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Macromonomers
Selected AbstractsSynthesis of Substituted Polyacetylenes Grafted with Polystyrene Chains by the Macromonomer Method and Their CharacterizationMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 11 2006Wei Zhang Abstract Summary: A macromonomer (1) consisting of a polystyrene chain and an acetylenic chain end (,=,2,500, ,=,1.20) was prepared by atom transfer radical polymerization. Macromonomer 1 was copolymerized with phenylacetylene (2) and propargyl 2-bromopropionate (3) by using Rh catalysts at varying feed ratios from 10 to 50 wt.-% to produce graft copolymers 4 and 5, respectively. The synthesized copolymers 4 and 5 possessed a conjugated polyene main-chain and polystyrene grafts, and contained 11,34 and 16,77 wt.-% of polystyrene with of 61,400,144,000 and 19,300,22,500, respectively. Graft copolymer 4 was a yellow solid and thermally stable up to 225,°C, whereas 5 was a brown solid with weight loss beginning at 175,°C. Graft copolymers 4 and 5 exhibited UV-vis absorption edges at 525 and 425 nm, respectively, which are attributable to the conjugated main-chain structure. Copolymerization of the acetylene-terminated polystyrene-based macromonomer with monosubstituted acetylenes. [source] Synthesis of a New Macromonomer from 2-(Dimethylamino)ethyl Methacrylate Bearing 1-(Isopropenylphenyl)-1,1-dimethylmethyl Isocyanate GroupMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 5 2004Cyril Boyer Abstract Summary: The telomerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with 2-mercaptoethanol in acetonitrile shows that the telogen can react with the monomer by nucleophilic addition. It is to say that the tertiary amino group leads to nucleophilic addition rather than telomerization. The oligomers thus obtained were functionalized with 1-(isopropenylphenyl)-1,1-dimethylmethyl isocyanate (TMI) in anhydrous toluene to afford macromonomers. These macromonomers were copolymerized with styrene and the r1, r2 ratio was determined according to Jaacks and Macret's methods. It was thereby demonstrated that the r1 value for this type of monomer is close to zero. Structure of the model molecule. [source] Chain Transfer and Efficiency of End-Group Introduction in Free Radical Polymerization of Methyl Methacrylate in the Presence of Poly(methyl methacrylate) MacromonomerMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2004Kazuki Miyake Abstract Summary: Experimental and modeling studies of addition,fragmentation chain transfer (AFCT) during radical polymerization of methyl methacrylate in the presence of poly(methyl methacrylate) macromonomer with 2-carbomethoxy-2-propenyl , -ends (PMMA-CO2Me) at 60,°C are reported. The results revealed that AFCT involving PMMA-CO2Me formed in situ during methyl methacrylate polymerization has a negligible effect on the molecular weight distribution. [source] Preparation of Core-shell Microspheres by ATRP Synthesized MacromonomerCHINESE JOURNAL OF CHEMISTRY, Issue 10 2008Hong CHU Abstract Poly(tert -butyl methacrylate) macrointermediates (PtBMA-Br) with an end of bromine atom were synthesized by atom transfer radical polymerization using ethylbromopropionate as an initiator in bulk in the presence of N,N,N,,N,,,N,, -pentamethyl diethylenetriamine (PMDETA) as a single ligand. A new macromonomer (MAA- PtBMA) was successfully prepared via end-group nucleophilic substitution with methacrylic acid to attain a high efficiency of C=C incorporation. The molecular weights of MAA-PtBMA macromonomers were controllable from 5400 to 11000 g/mol, and the molecular weight distribution was narrow (,1.20). Then, the PtBMA graft polystyrene (PtBMA-g-PSt) microspheres were prepared by dispersion copolymerization of MAA-PtBMA macromonomers with styrene using 2,2,-azobisisobutyronitrile as a free radical initiator in ethanol. The resulting PtBMA-g-PSt microspheres were regulated in diameter on a micron scale. [source] Synthesis of a linear polyethylene macromonomer and preparation of polystyrene- graft -polyethylene copolymers via grafting-through atom transfer radical polymerization,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Hiromu Kaneyoshi Abstract A vinyl-terminated linear polyethylene (number-average molecular weight = 