記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nihon Reoroji Gakkaishi  

Liquid crystalline (LC) phase behavior, higer-order structure, and mobility of mesogenic groups were investigated by using DSC, polarizing optical microscopy, small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD) and dielectric relaxation spectroscopy (DRS) for random copolymers composed of cyanobiphenyl-based side-chain LC and the amorphous components with various compositions. LC phase behavior of the copolymers was systematically changed depending on the mole fraction of the LC component, fLC11. When fLC11 > 0.75, incorporation of small fraction of the amorphous component resulted in slightly highered LC order and almost unchanged LC-isotropic transition temperature, Tiso. This may be because the copolymerization of the amorphous component canceled the inherent frustration in the LC homopolymer, which comes from the dissidence between lateral distance of adjacent nearest mesogenic groups in the smectic LC phase and that of the side-chains on mainchain. According to the DRS measurements, incorporation of the amorphous component also accelerated the molecular mobility of the mesogenic groups, which may be also related to the relaxation of the internal conformational frustration because of the dissidence.

DOI： 10.1678/rheology.50.189

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Macromolecules  

We designed a hydrogel with a thermoresponsive crosslinked domain (CD) structure, which expressed thermoresponsive toughening in an isochoric manner in air. The responsive behavior of conventional thermoresponsive hydrogels is usually a macroscopic volume change along with water transfer to and from the outside of the polymer network. In order to expand the scope of thermoresponsive hydrogels, a network design that requires no external water for thermoresponsive transition has been demanded. To this end, we focused on the polymerization-induced self-assembly process for the direct synthesis of gels with designed domains and performed reversible addition-fragmentation chain transfer polymerization of N-isopropylacrylamide in water at a high temperature using a bifunctional macro-chain transfer agent, yielding a transparent gel. The structural analysis of the obtained gel revealed that dispersed CDs reversibly swelled and shrunk in response to temperature change in air without aggregation. Such an internal structural change induced the increase of elastic modulus and elongation at a high temperature.

DOI： 10.1021/acs.macromol.0c02569

Scopus

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Zairyo/Journal of the Society of Materials Science, Japan  

The mechanism of heat resistance improvement of polystyrene injection moldings by heat treatment was studied. The increase in the Heat Distortion Temperature (HDT) by heat treatment was confirmed. Meanwhile, in dynamic viscoelasticity measurement, the shoulder of the loss tangent (tanδ) appeared at 60 to 90°C in untreated specimen. In the heat-treated specimen, the shoulder at that temperature range disappeared. Further, when the frequency dependence of tanδ was evaluated, it was found that the mobility of molecular chain in the main dispersion did not change by the heat treatment, and the mobility in the temperature range where the tanδ shoulder appeared was reduced by the heat treatment. By differential scanning calorimetry, the progress of enthalpy relaxation by heat treatment was confirmed. Also, excellent correlation existed between the progress of enthalpy relaxation and the disappearance of the tanδ shoulder by heat treatment. Since the tanδ shoulder disappeared in the heat-treated specimen in which relaxation has progressed yet, it was considered that the tanδ shoulder was caused by molecular motion accompanying the relaxation phenomenon. Addisionally, as well as the disappearance of the tanδ shoulder, the increase in HDT correlated with the progress of enthalpy relaxation by heat treatment. In conclusion, with the progress of the relaxation by the heat treatment, the tanδ shoulder disappeared, and thereby the molecular mobility at 60 to 90°C decreasesed. Since the HDT of the untreated specimen was 78°C, the HDT increased due to the decrease in the molecular mobility below 78°C by heat treatment. Thus, it is considered that the increase in HDT correlated with the progress of enthalpy relaxation by heat treatement.

DOI： 10.2472/jsms.70.11

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Macromolecular Rapid Communications  

Soft tissue in biological system is a hydrogel with elaborate structure exhibiting repeatable dynamic function. In order to approach such sophisticated system, precise construction of a designed network with multi-components is desired. This communication presents a novel hydrogel having highly dense stimuli-responsive free-end chains around crosslinking structure. A key molecule is a core-crosslinked star-shaped polymer with multiple thermoresponsive arms, which can be prepared by reversible addition–fragmentation chain transfer polymerization of divinyl crosslinker with poly(N-isopropylacrylamide) (PNIPAAm) macro-chain transfer agent and have a number of unreacted carbon–carbon double bonds in the core. These unreacted double bonds can be utilized as a crosslinker for poly(acrylamide) (PAAm) gel synthesis by free radical polymerization. The obtained gel contains homogeneously dispersed star PNIPAAms as crosslinking points and exhibits thermoresponsive swelling behavior in water depending on the star contents. In particular, the gel with low content of the star crosslinker shows localized responsive behavior with expansion and shrinkage of the star in one molecule. The mechanical properties of the star-crosslinked gel are significantly high compared to the conventional PAAm gels particularly in compressive strength (≈9 MPa). Moreover, the star-crosslinked gel has thermoresponsive mechanical toughening property.

