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91.
92.
Synthesis of highly crosslinked methacrylate copolymers of in form of microspheres is presented. They are prepared from tetrafunctional methacrylate derivative of bis(4‐hydroxyphenyl)sulfide, bis[4‐(2‐hydroxy‐3‐methacryloyloxypropoxy)phenyl]sulfide (BES‐DM), and divinylbenzene (DVB). In chemical structure of these copolymers exhibit hydroxyl and ester groups of hydrophilic nature. Additionally, copolymer contains sulfur atoms coming from BES‐DM monomer. Porous structure of the copolymers in the dry and wet state was studied. Microspheres possessing the largest pore volume and specific surface area were subjected to chromatographic investigations. The results show that polar functional groups existing in the chemical structure of the studied microspheres have influence on reversed‐phase HPLC retention mechanism. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
93.
Olga Sosedov Kathrin Matzer Sibylle Bürger Christoph Kiziak Stefanie Baum Josef Altenbuchner Andrzej Chmura Fred van Rantwijk Andreas Stolz 《Advanced Synthesis \u0026amp; Catalysis》2009,351(10):1531-1538
Recombinant Escherichia coli strains were constructed which simultaneously expressed the genes encoding the (S)‐oxynitrilase from cassava (Manihot esculenta) together with the wild‐type or a mutant variant of the arylacetonitrilase from Pseudomonas fluorescens EBC191 in a single organism under the control of a rhamnose‐inducible promoter. The whole cell catalysts obtained converted benzaldehyde and potassium cyanide in aqueous media at pH 5.2 mainly to (S)‐mandelic acid and/or (S)‐mandelic amide and synthesized only low amounts of the corresponding (R)‐enantiomers. The conversion of benzaldehyde and potassium cyanide (KCN) by a whole‐cell catalyst simultaneously expressing the (S)‐oxynitrilase and the wild‐type nitrilase resulted in a ratio of (S)‐mandelic acid to (S)‐mandelic amide of about 4:3. This could be explained by the strong nitrile hydratase activity of the wild‐type nitrilase with (S)‐mandelonitrile as substrate. The relative proportion of (S)‐mandelic amide formed in this system was significantly increased by coexpressing the (S)‐oxynitrilase with a carboxy‐terminally truncated variant of the nitrilase. This whole‐cell catalyst converted benzaldehyde and KCN to mandelic amide and mandelic acid in a ratio of about 9:1. The ee of the (S)‐mandelic amide formed was calculated to be >95%. 相似文献
94.
Richard Lakerveld Herman J.M. Kramer Andrzej I. Stankiewicz Johan Grievink 《Chemical Engineering and Processing: Process Intensification》2010
The design of current industrial crystallizers is strongly focussed on optimization of known types of crystallization equipment. These crystallizers harbour various physical phenomena, which are strongly entangled. The application of generic principles of process intensification (PI) to crystallization processes requires individual control over physical phenomena. A new design method is applied that exploits elementary processing functions as building blocks for design instead of existing equipment, which enables the application of generic principles of PI. Innovations in the field of crystallization to manipulate shear forces, manipulate nucleation rates with external fields, and improve control over solvent removal with membranes are key technologies. A case study demonstrates the application of task-based design for solution crystallization. The results show how task-based design leads to high modularization of the process representation and model architecture. In addition, task-based design enables the application of generic PI principles, which results in a large flexibility to manipulate final product quality. Future needs include generalization of task-based design for crystallization and development of novel technologies for single task manipulation. 相似文献
95.
96.
97.
Variable temperature adsorption of nitric oxide on MoO3 supported on tetragonal zirconia (MoOx/t-ZrO2), obtained by slurry deposition, was investigated by EPR spectroscopy. The influence of molybdenum loading and co-adsorbed oxygen on the adsorption process of NO was elucidated. Particular attention was devoted to redox character of NO activation. Another important aspect concerned is the nature of surface nitrosyl complexes of molybdenum and their thermal stability. The role of oxygen in NO transformation over catalyst surface was also discussed. 相似文献
98.
Srikanth Pilla Shaoqin Gong Eric O'Neill Roger M. Rowell Andrzej M. Krzysik 《Polymer Engineering and Science》2008,48(3):578-587
Biobased and biodegradable polylactide (PLA)‐pine wood flour (PWF) composites were investigated as a means to reduce the overall material cost and tailor the material properties. The composites were prepared using a kinetic‐mixer and an injection molding machine. The tensile modulus of the PLA‐PWF composites increased with the PWF content whereas the toughness and strain‐at‐break decreased. The tensile strength remained the same irrespective of the PWF content (up to 40%). The storage modulus also increased with the PWF content. Additionally, composites containing PWF treated with silane showed higher storage modulus than those without the silane treatment. The area integration underneath the tan δ peaks decreased with increasing PWF, indicating that the PLA‐PWF composites exhibited more elastic behavior with increasing PWF. The degree of crystallinity of the PLA‐PWF composites increased significantly with the PWF content. Furthermore, the treatment of PWF with silane had a positive effect on its nucleating ability, as treated PLA‐PWF composites showed higher crystallinity compared with their untreated counterparts. The morphology of the fracture surfaces were studied using a scanning electron microscope. Finally, a Halpin‐Tsai analytical model to predict Young's modulus of PLA‐PWF composites was presented to compare the theoretical results with that of experimental results. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献
99.
Andrzej K. Biń 《臭氧:科学与工程》2008,30(1):13-20
The results of predictions of ozone solubility in the inert organic solvents based on the Peng-Robinson EOS have been reported. A hypothesis that there is a possible similarity of the values of the binary coefficients, k12, between oxygen and ozone has been tested. Some attempts to estimate ozone solubility in perfluorocarbons have been discussed. 相似文献
100.
Janis Zicans Martins Kalnins Tatjana Ivanova Valdis Kalkis Andrzej K. Bledzki 《大分子材料与工程》1999,271(1):37-42
The present paper surveys the investigation results of the adhesive behavior with steel of different polyethylenes (LDPE, HDPE) irradiated with γ-radiation in vacuum, oxygen, and air, using rheological, optical, thermomechanical and other methods. To study the adhesive contact, the technological parameters applicable to thermosetting polymer material were taken into consideration. The results show the suitable methods in order to obtain thermosetting polymer materials with improved adhesive and thermomechanical properties. 相似文献