共查询到20条相似文献,搜索用时 649 毫秒
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Vu Quoc Thang Toshiaki Taniike Masaki Umemori Mitsuhiro Ikeya Yuichi Hiraoka Nguyen Duc Nghia Minoru Terano 《大分子反应工程》2009,3(8):467-472
Preservation of initial polymer/catalyst particle morphology under air, was examined using stopped‐flow Ziegler–Natta polymerization with various quenching conditions and post‐chemical treatments. The exposure of the initial particles to air caused the fast formation of cracks on the surface, finally leading to significant reformation of the particle shape, when polymerizing particles were washed with heptane at ?65 °C under N2 or under CO2. On the other hand, when the particles were washed with heptane containing an appropriate amount of tetrahydrofuran under CO2, the particle morphology under air was almost completely maintained even after 1 h exposure. The present results are useful for various ex situ characterizations of unstable initial polymer/catalyst particles.
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Micro‐Raman spectroscopy has been used to investigate the chemical micro‐heterogeneity of multiphase‐separated poly(ether urethanes) (PETU). Analysis of PETU cross‐sections by means of micro‐Raman spectroscopy revealed the nearly complete absence of soft segments in AI aggregates (called globules). These aggregates are in the order of a few micrometers in size. The composition of the matrix and the AII aggregates (spherulites) was comparable.
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Kaushik Mallick Mike J. Witcomb Andy Dinsmore Mike S. Scurrell 《Macromolecular rapid communications》2005,26(4):232-235
Summary: We report a new method for the preparation of polyaniline nanoballs by using HAuCl4 as an oxidizing agent. During the reaction, aniline is oxidized and forms polyaniline whilst the hydrogen tetrachloroaurate is reduced and forms gold nanoparticles. These gold nanoparticles are found to decorate the nanoballs.
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Antonio B. Fuertes 《Macromolecular rapid communications》2005,26(13):1055-1059
Summary: This paper reports a facile route to fabricate high‐surface area hybrid carbon‐polymer nanocomposites following a template technique. The method presented here allows large amounts of polymer to be deposited inside one of the pore systems of a highly ordered carbon, while the other is kept empty. Such prepared composite has large polymer loadings (≈50%), high surface area (≈1 000 m2 · g−1), and a uniform porosity made up of mesopores.
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Hiroshi Yabu Kazutaka Koike Kiwamu Motoyoshi Takeshi Higuchi Masatsugu Shimomura 《Macromolecular rapid communications》2010,31(14):1267-1271
Au nanoparticles (NPs) and polymer composite particles with phase‐separation structures were prepared based on phase separation structures. Au NPs were successfully synthesized in amphiphilic block‐copolymer micelles, and then composite particles were formed by a simple solvent evaporation process from Au NPs and polymer solution. The phase separated structures (Janus and Core‐shell) were controlled by changing the combination of polymers having differing hydrophobicity.
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Carla Negele Johannes Haase Arne Budweg Alfred Leitenstorfer Stefan Mecking 《Macromolecular rapid communications》2013,34(14):1145-1150
Colloidal quantum dots are well‐established probes for quantum optical experiments. However, they possess a limited stability toward their environment. Herein, the generation of hybrid particles composed of a high optical quality quantum dot centered in a polymer particle by means of a miniemulsion polymerization procedure is reported. This embedding strongly enhances emission intensity and photochemical stability of these single‐photon emitters. At the same time, their colloidal mobile nature is not compromised.
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Philippe Mongondry Chantal Bonnans‐Plaisance Martine Jean Jean Franois Tassin 《Macromolecular rapid communications》2003,24(11):681-685
The hydroxyl end groups of poly(ethylene glycol) (PEG) have been transformed easily and quantitatively into amino groups via the Mitsunobu reaction. Phthalimide was alkylated with PEGs and the hydrazinolysis of the resulting phthalimido‐PEGs gave the amino compounds in high yields. Quaternization of the amino groups leads to hydrophilic polymer chains bearing a positive charge on one or two ends, depending on the chosen PEG. Such products can be used to protect sterically, negatively charged particles such as clays.
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Guohua Chen Malancha Gupta Kelvin Chan Karen K. Gleason 《Macromolecular rapid communications》2007,28(23):2205-2209
Furan ring‐functionalized solid surfaces are achieved by the initiated chemical vapor deposition (iCVD) method, a solvent‐free process to form films under mild conditions. The polymerization of furfuryl methacrylate monomer is initiated by a resistively heated filament wire. The functionality of the furan group in the iCVD film enabled Diels–Alder chemistry with 4‐phenyl‐1,2,3‐triazolin‐3,5‐dione (N‐PTD).
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Takashi Tsujimoto Hiroshi Uyama Shiro Kobayashi 《Macromolecular rapid communications》2003,24(12):711-714
Green nanocomposite coatings based on renewable plant oils have been developed. An acid‐catalyzed curing of epoxidized plant oils with 3‐glycidoxypropyltrimethoxysilane produced transparent nanocomposites. The hardness and mechanical strength improved by incorporating the silica network into the organic polymer matrix, and good flexibility was observed in the nanocomposite. The nanocomposites showed high biodegradability.
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Poly(methyl methacrylate) nanosize particles were synthesized by a differential microemulsion polymerization process. Sodium dodecylsulfate and ammonium persulfate were used as the surfactant and initiator, respectively. The effects of reaction conditions on the particle size have been investigated. A particle size of less than 20 nm in diameter has been achieved with surfactant/monomer and surfactant/water weight ratios of 1:18 and 1:120, i.e. much milder conditions than those previously reported in the literature.