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Hironori Kaji - One of the best experts on this subject based on the ideXlab platform.
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Distribution ratio of carbon black in polyisobutyrene/Polyisoprene Rubber blends using high-resolution solid-state ^13C NMR
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:We attempted to estimate the distribution ratio of carbon black (CB) in blends of polyisobutyrene Rubber and Polyisoprene Rubber using high-resolution solid-state ^13C nuclear magnetic resonance (NMR). Our NMR analysis revealed that, in polyisobutyrene Rubber/Polyisoprene Rubber/CB composites, CB more easily distributes in Polyisoprene Rubber than in polyisobutyrene Rubber. We found that more than 70% of CB is distributed into the Polyisoprene Rubber phase. The sum of the amounts of CB in both the polyisobutyrene Rubber and Polyisoprene Rubber phases estimated by our method using ^13C NMR closely corresponds with the amount of CB originally added to the compound, verifying the validity of the NMR method. Further, we observed the distribution of CB in polyisobutyrene/Polyisoprene Rubber blends using transmission electron microscopy and the Carbon-Black-Gel method, which can only be used for unvulcanized Rubber blends, for comparison. The results obtained using these three methods show similar tendencies, which confirms the accuracy of this method of using ^13C NMR to determine CB distribution in Rubber blends. We establish the ^13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in Rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene Rubber (IIR)/Polyisoprene Rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
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distribution ratio of carbon black in polyisobutyrene Polyisoprene Rubber blends using high resolution solid state 13 c nmr
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:We establish the 13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in Rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene Rubber (IIR)/Polyisoprene Rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
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Erratum: Distribution ratio of carbon black in polyisobutyrene/Polyisoprene Rubber blends using high-resolution solid-state ^13C NMR
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:Correction to: Polymer Journal advance online publication, 18 February 2015; doi:10.1038/pj.2015.3 After online publication of this article and its graphical abstract, the authors noticed an error in the graphical abstract. The error has now been rectified, and the corrected graphical abstract appears in this issue.
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Distribution ratio of carbon black in polyisobutyrene/Polyisoprene Rubber blends using high-resolution solid-state 13 C NMR
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:We establish the 13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in Rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene Rubber (IIR)/Polyisoprene Rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
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characterization of carbon filler distribution ratio in Polyisoprene polybutadiene Rubber blends by high resolution solid state 13c nmr
Macromolecules, 2007Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:The distribution ratio of carbon black (CB) in a blend of Polyisoprene Rubber (IR) and polybutadiene Rubber (BR) is characterized using high-resolution solid-state 13C NMR. The relationships between the line width of the polymer's resonance lines and CB contents are estimated for both the IR/CB and BR/CB composites from the dipolar decoupling/magic angle spinning (DD/MAS) 13C NMR spectra. For the IR/CB composite, the IR line width increases with the increasing CB content. A similar relationship is obtained between the BR line width and CB contents for the BR/CB composite. These relationships are used as calibration curves. On the basis of these calibration curves, the distribution ratio of CB in the IR/BR Rubber blend is determined. It is found for the IR/BR/CB composite that the amount of CB in the BR phase is approximately twice as high as that of CB in the IR phase, irrespective of the CB content. The sum of the amounts of CB in both the IR and BR phases, determined from the above 13C NMR experiments, ...
Shinzo Kohjiya - One of the best experts on this subject based on the ideXlab platform.
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Probing the Nature of Strain-Induced Crystallization in Polyisoprene Rubber by Combined Thermomechanical and In Situ X-ray Diffraction Techniques
Macromolecules, 2005Co-Authors: Shigeyuki Toki, Masaya Tosaka, Igors Sics, Benjamin S. Hsiao, Sirilux Poompradub, Yuko Ikeda, Shinzo KohjiyaAbstract:The nature of strain-induced crystallization in vulcanized Polyisoprene Rubbers was investigated by in situ synchrotron wide-angle X-ray diffraction under varying thermomechanical conditions. In particular, the methods of constrained cooling and constrained heating under constant strain were used to explore the relationships between the strain-induced crystalline network and corresponding stress. It was found that constrained cooling resulted in a large reduction of stress and a notable increase in the amount of strain-induced crystallites, while constrained heating led to an initial increase in stress and subsequent melting of strain-induced crystallites. Results indicate that strain-induced crystallization induces a new network structure, which reinforces the chemical network points. However, the sulfur bridges in the chemical network points would break down at high temperatures under high strains, despite the existence of strain-induced crystalline network.