DOI： 10.1002/marc.202000558

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：マテリアルライフ学会   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Macromolecular Chemistry and Physics  

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim In this study, the polymerization behavior of 2-hexyl[3]dendralene (H3D), which is an alkyl-group-derived [3]dendralene, is examined. The polymerization of H3D in tetrahydrofuran (THF) at −78 °C with potassium naphthalenide as the initiator affords poly(H3D) with a narrow molecular weight distribution, although a small shoulder peak is observed at a high molecular weight even before the monomer is completely consumed. The molecular weight distribution of poly(H3D) prepared in heptane is broader than that prepared in THF, indicating that the nucleophilic addition of a propagating carbanion to the carbon–carbon double bond in the polymer chain occurs in addition to polymerization. Furthermore, the microstructure of poly(H3D) is investigated by NMR. Signals corresponding to the conjugate addition structure, that is, 1,4- and 4,6-structures, are exclusively observed. Poly(H3D) prepared in heptane contains a higher content of the 4,6-structures compared with those prepared in THF.

DOI： 10.1002/macp.201700046

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（副担当）  

記述言語：英語   掲載種別：学位論文（博士）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   著書種別：学術書

記述言語：英語   出版者・発行元：SOC POLYMER SCIENCE JAPAN  

DOI： 10.1295/polymj.PJ2008212

Web of Science

DOI： 10.2324/ejsm.5.1

記述言語：日本語   出版者・発行元：THE SOCIRETY OF RUBBER SCIENCE AND TECHNOLOGYY, JAPAN  

Suzuki-Miyaura coupling reaction of brominated butyl rubber (BIIR) with 4-vinylphenylboronic acid were carried out in THF using cyclopalladated complex as catalyst. The degree of 4-vinylphenyl group introduction was estimated from the ratio of RI and UV peak area in the size exclusion chromatogram (SEC) of modified butyl rubber (St-IIR). Considerable amount of 4-vinylphenyl group could be introduced to butyl rubber in the presence of small amount (Pd/Br≈1/1000) of Pd catalyst.<br>Quantitative analysis for the degree of 4-vinylphenyl group introduction was made by ¹H-NMR. The <i>exo</i> methylene signals in BIIR decreased by the reaction whereas signals attributable to the viny protons of 4-vinylphenyl group increased with reaction time. When reaction was carried out in THF at reflux temperature for 12 h in the presence of 0.01 eq. of Pd catalyst, 4-vinylphenyl group was introduced quantitatively. The peroxide curing behavior of St-IIR was also examined.

DOI： 10.2324/gomu.82.241

CiNii Books

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記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

Phase behavior in liquid crystallization was studied for a series of liquid crystalline (LC) diblock copolymers consisting of rubbery amorphous and side-chain liquid crystalline components, poly(n-butyl acrylate) (PBA) andpoly[11-(4'-cyanophenyl-4 ''-phenoxy)undecyl acrylate] (PLC), respectively, using a time-resolved small-angle X-ray scattering (SAXS) techniques, DSC and polarized optical microscopy (POM). The block copolymers used had three kinds of copolymer compositions, 44, 20 and 15 wt% of PLC compositions (BLC44, BLC20 and BLC15, respectively). BLC44 showed a smectic liquid crystalline structure. In the process of liquid crystallization for BLC44, the SAXS peak due to the microphase separation structure existing before liquid crystallization was changed continuously to be at a smaller angular side, and at almost the same time, a new peak appeared at a further smaller angular side and developed. The former peak disappeared with the development of liquid crystallization. The behavior of these SAXS peaks suggests that the microphase separation structure was changed discretely at the transition from isotropic to smectic and that two phases coexist in the early stage of the liquid crystallization. The coexistence of two peaks in the early stage of the liquid crystallization corresponded to the POM observation. In the isotropization process, coexistence of two phases was not observed. For BLC20 exhibiting a cylindrical structure in both isotropic and liquid crystalline states, the liquid crystalline structure was not smectic but probably nematic, and the spacing was changed continuously in liquid crystallization. No liquid crystallization was observed in SAXS, POM and DSC for BLC15. The orientation of smectic layers within lamellar domains was investigated using 2D-SAXS images. The smectic layer was aligned perpendicularly to the lamellar interface. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2008.08.060

