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Olefin Copolymers (olefin + copolymer)
Kinds of Olefin Copolymers Selected AbstractsNew Cyclic Olefin Copolymer for the Preparation of Thermally Responsive Luminescent FilmsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 9 2009Filippo Donati Abstract Polymer films with optical properties as indicators to thermal stress were obtained through the controlled dispersion of moderate amounts (,0.1 wt.-%) of the 4,4,-bis(2-benzoxazolyl)stilbene (BBS) dye into a new semicrystalline ethylene-norbornene (E - co - N, N content of 15.3 mol.-%) copolymer characterized by a glass transition temperature (Tg) of about 64,°C. All the pristine films showed optical characteristics coming from noninteracting BBS chromophores. In contrast permanent optical changes were detected after film annealing at a T,,,Tg due to the variation of the BBS supramolecular structure. The easy modulation of the optical features of polymer films by thermal perturbations suggests applications as threshold temperature visual indicators in thermoplastic materials. [source] Underivatized cyclic olefin copolymer as substrate material and stationary phase for capillary and microchip electrochromatographyELECTROPHORESIS, Issue 15 2008Omar Gustafsson Abstract We report, for the first time, the use of underivatized cyclic olefin copolymer (COC, more specifically: Topas) as the substrate material and the stationary phase for capillary and microchip electrochromatography (CEC), and demonstrate chromatographic separations without the need of coating procedures. Electroosmotic mobility measurements in a 25,,m id Topas capillary showed a significant cathodic EOF that is pH-dependent. The magnitude of the electroosmotic mobility is comparable to that found in glass substrates and other polymeric materials. Open-tubular CEC was employed to baseline-separate three neutral compounds in an underivatized Topas capillary with plate heights ranging from 5.3 to 12.7,,m. The analytes were detected using UV absorbance at 254,nm, thus taking advantage of the optical transparency of Topas at short wavelengths. The fabrication of a Topas-based electrochromatography microchip by nanoimprint lithography is also presented. The microchip has an array of pillars in the separation column to increase the surface area. The smallest features that were successfully imprinted were around 2,,m wide and 5,,m high. No plasma treatment was used during the bonding, thus keeping the surface properties of the native material. An RP microchip electrochromatography separation of three fluorescently labeled amines is demonstrated on the underivatized microchip with plate heights ranging from 3.4 to 22,,m. [source] Poly(methylmethacrylate) and Topas capillary electrophoresis microchip performance with electrochemical detectionELECTROPHORESIS, Issue 16 2005Mario Castańo-Álvarez Abstract A capillary electrophoresis (CE) microchip made of a new and promising polymeric material: Topas (thermoplastic olefin polymer of amorphous structure), a cyclic olefin copolymer with high chemical resistance, has been tested for the first time with analytical purposes, employing an electrochemical detection. A simple end-channel platinum amperometric detector has been designed, checked, and optimized in a poly-(methylmethacrylate) (PMMA) CE microchip. The end-channel design is based on a platinum wire manually aligned at the exit of the separation channel. This is a simple and durable detection in which the working electrode is not pretreated. H2O2 was employed as model analyte to study the performance of the PMMA microchip and the detector. Factors influencing migration and detection processes were examined and optimized. Separation of H2O2 and L -ascorbic acid (AsA) was developed in order to evaluate the efficiency of microchips using different buffer systems. This detection has been checked for the first time with a microchip made of Topas, obtaining a good linear relationship for mixtures of H2O2 and AsA in different buffers. [source] A new approach for controlling birefringent property of cyclic olefin copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2008Hoang The Ban Abstract This article reports an original method to control the birefringent property of the cyclic olefin copolymer, which has been recently commercialized as a new type of optical resins, via introduction of a third monomer that possesses a negative birefringence into the cyclic olefin copolymer that exhibits an inherently positive birefringence. The mutual compensation between these opposite-sign birefringences effectively reduced the birefringent magnitude of the corresponding terpolymer. In fact, terpolymerization of norbornene (N), ethylene (E), and styrene (S), in which S exhibits a negative birefringence regarding to the positive birefringence of the NE copolymer was successfully prepared using fluorenylamidodimethyltitanium-based catalyst, yielding NES terpolymers with controllable birefringent property. Especially, when the S content in the NES terpolymer was controlled at optimum values, it is possible to synthesize a new type of the cyclic olefin copolymer that exhibits an extremely low birefringent magnitude close to zero regardless of high degrees of chain orientation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7395,7400, 2008 [source] Viscometric properties of viscosity index improvers in lubricant base oil over a wide temperature range.LUBRICATION SCIENCE, Issue 2 2000Part I: Group II base oil Capillary viscometry has been employed to measure the viscosities of dilute polymer solutions over the temperature range -10 to 150 °C. A Group II base oil containing 95% saturates was used as solvent for an olefin copolymer (OCP), a hydrogenated diene copolymer (HDP), and a polymethacrylate (PMA). These three polymers represent the three major families of viscosity index (VI) improvers used nowadays in lubricant formulations. Intrinsic viscosities and Huggins' constants were also determined. The thickening effects of the olefin copolymer and the hydrogenated diene copolymer were found to be higher at low temperatures (e.g., 40 °C) than at higher ones (e.g., 100 °C), which phenomenon was attributed to stronger intermolecular hydrodynamic interactions at low temperatures, as indicated by the Huggins constants. For the hydrogenated diene copolymer and the polymethacrylate polymer, the viscosity increased abruptly when the temperature went below 10 °C. This unusual observation was attributed to the crystallisation of a small fraction of the base oil. Based on the intrinsic viscosity data, it was concluded that at temperatures between 10 and 150 °C, the polymer coil dimension remains a constant for the olefin copolymer and the hydrogenated diene copolymer VI improvers, but increases with increasing temperature for the polymethacrylate VI improver. [source] Replication of sub-micron features using amorphous thermoplasticsPOLYMER ENGINEERING & SCIENCE, Issue 7 2002Kari mönkkönen A comprehensive experimental study was carried out to replicate sub-micron features using the injection molding technique. For the experiments, five different plastic materials were selected according to their flow properties. The materials were polycarbonate (PC), styrene-butadiene block copolymer (SBS), impact modified poly(methyl methacrylate), methyl methacrylate-acrylonitrile-butadiene-styrene polymer (MABS), and cyclic olefin copolymer (COC). Nanofeatures down to 200-nm line width and with aspect ratios (aspect ratio = depth/width) of 1:1 could be replicated. In all selected materials, the greatest differences between the materials emerged when the aspect ratio increased to 2:1. The most favorable results were obtained with the use of high flow polycarbonate as the molding material. The best replication results were achieved when melt and mold temperatures were higher than normal values. [source] Organic Electronics: High Tg Cyclic Olefin Copolymer Gate Dielectrics for N,N,-Ditridecyl Perylene Diimide Based Field-Effect Transistors: Improving Performance and Stability with Thermal Treatment (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Mater. Abstract A novel application of ethylene-norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field-effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally-treated N,N, -ditridecyl perylene diimide (PTCDI-C13)-based n-type FETs using a COC/SiO2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic surface (water contact angle = 95° ± 1°) and high thermal stability (glass transition temperature = 181 °C) without producing crosslinking. After thermal annealing, the crystallinity improves and the grain size of PTCDI-C13 domains grown on the COC/SiO2 gate dielectric increases significantly. The resulting n-type FETs exhibit high atmospheric field-effect mobilities, up to 0.90 cm2 V,1 s,1 in the 20 V saturation regime and long-term stability with respect to H2O/O2 degradation, hysteresis, or sweep-stress over 110 days. By integrating the n-type FETs with p-type pentacene-based FETs in a single device, high performance organic complementary inverters that exhibit high gain (exceeding 45 in ambient air) are realized. [source] High Tg Cyclic Olefin Copolymer Gate Dielectrics for N,N,-Ditridecyl Perylene Diimide Based Field-Effect Transistors: Improving Performance and Stability with Thermal TreatmentADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Jaeyoung Jang Abstract A novel application of ethylene-norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field-effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally-treated N,N, -ditridecyl perylene diimide (PTCDI-C13)-based n-type FETs using a COC/SiO2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic surface (water contact angle = 95° ± 1°) and high thermal stability (glass transition temperature = 181 °C) without producing crosslinking. After thermal annealing, the crystallinity improves and the grain size of PTCDI-C13 domains grown on the COC/SiO2 gate dielectric increases significantly. The resulting n-type FETs exhibit high atmospheric field-effect mobilities, up to 0.90 cm2 V,1 s,1 in the 20 V saturation regime and long-term stability with respect to H2O/O2 degradation, hysteresis, or sweep-stress over 110 days. By integrating the n-type FETs with p-type pentacene-based FETs in a single device, high performance organic complementary inverters that exhibit high gain (exceeding 45 in ambient air) are realized. [source] A new approach for controlling birefringent property of cyclic olefin copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2008Hoang The Ban Abstract This article reports an original method to control the birefringent property of the cyclic olefin copolymer, which has been recently commercialized as a new type of optical resins, via introduction of a third monomer that possesses a negative birefringence into the cyclic olefin copolymer that exhibits an inherently positive birefringence. The mutual compensation between these opposite-sign birefringences effectively reduced the birefringent magnitude of the corresponding terpolymer. In fact, terpolymerization of norbornene (N), ethylene (E), and styrene (S), in which S exhibits a negative birefringence regarding to the positive birefringence of the NE copolymer was successfully prepared using fluorenylamidodimethyltitanium-based catalyst, yielding NES terpolymers with controllable birefringent property. Especially, when the