All issues
Predecessor
Volume 77, Issue 5
Displaying 1-6 of 6 articles from this issue
- |<
- <
- 1
- >
- >|
-
Yukikazu TAKEOKA, Masayoshi WATANABE2004 Volume 77 Issue 5 Pages 155-158
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSA periodically ordered interconnecting porous structure could be imprinted in hydrogels by using closest packing silica colloidal crystals as mesoscopically sized templates. The interconnecting porous structure provides fast response to an infinitesimal change of environment for reversible swelling and shrinking of the hydrogels, while the periodically ordered mesoscopical structure endows a structural color in the gel. The structural color with different optical behaviors can be tuned by simply changing the amount of the cross-linker in the pre-gel solutions. The structural color imprinted in the gel is quickly synchronized with the change in the volume of the gels. The newly invented porous hydrogels possess optical properties as environmentally sensitive smart gels.View full abstractDownload PDF (919K) -
Anshun YOSHINAGA, Masayoshi KUBO, Yoshitada SHIMADA, Nobuyasu IKOMA2004 Volume 77 Issue 5 Pages 159-165
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSIn 2025, it is predicted that about 5 billions of people all over the world will face water shortage. In the case of Japan, on the other hand, it is thought that there are enough water resources in Japan. However, water is necessary not only for our daily life but also for the agricultural use. Considering these facts, it have come to clear that Japan actually imports a lot of water, about half of the needs. Therefore, effective uses of water resources are studied for the isolated islands such as Sakishima island, Okinawa, where water supply is almost constantly in iill-condition.
Water resources are transported to the water-shortage isolated islands from other area where rhere are enough water by the use of MEGA-BAG made of fiber-reinforced rubber and stored in reservoir there. This constant supply of water resources would encourage the agricultural economy in this area. The possibility for the generation of electricity by the use of wind force and biomass was also examined.
The keys technology for this study is the optimum design and manufacture of rubber materials.View full abstractDownload PDF (1526K) -
Rheology of Ideal SuspensionsToshiyuki SHIKATA2004 Volume 77 Issue 5 Pages 166-172
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSViscoelasticity is discussed for mono-disperse suspensions of spherical silica particles dispersed in ethylene glycol keeping hard-core inter-particle potential, so called ideal suspensions. The zero-shear viscosity and the high frequency limiting viscosity are functions only of the volume fraction of particles. The longest relaxation time is well described with time necessary for a particle to migrate by a distance equal to its own radius due to Brownian motion. Thus, the origin of vscoelasticity for the ideal suspension is the Brownian motion of particles. Viscoelasticity of bimodal ideal suspensions with the hard-core inter-particle potential is also discussed. When a ratio of particle radii< 3, the shape of relaxation spectra is essentially the same as that of the mono-disperse ideal suspension. However, when the ratio_??_5, the shape of the relaxation spectrum is much broader than that of the mono-disperse ideal suspension. Then, motion of two kinds of particles are likely averaged into that of a hypothetical particle with an average radius when the ratio<3 in the bimodal ideal suspension.View full abstractDownload PDF (1248K) -
Naoya AMINO, Yoshitaka UCHIYAMA, Tomoaki IWAI, Masato MAEDA2004 Volume 77 Issue 5 Pages 173-179
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSIt is known that silica-filled rubbers improve the trade-off between wet traction and the rolling resistance of tires, compared with carbon black-filled rubbers. It is generally considered that the adhesion component of the friction of silica-filled rubbers is higher than that of carbon-filled rubbers, however there are few reports that show this difference in the adhesion components of friction.
In this paper, the adhesion component and the hysteresis component of friction for carbon black-filled and silica-filled rubbers are investigated. Comparing the friction force-frequency curves (F-ω curves) and the viscoelastic properties establishes that the friction force F has the form:
F=As+kE'-1/3tanδ
where A is the area of contact, s is the shear strength of the rubbers and k is constant. The first term represents the adhesion component of the friction and the second term represents the hysteresis component. It is found that the adhesion component of silica-filled rubbers is higher than that of carbon black-filled rubbers.View full abstractDownload PDF (1482K) -
Part4, Proposal of a New Concept for the Carbon Black ReinforcementYoshihide FUKAHORI2004 Volume 77 Issue 5 Pages 180-185
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThe author proposes a new concept with a new interface model for carbon black reinforcement of elastomers, based on stress analysis. A new model consists of double uncross-linked polymer layers of different molecular mobility, the inner glassy hard(GH) layer and the outer sticky hard(SH) layer surrounding a carbon particle.
Large stress increase with filler content and with increasing strain amplitude results from the strong stress concentration generated around carbon particles and its transmission to the whole system. The great increase of tensile stress is only possible when the stress-hardened super structure produced in the SH layer under large extension supports the large stress concentration. The super structure is the network of carbon particles interconnected by strands of oriented molecules, which is formed through a craze-like phenomenon in accordance with micro-voids formation.
A large part of Mullins effect results from the buckling of the strand of riented molecules. Thus, the large and instant stress reduction takes place in unloading. At long periods, the extended molecules in the uncross-linked SH layer will considerably relax and return to its original state.View full abstractDownload PDF (1974K) -
4. Morphological Analysis at Peeling PSA Tapes-Part 2Yoshiaki URAHAMA2004 Volume 77 Issue 5 Pages 186-191
Published: 2004
Released on J-STAGE: May 28, 2007
JOURNAL FREE ACCESSThe unknown factors governing interfacial separation in cross-linked polymer adhesives at low pulling rates as demonstrated by their stringiness phenomenon are investigated.
Cohesive failure and adhesive/substrate interfacial separation of uncross-linked polymer adhesives have been adequately explained. However, in lightly cross-linked polymer adhesives, where cohesive failure cannot occur because there is no viscous flow, there are two regions of interfacial separation at low rate and this phenomena cannot be readily explained by present viscoelastic theories.
Investigation of the stringiness phenomenon of peeling pressure-sensitive adhesive tapes at constant loads shows that two peeling speeds exist for any peeling load up to the vicinity of 200g/25mm. Also it is clear that stringiness structure differs greatly at each peeling speed. The stringiness phenomenon of each of these two regions is analyzed using Miyagi's observation apparatus. These two measurements are then reversed and a comparison shows that the two peeling speeds correspond to each steady peeling region.
This field of investigation, when added to the present viscoelastic property studies should lead to a new peeling adhesive theory, which in turn will lead to the development of new high peel force pressure-sensitive adhesives.View full abstractDownload PDF (1279K)
- |<
- <
- 1
- >
- >|