Web of Science

記述言語：英語   出版者・発行元：THE SOCIETY OF RUBBER SCIENCE AND TECHNOLOGY, JAPAN  

Time-resolved simultaneous synchrotron small-angle X-ray scattering and differential scanning calorimetry experiments have been performed on crystallization of polyethylene-polyisoprene diblock copolymers (HEI or LEI) and their blends with corresponding homopolymers, polyethylene (PE) and polyisoprene (PIp). For the neat block copolymer having a 50 wt% of the crystalline component, preexisting microphase separation structure in the melt was kept at high and low crystallization temperatures <i>T</i>_c (<i>T</i>_c≥94°C and <i>T</i>_c<60°C), while disrupted at intermediate <i>T</i>_c (60°C≤<i>T</i>_c<94°C). This complex behavior was interpreted by combination of two mechanisms. The behavior in the crystallization below 94°C was attributed to the competition between the crystallization and chain diffusion rates, that is, the fast crystallization rate at lower <i>T</i>_c makes it difficult to rearrange the phase structure in the melt. On the other hand, at a higher <i>T</i>_c (≥94°C), the preservation of the microphase separation structure was explained by a small degree of crystallinity due to the ethyl branch of polyethylene (hydrogenated poly(butadiene)). For HEI/PE blends, crystallization behavior was the simple superposition of those for HEI and PE, while, for HEI/PIp with a small composition of PE, suppression of crystallinity was observed. Crystallization kinetics in the neat block copolymer and all the blends was not so different from that in the PE homopolymer.

DOI： 10.2324/ejsm.4.12

記述言語：英語   出版者・発行元：THE SOCIETY OF RUBBER SCIENCE AND TECHNOLOGY, JAPAN  

Anionic polymerization of <i>N</i>,<i>N</i>-diethyl-2-methylene-3-butenamide (DEA), which is a 1,3-butadiene derivative containing a diethylamide function, was carried out in tetrahydrofurane (THF) under various conditions. When DEA was polymerized in THF at −78°C using potassium naphthalenide (K-Naph) or diphenylmethylpotassium (DPMK) as an initiator, a polymer of predictable molecular weight with a narrow molecular weight distribution was obtained. However, the rate of polymerization was extremely slow to reach 80% conversion after 720 h. When the polymerization temperature was raised to 20°C, a low molecular weight oligomer with a broad molecular weight distribution was obtained because of a chain transfer reaction. On the other hand, no such side reaction occurred even at 20°C, when polymerization was carried out in the presence of LiCl. Also, the chain transfer reaction did not occur in lithium naphthalenide (Li-Naph) initiated polymerization. The microstructure of the polymer prepared using a potassium counter cation was a 1 : 1 mixture of 1,4-<i>E</i> and 1,2- structures. In the case of Li-Naph or DPMK/LiCl systems, the microstructure was a complicated mixture of 1,4-<i>E</i>, 1,4-<i>Z</i>, and 1,2-structures.

DOI： 10.2324/ejsm.4.23

記述言語：日本語   掲載種別：速報，短報，研究ノート等（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

The microphase separation structure in the molten state and the structure formation in crystallization from such ordered melt were investigated for the blends of polystyrene-polyethylene block copolymers (SE) with polystyrene homopolymer (PS) and polyethylene homopolymer (PE) and for the blends consisting of two kinds of SE with different copolymer compositions from each other, using synchrotron small-angle X-ray scattering techniques (SAXS). The copolymer compositions of SE block copolymers employed were 0.34, 0.58 and 0.73 wt. fraction of PE, and their melt morphologies were cylindrical, lamellar and lamellar, respectively. Macrophase separation or the morphology change in the melt occurred depending on the molecular weight and the blend composition, as reported so far. In crystallization from such macrophase-separated and microphase-separated melts, the melt morphology was completely kept for all the blends. Crystallization behavior was also investigated for the blends. The crystallization within the spherical and cylindrical domains surrounded by glassy PS was not observed for SE/PS blends. In the crystallization from the macrophase-separated melt, two exothermal peaks were observed in the DSC measurements, while a single peak was observed for other blends. For the blends with PS, the degree of crystallinity was depressed and the apparent activation energy of crystallization was high, compared to those for the corresponding neat SE. For SE/PE and SE/SE blends, those were changed depending on the blend composition. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2007.11.002

