SPR analysis of the total reduction of protein adsorption to surfaces coated with mixtures of long- and short-chain polyethylene oxide block copolymers
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Abstract The copolymerization of ethylene and 5‐ethylidene‐2‐norbornene (ENB) catalyzed by metallocene catalysts system is reported in this paper. The catalysts include Et(Ind) 2 ZrCl 2 /MAO and Cp 2 ZrCl 2 /MAO. The resulting copolymer contains an ethylidene group which can be readily converted to a hydroxyl group by hydrogen borane. Then the hydroxyl group in turn can be utilized for grafting with ϵ‐caprolactone. The dependence of the graft weight percentage on the reaction time was also studied. The graft copolymer is a compatibilizer for various polyethylene blends with engineering plastics. A functional polyethylene can be easily synthesized by the copolymerization of ethylene and 9‐decen‐l‐ol using a homogeneous catalytic system of El(Ind) 2 ZrCl 2 /MAO. The resulting functional polyethylene was characterized by NMR, DSC, IR and TGA; and can also be utilized for grafting with ϵ‐caprolactone. The grafted copolymer is also an effective compatibilizer.
Boranes
Norbornene
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The homopolymerization and the copolymerization of ethylene with functionalized 5-norbornen-2-yl derivatives by the nickel catalyst system L(iPr2)Ni(η1-CH2Ph)(PMe3) (1) [L = N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)propanamide] and Ni(COD)2 (bis(1,5-cyclooctadiene)nickel) produces polymers with high molecular weights and narrow molecular weight distributions. A typical ethylene polymerization reaction proceeds under 100 psi of ethylene and at 20 °C, using 1 (0.34 mM) and Ni(COD)2 (0.83 mM). Likewise, under similar conditions, the copolymerization of ethylene with 5-norbornen-2-yl acetate (3) (0.15 M) for 90 min by 1 (0.67 mM) and Ni(COD)2 (1.67 mM) produced a high molecular weight functionalized polyethylene bearing ester functionalities. 5-Norbornen-2-ol (0.15 M) underwent a similar copolymerization with ethylene for 20 min to yield a hydroxy-functionalized polyethylene. Narrow molecular weight distributions, coupled with the increase of polymer molar mass with time, are consistent with a quasi-living polymerization process in the case of ethylene homopolymerization and ethylene copolymerization with 3.
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Molar mass distribution
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A novel grafted copolymer with two different types of side chains was synthesized via a combination of grafting-onto and grafting-from strategy. Graft copolymer with one side chains polybutadiene-graft-polystyrene (PB-g-PS) was first synthesized though the grafting-onto method. Following the subsequent grafting-from method, the second kind of side chain was introduced to the copolymer with anionic ring open polymerization of ethylene oxide, obtaining dual-grafted copolymer polybutadiene-graft-(polystyrene; poly(ethylene oxide)) (PB-g-(PS;PEO)). By this combined strategy, linear and star-shaped dual-grafted copolymer were synthesized. The resulting dual-grafted copolymers had controlled molecular weights and narrow molecular weight distributions (Mw/Mn < 1.20). The thermal behavior of this dual-grafted copolymer bearing glassy and crystalline side chains was determined by differential scanning calorimetry (DSC), revealing that poly(ethylene oxide) grafts underwent confined crystallization, and the star-shaped copolymer had more confinement effects than did the linear ones.
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Photo-crosslinkable side-chain liquid-crystalline copolymers comprising 2-benzoylethoxybiphenyl and 3-methyl-2-butenyloxybiphenyl groups were synthesized and characterized. Thermal behavior of the copolymers was determined by differential scanning calorimetry and polarized optical microscopy. All synthesized copolymers were liquid-crystalline having nematic and/or smectic phases, and their mesomorphic transition temperatures hardly varied with composition of the copolymers. Photochemically crosslinked copolymer films obtained by UV-irradiation were insoluble in ordinary organic solvents.
