The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Susumu Tate - One of the best experts on this subject based on the ideXlab platform.
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Swollen-State Polymerization of poly(ethylene terephthalate) : kinetic analysis of reaction rate and Polymerization conditions
Polymer, 1995Co-Authors: Susumu Tate, Futoshi IshimaruAbstract:Ultra-high-molecular-weight poly(ethylene terephthalate) (UHMW-PET) with an intrinsic viscosity exceeding 2 dl g −1 ( M n ≈ 1.1 × 10 5 ) was obtained by swollen-State Polymerization with hydrogenated terphenyl as the solvent. The rate of swollen-State Polymerization was described well by Tomita's kinetics for a melt-phase polycondensation reaction. This suggested that there was no essential difference in the kinetics between swollen-State Polymerization and conventional melt-phase Polymerization. The activation energy of swollen-State Polymerization obtained was 21 kcal mol −1 , similar to that of conventional melt-phase Polymerization (23 kcal mol −1 ). Other Polymerization conditions, that is, the particle size of the starting PET, the flow rate of inert gas and the ratio of solvent to PET, are related to the rate of swollen-State Polymerization. Compared with the rate constants of conventional Polymerization methods such as melt-phase Polymerization and solid-State Polymerization, the propagation rate of swollen-State Polymerization was about three to five times faster than that of solid-State Polymerization at 220 °C, whereas the rate constant of the degradation reaction in the swollen State was of the same order as that in the solid State. These rate effects have resulted in UHMW-PET.
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Swollen-State Polymerization of poly(ethylene terephthalate) in fibre form
Polymer, 1995Co-Authors: Susumu Tate, Yhoichi WatanabeAbstract:Abstract The swollen-State Polymerization of poly(ethylene terephthalate) in fibre form was performed in hydrogenated terphenyl as the swelling solvent. Ultra-high-molecular-weight poly(ethylene terephthalate) (CHMW-PET) fibre with an intrinsic viscosity of 3–4dl g −1 ( M n = 2–3 × 10 5 ) was obtained. The Polymerization rate of as-spun PET fibres in the swollen State was greater than that of PET granules in the swollen State. It was clarified that the Polymerization rate was related to the chain mobility of the starting materials. The chain mobility was influenced by various conditions, such as changing rigidity of the segments during coPolymerization, the chain orientation of the starting fibre before swollen-State Polymerization and the temperature of pretreatment with the solvent. Pretreatment with solvent before Polymerization was effective in increasing the chain mobility. The relation between chain mobility and Polymerization rate was examined by wide-angle X-ray diffraction, density, differential scanning calorimetry, solvent content and viscoelastic measurements. Undrawn UHMW-PET fibres could be drawn 10 times or more by the zone drawing technique in spite of their high crystallinity, and the drawn fibre showed high tensile strength (12 g d −1 ) and high modulus (240 g d −1 ).
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Synthesis of ultra-high molecular weight poly(ethylene terephthalate) by swollen-State Polymerization
Polymer, 1993Co-Authors: Susumu Tate, Yhoichi Watanabe, Akira ChibaAbstract:Abstract A new Polymerization technique for ultra-high molecular weight poly(ethylene terephthalate) (UHMW-PET) has been developed. UHMW-PET was obtained by swollen-State Polymerization in specific solvents under bubbling nitrogen gas at atmospheric pressure. Suitable solvents for the swollen-State Polymerization were those that could swell PET but did not dissolve it. Solvents having a similar solubility parameter to PET were desirable for attaining higher ultimate intrinsic viscosity at the same Polymerization temperature. The rate of swollen-State Polymerization was strongly related to the degree of swelling, that is, the content of impregnated solvent in swollen PET. When a hydrogenated terphenyl was used as the solvent, UHMW-PET with an intrinsic viscosity of 2–3 dl g −1 was obtained, and a honeycomb-like structure was observed in the UHMW-PET particles.
Shuji Okada - One of the best experts on this subject based on the ideXlab platform.
