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1.
A polymeric film of a biodegradable poly(p‐dioxanone) was grown from 490 nm silica particles by monolayer formation via self‐assembly of hydroxy‐terminated triethoxysilane and subsequent surface‐initiated ring‐opening polymerization of p‐dioxanone. The resulting silica/poly(p‐dioxanone) hybrid particles were characterized by means of 1H NMR spectroscopy, IR spectroscopy, thermogravimetric analysis, field‐emission scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy.
2.
David Briers Guy Koeckelberghs Isabel Picard Thierry Verbiest Andr Persoons Celest Samyn 《Macromolecular rapid communications》2003,24(14):841-846
Nonlinear optical vinyl polymers with high glass transition temperature (Tg) were prepared by the functionalization of a fluorinated acrylate‐methyl vinyl isocyanate copolymer. A modified pathway to obtain a thiophene bridged chromophore was worked out. Poled films of the polymers show a fairly high and stable nonlinear optical response, even at elevated temperatures.
3.
Cdric Dever Alain Deffieux Henri Cramail Sergio Mastroianni 《Macromolecular rapid communications》2003,24(15):883-888
A novel approach to metallocene catalyst heterogenization is presented. Supported metallocenes are obtained by metallation of indenyl‐modified silica produced by a nonhydrolytic sol–gel process. The catalytic activities for ethylene polymerization are rather high for supported systems and may reach 190 grams of polyethylene per gram of catalyst per hour per bar. The influence of the preparation and composition of these supported metallocene systems on ethylene polymerization and polyethylene characteristics are reported.
4.
Moon Suk Kim Kwang Su Seo Gilson Khang Hai Bang Lee 《Macromolecular rapid communications》2005,26(8):643-648
Summary: The polymerization of ε‐caprolactone (CL) in the presence of HCl · Et2O by an activated monomer mechanism was performed to synthesize diblock or triblock copolymers composed of poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL). The obtained PCLs had molecular weights close to the theoretical values calculated from the CL to PEG molar ratios and exibited monomodal GPC curves. We successfully prepared PEG and PCL block copolymers by a metal‐free method.
5.
Vincenzo Busico Philippe Carbonniere Roberta Cipullo Roberta Pellecchia John R. Severn Giovanni Talarico 《Macromolecular rapid communications》2007,28(10):1128-1134
Suitably activated, (Cp*){N(tBu)C(Me)N(Et)}ZrMe2 is known to initiate the ‘living’ and isotactic‐selective polymerization of alk‐1‐enes, and it can be used to synthesize block copolymers and stereoblock polymers. We report a full molecular kinetic investigation of propene, but‐1‐ene, and hex‐1‐ene polymerization with a MAO‐activated catalyst system. By combining NMR microstructural polymer analysis with QM modeling of the active species, the complicated regio‐ and stereochemistry of the polyinsertion process, as well as the active chain‐transfer pathways, are investigated. The perspectives and limitations of this catalyst for application in (stereo)block polymerizations are discussed.
6.
Xiaofeng Sui Lennard van Ingen Mark A. Hempenius G. Julius Vancso 《Macromolecular rapid communications》2010,31(23):2059-2063
The synthesis of a rapidly forming redox responsive poly(ferrocenylsilane)‐poly(ethylene glycol) (PFS‐PEG)‐based hydrogel is described, achieved by a thiol‐Michael addition click reaction. PFS bearing acrylate side groups (PFS‐acryl) was synthesized by side group modification of poly(ferrocenyl(3‐iodopropyl)methylsilane) (PFS‐I) and characterized by 1H NMR, 13C NMR, and FT‐IR spectroscopy. The equilibrium swelling ratio, morphology, rheology, and redox responsive properties of the PFS‐PEG‐based hydrogel are reported.
7.
Min Ji Hwang Min Kyung Joo Bo Gyu Choi Min Hee Park Ian W. Hamley Byeongmoon Jeong 《Macromolecular rapid communications》2010,31(23):2064-2069
An aqueous solution of a poly(ethylene glycol)‐polycaprolactone‐poly(ethylene glycol) (PEG‐PCL‐PEG) with a composition of EG13CL23EG13 undergoes multiple transitions, from sol‐to‐gel (hard gel)‐to‐sol‐to‐gel (soft gel)‐to‐sol, in the concentration range 20.0∼35.0 wt.‐%. Through dynamic mechanical analysis, UV‐vis spectrophotometry, small angle X‐ray scattering, differential scanning calorimetry, microcalorimetry and 13C NMR spectroscopy, the mechanism of these transitions was investigated. The hard gel and soft gel are distinguished by the crystalline and amorphous state of the PCL. The extent of PEG dehydration and the molecular motion of each block also played a critical role in the multiple transitions. This paper suggests a new mechanism for these multiple transitions driven by temperature changes.
8.