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Characterization
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This study was conducted to synthesize novel vinyl copolymers bearing specific side-chain sequences via the radical copolymerization of allyl-functionalized sequence-regulated oligomers (oligomonomers) containing the common vinyl monomer, methyl acrylate (MA). The allyl-functionalized oligomonomers were successfully prepared via the sequential single-monomer radical addition of vinyl monomers such as acrylate and styrene via the Kharasch addition reaction to α-haloester followed by cationic allylation with allyltrimethylsilane. During the free radical copolymerization of the oligomonomer and MA, the use of fluoroalcohol [PhC(CF3)2OH] as the solvent enhanced the incorporation ratio of the oligomonomers into the produced copolymers, with the highest value reaching up to 40 mol%. The effects of the regulated side-chain sequences on the thermal properties of the produced copolymers were also evaluated.
Cationic polymerization
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Methyl acrylate
Vinyl polymer
Vinyl acetate
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Abstract The phase behavior of graft copolymers in aqueous solution was investigated. The graft copolymers consist of poly(propylene glycol) (PPG) side chains and N , N ‐dimethylacrylamide (dMA), N ‐vinylimidazole (VIm), and N ‐isopropylacrylamide (iPA), respectively, as backbones. Phase transition temperatures of the PPG copolymers increased with increasing the content of dMA and iPA as relatively more hydrophilic comonomers and with an increase in the degree of ionization of the incorporated VIm units. Chemical structure of the graft copolymers magnified image Chemical structure of the graft copolymers
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Polyvinyl Alcohol
Chemical modification
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Star (game theory)
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Static and dynamic adsorption have key role in chemical flooding process and they are important parameters in surfactant polymer degradation and decrease oil recovery. The effects of nano concentration on static adsorption of surfactant were investigated at variable condition polymer and surfactant concentration and nanoparticles are critical parameters influence the adsorption behavior at a flooding process. Surfactant polymer solutions and newly developed nanoparticles solutions were tested. The crude oil had a viscosity of 1320 mPa s at test conditions. In this paper, the role of nanoparticles in the adsorption of surfactant polymers onto solid surfaces of reservoir core is studied. The results which obtained by means of static adsorption tests, show that the adsorption is dominated by the clay and silica nanoparticles between the polymer molecules and the solid surface. Higher nanoparticles concentration leads to less adsorption, where the adsorption may decrease to 20 % of the adsorption level of surfactant polymer. The clay and Aerosil A300 nanoparticles in surfactant polymer solutions improved oil recovery by about the same amount. The clay, however, showed improved performance in comparison to Aerosil A300.
Fumed silica
Polymer Adsorption
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Abstract The design and preparation of liquid crystalline (LC) block copolymers by use of azo‐macroinitiators are outlined. This approach is very versatile and makes it possible to realize diverse architectures of block copolymers, including non‐LC/side‐chain, non‐LC/main‐chain and side‐chain/main‐chain block copolymers. The different blocks were phase separated and underwent their individual phase transitions. In side‐chain/main‐chain block copolymers different LC mesophases coexisted in equilibrium.
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Copolymerization of ethylene and propylene was carried out in slurry by using TiCl4/MgCl2 as catalyst.The influence of polymerization conditions on the copolymerization behavior and the chain structure of ethylene-propylene copolymers were studied.Using triethylaluminum/triisobutylaluminum(TiBA) mixture as cocatalyst,the length and amount of long polypropylene(PP)block increased,however,the amount of long polyethylene(PE)block decreased with the augmentation of TiBA dosage.External donor with higher steric hindrance could improve the isotacticity of PP,but it was harmful for the formation of long PP block.Properly decreasing the polymerization temperature was beneficial to the formation of long PP block.The amount of long PP block increased with the augmentation of TiBA.Therefore,changing the composition of the cocatalyst,using different external donors or adjusting the polymerization temperature could regulate the chain structure and its distribution of ethylene-propylene copolymer.
Polypropylene
Post-metallocene catalyst
Chain transfer
Tacticity
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