bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated Scanning Probe Microscopy as a New Tool for Combinatorial Polymer Research: Conductive Carbon Black/Poly(dimethylsiloxane) Composites
Authors: Neffati Riadh , Alexeev Alexander , Saunin Sergey , Brokken‐Zijp José C. M. , Wouters Daan , Schmatloch Stefan , Schubert Ulrich S. , Loos Joachim 
Published: February 2003

AbstractA systematic investigation into the surface properties of siloxane rubber/carbon black (CB) nanocomposites has been performed, using an automated scanning probe microscope. In this way the influence of CB concentration and curing rate of the siloxane rubber matrix on roughness and conductivity of the composites was studied. Decreasing the curing rate while keeping the CB concentration resulted in a decrease in both roughness and surface conductivity, which can be explained by an additional siloxane‐rubber layer formed during curing.magnified image
Combinatorial Mapping of Surface Energy Effects on Diblock Copolymer Thin Film Ordering
Authors: Smith Archie P. , Sehgal Amit , Douglas Jack F. , Karim Alamgir , Amis Eric J. 
Published: February 2003

AbstractCombinatorial gradient techniques are used to map the morphology dependence of thin symmetric diblock copolymer films on film thickness and substrate surface energy. An inversion from symmetric to anti‐symmetric lamellar morphology occurs with a progressive change in surface energy. An intermediate neutral region is found between these limiting types of ordering. The width ω of this transitional energy range scales as a power of copolymer mass M, ω ∝ M1.9.Optical photograph of a combinatorial map of the thin‐film block‐copolymer morphology on a film thickness and surface energy gradient. Island and holes on the surface scatter light causing the film to appear cloudy (lighter in color) in the areas where they exist. The darker areas do not have surface features and do not scatter light.magnified imageOptical photograph of a combinatorial map of the thin‐film block‐copolymer morphology on a film thickness and surface energy gradient. Island and holes on the surface scatter light causing the film to appear cloudy (lighter in color) in the areas where they exist. The darker areas do not have surface features and do not scatter light.
Application of a Parallel Synthetic Approach in Atom‐Transfer Radical Polymerization: Set‐Up and Feasibility Demonstration
Authors: Zhang Huiqi , Fijten Martin W. M. , Hoogenboom Richard , Reinierkens Roy , Schubert Ulrich S. 
Published: February 2003

AbstractA parallel synthetic approach toward homogeneous atom‐transfer radical polymerization of methyl methacrylate has been successfully applied by utilizing an automated synthesizer. Experimental set‐up, automated parallel synthesis and purification of the polymers via a solid‐phase extraction set‐up, as well as online and offline measurements of the molecular weights and monomer conversion are described in detail. In addition, a comparison with conventional experiments in the laboratory is provided.Kinetic plots of ln([M]0/[M]) versus reaction time of the ATRP of MMA in p‐xylene at 90 °C conducted in an automated synthesizer (three parallel reactions, ○, ▵, ⋄) and in a conventional set‐up (▪).magnified imageKinetic plots of ln([M]0/[M]) versus reaction time of the ATRP of MMA in p‐xylene at 90 °C conducted in an automated synthesizer (three parallel reactions, ○, ▵, ⋄) and in a conventional set‐up (▪).
Fast Liquid Chromatography for High‐Throughput Screening of Polymers
Authors: Pasch Harald , Kilz Peter 
Published: February 2003

AbstractLiquid chromatography of polymers is traditionally a slow technique with analysis times of typically 30 min per sample. For the application of liquid chromatographic techniques to combinatorial materials research the analysis time per sample must be reduced considerably. Analysis time in SEC can be reduced to about 2 min per sample when high‐throughput columns are used. For HPLC small columns with improved separation efficiencies can be used. As compared to conventional technology, time savings of more than 80% are achieved.
Chromatogram from conventional SEC column compared to high‐speed SEC column tested on an identical instrument with polystyrene standards in THF.magnified imageChromatogram from conventional SEC column compared to high‐speed SEC column tested on an identical instrument with polystyrene standards in THF.
Automated Raman Spectroscopy as a Tool for the High‐Throughput Characterization of Molecular Structure and Mechanical Properties of Polyethylenes
Authors: Gabriel Claus , Lilge Dieter , Kristen Marc O. 
Published: February 2003