Amphiphilic H‐shaped block copolymers (PTMSPMA)2PEG(PTMSPMA)2 with 91 ethylene glycol (EG) units and four PTMSPMA chains have been synthesized by atom transfer radical polymerization of trimethoxylsilylpropyl methacrylate (TMSPMA) at room temperature in methanol. The structure, molecular weight, and molecular weight distribution have been characterized by 1H NMR spectroscopy and GPC traces. These H‐shaped block copolymers can self‐assemble in DMF/water, and multiple vesicle aggregates from large‐compound vesicles, to multilayer vesicles and unilamillar vesicles are formed. These morphologies can be simply controlled by variation of the chain length ratios.
9.
A series of random copolymers and block copolymers containing water‐soluble 4AM and fluorescent VAK are synthesized by NMP. The homopolymerizations of 4AM and VAK and 4AM/VAK random copolymerization are performed in 50 wt% DMF using 10 mol% SG1, resulting in a linear increase in versus conversion, and final polymers with narrow molecular weight distributions ( < 1.4). Reactivity ratios rVAK = 0.64 ± 0.52 and r4AM = 0.86 ± 0.66 are obtained for the 4AM/VAK random copolymerization. In addition, a poly(4AM) macroinitiator is used to initiate a surfactant‐free suspension polymerization of VAK. After 2.5 h, the resulting amphiphilic block copolymer has = 12.6 kg · mol?1, = 1.48, molar composition FVAK = 0.38 with latex particle sizes between 270 and 475 nm.
10.
Sungjin Park Seung Woong Yoon Kyung‐Bok Lee Dong Jin Kim Young Hwan Jung Youngkyu Do Hyun‐jong Paik Insung S. Choi 《Macromolecular rapid communications》2006,27(1):47-50
Summary: We report a simple method for tuning catalytic property of a metallocene‐based catalyst, Cp2ZrCl2, for ethylene polymerization by the direct adsorption of Cp2ZrCl2 onto multi‐walled carbon nanotubes (MWCNTs). The direct interactions between MWCNTs and the Cp rings of Cp2ZrCl2 controlled the polymerization behaviors, and we could generate polyethylene with an extremely high molecular weight ( = 1 000 000) at 30 °C and under 1 atm of ethylene gas.
11.
Min‐Min Fan Zhi‐Jun Yu Hai‐Ya Luo Sheng Zhang Bang‐jing Li 《Macromolecular rapid communications》2009,30(11):897-903
A novel supramolecular network has been prepared based on the formation of inclusion complexes between γ‐cyclodextrin and poly(ethylene glycol), in which the PEG chains are interlocked by γ‐CD rings. This PEG/γ‐CD network exhibits good shape memory behavior because of the crosslinked structure. The crosslinked PEG/γ‐CD inclusion complexes and PEG crystallites account for the fixing phase and reversible phase, respectively. The characteristics of the materials have been investigated by 1H NMR spectroscopy, XRD, DSC, DMA, viscosity tests, and swelling measurements.
12.
Carlo Carlini Valentina De Luise Elizabeth Grillo Fernandes Marco Martinelli Anna Maria Raspolli Galletti Glauco Sbrana 《Macromolecular rapid communications》2005,26(10):808-812
Summary: The performances of ethylene polymerization catalysts based on III and commercial methylaluminoxane were investigated by reducing the content of free trimethylaluminum in methylaluminoxane by its reaction with 2,6‐di‐tert‐butylphenol. This allowed optimization of the formulation of the catalyst, affording a high‐molecular‐weight linear polyethylene (PE) with a productivity [(1 900 kg of PE/(mol of Ni × h)], ten‐fold higher than that previously achieved for the same system adopting commercial methylaluminoxane not pre‐treated with the above phenol derivative.
13.
Petra Feiertag Martin Albert Eva‐M. Ecker‐Eckhofen Gertraud Hayn Helmut Hnig Hanns W. Oberwalder Robert Saf Andreas Schmidt Oskar Schmidt Dmitrij Topchiev 《Macromolecular rapid communications》2003,24(9):567-570
Oligomeric guanidines can be obtained by polycondensation of guanidine hydrochloride and 1,2‐bis(2‐aminoethoxy)ethane. A comparative MALDI‐TOF mass spectrometry/NMR spectroscopy study with a 13C‐labeled sample enabled the unambiguous analysis of a guanidine‐based polymer. Among the four major product series unprecedented macrocyclic compounds were detected. The minimum inhibition concentrations for four different microorganisms were determined, showing excellent biocidal activities.
14.
