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21.
L. Oriol M. Piol S. Poelsma J. L. Serrano A. Viuales 《Journal of polymer science. Part A, Polymer chemistry》2000,38(24):4466-4477
Two series of salicylaldimines have been synthesized that consist of model compounds with terminal methylenic chains and reactive compounds in which the terminal chains have been modified with acrylate groups. The dicarbonylrhodium(I) complexes of these systems were prepared by reacting the ligands with the dimer [RhCl(cod)]2 and CO. Characterization of the metal‐containing acrylates by 1H NMR spectroscopy revealed that the Rh(I) can coordinate to the terminal double bond to produce pentacoordinated complexes. Furthermore, investigation of the mesogenic properties of the complexes revealed that the bulkiness of the metallic center requires the presence of at least a three‐ring aromatic core to avoid the suppression of liquid crystallinity. The study was extended to include the side‐chain polymers obtained from the acrylate‐functionalized Schiff bases. Chelation of the preformed polyacrylate with low percentages of Rh(I) emerged as the best strategy to prepare Rh(I)‐containing polyacrylates. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4466–4477, 2000 相似文献
22.
Cristina Berges Nélida Gimeno Luis Oriol Milagros Piñol Patricia Forcén Carlos Sánchez Rafael Alcalá 《European Polymer Journal》2012,48(3):613-620
Microstructure in two diblock methacrylic azo polymers and in some of their blends with PMMA of different molecular weights as well as their photoinduced anisotropy have been investigated. The block copolymers have similar structure but different azo content and degree of polymerization. A synthetic strategy based on a controlled radical polymerization (ATRP) of polymeric blocks and their coupling by click chemistry has been applied to obtain an azo block copolymer of high molecular weight. Microphase segregation has been observed in the block copolymers and in most of the blends. In blends of the block copolymer with lower degree of polymerization (Block 1) azo microdomains change from lamellar to spherical morphology when the azo content decreases from 24 to 3 wt.%. In the block copolymer with higher degree of polymerization (Block 2) and its blends, down to 3 wt.% azo content, spherical azo microdomains have been found. A decrease of the order parameter (η) and the photoinduced birefringence normalized to the azo content (|Δn|norm) has been found in blends of Block 1 when the azo content decreases. However, |Δn|norm and η values similar to those in the azo homopolymer have been observed in Block 2 and its blends. These blends can be used to lower the azo content while keeping a photoinduced response similar to that in the azo homopolymer. 相似文献
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On one approach to a posteriori error estimates for evolution problems solved by the method of lines 总被引:2,自引:0,他引:2
Summary. In this paper, we describe a new technique for a posteriori error estimates suitable to parabolic and hyperbolic equations
solved by the method of lines. One of our goals is to apply known estimates derived for elliptic problems to evolution equations.
We apply the new technique to three distinct problems: a general nonlinear parabolic problem with a strongly monotonic elliptic
operator, a linear nonstationary convection-diffusion problem, and a linear second order hyperbolic problem. The error is
measured with the aid of the -norm in the space-time cylinder combined with a special time-weighted energy norm. Theory as well as computational results
are presented.
Received September 2, 1999 / Revised version received March 6, 2000 / Published online March 20, 2001 相似文献
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Barberá J Gimeno N Monreal L Piñol R Ros MB Serrano JL 《Journal of the American Chemical Society》2004,126(23):7190-7191
The synthesis and characterization of reactive banana-shaped compounds have been carried out, and their ability to be photopolymerized in their SmCP mesophase has been assessed. The presence of a SmCP liquid crystalline phase in these compounds has been confirmed by X-ray studies. The polymerization of these molecules has been demonstrated by calorimetric techniques as well as by the preparation and characterization of SmCP-ordered free films that are mechanically stable at room temperature. Furthermore, polymerized films exhibit second harmonic generation activity at room temperature in the absence of an electric field. 相似文献
30.
J. J. Suñol N. Clavaguera M. T. Mora 《Journal of Thermal Analysis and Calorimetry》1998,52(3):853-862
The low-temperature parts of the temperature-heating rate-transformation (T-HR-T) and temperature-time transformation (T-T-T)
diagrams were obtained for crystallization processes. A knowledge of the kinetic model governing crystallization is not needed
because both transformation curves can be obtained from non-isothermal calorimetric experiments. The calorimetric study was
performed by means of differential scanning calorimetry. The method was applied to analyse crystallization processes of Fe-Ni-based
amorphous alloys prepared by melt spinning. The compositions studied were Fe40Ni40P14Si6, Fe40Ni40P10Si10 and Fe40Ni40P6Si14.
A good concordance was observed between the experimental T-HR-T curves obtained by calculation and the experimental data,
which verifies the reliability of the method. In the T-T-T diagrams, the agreement was good in process B1, while in processes
A1 and C1 there are small differences that could be related to different crystallization products obtained in isothermal/non-isothermal
experiments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献