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Solid-State Polymerization of 1,4-bis(hexatriynyl)benzene derivatives
Polymer Journal, 2018Co-Authors: Keita Sasamura, Yoko Tatewaki, Kei Mizuguchi, Shuji OkadaAbstract:Two 1,4-bis(hexatriynyl)benzene derivatives with urethane groups, i.e., 10,10′-(1,4-phenylene)bis(5,7,9-decatriynyl N -(butoxycarbonylmethyl)carbamate) 1 and its perfluorophenylene derivative 2 , were synthesized, and their solid-State photoPolymerization was investigated. Upon UV irradiation, both of them showed excitonic absorption characteristic of polydiacetylene (PDA). In particular, 2 showed an absorption maximum at 743 nm, which was approximately 100 nm longer than that of conventional PDAs because of the effective conjugation between the polymer backbone and π-conjugated substituents. The conversion of 1 to the corresponding polymer was quite low. On the other hand, more than half of the hexatriynyl moieties of 2 were found to polymerize, indicating that most of the monomers were converted to the polymer upon prolonged UV irradiation. 10,10′-(1,4-Phenylene)bis(5,7,9-decatriynyl N -(butoxycarbonylmethyl)carbamate) 1 and its perfluorophenylene derivative 2 were synthesized. Upon UV irradiation, both of them showed excitonic absorption of polydiacetylene. In particular, 2 showed an absorption maximum at 743 nm, which was approximately 100 nm longer than that of conventional polydiacetylenes, and its solid-State Polymerization scheme was investigated.
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thermal solid State Polymerization of a divalent metal salt of an unsaturated carboxylic acid and the effects of additives
Polymer Journal, 2013Co-Authors: Junki Tsuchida, Shuji Okada, Yoko Tatewaki, Satoshi Inayama, Yosuke Saito, Saki Sato, Ushio Yuki, Ayaka Shindo, Chiemi Mikura, Kazuhisa FushiharaAbstract:Thermal solid-State Polymerization of zinc diacrylate (ZDA) alone and with additives, such as diphenyl disulfide (DPDS) and thiophenol (TP) derivatives and dicumyl peroxide (DCP), was investigated. The solid-State Polymerization of ZDA was confirmed to be non-topochemical, and the main polymer structure was found to be polyacrylate with acrylate or polyacrylate connected by Zn2+ although a part of the monomer structure was eliminated during the Polymerization. The Polymerization rates were estimated by conversion from ZDA to its polymer, which was determined gravimetrically. The qualitative order of the Polymerization rate was ZDA
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Thermal solid-State Polymerization of a divalent metal salt of an unsaturated carboxylic acid and the effects of additives
Polymer Journal, 2013Co-Authors: Junki Tsuchida, Shuji Okada, Yoko Tatewaki, Satoshi Inayama, Yosuke Saito, Saki Sato, Ushio Yuki, Ayaka Shindo, Chiemi Mikura, Kazuhisa FushiharaAbstract:Thermal solid-State Polymerization of zinc diacrylate (ZDA) alone and with additives, such as diphenyl disulfide (DPDS) and thiophenol (TP) derivatives and dicumyl peroxide (DCP), was investigated. The solid-State Polymerization of ZDA was confirmed to be non-topochemical, and the main polymer structure was found to be polyacrylate with acrylate or polyacrylate connected by Zn^2+ although a part of the monomer structure was eliminated during the Polymerization. The Polymerization rates were estimated by conversion from ZDA to its polymer, which was determined gravimetrically. The qualitative order of the Polymerization rate was ZDA
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Radical-initiator-Induced solid-State Polymerization of butadiyne nanocrystals in water and their dispersion stabilization.