1800, weight-average molecular weight/number-average molecular weight = 1.7, functionality = 92%) prepared by ethylene coordination polymerization was transformed into a monohydroxy-terminated linear polyethylene by hydroalumination of the vinyl group with diisobutylaluminum hydride and subsequent oxidation and hydrolysis. This monohydroxy-terminated linear polyethylene was quantitatively converted into a linear polyethylene macromonomer with a terminal ,-methacrylate group through esterification followed by dehydrobromination. A grafting-through atom transfer radical polymerization of the ,-methacrylate-terminated polyethylene and styrene was performed to yield a well-defined polystyrene- graft -polyethylene copolymer. The number-average molecular weight of the graft copolymers, measured by gel permeation chromatography, was lower than the predetermined number-average molecular weight, presumably because of the intramolecular aggregation of polyethylene side chains. The ,-methacrylate-terminated polyethylene content and number-average molecular weight of polystyrene- graft -polyethylene were determined by 1H-NMR. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 3,13, 2007 [source] Star polymers by cross-linking of linear poly(benzyl- L -glutamate) macromonomers via free-radical and RAFT polymerization.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2010A simple route toward peptide-stabilized nanoparticles Abstract Poly(benzyl- L -glutamate) (PBLG) macromonomers were synthesized by N -carboxyanhydride (NCA) polymerization initiated with 4-vinyl benzylamine. MALDI-ToF analysis confirmed the presence of styrenic end-groups in the PBLG. Free-radical and RAFT polymerization of the macromonomer in the presence of divinyl benzene produced star polymers of various molecular weights, polydispersity, and yield depending on the reaction conditions applied. The highest molecular weight (Mw) of 10,170,000 g/mol was obtained in a free-radical multibatch approach. It was shown that the PBLG star polymers can be deprotected to obtain poly(glutamic acid) star polymers, which form water soluble pH responsive nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Titanium-mediated [CpTiCl2(OEt)] ring-opening polymerization of lactides: A novel route to well-defined polylactide-based complex macromolecular architecturesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2010Nikolaos Petzetakis Abstract Among three cyclopentadienyl titanium complexes studied, CpTiCl2(OEt), containing a 5% excess CpTiCl3, has proven to be a very efficient catalyst for the ring-opening polymerization (ROP) of L -lactide (LLA) in toluene at 130 °C. Kinetic studies revealed that the polymerization yield (up to 100%) and the molecular weight increase linearly with time, leading to well-defined PLLA with narrow molecular weight distributions (Mw/Mn , 1.1). Based on the above results, PS- b -PLLA, PI- b -PLLA, PEO- b -PLLA block copolymers, and a PS- b -PI- b -PLLA triblock terpolymer were synthesized. The synthetic strategy involved: (a) the preparation of OH-end-functionalized homopolymers or diblock copolymers by anionic polymerization, (b) the reaction of the OH-functionalized polymers with CpTiCl3 to give the corresponding Ti-macrocatalyst, and (c) the ROP of LLA to afford the final block copolymers. PMMA- g -PLLA [PMMA: poly(methyl methacrylate)] was also synthesized by: (a) the reaction of CpTiCl3 with 2-hydroxy ethyl methacrylate, HEMA, to give the Ti-HEMA-catalyst, (b) the ROP of LLA to afford a PLLA methacrylic-macromonomer, and (c) the copolymerization (conventional and ATRP) of the macromonomer with MMA to afford the final graft copolymer. Intermediate and final products were characterized by NMR spectroscopy and size exclusion chromatography, equipped with refractive index and two-angle laser light scattering detectors. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1092,1103, 2010 [source] Polymerization of N -isopropylacrylamide in the presence of poly(acrylic acid) and poly(methacrylic acid) containing ,-unsaturated end-groupsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2007Ronan Mchale Poly(N -Isopropylacrylamide, NIPAM) propagating radicals add to acrylic acid (AA) macromonomer and methacrylic acid polymer containing unsaturated ,-end-group to respectively give novel graft copolymer (represented as , (AA) and , (NIPAM) units) and addition fragmentation chain transfer (AFCT). [Color figure can be viewed in the online issue, which is available at www.interscience.wiley. com.] [source] Frontal free-radical copolymerization of urethane,acrylatesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2006Ting Hu Abstract We report the first synthesis of urethane,acrylate copolymers via free-radical frontal polymerization. In a typical run, the appropriate amounts of the reactants (urethane,acrylate macromonomer and 2-hydroxyethyl acrylate) and initiator (ammonium persulfate) were dissolved in dimethyl sulfoxide. Frontal polymerization was initiated by the heating of the wall of the tube with a soldering iron, and the resultant hot fronts were allowed to self-propagate throughout the reaction vessel. Once it was initiated, no further energy was required for the polymerization to occur. The dependence of the front velocity and front temperature on the initiator concentration was investigated. The front temperatures were between 55 and 65 °C, depending on the persulfate concentration. Thermogravimetric analysis indicated that the urethane,acrylate copolymers had higher thermal stability than pure frontally prepared polyurethane. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3018,3024, 2006 [source] Synthesis and characterization of poly(ethylene oxide- co -ethylene carbonate) macromonomers and their use in the preparation of crosslinked polymer electrolytesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2006Anette Munch Elmér Abstract Methacrylate-functionalized poly(ethylene oxide- co -ethylene carbonate) macromonomers were prepared in two steps by the anionic ring-opening polymerization of ethylene carbonate at 180 °C, with potassium methoxide as the initiator, followed by the reaction of the terminal hydroxyl groups of the polymers with methacryloyl chloride. The molecular weight of the polymer went through a maximum after approximately 45 min of polymerization, and the content of ethylene carbonate units in the polymer decreased with the reaction time. A polymer having a number-average molecular weight of 2650 g mol,1 and an ethylene carbonate content of 28 mol % was selected and used to prepare a macromonomer, which was subsequently polymerized by UV irradiation in the presence of different concentrations of lithium bis(trifluoromethanesulfonyl)imide salt. The resulting self-supportive crosslinked polymer electrolyte membranes reached ionic conductivities of 6.3 × 10,6 S cm,1 at 20 °C. The coordination of the lithium ions by both the ether and carbonate oxygens in the polymer structure was indicated by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2195,2205, 2006 [source] Synthesis of poly[N -isopropylacrylamide- g -poly(ethylene glycol)] with a reactive group at the poly(ethylene glycol) end and its thermosensitive self-assembling characterJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2006Michihiro Iijima Abstract Poly[N -isopropylacrylamide- g -poly(ethylene glycol)]s with a reactive group at the poly(ethylene glycol) (PEG) end were synthesized by the radical copolymerization of N -isopropylacrylamide with a PEG macromonomer having an acetal group at one end and a methacryloyl group at the other chain end. The temperature dependence of the aqueous solutions of the obtained graft copolymers was estimated by light scattering measurements. The intensity of the light scattering from aqueous polymer solutions increased with increasing temperature. In particular, at temperatures above 40°C, the intensity abruptly increased, indicating a phase separation of the graft copolymer due to the lower critical solution temperature (LCST) of the poly(N -isopropylacrylamide) segment. No turbidity was observed even above the LCST, and this suggested a nanoscale self-assembling structure of the graft copolymer. The dynamic light scattering measurements confirmed that the size of the aggregate was in the range of several tens of nanometers. The acetal group at the end of the PEG graft chain was easily converted to the aldehyde group by an acid treatment, which was analyzed by 1H NMR. Such a temperature-induced nanosphere possessing reactive PEG