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Shuichi Nojima - One of the best experts on this subject based on the ideXlab platform.
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effects of crystal structure of poly β Propiolactone blocks on the cooperative crystallization of a polyethylene block poly β Propiolactone diblock copolymer
Polymer, 2017Co-Authors: Satoshi Osawa, Rei Hijikawa, Hironori Marubayashi, Shuichi NojimaAbstract:Abstract The crystalline morphology of a double crystalline polyethylene- block -poly(β-Propiolactone) diblock copolymer (PE- b -PPL) was examined using synchrotron small-angle X-ray scattering (SR-SAXS), where the PPL block crystallized into δ- or β-form according to the thermal history during sample preparation. Furthermore, the isothermal crystallization process of PE- b -PPL was pursued using simultaneous time-resolved SR-SAXS and wide-angle X-ray diffraction (SR-WAXD). The crystallization behavior of δPPL blocks (i.e., PPL blocks to crystallize into δ-form) was similar to that of PE blocks without any detectable induction time, so simultaneous crystallization of PE and δPPL blocks was observed on quenching from a lamellar microdomain structure (LMS), yielding a largely distorted LMS (with the standard deviation of each lamella thickness ∼ 36%). On the other hand, the βPPL blocks (i.e., PPL blocks to crystallize into β-form) started to crystallize after an appreciable induction time, showing sequential crystallization (i.e., advance crystallization of PE blocks and subsequent crystallization of βPPL blocks) to form a slightly distorted LMS (18%). Consequently, the final crystalline morphology was significantly different depending on the crystal structure of PPL blocks, though the crystallization started from an identical LMS. The crystallization mechanism of PE- b -PPL was discussed by considering the difference in crystallization kinetics between PE blocks and PPL (δPPL or βPPL) blocks.
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crystallization behavior of poly β Propiolactone block polyethylene copolymers with varying polyethylene crystallinities
Polymer, 2014Co-Authors: Rei Hijikawa, Liang Huang, Gaito Kiyofuji, Hironori Marubayashi, Shuichi NojimaAbstract:Abstract The crystallization behavior of poly(β-Propiolactone)- block -polyethylene (PPL- b -PE) copolymers with high PE crystallinities χ PE (>0.30) has been examined using time-resolved synchrotron small-angle X-ray scattering and Fourier transform infrared spectroscopy, where the PE block crystallized first and subsequently the PPL block crystallized on quenching from a strongly segregated melt. The crystallization of PE blocks destroyed the lamellar microdomain structure (LMS) existing in the melt to form the crystalline lamellar morphology (CLM), and then PPL blocks crystallized within CLM. This morphology formation was compared to our previous results for the crystallization of PPL- b -PE copolymers with low χ PE (0.12 χ PE χ PE = 0, and propose three mechanisms of morphology formation occurring in PPL- b -PE copolymers according to χ PE (i.e., high, low, or zero).
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isothermal crystallization of poly β Propiolactone blocks starting from lamellar microdomain structures of double crystalline poly β Propiolactone block polyethylene copolymers
Polymer, 2012Co-Authors: Liang Huang, Gaito Kiyofuji, Jun Matsumoto, Yasumasa Fukagawa, Cheng Gong, Shuichi NojimaAbstract:Abstract The isothermal crystallization behavior of poly(β-Propiolactone) (PPL) blocks starting from lamellar microdomain structures (LMS) formed in molten PPL- block -polyethylene (PPL- b -PE) copolymers has been examined using time-resolved synchrotron small-angle X-ray scattering and Fourier transform infrared spectroscopy as a function of the crystallinity of PE blocks χ PE . For getting PPL- b -PE copolymers with varying χ PE , the amount of ethyl branches in PE blocks was controlled during polymerization. The crystallizable temperature of PE blocks was slightly higher than that of PPL blocks and the crystallization rate of PE blocks was extremely fast, so the crystallization of PE blocks occurred first on quenching to form the crystallized LMS, in which the PPL block crystallized. The time evolution for the crystallinity of PPL blocks χ PPL showed an exponential-type increase with no induction time. In contrast, LMS was replaced with the crystallized lamellar morphology and χ PPL showed a sigmoidal time evolution in PPL- b -PE with a higher amount of ethyl branches, where the PE block did not crystallize ( i.e., χ PE = 0) prior to the crystallization of PPL blocks. It was concluded that the prompt crystallization of PE blocks just after quenching reinforced the existing LMS to make it stable against subsequent crystallization, yielding the confined crystallization of PPL blocks.
