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In this communication, β‐cyclodextrin modified quantum dots were used as a water‐soluble “supramolecular” cross‐linker (SCL) because of its surface's supramolecular activity. The guest monomer‐loaded SCL (mSCL) can be used to copolymerize with water‐soluble monomers leading to transparent hybrid supramolecular hydrogels. This simple and versatile method opens new venues for the preparation of hybrid supramolecular hydrogels and the host–guest chemistry of cyclodextrins.
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Marco Sangermano Sven Pegel Petra Ptschke Brigitte Voit 《Macromolecular rapid communications》2008,29(5):396-400
Antistatic epoxy coatings are obtained, for the first time, by cationic UV curing of an epoxy resin in the presence of a very low content of carbon nanotubes (CNTs). It is shown that the addition of only 0.025 wt.‐% of CNTs into the resin is sufficient to obtain a composite suitable for applications that require electrostatic discharge. An extended percolative structure that forms a conductive CNT network is clearly evidenced within the polymeric matrix, notwithstanding the very small CNT content. The use of such UV‐cured epoxy material systems for antistatic coatings is quite realistic and promising.
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Xiaolin Tang Linxia Zhang Tao Wang Yingfeng Yu Wenjun Gan Shanjun Li 《Macromolecular rapid communications》2004,25(15):1419-1424
Summary: The evolution of the morphologies in blends of epoxy/4,4′‐methylenebis(2,6‐dimethylaniline)/polyethersulfone was followed by time‐resolved light scattering, optical microscopy and scanning electron microscopy. The results suggest that, once the diffusion of epoxy molecules cannot follow the geometrical growth, a secondary phase separation occurs, even in the droplet morphology, in which the size of the epoxy‐rich domain grows as usual. The viscoelastic effect of polyethersulfone is also discussed.
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Qianqian Li Gui Yu Jing Huang Haijie Liu Zhen Li Cheng Ye Yunqi Liu Jingui Qin 《Macromolecular rapid communications》2008,29(10):798-803
Two new “H” type of indole‐based chromophores were designed and successfully introduced to the polymeric system, the resultant polymers demonstrated enhanced NLO effects, good processability, thermal stability and nearly excellent transparency, indicating the advantages of “H” type chromophore moieties. And they could be promising candidates for the practical applications as new photonic materials.
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We report for the first time the preparation of single polypyrrole (PPy) molecule chains using a “metal‐organic framework” with 1 nm channels as a template. The obtained one‐dimensional (1‐D) PPy has highly structure order and excellent conductivity, which has improved by as much as five orders of magnitude in comparison with that of 2‐D PPy.
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Shuangjun Chen Wei Chen Zhihuai Si Dongshan Zhou Gi Xue 《Macromolecular rapid communications》2006,27(5):328-332
Summary: SEBS is used as building blocks to fabricate size controllable polypyrrole (PPy) capsules. Polypyrrole shells grow on the surfaces of the size controllable oxidant sub‐microparticles dispersed in the solution cast film of a SEBS copolymer by vapor phase polymerization. After washing in ethanol, PPy sub‐microcapsules dispersed in a SEBS matrix are obtained. This technique shows advantages of lower cost and less pollution, as compared with the gold‐template method reported in the literature.
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The gecko adhesion phenomenon has stimulated efforts to produce synthetic patterned dry adhesives. Besides introducing surface patterns on dry adhesives, it is also highly desirable to understand their intrinsic material properties. This communication reports the viscoelastic behavior of non‐patterned epoxy elastomers exhibiting intrinsic adhesion that is much higher than that of elastomers typically used for structure patterning. The diverse molecular origin of the adhesion is revealed through the study of adhesion against various substrates.
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Ann‐Sofie Leppnen Chunlin Xu Jun Liu Xiaoju Wang Markus Pesonen Stefan Willfr 《Macromolecular rapid communications》2013,34(13):1056-1061
A green chemoenzymatic pathway for the synthesis of conducting polyaniline (PANI) composites is presented. Laccase‐catalyzed polymerization in combination with anionic polysaccharides is used to produce polysaccharide/PANI composites, which can be processed into flexible films or coated onto cellulose surfaces. Different polysaccharide templates are assessed, including κ‐carrageenan, native spruce O‐acetyl galactoglucomannan (GGM), and TEMPO‐oxidized cellulose and GGM. The resulted conducting biocomposites derived from natural materials provide a broad range of potential applications, such as in biosensors, electronic devices, and tissue engineering.
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Ping Xu Xijiang Han Chao Wang Bin Zhang Xiaohong Wang Hsing‐Lin Wang 《Macromolecular rapid communications》2008,29(16):1392-1397
Polyaniline‐polypyrrole (PANI‐PPy) nanofibers with high aspect ratios have been synthesized by a one‐step, surfactant‐assisted chemical oxidative polymerization from mixtures of aniline (An) and pyrrole (Py) monomers. PANI‐PPy nanofibers synthesized with an excess of either PANI or PPy show similar spectral (UV‐vis and FT‐IR) characteristics as the individual homopolymers, whereas nanofibers from an equimolar mixture of An and Py display unique spectral characteristics. PANI‐PPy nanofibers undergo a spontaneous redox reaction with metal ions to produce metal nanoparticles with various morphologies and/or sizes. These findings may open new opportunities for synthesizing functional polymer nanofibers and metal nanoparticles with controllable sizes and/or morphologies.