Journal of Nanoscience and Nanotechnology, 2011Co-Authors: Shuhei Kato, Takahiro Kinemuchi, Akito Masuhara, Shuji Okada, Yoko Tatewaki, Hitoshi Kasai, Hidetoshi OikawaAbstract:: Butadiyne nanocrystals in water are usually polymerized by UV or gamma-ray irradiation to give polydiacetylene (PDA) nanocrystals. In this study, we confirmed that solid-State Polymerization of 1,6-di(N-carbazolyl)-2,4-hexadiyne (DCHD) and 5,7-dodecadiyn-1,12-diyl bis[N-(butoxycarbonyl-methyl)carbamate] (4BCMU) could be stimulated by water-soluble radical initiators. The radical initiators used were potassium peroxodisulfate, three kinds of azo-type compounds and a redox initiator. In all cases, the solid-State Polymerization was confirmed by color change into blue indicating that PDA modified by the radical residues at the end was formed. However, nanocrystal cohesion occurred especially when the concentration of the initiators was high or the dispersion was kept for a long time. In order to improve the dispersion stability, two kinds of surfactants, i.e., sodium dodecyl sulfate (SDS) or dodecyltrimethylammonium chloride (DTMAC), were added to the DCHD nanocrystal aqueous dispersion. As a result, when anionic SDS was added, the solid-State Polymerization of nanocrystals proceeded without coagulation and quantitative conversion was confirmed for all initiators. Cationic DTMAC has no effect on dispersion stabilization. PDA nanocrystal surfaces in water are negatively charged in nature and electric interaction of nanocrystals with the cations results in decrease of surface charge and aggregation of nanocrystals.
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Solid-State Polymerization of conjugated hexayne derivatives with different end groups
Polymer Journal, 2010Co-Authors: Satoshi Inayama, Yoko Tatewaki, Shuji OkadaAbstract:10,12,14,16,18,20-Triacontahexayne-1,30-diol and its diphenylurethane and diphenylester were synthesized, and their solid-State Polymerization behaviors were investigated. The regular two-step solid-State Polymerization was confirmed for the diphenylurethane derivative. Three hexayne derivatives with different end groups—that is, 10,12,14,16,18,20-triacontahexayne-1,30-diol ( 1 ) and its diphenylurethane ( 2 ) and diphenylester ( 3 )—were synthesized, and their solid-State Polymerization behaviors were investigated. All three monomers were thermally polymerizable. Polymers from 1 and 2 showed an absorption maximum at about 730 nm, indicating that linear polydiacetylenes (PDAs) with octatetraynyl substituents were synthesized. However, broad absorption bands in the near-infrared region were only observed for 2 at 980 and 860 nm, indicating that regular Polymerization occurred in 2 to give ladder-type PDA. On the other hand, a polymer from 3 showed a visible absorption increase but no clear absorption maximum. It was estimated that intermolecular hydrogen bonding between hexayne monomers helps to form polymerizable stacks in 1 and 2 . In particular, urethane groups are more effective, and 2 showed the highest reactivity in this study with an ordered interlayer structure even after a two-step solid-State Polymerization to give ladder-type PDA.
Joseph M. Desimone - One of the best experts on this subject based on the ideXlab platform.
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Reaction Kinetics of the Solid State Polymerization of Poly(bisphenol A carbonate)
Macromolecules, 2001Co-Authors: Chunmei Shi, Stephen M. Gross, Douglas J. Kiserow, Joseph M. Desimone, George W. RobertsAbstract:The kinetics of solid-State Polymerization (SSP) of poly(bisphenol A carbonate) was investigated with N2 as the sweep gas. The N2 flow rate and prepolymer particle size were chosen to eliminate the...
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Synthesis of High Molecular Weight Polycarbonate by Solid-State Polymerization
Macromolecules, 2001Co-Authors: Stephen M. Gross, George W. Roberts, Douglas J. Kiserow, Joseph M. DesimoneAbstract:The solid-State Polymerization (SSP) of small particles (20 μm) of poly(bisphenol A carbonate) resulted in high molecular weight material (Mw of 36 000 g/mol). Molecular weight distribution broaden...
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Solid-State Polymerization of Polycarbonates Using Supercritical CO2
Macromolecules, 1999Co-Authors: Stephen M. Gross, Devin Flowers, George W. Roberts, Douglas J. Kiserow, Joseph M. DesimoneAbstract:We report the extension of the crystallization process with supercritical CO 2 to granules or beads of low molecular weight polycarbonate in an effort to create a material that can undergo slid-State Polymerization without using toxic organic solvents
Kazuhisa Fushihara - One of the best experts on this subject based on the ideXlab platform.