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Phase behavior of crosslinked Polyisoprene Rubber and supercritical carbon dioxide
The Journal of Supercritical Fluids, 2005Co-Authors: M Kojima, Masaya Tosaka, Eita Funami, Kouei Nitta, Masahiro Ohshima, Shinzo KohjiyaAbstract:Abstract The phase behavior of crosslinked Polyisoprene Rubber (PIR) in CO 2 at temperatures ranging from 293 to 453 K and pressures ranging from 0.1 to 20 MPa were investigated. Visual swelling measurements based on the sample dimensions were performed using a high-pressure view cell. The change of the degree of swelling with time provided a diffusion coefficient of CO 2 in crosslinked PIR. The solubility measurements were carried out by using a magnetic suspension balance (MSB) method. The weight change of the sample in CO 2 under elevated pressure and temperature was converted to solubility taking the buoyancy effect and the degree of swelling into account; the degree of swelling was derived both from the visual swelling measurement and from theoretical estimation on the basis of the Sanchez–Lacombe equation of state. The solubility from the two methods was in good agreement with each other in the range from 8 to 13 MPa.
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Devulcanization of Sulfur-Cured Isoprene Rubber in Supercritical Carbon Dioxide
Rubber Chemistry and Technology, 2003Co-Authors: M Kojima, H. Mizoshima, Masaya Tosaka, Shinzo Kohjiya, K. Ogawa, Y. IkedaAbstract:Abstract A new devulcanization process that utilizes supercritical CO2 (scCO2) along with devulcanizing reagents was studied. Unfilled Polyisoprene Rubber samples (vulcanizates) with different crosslink distributions were prepared by controlling the cure time and the curatives. Each of the vulcanizates was subjected to the Soxhlet extraction using azeotropic acetone/chloroform to remove residual curatives. The devulcanization was performed at various temperatures (140–200 °C) in the presence of scCO2 for 60 min. The product was fractionated into sol and gel components, and molecular weight of the sol component and the crosslink density of the gel component were determined. Thiol-amine reagent was found to be effective among several devulcanizing reagents; the molecular weight of the resulted sol component was about tens of thousands and the crosslink density of gel component decreased substantially from the initial ones. Yield of the sol component increased with the increase in the CO2 pressure. In the su...
Benjamin S. Hsiao - One of the best experts on this subject based on the ideXlab platform.
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Crystal and Crystallites Structure of Natural Rubber and Synthetic cis- 1,4-Polyisoprene by a New Two Dimensional Wide Angle X‑ray Diffraction Simulation Method. I. Strain-Induced Crystallization
Macromolecules, 2013Co-Authors: Justin Che, Shigeyuki Toki, Benjamin S. Hsiao, Christian Burger, Lixia Rong, Sureerut Amnuaypornsri, Jitladda SakdapipanichAbstract:A novel two-dimensional simulation method to analyze a wide-angle X-ray diffraction (WAXD) pattern is applied to crystal and crystallites of strain-induced crystallization (SIC) of unvulcanized natural Rubber (NR) and synthetic Polyisoprene Rubber (IR) at −50 °C. The unit cell dimensions of SIC were determined by calculation of scattering factors based on atomic coordinates and symmetry, and were compared with the observed data. The unit cell dimensions are the same in NR and IR, and do not change during extension. The crystallites’ dimensions in NR and IR are almost the same at −50 C. The orientation of crystallites in NR is lower than in IR. The order of crystals in NR is lower than in IR. The crystalline fraction increases with strain because of the increase in the number of crystallites. The onset strain of SIC in NR is smaller than the one in IR. The different behaviors of SIC in NR and IR seem to be caused by the pseudonetwork of NR.
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Probing the Nature of Strain-Induced Crystallization in Polyisoprene Rubber by Combined Thermomechanical and In Situ X-ray Diffraction Techniques
Macromolecules, 2005Co-Authors: Shigeyuki Toki, Masaya Tosaka, Igors Sics, Benjamin S. Hsiao, Sirilux Poompradub, Yuko Ikeda, Shinzo KohjiyaAbstract:The nature of strain-induced crystallization in vulcanized Polyisoprene Rubbers was investigated by in situ synchrotron wide-angle X-ray diffraction under varying thermomechanical conditions. In particular, the methods of constrained cooling and constrained heating under constant strain were used to explore the relationships between the strain-induced crystalline network and corresponding stress. It was found that constrained cooling resulted in a large reduction of stress and a notable increase in the amount of strain-induced crystallites, while constrained heating led to an initial increase in stress and subsequent melting of strain-induced crystallites. Results indicate that strain-induced crystallization induces a new network structure, which reinforces the chemical network points. However, the sulfur bridges in the chemical network points would break down at high temperatures under high strains, despite the existence of strain-induced crystalline network.
