Documents disponibles écrits par cet auteur

Cross - linking structural effect of hydrogel based on 2 - hydroxyethyl methacrylate / Loredana E. Nita in Industrial & engineering chemistry research, Vol. 51 N° 22 (Juin 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 22 (Juin 2012) . - pp. 7769-7776 Titre : Cross - linking structural effect of hydrogel based on 2 - hydroxyethyl methacrylate Type de document : texte imprimé Auteurs : Loredana E. Nita, Auteur ; Manuela T. Nistor, Auteur ; Aurica P. Chiriac, Auteur Année de publication : 2012 Article en page(s) : pp. 7769-7776 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydrogel  Hydroxyethyl Résumé : The study presents the possibility to prepare copolymers based on 2-hydroxyethyl methacrylate using two variants of comonomers: ethylene glycol dimethacrylate (1) and 3,9-divinyl-2,4,8,10.tetraoxaspiro[5.5]-undecane (2) that act as crosslinkers for the methacrylate networks generation. The chemical structure of the copolymers—synthesized through redox polymerization process using ammonium persulfate and N,N,N',N'-tetramethylethylenediamine as initiator pair was confirmed by FT-IR spectroscopy. The transparent gel structures were prepared in ethylene glycol. The influence of the comonomers type upon gel copolymers formation was put into evidence by the swelling behavior of the polymeric structure. The morphological information concerning the studied polymeric compounds by SEM evidenced the differences between the hydrogels with respect to cross-linker type and its amount in the monomer feed. Also the thermal stability is a function of the type and amount of the cross-linker. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2029317 [article] Cross - linking structural effect of hydrogel based on 2 - hydroxyethyl methacrylate [texte imprimé] / Loredana E. Nita, Auteur ; Manuela T. Nistor, Auteur ; Aurica P. Chiriac, Auteur . - 2012 . - pp. 7769-7776. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 22 (Juin 2012) . - pp. 7769-7776 Mots-clés : Hydrogel  Hydroxyethyl Résumé : The study presents the possibility to prepare copolymers based on 2-hydroxyethyl methacrylate using two variants of comonomers: ethylene glycol dimethacrylate (1) and 3,9-divinyl-2,4,8,10.tetraoxaspiro[5.5]-undecane (2) that act as crosslinkers for the methacrylate networks generation. The chemical structure of the copolymers—synthesized through redox polymerization process using ammonium persulfate and N,N,N',N'-tetramethylethylenediamine as initiator pair was confirmed by FT-IR spectroscopy. The transparent gel structures were prepared in ethylene glycol. The influence of the comonomers type upon gel copolymers formation was put into evidence by the swelling behavior of the polymeric structure. The morphological information concerning the studied polymeric compounds by SEM evidenced the differences between the hydrogels with respect to cross-linker type and its amount in the monomer feed. Also the thermal stability is a function of the type and amount of the cross-linker. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2029317

