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Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present the first study of the shear mechanical properties of monodomain nematic side-chain liquid-crystal elastomers (SCLCEs) prepared by cross-linking with UV irradiation a nematic side-chain liquid-crystal polymer oriented with an electric or a magnetic field. Their elastic behavior was studied in the dry, swollen and stretched states, in order to check the various theoretical descriptions of these systems. The shear measurements taken on the dry samples show that the shear anisotropy is much smaller than that of the usual twice cross-linked samples oriented by a mechanical stretching of the network formed after the first cross-linking step, demonstrating that the elasticity of the networks strongly depends on the preparation procedure used. The shear experiments performed on the swollen state of these two different types of elastomers reveal that the elasticity of the network is Gaussian for the elastomers oriented with the electric or the magnetic field, and non-Gaussian for the elastomers oriented with the usual stretching procedure. The analysis of the stress-strain curves of both types of elastomers with the neoclassical model based on Gaussian rubber elasticity confirms the Gaussian and non-Gaussian nature of their elasticity. The shear experiments performed as a function of the elongation of the homeotropically oriented elastomer when the shear is applied in a direction parallel to the elongation, do not show the decrease of the associated shear modulus, which is theoretically expected when the strain approaches the threshold value marking the beginning of the elastic plateau. However, the observation of this effect could be prevented by possible small misalignments of the director, as suggested by a calculation presented in one of the theories describing this effect. [ABSTRACT FROM AUTHOR]

Copyright of Lettre de Medecine Physique et de Readaptation is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pelvi-Perineologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pelvi-Perineologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, the industry has succeeded in achieving adequate performance of coatings for automotive, industrial, and decorative applications, both in terms of mechanical and aesthetical properties. Nevertheless, there is an increasing demand for novel light stabilizers which can meet even today's higher performance and quality requirements as well as cost pressures. It is well known, for example in the automotive industry, that UV-absorbers (UVA) based on hydroxyphenyl-s-triazines (HPT) are capable of fulfilling these requirements where 2-(2-hydroxyphenyl)-benzotriazoles (BTZ) tend to fail or show inferior properties. Besides the well-known HPT for automotive applications, other high-performance products have been developed for an even broader range of applications comprising, for example, thin- or reduced-film applications, powder coatings, and extremely durable wood coatings. New encapsulation techniques make it even possible to convert most of these hydrophobic products into highly compatible and stable water-based product forms. This opens the door for the advanced HPT UVA for a broad range of possible waterborne and solventborne applications. [ABSTRACT FROM AUTHOR]

We study the mechanical anisotropy of a series of uniaxial side chain nematic elastomers prepared with the same chemical composition but with different preparation protocols. For all the compounds, the experiments performed as a function of temperature show no discontinuity in both G' // and G' ⊥ (the labels // and ⊥ stand for the director parallel, respectively perpendicular to the shear displacement) around the nematic-isotropic (N-I) phase transition temperature determined by DSC. They also all show a small decrease in G' // starting at temperatures well above this temperature (from ∼ 4° C to ∼ 20° C depending on the compound studied) and leading to a small hydrodynamic value of the G' ⊥/ G' // ratio. The measurements taken as a function of frequency show that the second plateau in G' // and the associated dip in G //” expected from dynamic semi-soft elasticity are not observed. These results can be described by the de Gennes model, which predicts small elastic anisotropy in the hydrodynamic and linear regimes. They correspond to the behavior expected for compounds beyond the mechanical critical point, which is consistent with the NMR and specific heat measurements taken on similar compounds. We also show that a reduction in the cross-linking density does not change the non-soft character of the mechanical response. From the measurements taken as a function of frequency at several temperatures we deduce that the time-temperature superposition method does not apply. From these measurements, we also determine the temperature dependence of the longest relaxation time τE of the network for the situations where the director is either parallel or perpendicular to the shear velocity. Finally, we discuss the influence on the measurements of the mechanical constraint associated with the fact that the samples cannot change their shape around the pseudo phase transition, because of their strong adherence on the sample-bearing glass slides. [ABSTRACT FROM AUTHOR]

We present the first study of the layer compression modulus B carried out near, above and below the Smectic C-Hexatic I critical point in racemic mixtures of methylbutyl phenyl octylbiphenyl-carboxylate (8SI) and the octyloxy biphenyl analog (8OSI), at frequencies ranging from 0.2 Hz to 2 ×103 Hz. The behavior of B as a function of temperature shows a progressive evolution from a first order transition in 8SI to a continuous supercritical behavior in 8OSI. The latter is characterized by an increase in B, which appears above the transition, and which is followed by a leveling off when the temperature is decreased towards the transition. It is proposed that this behavior stems from the relaxation of the hexatic domains which are frozen in the frequency range studied. For the supercritical and near-critical compounds, B exhibits a small dip near the transition temperature, which is visible in the low frequency range only, indicating that the dynamics associated with the critical point is very slow. We also report measurements in the Crystal-J phase of the pure compounds, and show that 8SI behaves mechanically as a hexatic phase and 8OSI as a soft crystal phase. [ABSTRACT FROM AUTHOR]

Presents a study of the behavior of layer compression modulus B as a function of frequency near the nematic-smectic-A and re-entrant nematic-smectic-A phase transitions. Thermal behavior of B for 4-octyloxy-4'-cyanobiphenyl; Methods used; Results and discussion.

UV-curable powder coatings have opened up new possibilites in actually combining the advantages of both powder and UV-curable systems. UV powders provide better flow (little or no orange peeling), no monomer emission, better cost effectiveness (shorter, low temperature melting and short UV curing cycles) and new application possibilities on heat sensitive substrates such as wood and plastics. In addition to the resins available (several radical and cationic curing systems are offered by resin suppliers), the choice of proper photo-initiators and light stabilisers is vital to obtain the required quality and durability properties for exterior applications. The widespread use of this technology will require still further developments from both formulators and applicators. The UV curing of 3D objects also needs optimisation. However, relatively complex-shaped objects, eg in the furniture industry, are already being coated with liquid UV-curable formulations and cured in 3D UV ovens. It is highly probable that in the foreseenable future solutions will be found so that UV powders can be applied and cured on 3D objects not only for automotive parts or even complete car or truck bodies but also for numerous industrial applications. [ABSTRACT FROM AUTHOR]