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Molecular orientation and structural development in vulcanized Polyisoprene Rubbers during uniaxial deformation by in situ synchrotron X-ray diffraction
Polymer, 2003Co-Authors: Shigeyuki Toki, Igors Sics, Shaofeng Ran, Lizhi Liu, Benjamin S. HsiaoAbstract:Abstract Molecular orientation and strain-induced crystallization of vulcanized natural Rubbers (by sulfur and peroxide) and synthetic Polyisoprene Rubber (by sulfur) during uniaxial deformation at 0 °C were studied by in situ synchrotron wide-angle X-ray diffraction. The high intensity of synchrotron X-rays and new image analysis methods made it possible to estimate the mass fractions of strain-induced crystals and amorphous chains in both oriented and unoriented states. Most of the polymer chains (∼75%) were found to be in the random coil state even at large strains (>5.0). Only about 5% the amorphous chains were oriented, whereas the rest of the chains (∼20%) were in the crystalline phase. Sulfur vulcanized and peroxide vulcanized natural Rubbers did not exhibit notable differences in structure and property relationships. In contrast, synthetic Polyisoprene Rubber showed a different behavior of deformation-induced structural changes, which can be attributed to the difference in cross-link topology. Our results indicated that strain induces a network of microfibrillar crystals in both natural and synthetic Polyisoprene Rubbers due to the inhomogeneity of cross-link distribution that is responsible for their elastic properties.
Shigeyuki Toki - One of the best experts on this subject based on the ideXlab platform.
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Crystal and Crystallites Structure of Natural Rubber and Synthetic cis- 1,4-Polyisoprene by a New Two Dimensional Wide Angle X‑ray Diffraction Simulation Method. I. Strain-Induced Crystallization
Macromolecules, 2013Co-Authors: Justin Che, Shigeyuki Toki, Benjamin S. Hsiao, Christian Burger, Lixia Rong, Sureerut Amnuaypornsri, Jitladda SakdapipanichAbstract:A novel two-dimensional simulation method to analyze a wide-angle X-ray diffraction (WAXD) pattern is applied to crystal and crystallites of strain-induced crystallization (SIC) of unvulcanized natural Rubber (NR) and synthetic Polyisoprene Rubber (IR) at −50 °C. The unit cell dimensions of SIC were determined by calculation of scattering factors based on atomic coordinates and symmetry, and were compared with the observed data. The unit cell dimensions are the same in NR and IR, and do not change during extension. The crystallites’ dimensions in NR and IR are almost the same at −50 C. The orientation of crystallites in NR is lower than in IR. The order of crystals in NR is lower than in IR. The crystalline fraction increases with strain because of the increase in the number of crystallites. The onset strain of SIC in NR is smaller than the one in IR. The different behaviors of SIC in NR and IR seem to be caused by the pseudonetwork of NR.
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Probing the Nature of Strain-Induced Crystallization in Polyisoprene Rubber by Combined Thermomechanical and In Situ X-ray Diffraction Techniques
Macromolecules, 2005Co-Authors: Shigeyuki Toki, Masaya Tosaka, Igors Sics, Benjamin S. Hsiao, Sirilux Poompradub, Yuko Ikeda, Shinzo KohjiyaAbstract:The nature of strain-induced crystallization in vulcanized Polyisoprene Rubbers was investigated by in situ synchrotron wide-angle X-ray diffraction under varying thermomechanical conditions. In particular, the methods of constrained cooling and constrained heating under constant strain were used to explore the relationships between the strain-induced crystalline network and corresponding stress. It was found that constrained cooling resulted in a large reduction of stress and a notable increase in the amount of strain-induced crystallites, while constrained heating led to an initial increase in stress and subsequent melting of strain-induced crystallites. Results indicate that strain-induced crystallization induces a new network structure, which reinforces the chemical network points. However, the sulfur bridges in the chemical network points would break down at high temperatures under high strains, despite the existence of strain-induced crystalline network.
