO2. Also, the tensile stress at yield（ sy） was higher for the PP/PP-g-MA/Al2O3 composite than for the PP/PP-g-MA/SiO2 composite. Thus, it can be claimed that the control of the interfacial interaction between polymer matrix and filler based on the addition of the functionalized polymer is a promising way to improve the mechanical properties of polymer composites.

Most of the adhesive joint strength can be expressed as a constant value of the intensity of singular stress

field （ISSF）. The detail microscopic observation showed the adhesive fracture is cohesive and most of the

facture surface is close to the interface. This is because typical fracture pattern such as mirror, mist and

hackle pattern can be seen for butt joint and feather pattern can be seen for scarf joint. For the scarf joint, the

characteristic feather pattern can be seen due to the large shear stress at the interface. For both scarf and butt

joints, it is seen that the fracture originates from microcracks about 20μm depth at the interface edge. When

the adhesive thickness is larger than 5mm, the adhesive strength is smaller because the fracture occurs across

the adhesive layer and no fracture near the interface.

Effects of the coating-process conditions on the structure and mechanical properties of pressure-sensitive adhesive layers composed of block copolymers have been revealed using neat triblock copolymer and triblock/ diblock copolymer blend. For this purpose, atomic force microscope （AFM） observation, two-dimensional small-angle X-ray scattering （2D-SAXS） measurement and stress-strain measurement were performed. The coated layers of the block copolymer were prepared by the solution coating and the hot-melt coating process at various conditions. As for the solution coating process, it was found that the ordering regularity of spheres and d spacing of body-centered cubic （BCC） lattice exhibited very complicated behaviors as a function of the drying temperature. The effect of structure freezing during the solvent evaporation was taken into account and such complicated behaviors of experimental results could be almost perfectly explained. It was also found that the degree of clarity of the reflection planes in the uniaxial stretching direction is enhanced with stretching and the rate of improvement in the degree of clarity along the uniaxial stretching depends on the drying temperature. We could correlate the fracture of the block copolymer film having spherical microdomains with the completion of the stretching-induced ordering of spheres in the stretching direction. As for the hot-melt coating process, the coated layer had the anisotropic distribution of the spheres where the d spacing of the reflection plane in the machine direction （MD） is longer and the regularity of the ordering of the reflection planes is lower in the MD as compared to that in the directly solidified specimen by quenching from 190 ºC to room temperature without application of shear. These facts are ascribed to shear and elongational deformation during the hot-melt coating process. Furthermore, it was found that the effects of the coating rate and the extent of the remained strain were increased with the coating rate when the discharge rate （the flux of materials provided onto the substrate through the die lip） was kept constant. On the contrary, no effects were confirmed when the discharge rate was so controlled to maintain the thickness of the as-coated layer constant. Regarding the effects of the cooling-roll temperature, it was found that the extent of the remained strain was decreased with an increase in the cooling-roll temperature.