| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Andrade, Maria Madalena Dionísio
Universidade Nova de Lisboa
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (31/31 displayed)
- 2024Cryoprotective Polysaccharides with Ordered Gel Structures Induce Ice Growth Anticipation and Survival Enhancement during Cell Cryopreservationcitations
- 2023Study of the mesomorphic properties and conductivity of n-alkyl-2-picolinium ionic liquid crystalscitations
- 2022Polyhydroxyalkanoates from A Mixed Microbial Culturecitations
- 2022Synthesis and characterisation of ionic liquid crystals based on substituted pyridinium cationscitations
- 2021How Molecular Mobility, Physical State, and Drug Distribution Influence the Naproxen Release Profile from Different Mesoporous Silica Matricescitations
- 2021Influence of natural deep eutectic systems in water thermal behavior and their applications in cryopreservationcitations
- 2021Poly(L-lactic acid)/lithium ferrite compositescitations
- 2019A process engineering approach to improve production of P(3HB) by cupriavidus necator from used cooking oilcitations
- 2017Relaxation behavior of polyurethane networks with different composition and crosslinking densitycitations
- 2017Stabilizing Unstable Amorphous Menthol through Inclusion in Mesoporous Silica Hostscitations
- 2016Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systemscitations
- 2016Accessing the Physical State and Molecular Mobility of Naproxen Confined to Nanoporous Silica Matrixescitations
- 2015Design of controlled release systems for THEDES - Therapeutic deep eutectic solvents, using supercritical fluid technologycitations
- 2015Electrical properties of lithium ferrite nanoparticles dispersed in a styrene-isoprene-styrene copolymer matrixcitations
- 2015Dipolar motions and ionic conduction in an ibuprofen derived ionic liquidcitations
- 2014Influence of nanoscale confinement on the molecular mobility of ibuprofencitations
- 2014Conversion of fat-containing waste from the margarine manufacturing process into bacterial polyhydroxyalkanoatescitations
- 2014Ion jelly conductive properties using dicyanamide-based ionic liquidscitations
- 2014Self-standing elastomeric composites based on lithium ferrites and their dielectric behaviorcitations
- 2013New method to analyze dielectric relaxation processescitations
- 2012Probing radiation damage by alternated current conductivity as a method to characterize electron hopping conduction in DNA moleculescitations
- 2012Understanding the Ion Jelly Conductivity Mechanismcitations
- 2011Kinetics of free radical polymerization probed by dielectric relaxation spectroscopy under high conductivity conditionscitations
- 2011Molecular dynamics of poly(ATRIF) homopolymer and poly(AN-co-ATRIF) copolymer investigated by dielectric relaxation spectroscopycitations
- 2011Phase Transformations Undergone by Triton X-100 Probed by Differential Scanning Calorimetry and Dielectric Relaxation Spectroscopycitations
- 2007Dielectric and mechanical relaxation processes in methyl acrylate/tri-ethyleneglycol dimethacrylate copolymer networkscitations
- 2007Temperature modulated DSC study of the kinetics of free radical isothermal network polymerizationcitations
- 2007Origin of glassy dynamics in a liquid crystal studied by broadband dielectric and specific heat spectroscopycitations
- 2006Changes in molecular dynamics upon formation of a polymer dispersed liquid crystalcitations
- 2005Rotational Mobility in a Crystal Studied by Dielectric Relaxation Spectroscopy. An Experiment for the Physical Chemistry laboratorycitations
- 2002Dielectric studies of the nematic mixture E7 on a hdroxypropylcellulose substratecitations
Places of action
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article
Molecular dynamics of poly(ATRIF) homopolymer and poly(AN-co-ATRIF) copolymer investigated by dielectric relaxation spectroscopy
Abstract
Aiming to develop new dielectric polymers containing CN and F groups with strong dipole moments, a novel copolymer of acrylonitrile (AN) and 2,2,2-trifluoroethyl acrylate (ATRIF) was synthesized in acetonitrile by free radical process as well as the respective homopolymer (poly(ATRIF)). The copolymer's composition and microstructure were analyzed by FTIR, (1)H and (13)C NMR spectroscopy and SEC. The molar incorporation of AN determined in the copolymer by NMR was 58 mol%. Thermogravimetric analysis of poly(AN-co-ATRIF) copolymer showed good thermal stability comparatively to the fluorinated homopolymer. Both copolymer, poly(AN-co-ATRIF), and homopolymer, poly(ATRIF), were dielectrically characterized over a frequency range from 10(-1) to 10(6) Hz, and in a temperature range from 223 to 393 K. The dominating relaxation process detected in both materials is the alpha-relaxation, associated with the dynamic glass transition. A VFTH temperature dependence of the relaxation times (tau) was found for both materials, as characteristic of cooperative processes, from which the respective glass transition temperatures (T(g)(tau = 100 s)) were estimated, which differ similar to 40 K, the one of the copolymer being higher (307 K) in accordance to the calorimetric analysis. This effect was attributed to a higher stiffness of the backbone in the copolymer originated by the inclusion of the acrylonitrile groups. Both relaxation functions have the same breath of relaxation times allowing constructing a single master curve, indicating similar non-exponential character. A less fragile behavior was found for the copolymer. This was rationalized in a more straightforward way by the free volume approach instead from a correlation between fragility and intermolecular coupling. It was found that in the copolymer the free volume increases at a lower rate with the temperature increase. It was inferred from the VFTH temperature dependence of the dc conductivity and low values of the decoupling index that ion motion is significantly influenced by the dynamics of the alpha-process. <br/>