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Predecessor
Volume 81, Issue 8
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2008 Volume 81 Issue 8 Pages 184
Published: 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSDownload PDF (2214K) -
Yoichiro WATANABE, Hidetoshi HIRAHARA, Masashi NEMOTO, Kazuhisa TAKAGI ...2008 Volume 81 Issue 8 Pages 317-322
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSContinuous open cell elastomer sheets were prepared by immersing continuous open cell polymer compounds in hot water, which are obtained by the extrusion and injection of thermoplastic elastomers, pentaerythritol (PETH), polypropylene (PP) and polytetrafluoroethylene (A-PTFE) modified by methyl methacrylate. A styrene-isoprene block copolymer (PSt-E), thermoplastic elastomer, was used as a main polymer in the compounds, giving strength, shock absorptivity and water resistance to the sheets. PETH was added as an open cell forming agent in the compounds, giving continuous open cell to the sheets obtained by immersing the compounds in hot water. The addition of 10phr of PP was effective for decreasing the linear shrinkage of the sheets in the process of the extraction of PETH from the compounds. The addition of 5phr of A-PTFE was also effective for improving the melting tension of the compounds at a molding temperature and the sheeting properties such as roughness, checking, crack, end tear. Molding temperature range of 180 to 230°C was very effective for giving good sheet properties and air flow rate, at which PSt-E and PETH are blended smoothly and continuous open cells were obtained. An extrusion molding gave better continuous open cell elastomer sheets in the point of air flow rate and open cell diameter than an injection molding.View full abstractDownload PDF (9319K) -
Fei SHEN, Xiao-fang YUAN, Wei-hong GUO, Hideshi YANAGI, Chi-fei WU2008 Volume 81 Issue 8 Pages 323-328
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSA novel vulcanization method, vulcanization through metal coordination crosslinking, is developed. In this method copper sulfate (CuSO4) particles are simply incorporated into acrylonitrile-butadiene rubber (NBR), and no other vulcanizing agent nor additional additives are involved. It is totally different from traditional covalent or non-covalent vulcanization approaches of rubber. The crosslinking of CuSO4 particles filled NBR was induced by in situ coordination between nitrogen atoms of nitrile groups (-CN) and copper ions (Cu2+) from CuSO4. Several factors including heating temperature and time, the contents of CuSO4 and nitrile groups were investigated in this paper. The generation of a core (CuSO4 solid particle) -shell (adherent NBR) structure leads to the excellent mechanical properties of the coordination vulcanizates.View full abstractDownload PDF (3504K) -
Shuichi AKASAKA, Jun HASEGAWA, Takashi AKASAKA2008 Volume 81 Issue 8 Pages 329-333
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSIt is well-known that the rubber-coated roll occurs abnormal vibration, when operating roll speed of rotation becomes higher than the critical speed. We investigated the vibration of the rubber-coated roll from the view point of a standing wave generated on the rubber surface. The limit curve to occur the standing wave was derived by using approximation technique. Moreover, we solved the relationship between the occurrence conditions of the vibration and parameters of rubber coated roll. The standing wave is easier to occur, as tan δ becomes lower and rubber thickness relative to the diameter of roll core increases. The wave number of occurred standing wave becomes greatly lower with increasing the operating speed of the roll.View full abstractDownload PDF (3375K) -
Mikihito TAKENAKA, Shotaro NISHITSUJI, Naoya AMINO, Yasuhiro ISHIKAWA, ...2008 Volume 81 Issue 8 Pages 334-338
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSThe polymer layers adsorbed on silica particles in rubber-silica systems have investigated with contrast variation small-angle neutron scattering (SANS) method. Specimens were swollen by the solvents having various scattering length densities, and their scattering intensities were measured. The contrast variation SANS for the specimens yielded partial scattering functions: the scattering function for polymer-polymer correlation SPP(q), the scattering function for silica- silica correlation SSS(q), and the scattering function for polymer- silica correlation SPS(q). SSS(q) reflects hierarchical structures formed by silica particles. The analyses of SPS(q) and SSS(q) explored the existence of dense polymer layers around silica aggregates. Several characteristic parameters such as the size of aggregates, the thickness of layers, the volume fractions of polymer of layers and matrix, and the correlation length of the matrix network are estimated from the analyses. The contrast variation SANS is found to be a powerful tool of the analyses of the structures of the rubber-filler systems.View full abstractDownload PDF (7177K) -
Hideaki ICHISE, Mutsuhisa FURUKAWA2008 Volume 81 Issue 8 Pages 339-345
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSEffects of hard segment content on the mechanical and thermal properties of liquefied wood (LW) based polyurethanes (PUs) were studied. LW was prepared from Hinoki cypress (Chamaecyparis obtusa) wood meal using poly (oxyethylene) glycol as a liquefaction solvent. PUs with various hard segment content were prepared from LW as a polyol, polymeric diphenyl methane diisocyanate (pMDI) or hexamethylene diisocyanate (HDI) and 1, 4-butanediol using a one-shot method in bulk state. Gel fraction of pMDI based PUs exceeded over 94%, while that of HDI based PUs was about 43-46%. Glass transition temperature (Tg) and peak temperature of loss tangent (Tα) of pMDI based PUs drastically increased with increasing hard segment content. However, Tg and Tα of HDI based PUs increased slightly. These results suggest that pMDI based PUs had microphase mixing, but HDI based PUs had microphase separation. The degradation initiation temperature (Ts) of HDI based PUs increased with increasing hard segment content. However, there was no clear relation between Ts of pMDI based PUs and hard segment content. Tensile strength and Young's modulus of PUs increased with increasing hard segment content, respectively. Elongation at break of PUs decreased with increasing hard segment content.View full abstractDownload PDF (2722K) -
Naoya AMINO, Yoshitaka UCHIYAMA, Tomoaki IWAI2008 Volume 81 Issue 8 Pages 346-350
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSWear properties of silica-filled SBR and three kinds of carbon black-filled SBRs were investigated. The wear volume of rubber was measured when rubber specimens were rubbed against metal gauze using a pin-on-cylinder type tribometer.
The coefficient of friction consists of adhesion component of friction, μA and hysteresis component of friction, μH. The adhesion component of friction is given by μA=A·s/W, where A is contact area, s is shear strength, W is applied load. It is thought that the wear volume depends on friction energy dissipated.
In this paper the wear volume per unit friction energy K/μA was compared with the energy density at break U. It is found that K/μA and 1/U showed linear correlation for the carbon black-filled SBRs, while the silica-filled SBR showed higher K/μA value compared to that of the carbon black-filled SBRs.View full abstractDownload PDF (6663K) -
Ken Nakajima2008 Volume 81 Issue 8 Pages 351-352
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSDownload PDF (3092K) -
[in Japanese]2008 Volume 81 Issue 8 Pages 356
Published: August 15, 2008
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSDownload PDF (2503K)
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