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Molecular orientation and structural development in vulcanized Polyisoprene Rubbers during uniaxial deformation by in situ synchrotron X-ray diffraction
Polymer, 2003Co-Authors: Shigeyuki Toki, Igors Sics, Shaofeng Ran, Lizhi Liu, Benjamin S. HsiaoAbstract:Abstract Molecular orientation and strain-induced crystallization of vulcanized natural Rubbers (by sulfur and peroxide) and synthetic Polyisoprene Rubber (by sulfur) during uniaxial deformation at 0 °C were studied by in situ synchrotron wide-angle X-ray diffraction. The high intensity of synchrotron X-rays and new image analysis methods made it possible to estimate the mass fractions of strain-induced crystals and amorphous chains in both oriented and unoriented states. Most of the polymer chains (∼75%) were found to be in the random coil state even at large strains (>5.0). Only about 5% the amorphous chains were oriented, whereas the rest of the chains (∼20%) were in the crystalline phase. Sulfur vulcanized and peroxide vulcanized natural Rubbers did not exhibit notable differences in structure and property relationships. In contrast, synthetic Polyisoprene Rubber showed a different behavior of deformation-induced structural changes, which can be attributed to the difference in cross-link topology. Our results indicated that strain induces a network of microfibrillar crystals in both natural and synthetic Polyisoprene Rubbers due to the inhomogeneity of cross-link distribution that is responsible for their elastic properties.
Marina Kotani - One of the best experts on this subject based on the ideXlab platform.
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Distribution ratio of carbon black in polyisobutyrene/Polyisoprene Rubber blends using high-resolution solid-state ^13C NMR
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:We attempted to estimate the distribution ratio of carbon black (CB) in blends of polyisobutyrene Rubber and Polyisoprene Rubber using high-resolution solid-state ^13C nuclear magnetic resonance (NMR). Our NMR analysis revealed that, in polyisobutyrene Rubber/Polyisoprene Rubber/CB composites, CB more easily distributes in Polyisoprene Rubber than in polyisobutyrene Rubber. We found that more than 70% of CB is distributed into the Polyisoprene Rubber phase. The sum of the amounts of CB in both the polyisobutyrene Rubber and Polyisoprene Rubber phases estimated by our method using ^13C NMR closely corresponds with the amount of CB originally added to the compound, verifying the validity of the NMR method. Further, we observed the distribution of CB in polyisobutyrene/Polyisoprene Rubber blends using transmission electron microscopy and the Carbon-Black-Gel method, which can only be used for unvulcanized Rubber blends, for comparison. The results obtained using these three methods show similar tendencies, which confirms the accuracy of this method of using ^13C NMR to determine CB distribution in Rubber blends. We establish the ^13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in Rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene Rubber (IIR)/Polyisoprene Rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
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distribution ratio of carbon black in polyisobutyrene Polyisoprene Rubber blends using high resolution solid state 13 c nmr
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:We establish the 13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in Rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene Rubber (IIR)/Polyisoprene Rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
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Erratum: Distribution ratio of carbon black in polyisobutyrene/Polyisoprene Rubber blends using high-resolution solid-state ^13C NMR
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:Correction to: Polymer Journal advance online publication, 18 February 2015; doi:10.1038/pj.2015.3 After online publication of this article and its graphical abstract, the authors noticed an error in the graphical abstract. The error has now been rectified, and the corrected graphical abstract appears in this issue.
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Distribution ratio of carbon black in polyisobutyrene/Polyisoprene Rubber blends using high-resolution solid-state 13 C NMR
Polymer Journal, 2015Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:We establish the 13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in Rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene Rubber (IIR)/Polyisoprene Rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.
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characterization of carbon filler distribution ratio in Polyisoprene polybutadiene Rubber blends by high resolution solid state 13c nmr
Macromolecules, 2007Co-Authors: Marina Kotani, Hidehiko Dohi, Hideaki Kimura, Kiyoshige Muraoka, Hironori KajiAbstract:The distribution ratio of carbon black (CB) in a blend of Polyisoprene Rubber (IR) and polybutadiene Rubber (BR) is characterized using high-resolution solid-state 13C NMR. The relationships between the line width of the polymer's resonance lines and CB contents are estimated for both the IR/CB and BR/CB composites from the dipolar decoupling/magic angle spinning (DD/MAS) 13C NMR spectra. For the IR/CB composite, the IR line width increases with the increasing CB content. A similar relationship is obtained between the BR line width and CB contents for the BR/CB composite. These relationships are used as calibration curves. On the basis of these calibration curves, the distribution ratio of CB in the IR/BR Rubber blend is determined. It is found for the IR/BR/CB composite that the amount of CB in the BR phase is approximately twice as high as that of CB in the IR phase, irrespective of the CB content. The sum of the amounts of CB in both the IR and BR phases, determined from the above 13C NMR experiments, ...