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thermal solid State Polymerization of a divalent metal salt of an unsaturated carboxylic acid and the effects of additives
Polymer Journal, 2013Co-Authors: Junki Tsuchida, Shuji Okada, Yoko Tatewaki, Satoshi Inayama, Yosuke Saito, Saki Sato, Ushio Yuki, Ayaka Shindo, Chiemi Mikura, Kazuhisa FushiharaAbstract:Thermal solid-State Polymerization of zinc diacrylate (ZDA) alone and with additives, such as diphenyl disulfide (DPDS) and thiophenol (TP) derivatives and dicumyl peroxide (DCP), was investigated. The solid-State Polymerization of ZDA was confirmed to be non-topochemical, and the main polymer structure was found to be polyacrylate with acrylate or polyacrylate connected by Zn2+ although a part of the monomer structure was eliminated during the Polymerization. The Polymerization rates were estimated by conversion from ZDA to its polymer, which was determined gravimetrically. The qualitative order of the Polymerization rate was ZDA
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Thermal solid-State Polymerization of a divalent metal salt of an unsaturated carboxylic acid and the effects of additives
Polymer Journal, 2013Co-Authors: Junki Tsuchida, Shuji Okada, Yoko Tatewaki, Satoshi Inayama, Yosuke Saito, Saki Sato, Ushio Yuki, Ayaka Shindo, Chiemi Mikura, Kazuhisa FushiharaAbstract:Thermal solid-State Polymerization of zinc diacrylate (ZDA) alone and with additives, such as diphenyl disulfide (DPDS) and thiophenol (TP) derivatives and dicumyl peroxide (DCP), was investigated. The solid-State Polymerization of ZDA was confirmed to be non-topochemical, and the main polymer structure was found to be polyacrylate with acrylate or polyacrylate connected by Zn^2+ although a part of the monomer structure was eliminated during the Polymerization. The Polymerization rates were estimated by conversion from ZDA to its polymer, which was determined gravimetrically. The qualitative order of the Polymerization rate was ZDA
Yhoichi Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Swollen-State Polymerization of poly(ethylene terephthalate) in fibre form
Polymer, 1995Co-Authors: Susumu Tate, Yhoichi WatanabeAbstract:Abstract The swollen-State Polymerization of poly(ethylene terephthalate) in fibre form was performed in hydrogenated terphenyl as the swelling solvent. Ultra-high-molecular-weight poly(ethylene terephthalate) (CHMW-PET) fibre with an intrinsic viscosity of 3–4dl g −1 ( M n = 2–3 × 10 5 ) was obtained. The Polymerization rate of as-spun PET fibres in the swollen State was greater than that of PET granules in the swollen State. It was clarified that the Polymerization rate was related to the chain mobility of the starting materials. The chain mobility was influenced by various conditions, such as changing rigidity of the segments during coPolymerization, the chain orientation of the starting fibre before swollen-State Polymerization and the temperature of pretreatment with the solvent. Pretreatment with solvent before Polymerization was effective in increasing the chain mobility. The relation between chain mobility and Polymerization rate was examined by wide-angle X-ray diffraction, density, differential scanning calorimetry, solvent content and viscoelastic measurements. Undrawn UHMW-PET fibres could be drawn 10 times or more by the zone drawing technique in spite of their high crystallinity, and the drawn fibre showed high tensile strength (12 g d −1 ) and high modulus (240 g d −1 ).
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Synthesis of ultra-high molecular weight poly(ethylene terephthalate) by swollen-State Polymerization
Polymer, 1993Co-Authors: Susumu Tate, Yhoichi Watanabe, Akira ChibaAbstract:Abstract A new Polymerization technique for ultra-high molecular weight poly(ethylene terephthalate) (UHMW-PET) has been developed. UHMW-PET was obtained by swollen-State Polymerization in specific solvents under bubbling nitrogen gas at atmospheric pressure. Suitable solvents for the swollen-State Polymerization were those that could swell PET but did not dissolve it. Solvents having a similar solubility parameter to PET were desirable for attaining higher ultimate intrinsic viscosity at the same Polymerization temperature. The rate of swollen-State Polymerization was strongly related to the degree of swelling, that is, the content of impregnated solvent in swollen PET. When a hydrogenated terphenyl was used as the solvent, UHMW-PET with an intrinsic viscosity of 2–3 dl g −1 was obtained, and a honeycomb-like structure was observed in the UHMW-PET particles.
