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Polymer Resin (polymer + resin)
Selected AbstractsHyperbranched Polymers for Photolithographic Applications , Towards Understanding the Relationship between Chemical Structure of Polymer Resin and Lithographic PerformancesADVANCED MATERIALS, Issue 10-11 2009Christos L. Chochos A chemically amplified resist based on a hyperbranched polymer resin is demonstrated for the first time. The hyperbranched polymer is synthesized using the atom-transfer radical polymerization (ATRP) technique, and resists prepared from this hyperbranched polymer present good pattern profiles and line-edge roughness (3,) values comparable to those of the reference (commercial) resist. [source] Simple model to predict gel formation in olefin-diene copolymerizations catalyzed by constrained-geometry complexesAICHE JOURNAL, Issue 5 2010Job D. Guzmán Abstract We have developed an analytical model to predict the onset of gel formation in ethylene/1-octene/1,9-decadiene terpolymerizations using constrained-geometry catalysts. The model relies on three kinetic parameters to characterize the catalyst response. Polymer resins have been synthesized in a continuous stirred-tank reactor to determine the model parameters, and to validate the model predictions for polymer properties and for the onset of gel formation and reactor fouling. The experimental results indicate that the free double bonds in 1,9-decadiene are as reactive as those found in 1-octene, and that the reactivity of 1,9-decadiene double bonds decreases after the 1,9-decadiene molecules become part of a polymer chain. The model predictions of polymer properties agree well with chromatographic, density, and mass-balance data. Moreover, the model was successful in preventing unintended reactor fouling during the duration of the experimental campaign. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Hyperbranched Polymers for Photolithographic Applications , Towards Understanding the Relationship between Chemical Structure of Polymer Resin and Lithographic PerformancesADVANCED MATERIALS, Issue 10-11 2009Christos L. Chochos A chemically amplified resist based on a hyperbranched polymer resin is demonstrated for the first time. The hyperbranched polymer is synthesized using the atom-transfer radical polymerization (ATRP) technique, and resists prepared from this hyperbranched polymer present good pattern profiles and line-edge roughness (3,) values comparable to those of the reference (commercial) resist. [source] Well-defined diblock and triblock copolymers for KrF lithographyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Ting-Yu Lee Abstract One of the major components of a photoresist formulation is polymer resin. Well-defined diblock and random copolymer of tert -butyl acrylate (tBA) and 4-acetoxystyrene (StyOAc), as well as triblock and random tertpolymer of tBA, StyOAc, and Sty were prepared by reversible addition fragmentation chain transfer polymerization (RAFT) process. The polymers all possess Mw about ten thousand and PDI less than 1.23. After hydrolysis under basic condition, the hydroxystyrene (StyOH) analogs are obtained and then are formulated as photoresist. Lithographic evaluation under KrF excimer laser shows that random copolymer based photoresist exhibits better S/L patterns according to SEM images. However, the lithographic performance of the terpolymer based resists is similar. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Evaluation of sulfobetaine-type polymer resin as an SPE adsorbent in the analysis of trace tetracycline antibiotics in honeyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 21 2009Tomoyasu Tsukamoto Abstract A new sulfobetaine polymer resin SPE method combined with HPLC-MS/MS for the determination of tetracycline (TC) antibiotics residues from honey samples is presented. The sulfobetaine resin was synthesized and was packed into a syringe-type tube, which served as the SPE cartridge for selective adsorption of TCs. TCs were quantitatively adsorbed on the sulfobetaine cartridge, when the loading solvent was 95%,v/v acetonitrile solution, and TCs adsorbed were not eluted by aqueous acetonitrile washing solution. TFA aqueous solution was used for eluting the adsorbed TCs. The proposed SPE method has been applied to the determination of TCs in honey samples. The recoveries of TCs spiked in honey samples ranged from 70 to 80%. Reduction of the recoveries might be derived from low solubility of TCs in acetonitrile. Compared with other SPE resins, this resin was superior in terms of selectivity with simple pretreatment. [source] Bio-Based Nanocomposites from Corn Oil and Functionalized Organoclay Prepared by Cationic PolymerizationMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007Yongshang Lu Abstract A reactive organic montmorillonite clay (VMMT), modified with (4-vinylbenzyl) triethylammonium cations, has been prepared and used as a nanofiller to reinforce a corn-oil-based polymer resin. The polymer resin was prepared by the cationic polymerization of conjugated corn oil, styrene and divinylbenzene, using boron trifluoride diethyl etherate modified with Norway fish oil as the initiator. The results indicate that the VMMT is intercalated in the corn-oil-based polymer resins. When compared with the pure polymers, these novel nanocomposites reinforced with 2 to 3 wt.