tethered chains on the surface is promising for new nanobased biomedical materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1457,1469, 2006 [source] Preparation and polymerization of a water-soluble, nonbonding crosslinking agent for a mechanically crosslinked hydrogelJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2005Masataka Kubo Abstract A novel water-soluble cyclic macromonomer based on a cyclic potassium polyacrylate was prepared. The radical polymerization of acrylamide in the presence of the cyclic macromonomer was carried out to obtain a mechanically crosslinked polyacrylamide. The terpolymerization of acrylamide, sodium acrylate, and the cyclic macromonomer gave a mechanically crosslinked polyelectrolyte with high swellability. The mechanically crosslinked polyelectrolyte exhibited large volume shrinkage in a water solution of Cu(II) salt. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5032,5040, 2005 [source] High molecular weight monodisperse polystyrene microspheres prepared by dispersion polymerization, using a novel bifunctional macromonomerJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2005Hyejun Jung Abstract A novel bifunctional vinyl-terminated polyurethane macromonomer was applied to the dispersion polymerization of styrene in ethanol. Monodisperse polystyrene (PS) microspheres were successfully obtained above 15 wt % of macromonomer relative to styrene. The steep slope from the reduction of the average particle size reveals that the macromonomer can efficiently stabilize higher surface area of the particles when compared with a conventional stabilizer, poly(N -vinylpyrrolidone). The stable and monodisperse PS microspheres having the weight-average diameter of 1.2 ,m and a good uniformity of 1.01 were obtained with 20 wt % polyurethane macromonomer. The grafting ratio of the PS calculated from 1H NMR spectra linearly increased up to 0.048 with 20 wt % of the macromonomer. In addition, the high molecular weights (501,300 g/mol) of PS with increased glass transition and enhanced thermal degradation temperature were obtained. Thus, these results suggest that the bifunctional vinyl-terminated polyurethane macromonomer acts as a reactive stabilizer, which gives polyurethane-grafted PS with a high molecular weight. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3566,3573, 2005 [source] Synthesis and characterization of new alternating, amphiphilic, comblike copolymers of poly(ethylene oxide) macromonomer and N -phenylmaleimideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2005Luminita Cianga Abstract A surface-active p -vinyl benzyloxy-,-hydroxy-poly(ethylene oxide) macromonomer containing 22 pendant structural units of ethylene oxide (St,PEO22) was synthesized with an initiation method. Because of its solubility in a large variety of solvents, the free-radical copolymerization with electron-acceptor N -phenylmaleimide (NPMI) was performed at 60 °C in benzene and tetrahydrofuran (THF) as isotropic media and in a water,THF mixture or water as a heterogeneous medium. Oil-soluble 2,2,-azobisisobutyronitrile and water-soluble 4,4,-azobis(4-cyanovaleric acid) were used as the initiators at fixed concentrations. Two different St,PEO22/NPMI comonomer ratios (1/1 and 3/7) at a fixed total comonomer concentration in the polymerization system were used. The structures, compositions, and microstructure peculiarities of the obtained alternating, amphiphilic, comblike copolymers were determined by NMR analysis. For the copolymers synthesized in hydrophilic media, differential scanning calorimetry showed, near the endothermic peak attributed to the melting of the poly(ethylene oxide) side chains, the presence of a second peak due to the partially ordered phase that could exist between the crystalline state and the isotropic melt. Also, the thermal stability of the obtained copolymers was studied with thermogravimetric analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 479,492, 2005 [source] Novel synthesis of polyethylene,poly(dimethylsiloxane) copolymers with a metallocene catalystJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2004Andrés E. Ciolino Abstract Polyethylene,poly(dimethylsiloxane) copolymers were synthesized in solution from an ethylene monomer and an ,-vinyl