S content in the NES terpolymer was controlled at optimum values, it is possible to synthesize a new type of the cyclic olefin copolymer that exhibits an extremely low birefringent magnitude close to zero regardless of high degrees of chain orientation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7395,7400, 2008 [source] 13Carbon nuclear magnetic resonance of ethylene,propylene,1-decene terpolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2003Fernanda F. Nunes Escher Abstract Many studies have been reported on the 13C NMR characterization of ethylene,,-olefin copolymers, but only a few have been reported on terpolymers. The incorporation of an ,-olefin into the polyethylene chain changes the structure and, consequently, the properties of the polymer obtained. Looking for new products, we obtained a series of ethylene,propylene,1-decene terpolymers with the metallocenic system rac -ethylene bisindenyl zirconium dichloride/methylaluminoxane. We performed a complete 13C NMR characterization of these terpolymers qualitatively and quantitatively. Here we present a detailed study of the 13C NMR chemical shifts, triad sequence distributions, monomer average sequence lengths, and reactivity ratios for these terpolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2531,2541, 2003 [source] Functionalization of COC Surfaces by Microwave PlasmasPLASMA PROCESSES AND POLYMERS, Issue S1 2007Hartmut Steffen Abstract Cyclic olefin copolymers (COC) combine excellent transparency, high moisture barrier, high strength and stiffness and very low shrinkage. COCs have excellent chemical resistance to aqueous acids and bases and to most polar solvents. This property combination makes them excellent candidates for diverse diagnostic applications in biomedical science. But they are very hydrophobic and thus not suitable for cell-contacting applications. This work investigates the surface functionalization of COC compared to PS by NH3 and SO2 microwave plasmas. The surfaces were mainly analysed by high-resolution X-ray photoelectron spectroscopy (XPS). Moreover, cells were cultivated on both substrates to verify the applicability of COC for cell-based disposables. Actually, microwave plasma-functionalized COC surfaces support the adhesion and proliferation of adherent cell lines, which usually require the coating of the substrate with extra cellular matrix molecules. [source] Influence of supported vanadium catalyst on ethylene polymerization reactionsPOLYMER INTERNATIONAL, Issue 2 2008Sutapa Ghosh Abstract BACKGROUND: In the research area of homogeneous Ziegler,Natta olefin polymerization, classic vanadium catalyst systems have shown a number of favourable performances. These catalysts are useful for (i) the preparation of high molecular weight polymers with narrow molecular weight distributions, (ii) the preparation of ethylene/R -olefin copolymers with high R -olefin incorporation and (iii) the preparation of syndiotactic polypropylenes. In view of the above merits of vanadium-based catalysts for polymerization reactions, the development of well-defined single-site vanadium catalysts for polymerization reactions is presently an extremely important industrial goal. The main aim of this work was the synthesis and characterization of a heterogeneous low-coordinate non-metallocene (phenyl)imido vanadium catalyst, V(NAr)Cl3, and its utility for ethylene polymerization. RESULTS: Imido vanadium complex V(NAr)Cl3 was synthesized and immobilized onto a series of inorganic supports: SiO2, methylaluminoxane (MAO)-modified SiO2 (4.5 and 23 wt% Al/SiO2), SiO2 Al2O3, MgCl2, MCM-41 and MgO. Metal contents on the supported catalysts determined by X-ray fluorescence spectroscopy remained between 0.050 and 0.100 mmol V g,1 support. Thermal stability of the catalysts was determined by differential scanning calorimetry (DSC). Characterization of polyethylene was done by gel permeation chromatography and DSC. All catalyst systems were found to be active in ethylene polymerization in the presence of MAO or triisobutylaluminium/MAO mixture (Al/V = 1000). Catalyst activity was found to depend on the support nature, being between 7.5 and 80.0 kg PE (mol V),1 h,1. Finally, all catalyst systems were found to be reusable for up to three cycles. CONCLUSION: Best results were observed in the case of silica as support. Acid or basic supports afforded less active systems. In situ immobilization led to higher catalyst activity. The resulting polyethylenes in all experiments had ultrahigh molecular weight. Finally, this work explains the synthesis and characterization of reusable supported novel vanadium catalysts, which are useful in the synthesis of very high molecular weight ethylene polymers. Copyright © 2007 Society of Chemical Industry [source] Synthesis of polar vinyl monomer,olefin copolymers by ,-diimine nickel catalystPOLYMER INTERNATIONAL, Issue 5 2001Maria M Marques Abstract Vinyl acetate, methyl methacrylate, acrylonitrile and methyl vinyl ketone were investigated for co- and terpolymerization with ethylene and ethylene,propylene. Precursor [bis(N,N,,-dimesitylimino)acenaphthene]dibromonickel, activated by methylaluminoxane was used as a catalyst system and trialkylaluminium was employed to block the polar groups for these polymerizations. Polymerization activities of the order of magnitude of 106 in the case of vinyl acetate and methyl methacrylate, and 105 in the case of acrylonitrile were achieved. Microanalysis and GPC of acrylonitrile copolymers found about 17 units of acrylonitrile per polymer chain. Copolymers with very different properties from the parent homopolymers were obtained in all cases except that of methyl vinyl ketone. © 2001 Society of Chemical Industry [source] | ||||||||||