The Experts below are selected from a list of 1845 Experts worldwide ranked by ideXlab platform
Minoru Terano - One of the best experts on this subject based on the ideXlab platform.
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degradation behavior of polymer blend of isotactic polypropylenes with and without unsaturated chain end group
Science and Technology of Advanced Materials, 2008Co-Authors: Hisayuki Nakatani, Dodik Kurniawan, Toshiaki Taniike, Minoru TeranoAbstract:In this work, the relationship between the unsaturated chain end group content and the thermal oxidative degradation rate was systematically studied with binary polymer blends of isotactic polypropylene (iPP) with and without the unsaturated chain end group. The iPPs with and without the unsaturated chain end group were synthesized by a metallocene Catalyst in the absence of hydrogen and by a Ziegler Catalyst in the presence of one, respectively. The thermal oxidative degradation rate of the binary iPP blends was estimated from the molecular weight and the apparent activation energy (ΔE), which were obtained through size exclusion chromatography (SEC) and thermogravimetric analysis (TGA) measurements, respectively. These values exhibited a negative correlation against the mole content of the unsaturated chain end group. The thermal oxidative degradation rate apparently depends on the content of the unsaturated chain end group. This tendency suggests that the unsaturated chain end acts as a radical initiator of the iPP degradation reaction.
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synthesis and basic characteristics of polypropene block poly ethene co propene by modified stopped flow polymerization with an mgcl2 supported Ziegler Catalyst
Macromolecular Chemistry and Physics, 1999Co-Authors: Mikio Yamahiro, Hideharu Mori, Kohhei Nitta, Minoru TeranoAbstract:A well-defined diblock copolymer, polypropene-block-poly(ethene-co-propene) was synthesized by modified stopped-flow polymerization with an MgCl 2 -supported Ziegler Catalyst. The copolymer shows a unimodal gel permeation chromatography (GPC) elution curve without any material in the low molecular weight region. The molecular weight can be controlled by the polymerization time (ca. 0.1 to 0.2 s). Furthermore, the elution pattern by cross fractionation chromatography showed that the block copolymer eluted at each temperature region between 0°C to 120 C is composed of a uniform material. After extraction with heptane, the 13 C NMR spectra showed that the signals from poly(ethene-co-propene) remain unchanged in the block copolymer but are absent in a corresponding polypropene/poly(ethene-co-propene) blend. The results of differential scanning calorimetry (DSC) and optical microscopic observation indicate not only the formation of a block copolymer with a chemical linkage between the polypropene block and the poly(ethene-co-propene) block, but also the regulation of the crystalline morphology in the block copolymer by changing the composition.
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synthesis of polypropene block poly ethylene co propene by short period polymerization with mgcl2 supported Ziegler Catalyst
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Mikio Yamahiro, Kouki Ohnishi, Kohhei Nitta, Minoru TeranoAbstract:The short-period polymerization method was successfully applied to the synthesis of a novel diblock copolymer, polypropene-block-poly(ethylene-co-propene). The polymerization was carried out for ca. 0,1 s with a MgCl2-supported Ziegler Catalyst. The copolymers obtained showed unimodal curves in gel-permeation chromatography without any peak in the low-molecular-weight region. After extraction with heptane, the fraction of poly(ethylene-co-propene) remained unchanged in the copolymer but disappeared in a commercial so-called block-type copolymer. All the results the formation of polypropene-block-poly(ethylene-co-propene), in which poly(ethylene-co-propene) is chemically linked with polypropene.
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Study of the chain transfer reaction by hydrogen in the initial stage of propene polymerization
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Minoru TeranoAbstract:The chain transfer reaction by hydrogen in the initial stage of propene polymerization with MgCl2-supported Ziegler Catalyst was studied by means of the stopped-flow polymerization. The yield and molecular weight of polypropene produced in the initial stage were not affected by hydrogen. Thus, the method was successfully applied to find the region in which hydrogen does not act as a chain transfer reagent. On the other hand, a chain transfer reaction proceeded in the initial stage of polymerization by using Zn(C2H5)2. Furthermore, when the Catalyst was treated with Al(C2H5)3 before polymerization, the molecular weight of the produced polymer was decreased by using hydrogen, indicating that it acted as a chain transfer agent for the Catalyst modified by pre-treatment.
Hideharu Mori - One of the best experts on this subject based on the ideXlab platform.
