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Resulting Copolymers (resulting + copolymer)
Selected AbstractsRegioselective Grafting of Poly(ethylene glycol) onto Chitosan and the Properties of the Resulting CopolymersMACROMOLECULAR BIOSCIENCE, Issue 10 2006Li Liu Abstract Summary: PEG was grafted onto chitosan regioselectively at the hydroxyl groups with phthaloylchitosan as an intermediate. After the graft reaction, the phthaloyl groups were deprotected to give chitosan- g -PEG copolymers with free amino groups. The chemical structure of the graft copolymers was confirmed by FT-IR, 1H and 13C NMR spectroscopy. The resulting graft copolymers showed improved thermal stability compared to the original chitosan, and showed a lower thermal transition temperature at around 185,°C. Chitosan- g -PEG exhibited a high affinity not only for aqueous acid but also for some organic solvents because of the presence of abundant free amino groups and PEG branches, and it exhibited higher hygroscopicity and moisture retention ability than chitosan. [source] Copolymerization of norbornene and styrene catalyzed by a novel anilido,imino nickel complex/methylaluminoxane systemJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2006Haiyang Gao Abstract Copolymerizations of norbornene with styrene were carried out with a catalytic system of anilido,imino nickel complex (ArNCHC6H4NAr)NiBr (Ar = 2,6-dimethylphenyl) and methylaluminoxane in toluene. The influence of the comonomer feed content and polymerization temperature on the conversion and composition of the copolymers with (ArNCHC6H4NAr)NiBr/methylaluminoxane was investigated. An increase in the initial styrene feed content led to an increase in the incorporated styrene content of the resulting copolymer. The determination of the reactivity ratios showed a much high reactivity for norbornene (reactivity ratio for styrene = 0.26, reactivity ratio for norbornene = 20.78), which was consistent with a coordination mechanism. NMR analysis of the end groups further confirmed that the chain was initiated through a styrene secondary insertion or a norbornene insertion into NiH and terminated through ,-H elimination from an inserted styrene unit. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5237,5246, 2006 [source] Copolymerization of ethylene and N -(vinylphenyl)carbazole with titanium and zirconium catalystsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2005Naofumi Naga Copolymerization of ethylene and N -(vinylphenyl)carbazole (VPC) was investigated with dimethylsilylene(tetramethylcyclopentadienyl)(N-tert -butyl)titanium dichloride (1) and isopropylidenebis(indenyl)zirconium dichloride (2) catalysts. The corresponding copolymers were obtained in the copolymerization, and the copolymerization behavior and structure of the resulting copolymer were studied. [source] A Novel ABC Triblock Copolymer with Very Low Surface Energy: Poly(dimethylsiloxane)- block -Poly(methyl methacrylate)- block -Poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate)MACROMOLECULAR REACTION ENGINEERING, Issue 5 2008Zhenghong Luo Abstract Poly(dimethylsiloxane)- block -poly(methyl methacrylate)- block -poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate) was successfully synthesized via ATRP. The chemical composition and structure of the copolymer was characterized by NMR and FT-IR spectroscopy and molecular weight measurement. Gel permeation chromatography was used to study the molecular weight distribution of the triblock copolymer. The surface properties of the resulting copolymer were investigated. The effects of fluorine content and bulk structure on surface energy were investigated by static water contact angle measurements. Surface composition was studied by XPS. [source] UV Absorption and Photoisomerixation of p -Methoxycinnamate Grafted Silicone,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2004Supason Pattanaargson ABSTRACT p -Methoxycinnamate moieties, UV-B-absorptive chromophores of the widely used UV-B filter, 2-ethylhexyl p -methoxycinnamate (OMC), were grafted onto the 7 mol% amino functionalized silicone polymer through amide linkages. Comparing with OMC, the resulting poly [3(p -methoxycinnamido)(propyl)(methyl)-dimethyl] siloxane copolymer (CAS) showed less E to Z isomerization when exposed to UV-B light. The absorption profiles of the product showed the maximum absorption wavelength to be similar to that of OMC but with less sensitivity to the type of solvent. Poly (methylhydrosiloxane) grafted with 10 mol%p -methoxycinnamoyl moieties was prepared through hydrosilylations of 2-propenyl- p -methoxycinnamate, in which the resulting copolymer showed similar results to those of CAS. [source] Synthesis of copolymer from 1,3,5-trioxane and 1,3-dioxolane catalyzed by Maghnite-H+JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Khadidja Beloufa Abstract Copolymers (polyoxymethylene) were prepared by cationic copolymerization of 1,3,5-trioxane (TOX) with 1,3-dioxolane (DOX) in the presence of Maghnite-H+ (Mag-H+) in solution. Maghnite is a Montmorillonite sheet silicate clay, with exchanged protons to produce Mag-H+. Various techniques, including 1H-NMR, 13C-NMR, FT-IR spectroscopy, and Ubbelohde viscometer were used to elucidate structural characteristics properties of the resulting copolymers. The influence of the amount of catalyst, of dioxolane (DOX), temperature, solvent, and time of copolymerization on yield and on intrinsic viscosity of copolymers was studied. The yield of copolymerization depends on the amount of Mag-H+ used and the reaction time. We also propose mechanisms involved in the synthesis of copolymer (polyoxymethylene). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Magnetic field effects on the copolymerization of water-soluble and ionic monomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2009Ignacio Rintoul Abstract The effect of magnetic field (MF) on the radical copolymerization of a series of water-soluble and ionic monomers is presented including acrylamide (AM), acrylic acid (AA), its ionized form acrylate (A,), and diallyldimethylammonium chloride (DADMAC). The following combinations have been studied: AM/AA, AM/A,, AM/DADMAC, and AA/DADMAC. In addition to the MF, strong electrostatic interactions are present for the majority of monomer combinations and conditions. Although the monomer consumption rate (Rp) increased up to 65% applying a MF of 0.1 Tesla, the composition of the resulting copolymers was not affected under such conditions. Despite this increase of Rp by MF, the electrostatic repulsion between ionic monomers and charged growing radicals dominates Rp and governs the copolymer composition with and without MF. The order of the experimentally obtained reactivity ratios reflects the extent of electrostatic interaction: rAM/AA (1.41) < r (3.10) < rAA/DADMAC (4.25) < rAM/DADMAC (6.95) and rAA/AM (2.20) > rDADMAC/AA (0.25) > r (0.17) > rDADMAC/AM (0.03). Overall, weak MF offers to reduce the production time without modifying the product composition. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 373,383, 2009 [source] Synthesis, characterization, and cross-linking of a library of statistical copolymers based on 2-"soy alkyl"-2-oxazoline and 2-ethyl-2-oxazolineJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2007Richard Hoogenboom Abstract The synthesis of statistical copolymers consisting of 2-ethyl-2-oxazoline (EtOx) and 2-"soy alkyl"-2-oxazoline (SoyOx) via a microwave-assisted cationic ring-opening polymerization procedure is described. The majority of the resulting copolymers revealed polydispersity indices below 1.30. The reactivity ratios (rEtOx 1.4 ± 0.3; rSoyOx = 1.7 ± 0.3) revealed a clustered monomer distribution throughout the polymer chains. The thermal and surface properties of the pEtOx- stat -SoyOx copolymers were analyzed before and after UV-curing demonstrating the decreased chain mobility after cross-linking. In addition, the cross-linked materials showed shape-persistent swelling upon absorption of water from the air, whereby as little as 5 mol % SoyOx was found to provide efficient cross-linking. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5371,,5379, 2007 [source] Synthesis and characterization of electrically conducting poly(o -/m -toluidine- co - o -/m -aminoacetophenone) copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2004P. Savitha Abstract A series of poly(o -/m -toluidine- co - o -/m -aminoacetophenone) copolymers combining the features of high conductivity and processibility are synthesized and characterized by a number of techniques including 1H NMR; thermogravimetry; IR, Raman, and UV,visible spectroscopy; scanning electron microscopy; and X-ray diffraction. The copolymers are synthesized by the emulsion and inverse emulsion methods using conventional ammonium persulfate and a new oxidant, benzoyl peroxide, respectively. The influence of the polymerization conditions such as the monomer feed ratios, solvent, and the nonsolvent is investigated. The composition of the resulting copolymers is determined by 1H NMR analysis. The conductivity of the copolymers varies with the aminoacetophenone content in the feed and the polymerization conditions. It is interesting that the conductivity of the copolymers is higher than that of the corresponding homopolymers. The results are rationalized on the basis of the effect of the COCH3 substituent on the polymer structure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4300,4310, 2004 [source] Copolymerization of propylene with various higher ,-olefins using silica-supported rac -Me2Si(Ind)2ZrCl2JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2001Jun-Ting Xu Abstract The copolymerization of propylene with 1-hexene, 1-octene, 1-decene, and 1-dodecene was carried out with silica-supported rac -Me2Si(Ind)2ZrCl2 as a catalyst. The copolymerization activities of the homogeneous and supported catalysts and the microstructures of the resulting copolymers were compared. The activity of the supported catalyst was only one-half to one-eighth of that of the homogeneous catalyst, depending on the comonomer type. The supported catalyst copolymerized more comonomer into the polymer chain than the homogeneous catalyst at the same monomer feed ratio. Data of reactivity ratios showed that the depression in the activity of propylene instead of an enhancement in the activity of olefinic comonomer was responsible for this phenomenon. We also found that copolymerization with ,-olefins and supporting the metallocene on a carrier improved the stereoregularity and regioregularity of the copolymers. The melting temperature of all the copolymers decreased linearly with growing comonomer content, regardless of the comonomer type and catalyst system. Low mobility of the propagation chain in the supported catalyst was suggested as the reason for the different polymerization behaviors of the supported catalyst with the homogeneous system. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3294,3303, 2001 [source] Design and Synthesis of Functionalized Styrene-Butadiene Copolymers by Means of Living Anionic PolymerizationMACROMOLECULAR SYMPOSIA, Issue 1 2004Mayumi Hayashi Abstract Styrene-butadiene copolymers (SBR) end-functionalized with dimethylamino groups at the initiating and terminating chain-ends were successfully synthesized by a one-step methodology based on living anionic polymerization using 1-(4-dimethylaminophenyl)-1-phenylethylene. The expected structures of the resulting copolymers were confirmed by 1H-NMR, SEC, and SLS analyses, titration, and model reactions. Furthermore, the possible synthesis of tri-functionalized styrene-butadiene copolymer with dimethylamino groups in a chain by extending the methodology is described. [source] Synthesis and characterization of homo- and copolymers of 3-(2-cyano ethoxy)methyl- and 3-[methoxy(triethylenoxy)]methyl-3,-methyl-oxetanePOLYMER INTERNATIONAL, Issue 10 2005Lin Ye Abstract Two oxetane-derived monomers 3-(2-cyanoethoxy)methyl- and 3-(methoxy(triethylenoxy)) methyl-3,-methyloxetane were prepared from the reaction of 3-methyl-3,-hydroxymethyloxetane with acrylonitrile and triethylene glycol monomethyl ether, respectively. Their homo- and copolyethers were synthesized with BF3· Et2O/1,4-butanediol and trifluoromethane sulfonic acid as initiator through cationic ring-opening polymerization. The structure of the polymers was characterized by FTIR and1H NMR. The ratio of two repeating units incorporated into the copolymers is well consistent with the feed ratio. Regarding glass transition temperature (Tg), the DSC data imply that the resulting copolymers have a lower Tg than pure poly(ethylene oxide). Moreover, the TGA measurements reveal that they possess in general a high heat decomposition temperature. The ion conductivity of a sample (P-AN 20) is 1.07 × 10,5 S cm,1 at room temperature and 2.79 × 10,4 S cm,1 at 80 °C, thus presenting the potential to meet the practical requirement of lithium ion batteries for polymer electrolytes. Copyright © 2005 Society of Chemical Industry [source] Synthesis of poly(aryl ether ketone)s containing diphenyl moieties by electrophilic Friedel,Crafts solution polycondensationPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Mingzhong Cai Abstract A new monomer, 4,4,-bis(4-phenoxybenzoyl)diphenyl (BPOBDP), was prepared by Friedel,Crafts reaction of 4-bromobenzoyl chloride and diphenyl, followed by condensation with potassium phenoxide. Novel poly(ether ketone ketone) (PEKK)/poly(ether ketone diphenyl ketone ether ketone ketone) (PEKDKEKK) copolymers were synthesized by electrophilic Friedel,Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of diphenyl ether (DPE) and BPOBDP, in the presence of anhydrous aluminum chloride and N -methyl-pyrrolidone (NMP) in 1,2-dichloroethane (DCE). The copolymers obtained were characterized by various analytical techniques such as FT-IR, DSC, TGA, and wide-angle X-ray diffraction (WAXD). The results showed that the resulting copolymers exhibited excellent thermal stability due to the existence of diphenyl moieties in the main chain. The glass transition temperatures are above 152°C, the melting temperatures are above 276°C, and the temperatures at a 5% weight loss are above 548°C in nitrogen. The copolymers with 50,70,mol% BPOBDP had tensile strengths of 101.5,102.7,MPa, Young's moduli of 3.23,3.41,GPa, and elongations at break of 12,17%. All these copolymers were semicrystalline and insoluble in organic solvents. Copyright © 2008 John Wiley & Sons, Ltd. [source] Regulation of comonomer-Sequenceand stereosequence in radical copolymerization of methyl methacrylate and styrene,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3-5 2003Hidefumi Hirai Abstract The radical copolymerization of methyl methacrylate (MMA) and styrene (St) in the presence of various metal halides was conducted to achieve the advanced regulation of comonomer-sequence and stereosequence in the resulting copolymers. The alternation-regulating activities of various metal halides were determined quantitatively by the MMA content in the copolymer prepared under the specific conditions. Boron trichloride, aluminum tribromide and ethyl boron dichloride were found to have large alternation-regulating activities, yielding the strictly alternating MMA-St copolymers with high regulation of comonomer-sequence. The cotacticities of the -MMA-St- diad, the -St-MMA-St- triad and the-MMA-St-MMA- triad in the alternating copolymer were determined by 1H- and 13C-NMR spectroscopies. The cotacticities depend on the species and the concentrations of the metal halides, and on the polymerization temperatures. The alternating MMA-St copolymer with the highest coheterotacticity has been prepared by using boron trichloride at,,,95,°C. The mechanism of the stereosequence regulation is described in detail. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||