The estimation of thermal sensation at the instant when a certain object is touched is becoming an important consideration in material evaluation. In a previous paper, we showed that the effective contact temperature of the object –when covered with a thin surface of a different material– could be implied from the thermal contact resistance of the nonsteady heat conduction between half infinite solids. However, when the thickness of the surface material of the contact object becomes the same depth as the thermoreceptor in the skin, the approximation by the thermal contact resistance no longer applies, and, therefore, deriving a strict analytical solution becomes difficult. We calculated the temperature distributions in the material for various material surfaces and the skin using a numerical method. We examined the influence on the effective contact temperature of the thickness and the heat properties of each surface material. As a result, deflection of effective contact temperature from the temperature of a material is determined by the temperature difference between the skin and the surface material/object, the heat properties of each, the thickness of the surface material, and the depth of thermoreceptor in the skin. This can be expressed by the relation of the nondimensional parameter function. When the thickness of surface material is thick enough, effective contact temperature is determined only by the heat property of the surface material, and it is unrelated to the thickness of the surface material and the thermal property of the object under it. The influences of the thickness of the surface material and the thermal property of the object on effective contact temperature appear when the thickness of surface material becomes very thin, and increases rapidly with a decrease in the thickness of the surface material. The criterion between thermally thick and/or thin material is quantitatively presented by the numerical simulation.

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Epoxy and unsaturated polyester resins are typical thermosetting resins used as matrix for composites, and generally difficult to recycle. In this study, reprocessed epoxy and unsaturated polyester resins were prepared with ground epoxy or unsaturated polyester resin. We measured the impact fracture energy of reprocessed epoxy and unsaturated polyester resins with different volume fraction of ground epoxy or unsaturated polyester resin. The impact fracture energy lowered with increasing the size and the volume fraction of ground resins. The impact fracture energy of reprocessed resin was described by the sum of the fracture energy of the matrix resin and the mixed ground particles and the energy necessary to strip the ground particles on the fracture surface. The calculated values of the impact fracture energy were almost agreed the experimental values. It was found that in any resin, the impact fracture energy of the matrix resin mainly contributes to the impact fracture energy.

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We investigated the effect of impurities on gel properties of 12-hydroxystearic acid (12-HSA) in organic solvents by means of differential scanning calorimetry (DSC), small-angle and wide-angle X-ray scattering (SAXS and WAXS). The melting and crystallization behaviors of unpurified 12-HSA powder are quite different from those of purified 12-HSA powder. The former melting point is by 2.9 °C lower than that of purified 12-HSA and the endothermic peak is very broad because of existence of impurities. On the other hand, the melting and crystallization behaviors of unpurified 12-HSA gel are slightly different from those of purified 12-HSA gels. The SAXS experiments reveal that the fiber structure of unpurified 12-HSA gel is similar to that of purified 12-HSA gel. For the 12-HSA gel in toluene which forms transparent gel, the cross-sectional size of the fiber estimated to be 110 Å for both purified gels and unpurified gels. These results suggest that gel properties of 12-HSA solutions are relatively insensitive to existence of impurities.

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The aminolysis of polyethylene terephthalate (PET) fibers with diamine, such as ethylenediamine, is one of the important methods to introduce free amino groups on their surface chemically. The aminolyzed PET fibers can easily interact with various dyestuffs or functional materials, similar to conventional fibers having amino groups, such as wool, silk, and nylon fibers. However, the vapor of ethylenediamine is a toxic and corrosive gas for human skin. In this paper, the reactions of PET fibers with ethylenediamine in an aqueous solution containing various surfactants were investigated to introduce amino groups on their surface safely. Interestingly, the obtained fibers are not only dyed more deeply by acid dyes but also maintain stronger mechanical strength than fibers reacted in an aqueous solution not containing surfactants.

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