E. I. Budowsky - One of the best experts on this subject based on the ideXlab platform.
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principles of selective inactivation of viral genome viii the influence of β Propiolactone on immunogenic and protective activities of influenza virus
Vaccine, 1993Co-Authors: E. I. Budowsky, Yu A Smirnov, S F ShenderovichAbstract:The influence of beta-Propiolactone action on the immunogenic and protective activity of the influenza virus A/WSN/33 (H1N1) has been studied. The production of antibodies against virion surface antigens in mice immunized intramuscularly by the modified virus was enhanced with the increase of inoculating dose from 6 x 10(7) to 1.5 x 10(8) viral particles per animal. The immunizing dose of 6 x 10(7) produced complete protection of immunized animals against a lethal challenge of A/WSN/33 virus. The inhibition of virus reproduction in animal lungs was increased with the increase of the virus immunizing dose up to 6 x 10(8). At a constant dose the inhibition of virus reproduction decreases with the increase of the virus modification extent.
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principles of selective inactivation of viral genome v rational selection of conditions for inactivation of the viral suspension infectivity to a given extent by the action of β Propiolactone
Vaccine, 1991Co-Authors: E. I. Budowsky, M A ZalesskayaAbstract:Abstract The influence of the initial concentration of β-Propiolactone, the composition of the solution, temperature, and pH on the bacteriophage MS2 infectivity inactivation kinetics has been studied. Rate constants have been determined for the infectivity inactivation and for the change in the concentration (the consumption) of the reactant under inactivation conditions. These constants have been shown to permit a sufficiently precise description of the phage MS2 survival curves under the action of β-Propiolactone. These data have been used to put forward a kinetic approach for the rational determination of conditions for inactivation of the viral infectivity to a required extent with agents whose concentration decreases during inactivation as a result of hydrolysis and reactions involving the medium components.
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Principles of selective inactivation of viral genome. VI, Inactivation of the infectivity of the influenza virus by the action of β-Propiolactone
Vaccine, 1991Co-Authors: E. I. Budowsky, E. A. Friedman, N. V. Zheleznova, F S NoskovAbstract:The kinetics of inactivation of the infectivity of the influenza virus by beta-Propiolactone have been studied. Rate constants have been determined for inactivation of the A/Leningrad/385 (H3N2) and B/Leningrad/489/80 influenza virus under the action of beta-Propiolactone on a virus-containing allantoic fluid and on a purified viral suspension. The data obtained allow calculation of the time required for inactivation of the influenza virus infectivity to a given extent in virus-containing solutions at any initial concentration of beta-Propiolactone.
Shunzo Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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13c selective infrared multiple photon decomposition of β Propiolactone β butyrolactone and diketene with a co2 tea laser
Journal of Physical Chemistry A, 2000Co-Authors: Kyoko Sugita, Yoshiki Miyamoto, Shigeyoshi Arai, Shizuma Kuribayashi, Tetsuro Majima, Shunzo YamamotoAbstract:13C-Selective infrared multiple photon decomposition of lactone compounds has been studied using a CO2 TEA (transversely excited atmospheric) laser. The main decomposition products were ethylene and CO2 in β-Propiolactone. We obtained CO2 with a 13C atomic fraction of 55% in the irradiation of 2 Torr (1 Torr = 1 mmHg = 133.322 Pa) β-Propiolactone at 1035.47 cm-1. The addition of 100 Torr of N2 to 2 Torr of β-Propiolactone resulted in a remarkable increase in selectivity, i.e., 75% 13C in CO2, while the yield was considerably decreased. Respective olefinic products were propylene and allene in the multiple photon decompositions of β-butyrolactone and diketene. The common product CO2 was also found to be significantly enriched with 13C in these lactone compounds.
Graham Swift - One of the best experts on this subject based on the ideXlab platform.
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enzyme catalyzed stereoelective ring opening polymerization of α methyl β Propiolactone
Macromolecules, 1996Co-Authors: Yuri Y Svirkin, Richard A Gross, David L Kaplan, Graham SwiftAbstract:The lipase-catalyzed stereoelective ring-opening polymerization of racemic α-methyl-β-Propiolactone (MPL) was investigated. Using the lipase PS-30 from Pseudomonas fluorescens, a direct route to optically active (S)-enriched poly(α-methyl-β-Propiolactone), PMPL, was demonstrated. From a comparative study of different organic media, polymerizations conducted in toluene and heptane proceeded more rapidly than those carried out in dioxane. The enantiomeric ratios E in toluene, heptane, and dioxane were 4.1 ± 0.2, 0.9, and 2.0, respectively. Thus, from the point of view of reaction rates and enantioselectivity, toluene was found to be the preferred solvent. PMPL products prepared in toluene by PS-30 catalysis had Mn values from 2600 to 2900 g/mol and [α]25D +12.2° to +19.0° (c 0.9 g/dL, CHCl3). Analysis of the polymer chain end structure by 1H and 13C NMR showed that these products have hydroxyl and carboxylic acid termini. Based on the analysis of chain stereosequence distributions by 13C NMR, it was conclud...