Web of Science

記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

Crystallization and structure formation of poly(ethylene oxide)-poly(epsilon-caprolactone) block copolymers (PEG-PCL) in which the melting temperatures of the components are close to each other were elucidated using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. The diblock copolymers with 33, 46 and 59 wt% of PEG composition formed ordinary single spherulites similar to those of PCL homopolymers, while concentric double-circled spherulites appeared for the PCL-PEG-PCL triblock copolymer with 66 wt% PEG composition as observed previously. For the diblock copolymers, despite of the ordinary appearance of the single spherulites, the DSC thermograms and the WARD patterns indicated the crystallization of PEG as well as PCL. The time-resolved SAXS profiles for the diblock copolymers showed that long spacings of the crystal lamellae decreased stepwise in the crystallization process. Synthesizing these results for the single spherulites, it was concluded that PCL crystallized first followed by the crystallization of PEG with preservation of the PCL crystal lamellar structure. This means that PEG must crystallize within confined space between the formerly formed PCL crystal lamellae. Such confined crystallization of PEG caused the suppressed melting temperature, crystallinity and crystallization rate especially in the smaller PEG compositions. In the melting process of the diblock copolymers, it was observed that the PEG component first melted with a stepwise increase in the long spacing. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2006.09.043

Web of Science

記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

Miscibility in the blends of poly(ethylene oxide) (PEO) with n-hexyl methacrylate-methyl methacrylate random copolymers (HMA-MMA) and 2-ethylhexyl methacrylate-MMA random copolymers (EHMA-MMA) Was evaluated using glass transition and light scattering methods. EHMA-MMA was more miscible with PEO than HMA-MMA. Both blends of PEO with HMA-MMA and EHMA-MMA showed UCST-type miscibility although homopolymer blends PEO/PMMA were predicted to be of LCST-type. This was attributed to an increase in the exchange enthalpy with increasing HMA or EHMA composition in the random copolymer. From the copolymer composition dependence of miscibility the segmental x parameters of HMA/MMA, EHMA/MMA, EO/HMA and EO/EHMA were estimated using the Flory-Huggins theory extended to random copolymer systems. Miscibility in the blends of branched PEO with HMA-MMA whose HMA copolymer composition was 0.16 was compared with that in the linear PEO blends. The former blends were more miscible with HMA-MMA than the latter one by about 35 degrees C at the Maximum Cloud point temperature. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.polymer.2005.10.067

Web of Science

記述言語：日本語   掲載種別：速報，短報，研究ノート等（学術雑誌）   参加形態：共同（主担当）  

記述言語：英語   出版者・発行元：JOHN WILEY & SONS INC  

Formation of higher-order structure in crystallization from microphase-separated melts was studied for polystyrene-polyethylene (PS-PE) diblock copolymers and PS-PE-PS triblock copolymers with time-resolved synchrotron small-angle X-ray scattering (SR-SAXS) techniques. The PE block was crystallized at temperatures when the PS block was in the glassy state. In both crystallization and melting processes, only the peak intensity in the SR-SAXS curve changed, however, the peak positions including higher-order peaks did not change. This means that the microphase-structure in the crystalline state was completely the same as that in the molten state. These behaviors were observed regardless of any melt microphase structure. Also, once a stable microphase structure was formed in the molten state, the structure was not changed even if crystallization and melting were repeated. Behavior of crystallization from such microphase-separated melts was also studied. Apparent activation energies of crystallization were high for all block copolymers, compared with that for the PE homopolymer. In particular, the triblock copolymers showed higher apparent activation energies than the diblock copolymers. Both degrees of crystallinity and Avrami indices were greatly suppressed in crystallization from the cylindrical domain. (C) 2004 Wiley Periodicals, Inc.