AbstractRaman spectroscopy, which does not require a time‐consuming sample preparation, is described as an analytical tool for the high‐throughput characterization of polyethylenes. The content of comonomer and the amount of methyl groups per 1 000 carbon atoms of polyethylenes can be predicted from Raman spectra using multivariate data analysis. In addition, macroscopic properties, such as density and elastic modulus as well as yield stress, can be derived from Raman spectra.
Raman spectra of selected metallocene‐catalyzed polyethylenes of different comonomer content.magnified imageRaman spectra of selected metallocene‐catalyzed polyethylenes of different comonomer content.
High‐Throughput Fabrication, Performance Testing, and Characterization of One‐Dimensional Libraries of Polymeric Compositions
Authors: Potyrailo Radislav A. , Wroczynski Ronald J. , Pickett James E. , Rubinsztajn Malgorzata 
Published: February 2003

AbstractA new general approach for rapid performance‐screening of polymer compositions is provided. Multiple compositions are generated as one‐dimensional libraries in a microextruder with step‐ or gradient‐composition changes in 2–10 g of polymer in < 1 min. To accelerate testing, environmental stress is applied to only local regions, followed by high‐sensitivity spatially resolved characterization. We applied our methodology for weathering of arrays of polymeric compositions and provided ranking of polymer/UV absorber compositions equivalent to traditional weathering data while achieved 20 times faster.
Sampling and measurement strategies for HT analysis of combinatorial 1D polymeric libraries: (1) spectroscopic monitoring of chemical properties, (2) in‐situ monitoring of mass and viscoelastic properties, (3) scanning spectroscopic analysis, and (4) spectroscopic imaging of a coiled polymeric array.magnified imageSampling and measurement strategies for HT analysis of combinatorial 1D polymeric libraries: (1) spectroscopic monitoring of chemical properties, (2) in‐situ monitoring of mass and viscoelastic properties, (3) scanning spectroscopic analysis, and (4) spectroscopic imaging of a coiled polymeric array.
Bayer Symposium on High‐Throughput Experimentation in Materials Research and Process Optimization
Authors: Rothbarth Frank 
Published: February 2003

AbstractThis section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.
Combinatorial Methods, Automated Synthesis and High‐Throughput Screening in Polymer Research: Past and Present
Authors: Hoogenboom Richard , Meier Michael A. R. , Schubert Ulrich S. 
Published: February 2003

AbstractCombinatorial techniques, parallel experimentation and high‐throughput methods represent a very promising approach in order to speed up the preparation and investigation of new polymeric materials: a large variety of parameters can be screened simultaneously resulting in new structure/property relationships. The field of polymer research seems to be perfectly suited for parallel and combinatorial methods due to the fact that many parameters can be varied during synthesis, processing, blending as well as compounding. In addition, numerous important parameters have to be investigated, such as molecular weight, polydispersity, viscosity, hardness, stiffness and other application‐specific properties. A number of corresponding high‐throughput techniques have been developed in the last few years and their introduction into the commercial market further boosted the development. These combinatorial approaches can reduce the time‐to‐market for new polymeric materials drastically compared to traditional approaches and allow a much more detailed understanding of polymers from the macroscopic to the nanoscopic scale. Here we provide an overview of the present status of combinatorial and parallel polymer synthesis and high‐throughput screening.magnified image
High‐Output Polymer Screening: Exploiting Combinatorial Chemistry and Data Mining Tools in Catalyst and Polymer Development
Authors: Tuchbreiter Arno , Marquardt Jürgen , Kappler Bernd , Honerkamp Josef , Kristen Marc O. , Mülhaupt Rolf 
Published: February 2003