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chemoenzymatic synthesis and study of poly α methyl β Propiolactone stereocopolymers
Macromolecules, 1996Co-Authors: Richard A Gross, David L Kaplan, Graham SwiftAbstract:A chemoenzymatic route from racemic α-methyl-β-Propiolactone (MPL) to optically active (R)-poly(α-methyl-β-Propiolactone), (R)-PMPL, was demonstrated which involved lipase catalyzed resolution of MPL enantiomers in organic media and subsequent chemical polymerization. From a comparative study of different enzymes and organic media, catalysis by the lipase PS-30 from Pseudomonas fluorescens suspended in diethyl ether was found to be most suitable for MPL enantioselective alcoholysis reactions. MPL having up to 93% (R) content was thus obtained, mixed in various proportions with racemic MPL, and polymerized using CH3COOK/dibenzo-18-crown-6. From a plot of specific rotation vs % enantiopurity, it was estimated that the [α]25D for 100% (R)-PMPL is −38.4° (c 0.8 g/dL, CHCl3). 13C NMR analysis (62.9 MHz) provided information on triad sequence distributions from observation of methine carbons, while the methyl and carbonyl carbons were sensitive to diad sequences. The polymerization of 50% (R)-MPL followed Berno...
Liang Huang - One of the best experts on this subject based on the ideXlab platform.
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crystallization behavior of poly β Propiolactone block polyethylene copolymers with varying polyethylene crystallinities
Polymer, 2014Co-Authors: Rei Hijikawa, Liang Huang, Gaito Kiyofuji, Hironori Marubayashi, Shuichi NojimaAbstract:Abstract The crystallization behavior of poly(β-Propiolactone)- block -polyethylene (PPL- b -PE) copolymers with high PE crystallinities χ PE (>0.30) has been examined using time-resolved synchrotron small-angle X-ray scattering and Fourier transform infrared spectroscopy, where the PE block crystallized first and subsequently the PPL block crystallized on quenching from a strongly segregated melt. The crystallization of PE blocks destroyed the lamellar microdomain structure (LMS) existing in the melt to form the crystalline lamellar morphology (CLM), and then PPL blocks crystallized within CLM. This morphology formation was compared to our previous results for the crystallization of PPL- b -PE copolymers with low χ PE (0.12 χ PE χ PE = 0, and propose three mechanisms of morphology formation occurring in PPL- b -PE copolymers according to χ PE (i.e., high, low, or zero).
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isothermal crystallization of poly β Propiolactone blocks starting from lamellar microdomain structures of double crystalline poly β Propiolactone block polyethylene copolymers
Polymer, 2012Co-Authors: Liang Huang, Gaito Kiyofuji, Jun Matsumoto, Yasumasa Fukagawa, Cheng Gong, Shuichi NojimaAbstract:Abstract The isothermal crystallization behavior of poly(β-Propiolactone) (PPL) blocks starting from lamellar microdomain structures (LMS) formed in molten PPL- block -polyethylene (PPL- b -PE) copolymers has been examined using time-resolved synchrotron small-angle X-ray scattering and Fourier transform infrared spectroscopy as a function of the crystallinity of PE blocks χ PE . For getting PPL- b -PE copolymers with varying χ PE , the amount of ethyl branches in PE blocks was controlled during polymerization. The crystallizable temperature of PE blocks was slightly higher than that of PPL blocks and the crystallization rate of PE blocks was extremely fast, so the crystallization of PE blocks occurred first on quenching to form the crystallized LMS, in which the PPL block crystallized. The time evolution for the crystallinity of PPL blocks χ PPL showed an exponential-type increase with no induction time. In contrast, LMS was replaced with the crystallized lamellar morphology and χ PPL showed a sigmoidal time evolution in PPL- b -PE with a higher amount of ethyl branches, where the PE block did not crystallize ( i.e., χ PE = 0) prior to the crystallization of PPL blocks. It was concluded that the prompt crystallization of PE blocks just after quenching reinforced the existing LMS to make it stable against subsequent crystallization, yielding the confined crystallization of PPL blocks.