DOI： 10.1002/polb.20278

Web of Science

記述言語：英語   出版者・発行元：JOHN WILEY & SONS INC  

Free-radical homo- and copolymerization behavior of N,N-diethyl-2-methylene-3-butenamide (DEA) was investigated. When the monomer was heated in bulk at 60 degreesC for 25 h without initiator, rubbery, solid gel was formed by the thermal polymerization. No such reaction was observed when the polymerization was carried out in 2 mol/L of benzene solution with with I mol % of azobisisobutyronitrile (AIBN) as an initiator. The polymerization rate (R-P) equation was R-P proportional to [DEA](1.1)[AIBN](0.5), and the overall activation energy of polymerization was calculated 84.1 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4-structure where both 1,4-E and 1,4-Z structures were included. From the product analysis of the telomerization with tertbutylmercaptan as a telogen, the modes of monomer addition were estimated to be both 1,4- and 4,1-addition. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were also carried out in benzene solution at 60 degreesC. In the copolymerization with styrene, the monomer reactivity ratios obtained were r(1) = 5.83 and r(2) = 0.05, and the Q and e values were Q = 8.4 and e = 0.33, respectively. (C) 2004 Wiley Periodicals, Inc.

DOI： 10.1002/pola.11051

Web of Science

記述言語：英語   出版者・発行元：JOHN WILEY & SONS INC  

The free-radical homopolymerization and copolymerization behavior of N-(2-methylene-3-butenoyl)piperidine was investigated. When the monomer was heated in bulk at 60 degreesC for 25 h without an initiator, about 30% of the monomer was consumed by the thermal polymerization and the Diels-Alder reaction. No such side reaction was observed when the polymerization was carried out in a benzene solution with 1 mol % 2,2'-azobisisobutylonitrile (AIBN) as an initiator. The polymerization rate equation was found to be R-p proportional to [AIBN](0.507)[M](1.04), and the overall activation energy of polymerization was calculated to be 89.5 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4-structure that included both 1,4-E and 1,4-Z configurations. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were carried out in benzene solutions at 60 degreesC with AIBN as an initiator. In the copolymerization with styrene, the monomer reactivity ratios were r(1) = 6.10 and r(2) = 0.03, and the Q and e values were calculated to be 10.8 and 0.45, respectively. (C) 2003 Wiley Periodicals.

DOI： 10.1002/pola.10675

Web of Science

記述言語：日本語   出版者・発行元：THE SOCIRETY OF RUBBER SCIENCE AND TECHNOLOGYY, JAPAN  

Triethoxysilyl modified styrene-butadiene rubber latex was synthesized by the emulsion copolymerization of 2-(3-triethoxysilylpropyl)-1, 3-butadiene with styrene and 1, 3-butadiene. This latex was mixed with unmodified SBR latex and tetraethoxysilane to obtain SBR-silica composites by sol-gel reaction in the latex. Evaluation of mechanical properties demonstrated that tensile modulus and tensile strength, elongation at break improved with increasing of the amount of modified SBR. SEM observation for SBR-silica composites suggested that particle size of silica dispersed in unvulcanized rubber matrix grew larger with decreasing of silica content.

DOI： 10.2324/gomu.76.234

CiNii Books

その他リンク： https://jlc.jst.go.jp/DN/JALC/00229827310?from=CiNii

記述言語：英語   出版者・発行元：AMER CHEMICAL SOC  

Changes of higher-order structure of poly(ethylene glycol) - poly(butadione) (PEG-PBd) di- and triblock copolymers in isothermal crystallization from microphase-separated melts were studied using time-resolved synchrotron small-angle X-ray scattering (SR-SAXS) techniques. Lamellar microphase structure of PEG-PBd with weight fractions fl'EG = 0.57 and 0.51 was destroyed on crystallization and changed to a lamellar structure distinct from that in the melt. A diblock copolymer with f(PEG) = 0.34 crystallized, keeping the cylindrical structure preexisting in the melt. On the other hand, a f(PEG) = 0.7 diblock copolymer whose melt structure was cylindrical showed two kinds of structure changes: at low crystallization temperatures T, the SAXS peak positions changed discontinuously but the structure remained cylindrical, while the structure changed from cylindrical to lamellar at high T,. Triblock copolymers PBd-PEG-PBd with f(PEG) = 0.67 and 0.42 showed a structure change similar to the f(PEG) = 0.57 and 0.51 diblock copolymers. Behavior of structure changes in the melting process was the reverse of that in the crystallization process for all the samples. Crystallization behavior, in particular crystallization kinetics, was also investigated by DSC and polarized optical microscopy (POM.) with a 530 nm retardation plate. Avrami exponents evaluated from DSC results for the block copolymers were almost the same as those for PEG homopolymers even in crystallization from the cylindrical melt, which was quite different from the result in crystallization from a frozen microphase-separated melt reported previously. For the f(PEG) = 0.34 diblock and f(PEG) = 0.42 triblock copolymers with a small-sized microdomain in the melt, overall crystallization rates were suppressed and apparent activation energies were high. No spherulite with a clear Maltese cross was observed by POM, but the crystal region was propagated with irregularly distributed blue- and yellow-colored portions for all the block copolymers including the f(PEG) = 0.34 diblock copolymers. This behavior of the propagation and the above result of Avrami exponents for the f(PEG) = 0.34 copolymer suggest that crystallization can traverse from one cylinder domain to another with preservation of the melt structure. From the kinetic results obtained by both DSC and POM, it was suggested that nucleation was easy for the middle block in the triblock copolymers.