poly(dimethylsiloxane) (PDMS) macromonomer at 363 and 383 K with EtInd2ZrCl2/methylaluminoxane as a catalyst. The copolymers obtained were characterized with Fourier transform infrared spectroscopy, 1H and 13C NMR, size exclusion chromatography, and differential scanning calorimetry. The rheological properties of the molten polymers were determined under dynamic shear flow tests at small-amplitude oscillations, whereas the physical arrangement of the phase domains was analyzed with scanning electron microscopy (SEM)/energy dispersive X-ray (EDX). The analysis of the catalyst activity and the resulting polymers supported the idea of PDMS blocks or chains grafted to polyethylene. The changes in the rheological behavior and the changes in the Fourier transform infrared and NMR spectra were in agreement with this proposal. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2462,2473, 2004 [source] Synthesis of polybutadiene-based particles via dispersion ring-opening metathesis polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2004Abraham Chemtob Abstract Latex particles based on 1,4-polybutadiene were synthesized via dispersion ring-opening metathesis copolymerization of 1,5-cyclooctadiene with a ,-norbornenyl poly(ethylene oxide) macromonomer. Stable but polydisperse colloidal dispersions in the 50 nm to 10 ,m size range were obtained. In this work, particular attention was paid to the effects of the kinetics of copolymerization on the structure of the graft copolymers formed and on the onset of turbidity. Strategies to prepare monodisperse polybutadiene particles were also designed through the growth of a polybutadiene shell from a well-defined polynorbornene seed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1154,1163, 2004 [source] Synthesis of branched polypropylene with isotactic backbone and atactic side chains by binary iron and zirconium single-site catalystsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2003Zhibin Ye Abstract This article reports the use of a binary single-site catalyst system for synthesizing comb-branched polypropylene samples having isotactic polypropylene (iPP) backbones and atactic polypropylene (aPP) side chains from propylene feedstock. This catalyst system consisted of the bisiminepyridine iron catalyst {[2-ArNC(Me)]2C5H3N}FeCl2 [Ar = 2,6-C6H3(Me)2] (1) and the zirconocene catalyst rac -Me2Si(2-MeBenz[e]Ind)2ZrCl2 (2). The former in situ generated 1-propenyl-ended aPP macromonomer, whereas the latter incorporated the macromonomer into the copolymer. The effects of reaction conditions, such as the catalyst addition procedure and the ratio of 1/2 on the branching frequency, were examined. Copolymer samples having a branching density up to 8.6 aPP side chains per 1000 iPP monomer units were obtained. The branched copolymers were characterized by 13C NMR and differential scanning calorimetry. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1152,1159, 2003 [source] Multisensitive polymers based on 2-vinylpyridine and N -isopropylacrylamide ,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2001Sebastian Wohlrab Abstract Poly(2-vinylpyridine) (P2VP) containing functionalized end groups was synthesized using nitroxyl-mediated radical polymerization with a hydroxy-functionalized stable free radical. It was shown that P2VP could be synthesized with variable molar masses and low polydispersities. The transformation of the hydroxy groups to an acrylic ester led to the formation of macromonomers. A free-radical copolymerization of these macromonomers with N -isopropylacrylamide gave a graft copolymer with a poly(N -ispopropylacrylamide) backbone and P2VP side chains. Polymers containing different amounts of the monomers were synthesized. It was possible to vary both the amount of P2VP side chains at a constant chain length of the macromonomer and the chain length at a nearly constant chain number. The behavior of the multifunctional macromolecules at different temperatures and pH values was investigated using dynamic light scattering and DSC. The macromolecules were found to retain the specific properties of the homopolymers. The hydrodynamic radii of the synthesized graft copolymers were both dependent on the temperature and pH value. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3797,3804, 2001 [source] A novel solid phase for selective separation of flavonoid compoundsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2007Yong-qing Xia Abstract A novel straightforward approach to selective separation for flavonoid compounds was reported. The solid phase material was prepared by copolymerization using allyl-bromide-modified chitosan as macromonomer, and ethylene glycol dimethacrylate as cross-linker. The material was evaluated by chromatographic analysis; it exhibited high selectivity separation for quercetin and its structural analogues using different mobile phases. The material could directly trap a specific class of compounds including quercetin and kaempferol from the hydrolyzate of Ginkgo biloba extract. These results demonstrated the possibility of direct extraction of certain constituents from herb using this material. [source] Preparation of Cross-Linked Poly[(, -caprolactone)- co -lactide] and Biocompatibility Studies for Tissue Engineering MaterialsMACROMOLECULAR BIOSCIENCE, Issue 1 2007Hiroshi Miyasako Abstract In this study, cross-linked materials were prepared using the branched macromonomer with different CL/LA molar ratios, and feasibility studies for tissue engineering were carried out. The thermal and mechanical properties of these materials depended on the CL/LA compositions; however, there was no change in the wettability of each material. The HeLa cells adhesion and growth on the CL-LA7030c were equal to that on the commercially available polystyrene dish. The protein absorption experiment using the FBS proteins revealed that the materials with well-grown cells showed better adhesion of the proteins. [source] Principle of a New Immunoassay Based on Electrophoretic Mobility of Poly(styrene/, - tert -butoxy- , -vinylbenzyl-polyglycidol) Microspheres: Application for the Determination of Helicobacter pylori IgG in Blood SerumMACROMOLECULAR BIOSCIENCE, Issue 1 2005Teresa Basinska Abstract Summary: The principle of a novel latex diagnostic test for the determination of antibodies against Helicobacter pylori in blood sera is described. The test is based on the measurement of the electrophoretic mobility of the microspheres with immobilized H. pylori antigens. The electrophoretic mobility of these microspheres depends on the concentration of the antibodies against H. pylori in suspending medium. Particles with hydrophilic polyglycidol in the surface layer were used for the test. The microspheres were obtained by an emulsifier-free emulsion copolymerization of styrene and , - tert -butoxy- , -vinylbenzyl-polyglycidol macromonomer (,=,220 nm, diameter polydispersity factor ,=,1.02). Activation of polyglycidol hydroxyl groups with cyanuric chloride allowed for covalent immobilization of H. pylori antigens. The fraction of H. pylori not specifically adsorbed onto the microspheres was negligible. Changes of the electrophoretic mobility of the microspheres with the surface concentration of the covalently immobilized H. pylori antigens ,,=,(1.6,±,0.3),·,10,3 g m,2 were suitable for the detection of the antibodies in the sera of patients with titer in the range (determined by the indirect ELISA test) from 1:500 to 1:32,000. [source] Structure and Properties of Poly(, -caprolactone) Networks with Modulated Water UptakeMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 23 2006Jorge L. Escobar Ivirico Abstract Summary: A PCL macromonomer was obtained by the reaction of PCL diol with methacrylic anhydride. The effective incorporation of the polymerizable end groups was assessed by FT-IR and 1H NMR spectroscopy. PCL networks were then prepared by photopolymerization of the PCL macromonomer. Furthermore, the macromonomer was copolymerized with HEA, with the aim of tailoring the hydrophilicity of the system. A set of hydrophilic semicrystalline copolymer networks were obtained. The phase microstructure of the new system and the network architecture was investigated by DSC, IR, DMS, TG, dielectric spectroscopy and water sorption studies. The presence of the hydrophilic units in the system prevented PCL crystallization on cooling; yet there was no effect on the glass transition process. The copolymer networks showed microphase separation and the , relaxation of the HEA units moved