AbstractHigh‐output polymer screening (HOPS) combines automated polymerization with online reaction monitoring, rapid polymer characterization and novel fingerprint technology useful in polymer preparation as well as polymer processing and polymer additive development. Originally, HOPS was introduced to develop polymerization catalysts and polyolefin materials more effectively. In comparison to conventional high‐throughput screening, focusing on ultrahigh speed of catalyst screening using arrays of miniaturized reactors, output‐oriented, process‐relevant HOPS is aiming at generating and exploiting high information density (useful information/experiment). Catalyst systems for olefin polymerization are evaluated in automated workstations with multiparallel as well as semi‐ and fully automated, upgraded lab reactors. Automated polymerizations under standardized conditions afford large families of well‐characterized polymers which serve as calibration samples for data analysis. Data analysis, using multivariate calibration, is the key to basic correlations between spectroscopic information and catalyst and polymer properties as well as reaction parameters and processing conditions. IR spectroscopic fingerprints are used to measure chemical copolymer composition, density, molecular weight as well as thermal and even mechanical properties. This fingerprint technology can be applied in online quality control and facilitates transfer from lab results into pilot and production plants. Fingerprint methods are important components of rapid online analysis and can reduce the need for time‐ and money‐consuming polymer testing.
Fingerprint technology combines spectroscopic analysis by means of “cheap” spectrometers with multivariate calibration.magnified imageFingerprint technology combines spectroscopic analysis by means of “cheap” spectrometers with multivariate calibration.
R&D Intensification in Polymer Catalyst and Product Development by Using High‐Throughput Experimentation and Simulation
Authors: Gruter Gert‐Jan M. , Graham Alasdair , McKay Ben , Gilardoni François 
Published: February 2003

AbstractCurrently laboratory automation is a rapidly growing field of interest in chemical process research and development. The idea of using automated and parallel methods for the optimization of chemical processes was initiated by the extensive implementation of combinatorial techniques in medicinal chemistry. The techniques applied involve all methods and concepts aimed at dramatically increasing the output of research by extensive use of automation, parallelization and miniaturization, fast analysis, advanced data handling and by efficient automated planning, scheduling and tracking. In this paper, the “Combi” or high‐throughput experimentation approach consists of the integration of parallel experimentation with four key modeling and simulation methodologies, modeling, multivariate statistics, statistical design of experimentation and empirical model generation.
Integrated automated liquid and solid handling.magnified imageIntegrated automated liquid and solid handling.
Automated Parallel Synthesis of MADIX (Co)Polymers
Authors: Chapon Pascal , Mignaud Catherine , Lizarraga Gilda , Destarac Mathias 
Published: February 2003

AbstractAn automated parallel synthetic approach has been developed for synthesizing polymer libraries by the Macromolecular Design via the Interchange of Xanthates (MADIX) process. The experimental set‐up, parallel polymerizations, characterization, and reproducibility tests are detailed. Examples of acrylic diblock copolymers synthesized in this way are given.
Automated MADIX polymerizations of BA in the presence of a X1‐capped PEA.magnified imageAutomated MADIX polymerizations of BA in the presence of a X1‐capped PEA.
Automated Parallel Temperature Optimization and Determination of Activation Energy for the Living Cationic Polymerization of 2‐Ethyl‐2‐oxazoline
Authors: Hoogenboom Richard , Fijten Martin W. M. , Brändli Christof , Schroer Josef , Schubert Ulrich S. 
Published: February 2003

AbstractSixteen parallel polymerization reactions of 2‐ethyl‐2‐oxazoline have been performed at different temperatures in an automated synthesizer that allowed individual heating of each reactor. During the reactions samples were taken automatically, which were characterized by means of both online GPC and offline GC, in order to optimize the reaction temperature and to determine the activation energy of the polymerization.magnified image
Instrumentation for Combinatorial and High‐Throughput Polymer Research: A Short Overview
Authors: Schmatloch Stefan , Meier Michael A. R. , Schubert Ulrich S. 
Published: February 2003