DOI： 10.1021/ma0200118

Web of Science

記述言語：日本語   掲載種別：速報，短報，研究ノート等（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：速報，短報，研究ノート等（学術雑誌）   参加形態：共同（主担当）  

記述言語：日本語   掲載種別：速報，短報，研究ノート等（学術雑誌）   参加形態：共同（主担当）  

DOI： 10.1016/S0921-4526(01)01059-6

記述言語：英語   出版者・発行元：SOC POLYMER SCIENCE JAPAN  

The crystallization process in binary blends of poly(epsilon-caprolactone)-block-polybutadiene (PCL-b-PB) copolymers has been investigated by time-resolved small-angle X-Ray scattering with synchrotron radiation (SR-SAXS), where the crystallization of PCL blocks induces a morphological transition both in neat copolymers but the crystallization rate is extremely different between them. The microdomain structure in the melt and the final morphology after crystallization were also measured by conventional SAXS, and the melting behavior of crystallized samples was observed by differential scanning calorimetry (DSC). The binary blend forms a single microdomain structure in the melt over the whole composition range investigated, and the crystallization proceeds with an intermediate rate between those of the constituent PCL-b-PB copolymers to result in a single lamellar morphology. The time dependence of SR-SAXS curves is qualitatively similar in features to that for the crystallization of pure PCL-b-PB copolymers, suggesting that the crystallization of the blend is substantially controlled by a single crystallization mechanism. The remarkable change in the crystallization rate with composition is ascribed to the difference in the stability of preexisting microdomain structures. The conformation of (longer and shorter) PB blocks in the final lamellar morphology is qualitatively discussed.

DOI： 10.1295/polymj.34.593

Web of Science

記述言語：英語   出版者・発行元：AMER CHEMICAL SOC  

The phase separation of a network in the unstable region has been investigated using a homogeneous transparent poly(vinyl alcohol) (PVA) gel by volume and UV transmittance measurements as well as by time-resolved light scattering measurements. It was found that the light scattering intensity I(Q) shows a single peak which increases in intensity exponentially with time without shifting the peak position in the early stage of phase separation, suggesting that a spinodal decomposition (SD) type phase separation occurs in this system. In contrast to the usual fluids, the domain growth is extremely slowed down in the late stage because the elastic force of the gel suppresses the surface tension force, which is the driving force of domain growth. This is the so-called pinning effect. As the SD approaches the end, the UV transmittance of the gel increases gradually and the scattering intensity decreases during the shrinking process of volume (syneresis), which corresponds to a relaxation process of the microscopic internal fluctuations produced in the SD process.

DOI： 10.1021/ma010539x

Web of Science

記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

The effect of the microphase separation structure in the melt on crystallizability and crystallization kinetics was studied for poly(tetrahydrofuran)-polystyrene diblock copolymers (PTHF-PS) which has a glassy amorphous component. Four binds of copolymers, Block I, Block 2, Block 3 and Block 4 with PTHF compositions of 59, 51, 38 and 29 vol%, respectively, were employed and their crystallization behavior was compared with the PTHF/PS blends as well as the PTHF homopolymers. Crystallization of Block 2, Block 3 and Block 4 was much suppressed, in particular no crystallization was detected for Block 4 even in a long crystallization time and at a high supercooling degree. The blends of Block 4 with the PTHF homopolymer also did not crystallize in the total PTHF content less than about 40%. It was concluded from these results that crystallization from the semidiscontinuous microdomain such as lamellar and cylindrical ones was much suppressed and that crystallization did not occur inside the discontinuous or spherical microdomain surrounded by the glassy matrix. The Avrami exponent was extremely small for Block 2 and Block 3, which suggested that their crystallization occurred under a high spatial constraint. The linear overall rate constant of crystallization for Block 1 was smaller than the blends and homopolymers, but the apparent activation energy of crystallization of Block I was not so different from that of the blends and homopolymers. For Block 2 and Block 3, on the other hand, the rate constant was small and the apparent activation energy was much high. The interfacial free energy of Block 2 and Block 3 estimated using the Lauritzen-Hoffman theory was also large. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0032-3861(00)00894-6