Ikuo Taniguchi William A. Kuhlman Linda G. Griffith Anne M. Mayes 《Macromolecular rapid communications》2006,27(8):631-636
Summary: Commercial hydroxy‐terminated poly(ethylene glycol) monomethacrylates (PEG‐MAs) contain poly(ethylene glycol) dimethacrylate, which leads to unfavorable gel formation on polymerization. Here, hydroxy‐terminated PEG‐MA is readily isolated using a dimethylsilyl resin chlorinated with 1,3‐dichloro‐5,5‐dimethylhydantoin. Solution polymerization of the isolated PEG‐MA by free radical routes gives a high‐molecular‐weight amphiphilic graft copolymer without cross‐linking. The resulting polymer is stable for long periods in ambient conditions with preservation of the hydroxy end groups of PEG.
15.
Hunan Yi Ahmed Iraqi Mathew Stevenson Claire J. Elliott David G. Lidzey 《Macromolecular rapid communications》2007,28(10):1155-1160
Attachment of triarylamino‐functional groups at the 9‐position of 2,7‐linked carbazole polymers results in blue‐emitting materials with two independent redox processes that were attributed to the triarylamino groups and the polymer backbone, respectively. This new class of blue‐emitting conjugated polymers was prepared via a Suzuki cross‐coupling reaction and showed low turn‐on voltages in electroluminescent devices as a result of their low ionisation potentials. The photophysical, electrochemical and electroluminescent properties of these materials are discussed.
16.
Milena Ignatova Nevena Manolova Victoria Lachkova Sabi Varbanov Iliya Rashkov 《Macromolecular rapid communications》2008,29(23):1871-1876
Polystyrene microfibers containing lower‐rim substituted calix[4]arene with phosphinoyl pendant arms were easily prepared in one‐step procedure by electrospinning. A specific feature of the fibers is the difference in their functionality at the surface and in the bulk. The graded structure of the fibers was shown by XPS analyses. The calix[4]arene concentration in the 3–5 nm surface layer was 50% higher than the theoretically calculated if calix[4]arene was uniformly distributed in the fibers. A six‐coordinated complex was formed between the calix[4]arene included in the fibers and Ni2+ ions. The distribution of phosphorus along the fibers is uniform, as evidenced by X‐ray mapping.
17.
Sung‐Wook Choi Yongwoo Kim In Woo Cheong Jung‐Hyun Kim 《Macromolecular rapid communications》2008,29(2):175-180
This paper aims to report the fabrication of biodegradable thin films with micro‐domains of cylindrical nanochannels through the solvent‐induced microphase separation of poly(L ‐lactide)‐block‐poly(ethylene glycol)‐block‐poly(L ‐lactide) (PLA‐b‐PEG‐b‐PLA) triblock copolymers with different block ratios. In our experimental scope, an increase in each of the block lengths of the PLA and PEG blocks led to both a variation in the average number density (146 to 32 per 100 µm2) and the size of the micro‐domains (140 to 427 nm). Analyses by atomic force microscopy (AFM) and fluorescence microscopy indicated that the hydrophilic PEG nanochannels were dispersed in the PLA matrix of the PLA‐b‐PEG‐b‐PLA films. We demonstrated that the micro‐domain morphology could be controlled not only by the block length of PEG, but also by the solvent evaporation conditions.
18.
Veronica Marin Elisabeth Holder Michael A. R. Meier Richard Hoogenboom Ulrich S. Schubert 《Macromolecular rapid communications》2004,25(7):793-798
Summary: An amino‐functionalized bipyridine ligand was prepared in order to serve as a bridging unit to an activated low‐molecular‐weight monomethyl ether of poly(ethylene glycol) (PEG). Coordination of a ruthenium(II ) phenantroline precursor onto the formed PEG‐containing bipyridine ligand yielded a metal‐containing polymer which shows interesting properties for solar cell applications.
19.
Gelation of the reaction mixture and insolubility of the poly(p‐phenylene vinylenes) (PPVs) when isolated at this stage, but complete redissolution of the gel and excellent solubility of the resulting PPVs after further stirring for hours or days, is a phenomenon in Gilch polymerizations that has not been explained so far. It is verified that, in agreement with the literature, specific additives prevent gelation. However, it is also shown that chemical crosslinking is certainly not the reason for gel formation. Instead, it seems to be the consequence of a very high entanglement density in the pristine PPVs, which requires time for relaxation. The mentioned additives seem to support this dis‐entanglement process.
20.
Abraham Chemtob Valrie Heroguez Yves Gnanou 《Macromolecular rapid communications》2005,26(21):1711-1715
Summary: Fully linear polyethylene‐based latexes have been prepared by the hydrogenation of polybuta‐1,4‐diene dispersions. The latter were synthesized via dispersion ring‐opening metathesis polymerization of cycloocta‐1,5‐diene, and hydrogenated using RuCl2(PPh3)3 as catalyst, without any further treatment. A high hydrogenation efficiency was achieved as demonstrated by different techniques including DSC, and 1H NMR and FT‐IR spectroscopy. The hydrogenation process could be carried out without detrimental effect on particle size and colloidal stability as evidenced by optical microscopy and light scattering analysis.