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Jingjing Xu Jianchen Hu Baogang Quan Zhixiang Wei 《Macromolecular rapid communications》2009,30(11):936-940
Au nanoparticle‐decorated polypyrrole nanotubes (defined as PPy/Au nanocomposites) are prepared by an in situ reduction process. Polypyrrole (PPy) nanotubes are prepared by a self‐degraded template method, and Au nanoparticles are deposited in situ by the reduction of HAuCl4. The size and uniformity of the Au nanoparticles that decorate the PPy nanotubes can be controlled by adjusting the experimental conditions, such as the stabilizers used and the reaction temperature. The morphologies and optical properties of the nanocomposites have been characterized by scanning electron microscopy, transmission electron microscopy, UV‐vis, and FT‐IR spectroscopy. Conductivity measurements show that the conductivities of the nanocomposites decrease with a decrease of temperature, and the conductivity–temperature relationship obeys the quasi‐one dimensional variable range hopping model.
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Summary: Nanocomposites were formulated by curing a sonicated mixture of epoxy resin, C18 clay, and acrylic rubber dispersants. At 5.5 phr (parts per hundred) organoclay loading and a rubber concentration of 15 phr, the tensile‐failure strain of the nanocomposite was found to be higher than that of epoxy nanocomposite, rubber‐dispersed epoxy, and pristine epoxy. A plausible mechanism for improvement of the failure strain of nanocomposites is proposed.
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P. Pladis V. Kanellopoulos C. Chatzidoukas C. Kiparissides 《Macromolecular theory and simulations》2008,17(9):478-487
A model is developed to predict the viscoelastic behavior of polyolefins produced in catalytic polymerization reactors. The approach is based on the solution of different sub‐models (e.g., a kinetic model, a single particle model, a macroscopic reactor model and a rheological model). From the calculated rheological curve, the polymer melt index is determined. The ability of the proposed model to predict the viscoelastic behavior of linear polymer melts quantitatively is examined for the operation of a catalytic olefin polymerization cascade‐loop reactor process. In addition, the transient rheological properties of polyolefins produced in a Ziegler‐Natta gas‐phase olefin polymerization fluidized‐bed reactor are calculated.
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Vladimir E. Yudin Valentine M. Svetlichnyi Alexander N. Shumakov Dmitriy G. Letenko Alexander Y. Feldman Gad Marom 《Macromolecular rapid communications》2005,26(11):885-888
Summary: The relatively high degree of crystallinity of a new thermoplastic polyimide (PI) makes it a favorable matrix candidate for fiber reinforced composites. This advantage is the result of the ability of the matrix to recrystallize during the composite manufacturing process. In this study we examine the potential nucleating effect of carbon nanotubes on a thermoplastic PI. In addition to their inherent mechanical contribution, the carbon nanotubes help recover a significant proportion of the original crystallinity.
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Hongbin Lu Hongbin Shen Zhenlun Song Katherine S. Shing Wei Tao Steven Nutt 《Macromolecular rapid communications》2005,26(18):1445-1450
Summary: Epoxy nanocomposites containing rod‐like silicate (attapulgite) were prepared using a simple organic modification to the nanorods. The modification led to effective interfacial adhesion between the ceramic nanorods and the epoxy resin and hence good load transfer. Scanning electron microscopy examination revealed a uniform dispersion of nanorods in the epoxy resin. Compared to the neat resin, nanocomposites with 7.47 vol.‐% nanorods exhibited an increase in the (rubbery state) storage modulus of 122.5%. In addition, the nanocomposites exhibited improved dimensional stability both above and below the Tg.
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Kenneth D. Harris Cees W. M. Bastiaansen Dirk J. Broer 《Macromolecular rapid communications》2006,27(16):1323-1329
Summary: We investigate a series of glassy polymer actuators which are found to bend rapidly and reversibly in response to changes in the solvent environment. The actuators are based on hydrogen‐bonded liquid crystal networks, and bending motion is created using director profiles engineered to take advantage of the network swelling anisotropy. Strongly polar solvents easily swell the network, forcing bending in one direction, while the less polar solvents extract water to force bending in the opposite direction.
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Lei Liu Krishna C. Etika Kang‐Shyang Liao Lance A. Hess David E. Bergbreiter Jaime C. Grunlan 《Macromolecular rapid communications》2009,30(8):627-632
Carbon nanotubes typically require the use of a dispersing or stabilizing agent to prevent significant aggregation during incorporation into a polymer matrix. These additives must be strongly associated, either covalently or physically, to achieve their purpose. In this study, multi‐walled carbon nanotubes (MWNTs) were dispersed into an epoxy matrix using polyethylenimine (PEI) as a dispersant that was either covalently attached to the nanotubes or physically mixed to result in only noncovalent interaction. Epoxy composites containing covalently modified MWNTs exhibited greater storage modulus and reduced electrical conductivity.
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Burak Arikan Florian J. Stadler Joachim Kaschta Helmut Münstedt Walter Kaminsky 《Macromolecular rapid communications》2007,28(14):1472-1478
The synthesis of ethene/propene macromers with a high amount of sterically unhindered vinyl groups is described. These macromers are incorporated as long‐chain branches into polyethylene (PE). The remaining low molecular fractions were removed by Soxhlet extraction. Up to 60 wt.‐% macromer was included, which leads to comb‐like molecular topographies that distinctly affect the rheological behavior. The thermal activation energy increased significantly and the zero shear‐rate viscosity enhancement factor η 0 / η was also changed noticeably.
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Homogeneous nucleation in polymers and subsequent crystallization in spaces confined relative to spherulitic dimensions in one direction has been simulated for a wide range of nucleation and growth rates. An empirical equation based on simulation results relating an Avrami exponent of crystallization to growth and nucleation rates along with the characteristic dimension of crystallizing volume has been proposed. It was found that for ideal homogeneous crystallization, the Avrami exponent can be significantly lower than the anticipated values for free unconstrained growth; therefore, all crystallization conditions and parameters must be taken into account in order to make a conclusion on the character of the observed crystallization.