Synthesis and thermal analysis of a magnetic composite by thermogravimetry coupled to fourier transform infrared spectroscopy and mass spectrometry / Nita Tudorachi in Industrial & engineering chemistry research, Vol. 51 N° 1 (Janvier 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 1 (Janvier 2012) . - pp. 335–344 Titre : Synthesis and thermal analysis of a magnetic composite by thermogravimetry coupled to fourier transform infrared spectroscopy and mass spectrometry Type de document : texte imprimé Auteurs : Nita Tudorachi, Auteur ; Aurica P. Chiriac, Auteur ; Iordana Neamtu, Auteur Année de publication : 2012 Article en page(s) : pp. 335–344 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermal  analysis  Thermogravimetry  Spectrometry Résumé : This study presents the synthesis of the poly(succinimide)-co-poly(ethylene glycol) block copolymer (PSI-co-PEG) as a matrix for ferrite encapsulation via an in situ polycondensation reaction, by using manganese acetate as a catalyst and dodecane as a solvent. The copolymer and magnetic composite with ferrite in its composition were characterized by FT-IR spectroscopy and thermal analyses (TA) coupled with FT-IR and mass spectrometry (MS). The behaviors while heating and at thermal stability for the copolymer and magnetic composite are different. As a function of the heating rate, the block copolymer presents 3–4 thermal degradation stages, while the magnetic composite decomposed in a maximum of two stages; as compared with the magnetic composite, the weight losses are smaller in the case of the copolymer matrix. The ferrite in the magnetic composite may have an autocatalytic effect that contributes to the acceleration of the thermal degradation process. The analysis of the mass and FT-IR spectra for the released gases in the thermal decomposition process does not reveal an unusual difference, but the temperatures for their identification are different. Generally, using TG/FTIR/MS simultaneous analysis, more gaseous species were determined from the copolymer and magnetic composite in the temperature range of 30–600 °C. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2020203 [article] Synthesis and thermal analysis of a magnetic composite by thermogravimetry coupled to fourier transform infrared spectroscopy and mass spectrometry [texte imprimé] / Nita Tudorachi, Auteur ; Aurica P. Chiriac, Auteur ; Iordana Neamtu, Auteur . - 2012 . - pp. 335–344. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 1 (Janvier 2012) . - pp. 335–344 Mots-clés : Thermal  analysis  Thermogravimetry  Spectrometry Résumé : This study presents the synthesis of the poly(succinimide)-co-poly(ethylene glycol) block copolymer (PSI-co-PEG) as a matrix for ferrite encapsulation via an in situ polycondensation reaction, by using manganese acetate as a catalyst and dodecane as a solvent. The copolymer and magnetic composite with ferrite in its composition were characterized by FT-IR spectroscopy and thermal analyses (TA) coupled with FT-IR and mass spectrometry (MS). The behaviors while heating and at thermal stability for the copolymer and magnetic composite are different. As a function of the heating rate, the block copolymer presents 3–4 thermal degradation stages, while the magnetic composite decomposed in a maximum of two stages; as compared with the magnetic composite, the weight losses are smaller in the case of the copolymer matrix. The ferrite in the magnetic composite may have an autocatalytic effect that contributes to the acceleration of the thermal degradation process. The analysis of the mass and FT-IR spectra for the released gases in the thermal decomposition process does not reveal an unusual difference, but the temperatures for their identification are different. Generally, using TG/FTIR/MS simultaneous analysis, more gaseous species were determined from the copolymer and magnetic composite in the temperature range of 30–600 °C. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2020203

The temperature influence upon the complexation process between poly(aspartic acid) and poly(ethylene glycol) / Loredana E. Nita in Industrial & engineering chemistry research, Vol. 50 N° 9 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5369-5375 Titre : The temperature influence upon the complexation process between poly(aspartic acid) and poly(ethylene glycol) Type de document : texte imprimé Auteurs : Loredana E. Nita, Auteur ; Aurica P. Chiriac, Auteur ; Maria Bercea, Auteur Année de publication : 2011 Article en page(s) : pp. 5369-5375 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Complexation Résumé : The temperature influence upon the formation of an interpolymer complex (IPC) based on poly(aspartic acid) (PAS) and poly(ethylene glycol) (PEG), was investigated. The water PAS/PEG mixture was studied in the temperature range between 22 and 37 °C. The registered data were correlated with the blend composition and the molecular weight of PEG. The intervened interchain physical interactions, especially the hydrogen-bonds, were evidenced by FT-IR spectroscopy. The miscibility and polymer-polymer interactions were experimentally estimated from the dynamic viscosity. The determination of the zeta potential and electrical conductivity of the interpolymer complexes during their formation are in good agreement with the rheological and spectral data. The variation of the composition, respectively, the PAS/PEG ratio, and the different molecular weights of PEG were used in order to establish the optimum conditions for the IPC achievement. The information was correlated on the mentioned interval of temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128659 [article] The temperature influence upon the complexation process between poly(aspartic acid) and poly(ethylene glycol) [texte imprimé] / Loredana E. Nita, Auteur ; Aurica P. Chiriac, Auteur ; Maria Bercea, Auteur . - 2011 . - pp. 5369-5375. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 9 (Mai 2011) . - pp. 5369-5375 Mots-clés : Complexation Résumé : The temperature influence upon the formation of an interpolymer complex (IPC) based on poly(aspartic acid) (PAS) and poly(ethylene glycol) (PEG), was investigated. The water PAS/PEG mixture was studied in the temperature range between 22 and 37 °C. The registered data were correlated with the blend composition and the molecular weight of PEG. The intervened interchain physical interactions, especially the hydrogen-bonds, were evidenced by FT-IR spectroscopy. The miscibility and polymer-polymer interactions were experimentally estimated from the dynamic viscosity. The determination of the zeta potential and electrical conductivity of the interpolymer complexes during their formation are in good agreement with the rheological and spectral data. The variation of the composition, respectively, the PAS/PEG ratio, and the different molecular weights of PEG were used in order to establish the optimum conditions for the IPC achievement. The information was correlated on the mentioned interval of temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24128659