6 research outputs found
A Novel Green Synthesis Method of Poly (3-Glycidoxypropyltrimethoxysilane) Catalyzed by Treated Bentonite
The present work focuses on the preparation and characterization of poly(3-Glycidoxypropyltrimethoxysilane) (PGPTMS) under mild conditions. Ring-opening polymerization of the 3-Glycidoxypropyltrimethoxysilane (GPTMS) is initiated with the bentonite of Maghnite-H+ (Mag-H+), an ecologic and low-cost catalyst. The evolution of epoxy ring-opening was studied in bulk and in solution using CH2Cl2 as solvent, as well as the influences of several factors such as the amount of Mag-H+, polymerization time and temperature on the yield of polymer were investigated. The best polymer yield (30 %) was obtained in bulk polymerization at room temperature (20 °C) for a reaction time 8 h, and itâs increases with time and reaches 68 % for 7 days. The structures of the obtained polymers (PGPTMS) were confirmed respectively by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). The thermal properties of the prepared polymers were given by Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA), the Tg of PGPTMS is recorded at -31.27 °C, and it is thermally stable with a degradation start temperature greater than 300 °C, all decomposition stopped at 600 °C. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Analyse contrastive dâexpressions phatiques dans les interactions radiophonique et les interactions en ligne
RĂ©sumĂ©Â : Notre contribution objecte Ă rĂ©aliser une analyse comparative de deux schĂ©matismes communicationnels : lâinteraction en ligne (IL) et lâinteraction radiophonique (IR). La visĂ©e est dâapprĂ©hender le fonctionnement de lâexpression phatique et ses caractĂ©ristiques dans les rituels dâouverture et de clĂŽture en IL& IR. Lâapproche descriptive et analytique a Ă©tĂ© adoptĂ©e pour effectuer une analyse qualitative dâun corpus constituĂ© dâIR sur la chaine Alger chaine 3 et des IL dans un groupe Messenger (Facebook). Cette analyse a rĂ©vĂ©lĂ© la prĂ©sence du phatique dans les ouvertures et les clĂŽtures de lâĂ©change, dans les IR et celles en ligne. Elle a permis de mettre en contraste ces deux types dâinteractions en soulignant la spĂ©cificitĂ© des ILS dâautant plus que les utilisateurs se permettent de modeler leur comportement linguistique et interactif en vertu du potentiel offert par cet environnement numĂ©rique.
Mots-clĂ©s : Expression phatique, interaction en ligne, interaction radiophonique, environnement numĂ©rique ; rituels dâouverture, rituels de clĂŽture