AbstractStarting in biochemistry and pharmaceutical chemistry, combinatorial methods, automated synthesis and high‐throughput characterization are being further developed for organic synthesis and polymer research. The development is strongly driven by the achievements in biochemistry and pharmaceutical chemistry and the need to minimize the time‐to‐market for novel polymeric products. The success of high‐throughput methodologies in polymer science is partially limited by the commercially available hardware (synthesizers, workstations, robots, online‐characterization instruments, etc.) and software. A short overview of commercially available equipment for polymer research is provided in this Review.magnified image
Combinatorial Materials Research in the Polymer Industry: Speed versus Flexibility
Authors: Iden Ruediger , Schrof Wolfgang , Hadeler Joachim , Lehmann Stephan 
Published: February 2003

AbstractWith combinatorial materials research (CMR), a new research approach toward the development and optimization of materials has been established at BASF. While adopting the basic ideas of combinatorial chemistry, CMR faces a whole bunch of challenges throughout the entire combinatorial process loop. New concepts for sample preparation on a smaller scale, i.e. synthesis and formulation, for parallel or fast sequential screening and characterization, and for appropriate management of yet unknown amounts of data have been developed. The integration of as many as possible workflow steps and the interplay of experts from various relevant fields, such as chemistry, engineering, robotics, informatics, and physics, are necessary. First results in the fields of polymer synthesis and coatings formulation give an impression of the innovative power and efficiency of this new kind of research.
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Structure and ordering kinetics of micelles in triblock copolymer solutions in selective solvents
Authors: Bansil R. , Nie H. , Li Y. , Liao G. , Ludwig K. , Steinhart M. , Koňák Č. , Lal J. 
Published: February 2003

AbstractWe have used small‐angle x‐ray scattering (SAXS), and small‐angle neutron scattering (SANS) to study the micelle structure of a polystyrene‐block‐poly(ethene‐co‐butene)‐block‐polystyrene triblock copolymer in dilute ‐ semidilute solutions in solvents selective for either the outer styrene block (dioxane) or for the middle block (heptane or tetradecane). Measurements of equilibrium structure factors showed that micelles were formed in both types of selective solvents. In the case of dioxane, the micelles are isolated whereas in the case of heptane or tetradecane, a bridged micellar structure may be formed at higher copolymer concentrations. In both cases we observed an ordered cubic structure of insoluble domains (micellar cores) at high concentrations (> 8 %). The micellar scattering function was fit to the Percus‐Yevick interacting hard‐sphere model. The temperature dependence of the core radius, the hard‐sphere interaction radius and the volume fraction of hard spheres were obtained. We also used synchrotron‐based time‐resolved SAXS to examine the kinetics of ordering of the micelles on a cubic lattice for many different temperature jumps into the ordered cubic phase starting from the disordered micellar fluid phase in different solvents at different concentrations. The time evolution of the structure changes was determined by fitting the data with Gaussians to describe the structure factor of the ordered Bragg peaks and the Percus‐Yevick structure factor was used to describe the micellar fluid. The time dependence of the peak intensities and widths as well as of the micellar parameters will be presented. The results showing the kinetics of the transformation from the fluid to the ordered phase were analyzed using the Mehl‐Johnson‐Avrami theory of nucleation.
Time‐resolved SAXS studies on crystallization behavior of polyõethylene isophthalate‐co‐ethylene terephthalatešs
Authors: Lee B. , Shin T.J. , Lee S.W. , Lee J.W. , Ree M. 
Published: February 2003

AbstractSmall‐angle X‐ray scattering measurements using synchrotron radiation were carried out for poly(ethylene terephthalate) and poly(ethylene isophthalate‐co‐ethylene terephthalate)s. In addition, differential scanning calorimetric measurements were conducted. Measurements were made both on polymers undergoing isothermal crystallization and during subsequent remelting. The primary and secondary crystallization behaviors are examined. Isophthalate units were found to be excluded from the crystals into amorphous layers during crystallization. No crystal thickening was observed during isothermal crystallization, which may be due to the relatively high chain rigidity. Secondary crystallization, detected predominantly at the later stages of crystallization, causes densification and shrinkage of the amorphous layer. Considering the results, it is proposed that secondary crystallization involves the formation of short‐range molecular order in the amorphous layers of a lamellar stack as well as in the amorphous regions between lamellar stacks. This short‐range‐ordered phase has a lower density than the lamellar crystal formed by primary crystallization.
Neutron reflectivity of polymer‐plasticiser diffusion
Authors: Higgins J.S. , Butler S.A. , Bucknall D.G. 
Published: February 2003

