| 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
Dielectric and mechanical relaxation processes in methyl acrylate/tri-ethyleneglycol dimethacrylate copolymer networks
Abstract
The dielectric properties of methylacrylate (MA)/tri-ethyleneglycol dimethacrylate (TrEGDMA) copolymers at different compositions, ranging from 0 to 100, were measured between - 120 and 150 degrees C over the frequency range 0.1 Hz1 MHz. In the given frequency range, three relaxation processes were detected by dielectric relaxation spectroscopy in homo poly-TrEGDMA and copolymers: the alpha process associated with the glass transition, and two secondary processes due to localized mobility. In PMA only one secondary process was observed besides the alpha relaxation process. The influence of copolymerization going from PMA, monofunctional softer component with a glass transition determined calorimetrically as 284 K, to poly-TrEGDMA, higher glass transition component, bifunctional, that also forms a dense network due to cross linking, reflects mainly in the alpha process that shifts to higher temperatures and becomes broader. The raise and broadening in the glass transition with TrEGDMA increase was also observed by dynamic mechanical thermal analysis and differential scanning calorimetry. The glass transition temperature of poly-TrEGDMA was not detected calorimetrically but a value of 429 K was estimated from the best fit of the Fox equation. In what concerns the secondary relaxation process detected in poly-TrEGDMA and copolymers at the lowest temperatures, it is related with local twisting motions of ethyleneglycol moieties, being designated as gamma relaxation, while the process detected in the medium temperature range is associated with the rotation of the carboxylic groups as in poly(alkyl methacrylates), designated as beta relaxation. This process is detected at much lower temperatures in homo PMA in the same temperature region than the above mentioned gamma relaxation. The copolymerization influences mainly the alpha process while the gamma process remains almost unaffected in copolymers relative to homo poly-TrEGDMA. The beta process is largely determined by the presence o the tri-ethylene glycol dimethacrylate monomeric units even in copolymers with the lowest TrEGDMA content. (C) 2007 Elsevier Ltd. All rights reserved.