-% VMMT exhibit significant improvements in modulus, strength, strain and toughness. Furthermore, incorporating VMMT into the corn-oil-based polymer matrix also leads to improved thermal stability of the nanocomposites over the pure resins of up to 400,°C. [source] Continuous Soluble Ziegler-Natta Ethylene Polymerizations in Reactor Trains, 3 , Influence of Operating Conditions upon Process PerformanceMACROMOLECULAR REACTION ENGINEERING, Issue 2 2008Marcelo Embiruçu Abstract The behavior of continuous solution ethylene/but-1-ene polymerizations through Ziegler-Natta catalysts is analyzed, based on a previously developed mathematical model. In order to do that, dynamic simulations are carried out and process responses are analyzed as functions of process operating policies and flowsheet configuration, at conditions that resemble the actual operation of industrial sites. It is shown that system responses are highly nonlinear and very sensitive to disturbances of the operating conditions and that catalyst decay is of fundamental importance for proper understanding of process behavior. Results indicate that mixing conditions inside the reactor vessels exert a significant impact upon the final polymer quality and can be manipulated for in-line control of final resin properties. Finally, it is shown that the development of feed policies, based on the use of lateral feed streams, allows the simultaneous control of melt flow index, stress exponent and polymer density of the final polymer resin. [source] 3D reconstruction of high-resolution STED microscope imagesMICROSCOPY RESEARCH AND TECHNIQUE, Issue 9 2008Annedore Punge Abstract Tackling biological problems often involves the imaging and localization of cellular structures on the nanometer scale. Although optical super-resolution below 100 nm can be readily attained with stimulated emission depletion (STED) and photoswitching microscopy methods, attaining an axial resolution <100 nm with focused light generally required the use of two lenses in a 4Pi configuration or exceptionally bright photochromic fluorophores. Here, we describe a simple technical solution for 3D nanoscopy of fixed samples: biological specimens are fluorescently labeled, embedded in a polymer resin, cut into thin sections, and then imaged via STED microscopy with nanoscale resolution. This approach allows a 3D image reconstruction with a resolution <80 nm in all directions using available state-of-the art STED microscopes. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc. [source] Preparation and properties of nanoparticle and long-fiber-reinforced unsaturated polyester compositesPOLYMER COMPOSITES, Issue 7 2009Gang Zhou In this study, a new approach was used to prepare polymer composites reinforced by both nanoparticles and continuous fibers. Carbon nanofibers were prebound onto glass fiber mats, and then unsaturated polyester composites were prepared by vacuum-assisted resin transfer molding. Mechanical and thermal properties of these composites were measured and compared with those of the composites synthesized by premixing carbon nanofibers with the polymer resin. Flexural strength and modulus of composites improved with the incorporation of nanoparticles. Specifically, the property improvement was higher in the case of the composites prepared by the new prebound method. It was also found that carbon nanofibers increased the glass transition temperature and reduced the thermal expansion coefficient of unsaturated polyester composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Do adverse effects of dental materials exist?CLINICAL ORAL IMPLANTS RESEARCH, Issue 2007What are the consequences, how can they be diagnosed, treated? Abstract Objectives: All dental biomaterials release substances into the oral environment to a varying degree. Various preclinical biocompatibility test systems have been introduced, aiming at an evaluation of the potential risks of dental materials. Potential pathogenic effects of released substances from dental materials have been demonstrated. For the biocompatibility of a biomaterial, it is not only important that minimal diffusable substances are released when it is in body contact , the material must also fulfill the function for which it has been designed. This is also very much dependent on the material properties and its handling properties. The aim of this review was to generate an overview of the present status concerning adverse reactions among patients and personnel. Materials and methods: A systematic review was performed using a defined search strategy in order to evaluate all MEDLINE-literature published between 1996 and 2006. Results: The compilation of the literature available has revealed that the majority of studies have been carried out on patients compared with personnel. Adverse reactions towards dental materials do occur, but the prevalence and incidence are difficult to obtain. The results were essentially based on cohort studies. Clinical trials, especially randomized-controlled trials, are in the minority