to lower temperatures as the amount of PCL in the system increased. Ideal structure, compatible with the experimental results, for the hydrophilized poly(, -caprolactone) networks with modulated water uptake. [source] Electroactive Copolymers with Oligoanilines in the Main Chain via Oxidative Coupling PolymerizationMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 18 2006Danming Chao Abstract Summary: By oxidative coupling polymerization of the macromonomer of oligoaniline and p -phenylenediamine, we have prepared an electroactive copolymer, exhibiting an exciting molecular structure, and interesting spectroscopic and electrochemical properties. The polymerization characteristics and structure of the copolymer were systematically studied by gel permeation chromatography (GPC), Fourier-transform infrared (FTIR) spectroscopy, 1H NMR spectroscopy and X-ray powder diffraction (XRD). UV-vis spectra were used to monitor the chemical oxidation process of the reduced copolymer. The electrochemical activity of the copolymer was tested in 1.0 M H2SO4 aqueous solution. Three redox peaks were shown, which is different to that for polyaniline. The thermal properties of the copolymer were also evaluated, by thermogravimetric analysis (TGA); the electrical conductivity is about 5.53,×,10,5 Scm,1 at room temperature, upon a preliminarily, proton-doped experiment. Synthesis of the copolymer. [source] Synthesis of Substituted Polyacetylenes Grafted with Polystyrene Chains by the Macromonomer Method and Their CharacterizationMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 11 2006Wei Zhang Abstract Summary: A macromonomer (1) consisting of a polystyrene chain and an acetylenic chain end (,=,2,500, ,=,1.20) was prepared by atom transfer radical polymerization. Macromonomer 1 was copolymerized with phenylacetylene (2) and propargyl 2-bromopropionate (3) by using Rh catalysts at varying feed ratios from 10 to 50 wt.-% to produce graft copolymers 4 and 5, respectively. The synthesized copolymers 4 and 5 possessed a conjugated polyene main-chain and polystyrene grafts, and contained 11,34 and 16,77 wt.-% of polystyrene with of 61,400,144,000 and 19,300,22,500, respectively. Graft copolymer 4 was a yellow solid and thermally stable up to 225,°C, whereas 5 was a brown solid with weight loss beginning at 175,°C. Graft copolymers 4 and 5 exhibited UV-vis absorption edges at 525 and 425 nm, respectively, which are attributable to the conjugated main-chain structure. Copolymerization of the acetylene-terminated polystyrene-based macromonomer with monosubstituted acetylenes. [source] Novel Polyolefins Containing Crystallizable Isotactic Polystyrene Side ChainsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 18 2008Barbara T. Gall Abstract Vinyl-terminated isotactic polystyrene macromonomers were copolymerized with ethylene and 1-octene to new polyolefin graft copolymers with crystallizable polystyrene side chains. The iPS content was varied from 4 to 78 wt.-% using different metallocene and halfsandwich catalysts. No solubility problems of the stereoregular macromonomer occured, because iPS does not crystallize during polymerization. In addition the polymers show nanophase separation of the polyolefin backbone and the iPS side chains. The crystallization of iPS, having a melting point of about 200,°C, can be achieved by annealing. This synthesis strategy allows the fabrication of a new class of thermoplastic elastomers with improved heat distortion temperatures. [source] Electropolymerizable Terthiophene S,S -Dioxide-Fullerene Diels-Alder Adduct for Donor/Acceptor Double-Cable PolymersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 12 2007Yolanda Vida Abstract The preparation of a novel fullerene-thiophene derivative by Diels-Alder addition of terthiophene S,S -dioxide was demonstrated. Extrusion of SO2 from the adduct is an effective process that yields a stable cyclohexadiene-1,4-bisthiophene,C60 adduct in good isolable yield. The product has been accurately characterized and opens the way to synthesize new C60 derivatives "via" Diels-Alder methodology without the possibility of cycloreversion. Electrochemical and spectroscopic properties of this macromolecule were studied and supported by theoretical calculations to interpret its