AbstractNeutron reflectivity (NR) has been widely exploited to look at polymer thin films and in many ways is an ideal technique for studying polymer interfaces and surfaces, providing high‐resolution concentration ‐ depth profiles across the film thickness. Most NR studies to date have concentrated on thin films of amorphous polymers which possess Tg values well above room temperature. These polymers are ideally suited to NR measurements, firstly because they form homogeneously flat films and, secondly, heat‐quench cycles can be used to study time‐dependent processes. This has been used to great effect in NR studies of the initial stages of polymer ‐ polymer interdiffusion or the kinetics of surface segregated layers for instance. One of the biggest drawbacks to this approach is that in polymer systems where one or more of the components has a Tg close to or less than room temperature, the polymers can still move during the measurement time of an NR profile, which typically takes 1‐2 h for a full profile. Therefore, in order to study such systems, we have developed an approach to NR measurements that allows us to investigate diffusion processes in situ. Our new approach allows us to take NR profiles in only 20 s. This paper describes the method of real‐time NR measurements in detail and illustrates the capabilities of the technique with highlights from some of our recent work on the early stages of polymer‐plasticiser interdiffusion.
Structure and dynamics of silica‐filled polymers by SANS and coherent SAXS
Authors: Geissler Erik , Hecht Anne‐Marie , Rochas Cyrille , Horkay Ferenc , Bley Françoise , Livet Frédéric 
Published: February 2003

AbstractRandom crosslinking in elastomers gives birth to local variations in the crosslink density. When the network is swollen in a low‐molecular‐weight solvent, competition between the osmotic pressure and the local elastic constraints transforms these variations into differences in polymer concentration, the range and amplitude of which can be measured by small‐angle X‐ray or neutron scattering (SAXS or SANS). In filled systems, the distribution both of the polymer and of the elastic constraints is modified. By varying the proportion of deuterated solvent in the network, the scattering function of the polymer can be distinguished from that of the filler using SANS. Such measurements yield not only the internal surface area of the filler particles but also the fraction of that surface in contact with the polymer. The recently developed technique of quasi‐elastic SAXS detects slow dynamic processes at wave vectors larger than those accessible with visible light lasers. This technique is used to investigate the dynamics of filler particles in uncrosslinked polymer melts. It is directly shown that the structural reorganization process of the filler following an external mechanical perturbation is diffusion‐controlled.
Light scattering investigation of association phenomena in saline carrageenan solutions
Authors: Cuppo Fabio , Reynaers Harry 
Published: February 2003

AbstractIntermolecular association of ι‐ and κ‐carrageenan in aqueous solution has been studied by wide‐angle laser light scattering as a function of salt composition and temperature. For ι‐carragenan, the effect of three different salts (LiCl, NaCl, NaI) on the associative properties was investigated. As to κ‐carrageenan, the association‐inducing effect of Cs+ ions was studied, with particular interest in the time dependence of the aggregation process.
Glass capillaries as primary optics for X‐ray stress analysis
Authors: Gibmeier J. , Scholtes B. 
Published: February 2003

AbstractFor locally resolved X‐ray stress analysis the practical application of industrial glass capillaries was investigated. The capillaries were characterised with respect to their surface roughness and their deviation in alignment. X‐ray interference profiles were measured in order to evaluate the potential gain in primary intensity in comparison to measurements carried out by using conventional pinhole collimators. It can be concluded that industrial sodalime‐glass capillaries manufactured by the redraw‐process can be used as a suitable low‐cost alternative primary aperture in X‐ray stress analysis. For primary beam diameters ≤ Ø1.0 mm an immense gain of intensity was observed that increases with decreasing diameter of the aperture.