Web of Science

記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

A unique morphology of spherulites, namely double spherulites like concentric circles, was observed for poly(epsilon -caprolactone)-block-poly(ethylene glycol)-block-poly(epsilon -caprolactone) (PCL-b-PEG-b-PCL) triblock copolymers, ABA-2 and ABA-3, with PCL compositions of 66 and 60 wt%, respectively. The central and outer sections in the concentric spherulites were those of PCL and PEG, respectively. In formation of the concentric spherulites, the spherulites of the PCL component always appeared first and grew, and then the PEG spherulite developed from the growth front of the PCL spherulite, Any nucleation of the PEG spherulite prior to that of PCL was not observed. In the triblock copolymers, ABA-1 and ABA-4, with PCL compositions of 83 and 34 wt%, respectively, no concentric spherulites were observed but usual single-circle spherulites were formed; only PCL spherulites were formed for ABA-l while for ABA-4 only PEG spherulites were observed. For ABA-2 and ABA-3 having the concentric spherulites, two melting peaks appeared and the WAXD patterns were a superposition of those for the PEG and PCL homopolymers. The SAXS curves for ABA-2 and ABA-3 also had two kinds of peaks due to the long spacings relative to the PCL and PEG crystal lamellae, respectively. The values of the long spacing estimated from the peak positions suggested that the PEG (or PCL) segments located between the crystal lamellae of PCL (or PEG) existed as amorphous segments. (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0032-3861(00)00597-8

Web of Science

DOI： 10.1103/PhysRevE.61.2125

PubMed

DOI： 10.1021/ma990565j

記述言語：英語   出版者・発行元：ELSEVIER SCI LTD  

We studied the structure of poly(vinyl alcohol) (PVA) gels formed in mixtures of dimethyl sulfoxide (DMSO) and water using several scattering techniques such as wide-angle neutron scattering (WANS), small-angle neutron scattering (SANS), ultra-small-angle neutron scattering (U-SANS) and light scattering (LS) to cover a very wide Q range from 10(-4) to 10 Angstrom(-1). The WANS measurements have revealed that the cross-linking points of the gels are crystallites, and the size and its distribution have been evaluated by the SANS measurements. The SANS results have also shown that the structure observed in the low Q range below 10(-2) Angstrom(-1) is dominated by a liquid-liquid-phase separation. The early stage of the phase separation has been studied in detail using the time-resolved LS technique, while the late stage has been investigated by the U-SANS technique because the LS measurements cannot access the opaque samples. On the basis of the results, we present a quantitative sketch of the structure of the PVA gel. (C) 1998 Elsevier Science Limited. All rights reserved.

DOI： 10.1016/S0968-5677(98)00009-1

Web of Science

記述言語：日本語   出版者・発行元：SOC POLYMER SCIENCE JAPAN  

The structure of poly(vinyl alcohol) (PVA) gels formed in mixtures of dimethyl sulfoxide (DMSO) and water was studied using several scattering techniques such as wide-angle neutron scattering (WANS), small-angle neutron scattering (SANS), ultra-small angle neutron scattering (U-SANS), and light scattering (LS), covering a very wide Q range from 10(-4) to 10 Angstrom(-1). The WANS measurements have revealed that the cross-linking points of the gels are crystallites, and the spatial distribution has been evaluated by SANS measurements. The SANS results have also shown that the structure observed in a low Q range below 10(-2) Angstrom(-1) is dominated by a liquid-liquid phase separation. The early stage of the phase separation has been studied in more detail using a time-resolved LS technique, while the late stage has been investigated by a U-SANS technique because the LS technique cannot be applied to opaque samples. On the basis of the results, we have proposed a schematic model for the structure of PVA gels.

DOI： 10.1295/koron.55.595

Web of Science

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