electronic structure. The first approach to the electropolymerization of this macromonomer produces donor-acceptor molecular wires providing a new and versatile way to fullerene-based double cable polymers. [source] Poly(ethylene glycol) Surface Coated Magnetic ParticlesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 18 2005Christophe Flesch Abstract Summary: A methacrylate-functionalized poly(ethylene glycol) macromonomer was copolymerized at the surface of methacrylate-derivatized maghemite nanoparticles. After silylation of the magnetic core with methacryloxypropyltrimethoxysilane, two grafting procedures based on either a direct copolymerization reaction in water or an inverse emulsion polymerization were compared. A direct copolymerization led to low polymer surface amounts, whereas an inverse emulsion process allowed nanocomposite particles containing up to 90 wt.-% polymer to be obtained. TEM picture of maghemite-PEG hybrid particles. [source] Chain Transfer and Efficiency of End-Group Introduction in Free Radical Polymerization of Methyl Methacrylate in the Presence of Poly(methyl methacrylate) MacromonomerMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2004Kazuki Miyake Abstract Summary: Experimental and modeling studies of addition,fragmentation chain transfer (AFCT) during radical polymerization of methyl methacrylate in the presence of poly(methyl methacrylate) macromonomer with 2-carbomethoxy-2-propenyl , -ends (PMMA-CO2Me) at 60,°C are reported. The results revealed that AFCT involving PMMA-CO2Me formed in situ during methyl methacrylate polymerization has a negligible effect on the molecular weight distribution. [source] Polymacromonomers with polyolefin branches synthesized by free-radical homopolymerization of polyolefin macromonomer with a methacryloyl end groupMACROMOLECULAR SYMPOSIA, Issue 1 2004Hideyuki Kaneko Abstract Polymacromonomers with polyolefin branches were successfully synthesized by free-radical homopolymerization of polyolefin macromonomer with a methacryloyl end group. Propylene-ethylene random copolymer (PER) with a vinylidene end group was prepared by polymerization using a metallocene catalyst. Then, the unsaturated end group was converted to a hydroxy end group via hydroalumination and oxidation. The PER with the hydroxy end group was easily reacted with methacryloyl chloride to produce methacryloyl-terminated PER (PER macromonomer; PERM). The free-radical polymerization of thus-obtained PERM was done using 2,2,-azobis(isobutyronitorile) (AIBN) as a free-radical initiator. From NMR analyses, the obtained polymers were identified as poly(PERM). Based on gel permeation chromatography (GPC), the estimated degree of polymerization (Dp) of these polymers were about 30. Thus, new class of polymacromonomers with polyolefin branches was synthesized. [source] Synthesis of graft and block copolymers from 2-dimethylaminoethyl methacrylate and caprolactonePOLYMER INTERNATIONAL, Issue 8 2007Shaheen Motala-Timol Abstract This paper outlines the synthesis of a range of graft and block copolymers containing 2-dimethylaminoethyl methacrylate and caprolactone sequences by means of two distinct strategies. In the first place, common to both pathways, low-molar-mass hydroxyl end-capped polycaprolactone (PCL-OH) was prepared by the ring-opening polymerization of caprolactone in the presence of an aluminium alkoxide Schiff's base (HAPENAlOiPr) as initiator followed by hydrolysis of the AlO bond. For the synthesis of copolymers with a main vinyl carbon,carbon backbone and PCL grafts, PCL-OH was initially converted into ,-methacryl-PCL using methacryloyl chloride. This macromonomer was then copolymerized with 2-dimethylaminoethyl methacrylate (DMAEMA) by atom transfer radical polymerization (ATRP). For the synthesis of block copolymers, PCL-OH was first transformed into a bromine end-capped PCL (PCL-Br) with 2-bromoisobutyryl bromide. PCL-Br was then used as macroinitiator in various concentrations for the ATRP of 2-dimethylaminoethyl methacrylate, thus leading to PCL and poly(DMAEMA) blocks of varying lengths. The formation of both graft and block copolymers was thoroughly checked using NMR and size exclusion chromatography. Copyright © 2007 Society of Chemical Industry [source] | |||||||||||||