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synthesis and basic characteristics of polypropene block poly ethene co propene by modified stopped flow polymerization with an mgcl2 supported Ziegler Catalyst
Macromolecular Chemistry and Physics, 1999Co-Authors: Mikio Yamahiro, Hideharu Mori, Kohhei Nitta, Minoru TeranoAbstract:A well-defined diblock copolymer, polypropene-block-poly(ethene-co-propene) was synthesized by modified stopped-flow polymerization with an MgCl 2 -supported Ziegler Catalyst. The copolymer shows a unimodal gel permeation chromatography (GPC) elution curve without any material in the low molecular weight region. The molecular weight can be controlled by the polymerization time (ca. 0.1 to 0.2 s). Furthermore, the elution pattern by cross fractionation chromatography showed that the block copolymer eluted at each temperature region between 0°C to 120 C is composed of a uniform material. After extraction with heptane, the 13 C NMR spectra showed that the signals from poly(ethene-co-propene) remain unchanged in the block copolymer but are absent in a corresponding polypropene/poly(ethene-co-propene) blend. The results of differential scanning calorimetry (DSC) and optical microscopic observation indicate not only the formation of a block copolymer with a chemical linkage between the polypropene block and the poly(ethene-co-propene) block, but also the regulation of the crystalline morphology in the block copolymer by changing the composition.
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synthesis of polypropene block poly ethylene co propene by short period polymerization with mgcl2 supported Ziegler Catalyst
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Mikio Yamahiro, Kouki Ohnishi, Kohhei Nitta, Minoru TeranoAbstract:The short-period polymerization method was successfully applied to the synthesis of a novel diblock copolymer, polypropene-block-poly(ethylene-co-propene). The polymerization was carried out for ca. 0,1 s with a MgCl2-supported Ziegler Catalyst. The copolymers obtained showed unimodal curves in gel-permeation chromatography without any peak in the low-molecular-weight region. After extraction with heptane, the fraction of poly(ethylene-co-propene) remained unchanged in the copolymer but disappeared in a commercial so-called block-type copolymer. All the results the formation of polypropene-block-poly(ethylene-co-propene), in which poly(ethylene-co-propene) is chemically linked with polypropene.
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Study of the chain transfer reaction by hydrogen in the initial stage of propene polymerization
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Minoru TeranoAbstract:The chain transfer reaction by hydrogen in the initial stage of propene polymerization with MgCl2-supported Ziegler Catalyst was studied by means of the stopped-flow polymerization. The yield and molecular weight of polypropene produced in the initial stage were not affected by hydrogen. Thus, the method was successfully applied to find the region in which hydrogen does not act as a chain transfer reagent. On the other hand, a chain transfer reaction proceeded in the initial stage of polymerization by using Zn(C2H5)2. Furthermore, when the Catalyst was treated with Al(C2H5)3 before polymerization, the molecular weight of the produced polymer was decreased by using hydrogen, indicating that it acted as a chain transfer agent for the Catalyst modified by pre-treatment.
Mikio Yamahiro - One of the best experts on this subject based on the ideXlab platform.
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synthesis and basic characteristics of polypropene block poly ethene co propene by modified stopped flow polymerization with an mgcl2 supported Ziegler Catalyst
Macromolecular Chemistry and Physics, 1999Co-Authors: Mikio Yamahiro, Hideharu Mori, Kohhei Nitta, Minoru TeranoAbstract:A well-defined diblock copolymer, polypropene-block-poly(ethene-co-propene) was synthesized by modified stopped-flow polymerization with an MgCl 2 -supported Ziegler Catalyst. The copolymer shows a unimodal gel permeation chromatography (GPC) elution curve without any material in the low molecular weight region. The molecular weight can be controlled by the polymerization time (ca. 0.1 to 0.2 s). Furthermore, the elution pattern by cross fractionation chromatography showed that the block copolymer eluted at each temperature region between 0°C to 120 C is composed of a uniform material. After extraction with heptane, the 13 C NMR spectra showed that the signals from poly(ethene-co-propene) remain unchanged in the block copolymer but are absent in a corresponding polypropene/poly(ethene-co-propene) blend. The results of differential scanning calorimetry (DSC) and optical microscopic observation indicate not only the formation of a block copolymer with a chemical linkage between the polypropene block and the poly(ethene-co-propene) block, but also the regulation of the crystalline morphology in the block copolymer by changing the composition.