of all studies investigated, with the exception of composite and bonding studies, where clinical trials, but not randomized-controlled trials, represent the majority of studies. Patients and personnel were treated separately in the manuscript. Amalgam studies show the lowest degree of verified material-related diagnosis. Even if objective symptoms related to adverse reactions with polymer resin-based materials have been reported, postoperative sensitivity dominates reports concerning composites/bondings. Verified occupational effects among dental personnel show a low frequency of allergy/toxic reactions. Irritative hand eczema seemed to be more common than in the general population. Conclusions: Patient- and personnel-related studies are of variable quality and can be improved. There is a need for a better description of the content of materials. A registry for adverse effects of dental materials would be useful to detect the occurrence of low-incidence events. [source] Dispersion of graphite nanosheets in polymer resins via masterbatch techniqueJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Guohua Chen Abstract The dispersion of graphite nanosheets (GNs) in polymer matrices via the masterbatch technique was investigated. Modifying resin was added to GNs to prepare blend which is designated as the masterbatch. Such masterbatches, containing 70,80 wt % of GN filler, were blended with target polymers via melt extrusion process to prepare polymer/GN nanocomposites. The extruded nanocomposites showed characteristic conducting percolation behaviors with the percolation thresholds mainly dependent on the miscibility of the modifying resin with polymer matrix. The percolation thresholds of AS (Acrylonitrile-Styrene compolymer)/GN and high-density polyethylene (HDPE)/GN nanocomposites prepared by this technique were about 9 and 14 wt % of GN, respectively. Scanning electron microscopy and other characterizations showed that the GNs were well dispersed in AS and HDPE resins. The extrusion process and compatibility of the modifying resin with target polymer proved to be important factors for the homogeneity of the nanodispersion. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3470,3475, 2007 [source] Bio-Based Nanocomposites from Corn Oil and Functionalized Organoclay Prepared by Cationic PolymerizationMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007Yongshang Lu Abstract A reactive organic montmorillonite clay (VMMT), modified with (4-vinylbenzyl) triethylammonium cations, has been prepared and used as a nanofiller to reinforce a corn-oil-based polymer resin. The polymer resin was prepared by the cationic polymerization of conjugated corn oil, styrene and divinylbenzene, using boron trifluoride diethyl etherate modified with Norway fish oil as the initiator. The results indicate that the VMMT is intercalated in the corn-oil-based polymer resins. When compared with the pure polymers, these novel nanocomposites reinforced with 2 to 3 wt.-% VMMT exhibit significant improvements in modulus, strength, strain and toughness. Furthermore, incorporating VMMT into the corn-oil-based polymer matrix also leads to improved thermal stability of the nanocomposites over the pure resins of up to 400,°C. [source] Comparison of the degradability of poly(lactide) packages in composting and ambient exposure conditionsPACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2007Gaurav Kale Abstract The adoption of biodegradable polymeric materials is increasing in food and consumer goods packaging applications, due to concerns about the disposal of petroleum-based polymers and the increasing cost of petroleum-based polymer resins. Currently, poly(lactide) (PLA) polymers are the biggest commercially available bio-based polymeric packaging materials. As the main motivation for adopting biopolymers is environmental, there is a need to address the degradability and environmental performance of biodegradable packages. The aim of this study was to investigate and compare the degradation of two commercially available biodegradable packages made of PLA under real compost conditions and under ambient exposure, using visual inspection, gel permeation chromatography, differential scanning calorimetry and thermal gravimetric analysis. A novel technique to study and track the degradability of these packages under real compost conditions was used. Both packages were subjected to composting and ambient exposure conditions for 30 days, and the degradation of the physical properties was measured at 1, 2, 4, 6, 9, 15 and 30 days. PLA bottles made of 96% l -lactide exhibited lower degradation than PLA delicatessen (,deli') containers made of 94% l -lactide, mainly due to their highly ordered structure and, therefore, their higher crystallinity. The degradation rate changed as the initial crystallinity and the l -lactide content of the packages varied. Temperature, relative humidity and pH of the compost pile played an important role in the rate of degradation of the packages. First-order degradation kinetics and linear degradation trends were observed for both packages subjected to composting conditions. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||||||||