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synthesis of polypropene block poly ethylene co propene by short period polymerization with mgcl2 supported Ziegler Catalyst
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Mikio Yamahiro, Kouki Ohnishi, Kohhei Nitta, Minoru TeranoAbstract:The short-period polymerization method was successfully applied to the synthesis of a novel diblock copolymer, polypropene-block-poly(ethylene-co-propene). The polymerization was carried out for ca. 0,1 s with a MgCl2-supported Ziegler Catalyst. The copolymers obtained showed unimodal curves in gel-permeation chromatography without any peak in the low-molecular-weight region. After extraction with heptane, the fraction of poly(ethylene-co-propene) remained unchanged in the copolymer but disappeared in a commercial so-called block-type copolymer. All the results the formation of polypropene-block-poly(ethylene-co-propene), in which poly(ethylene-co-propene) is chemically linked with polypropene.
Kohhei Nitta - One of the best experts on this subject based on the ideXlab platform.
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synthesis and basic characteristics of polypropene block poly ethene co propene by modified stopped flow polymerization with an mgcl2 supported Ziegler Catalyst
Macromolecular Chemistry and Physics, 1999Co-Authors: Mikio Yamahiro, Hideharu Mori, Kohhei Nitta, Minoru TeranoAbstract:A well-defined diblock copolymer, polypropene-block-poly(ethene-co-propene) was synthesized by modified stopped-flow polymerization with an MgCl 2 -supported Ziegler Catalyst. The copolymer shows a unimodal gel permeation chromatography (GPC) elution curve without any material in the low molecular weight region. The molecular weight can be controlled by the polymerization time (ca. 0.1 to 0.2 s). Furthermore, the elution pattern by cross fractionation chromatography showed that the block copolymer eluted at each temperature region between 0°C to 120 C is composed of a uniform material. After extraction with heptane, the 13 C NMR spectra showed that the signals from poly(ethene-co-propene) remain unchanged in the block copolymer but are absent in a corresponding polypropene/poly(ethene-co-propene) blend. The results of differential scanning calorimetry (DSC) and optical microscopic observation indicate not only the formation of a block copolymer with a chemical linkage between the polypropene block and the poly(ethene-co-propene) block, but also the regulation of the crystalline morphology in the block copolymer by changing the composition.
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synthesis of polypropene block poly ethylene co propene by short period polymerization with mgcl2 supported Ziegler Catalyst
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Mikio Yamahiro, Kouki Ohnishi, Kohhei Nitta, Minoru TeranoAbstract:The short-period polymerization method was successfully applied to the synthesis of a novel diblock copolymer, polypropene-block-poly(ethylene-co-propene). The polymerization was carried out for ca. 0,1 s with a MgCl2-supported Ziegler Catalyst. The copolymers obtained showed unimodal curves in gel-permeation chromatography without any peak in the low-molecular-weight region. After extraction with heptane, the fraction of poly(ethylene-co-propene) remained unchanged in the copolymer but disappeared in a commercial so-called block-type copolymer. All the results the formation of polypropene-block-poly(ethylene-co-propene), in which poly(ethylene-co-propene) is chemically linked with polypropene.
Kunihiko Tashino - One of the best experts on this subject based on the ideXlab platform.
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synthesis of polypropene block poly ethylene co propene by short period polymerization with mgcl2 supported Ziegler Catalyst
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Mikio Yamahiro, Kouki Ohnishi, Kohhei Nitta, Minoru TeranoAbstract:The short-period polymerization method was successfully applied to the synthesis of a novel diblock copolymer, polypropene-block-poly(ethylene-co-propene). The polymerization was carried out for ca. 0,1 s with a MgCl2-supported Ziegler Catalyst. The copolymers obtained showed unimodal curves in gel-permeation chromatography without any peak in the low-molecular-weight region. After extraction with heptane, the fraction of poly(ethylene-co-propene) remained unchanged in the copolymer but disappeared in a commercial so-called block-type copolymer. All the results the formation of polypropene-block-poly(ethylene-co-propene), in which poly(ethylene-co-propene) is chemically linked with polypropene.
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Study of the chain transfer reaction by hydrogen in the initial stage of propene polymerization
Macromolecular Rapid Communications, 1995Co-Authors: Hideharu Mori, Kunihiko Tashino, Minoru TeranoAbstract:The chain transfer reaction by hydrogen in the initial stage of propene polymerization with MgCl2-supported Ziegler Catalyst was studied by means of the stopped-flow polymerization. The yield and molecular weight of polypropene produced in the initial stage were not affected by hydrogen. Thus, the method was successfully applied to find the region in which hydrogen does not act as a chain transfer reagent. On the other hand, a chain transfer reaction proceeded in the initial stage of polymerization by using Zn(C2H5)2. Furthermore, when the Catalyst was treated with Al(C2H5)3 before polymerization, the molecular weight of the produced polymer was decreased by using hydrogen, indicating that it acted as a chain transfer agent for the Catalyst modified by pre-treatment.
