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Investigation of water diffusion in low-density polyethylene by attenuated total reflectance fourier transform infrared spectroscopy and two-dimensional correlation analysis / Mengyin Wang in Industrial & engineering chemistry research, Vol. 50 N° 10 (Mai 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6447-6454 Titre : Investigation of water diffusion in low-density polyethylene by attenuated total reflectance fourier transform infrared spectroscopy and two-dimensional correlation analysis Type de document : texte imprimé Auteurs : Mengyin Wang, Auteur ; Peiyi Wu, Auteur ; Saurav S. Sengupta, Auteur Année de publication : 2011 Article en page(s) : pp. 6447-6454 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Correlation  analysis  Fourier-transformed  infrared  spectrometry  Reflectance  Density  Diffusion Résumé : Water diffusion through low density polyethylene (LDPE) film was investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and two-dimensional correlation spectroscopy (2DCOS) over a temperature range of 25-80 °C. The 2DCOS spectra of water diffusion in LDPE at different temperatures were very similar. The broad OH stretching vibration (v(OH)) was split into four bands assigned to three different types of water molecules, namely, bulk water, cluster water, and free water, which will be defined. It appeared that as water molecules disperse in LDPE, cluster water with moderate hydrogen bonds diffused faster than bulk water with strong hydrogen bonds. Additionally, the hydrogen bonds between water molecules may have been further weakened or even broken to form free water, possibly due to limited free volume. On the basis of a Fickian model, the diffusion coefficients could be calculated from overall, fast and slow diffusion process, respectively. The diffusion coefficients were observed to increase with temperature, possibly due to increased swelling of molecular chain, more free volume, and reduced size of the penetrants. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158942 [article] Investigation of water diffusion in low-density polyethylene by attenuated total reflectance fourier transform infrared spectroscopy and two-dimensional correlation analysis [texte imprimé] / Mengyin Wang, Auteur ; Peiyi Wu, Auteur ; Saurav S. Sengupta, Auteur . - 2011 . - pp. 6447-6454. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 10 (Mai 2011) . - pp. 6447-6454 Mots-clés : Correlation  analysis  Fourier-transformed  infrared  spectrometry  Reflectance  Density  Diffusion Résumé : Water diffusion through low density polyethylene (LDPE) film was investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and two-dimensional correlation spectroscopy (2DCOS) over a temperature range of 25-80 °C. The 2DCOS spectra of water diffusion in LDPE at different temperatures were very similar. The broad OH stretching vibration (v(OH)) was split into four bands assigned to three different types of water molecules, namely, bulk water, cluster water, and free water, which will be defined. It appeared that as water molecules disperse in LDPE, cluster water with moderate hydrogen bonds diffused faster than bulk water with strong hydrogen bonds. Additionally, the hydrogen bonds between water molecules may have been further weakened or even broken to form free water, possibly due to limited free volume. On the basis of a Fickian model, the diffusion coefficients could be calculated from overall, fast and slow diffusion process, respectively. The diffusion coefficients were observed to increase with temperature, possibly due to increased swelling of molecular chain, more free volume, and reduced size of the penetrants. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24158942

Structure and diffusion behavior of trioctyl trimellitate (TOTM) in PVC film studied by ATR - IR spectroscopy / Hengjie Lai in Industrial & engineering chemistry research, Vol. 51 N° 27 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9365-9375 Titre : Structure and diffusion behavior of trioctyl trimellitate (TOTM) in PVC film studied by ATR - IR spectroscopy Type de document : texte imprimé Auteurs : Hengjie Lai, Auteur ; Zhangwei Wang, Auteur ; Peiyi Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 9365-9375 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Diffusion Résumé : Tri-2-ethylhexyltrimellitate (TOTM) is one of the commercially used plasticizers for poly(vinyl chloride) (PVC). In this work, the diffusion behavior of TOTM in PVC films is investigated through real-time ATR-IR spectroscopy at 25, 40, and 70 °C, and the ratio changes of three C═O structures of TOTM are plotted as a function of diffusion time. TOTM itself is composed of two types of C═O structures: one C═O structure represents a free state and the other represents an aggregated C═O state formed by dipolar–dipolar interactions, as confirmed by the second derivative of FTIR and density functional theory (DFT). Furthermore, another new band related to C═O groups of TOTM was observed during diffusion experiments in PVC at different temperatures, which can be assigned to dipolar–dipolar interactions between TOTM and PVC (interacting C═O structure). These results show that the diffusion coefficients of TOTM in PVC increase with temperature. Conversely, the equilibrium concentrations of TOTM in PVC films decrease significantly with temperature due to rapid molecular movements and less interacting C═O structures. Moreover, it is also found that free C═O structures more easily interact with C–Cl groups of PVC at 25 °C, while aggregated C═O structures show prior contribution at 40 °C, which is effectively confirmed by two-dimensional (2D) correlation infrared spectroscopy. At 70 °C, however, free and aggregated C═O structures can reach an equilibrium much more quickly, but the content of interacting C═O structures has to keep a lower level because of higher temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132273 [article] Structure and diffusion behavior of trioctyl trimellitate (TOTM) in PVC film studied by ATR - IR spectroscopy [texte imprimé] / Hengjie Lai, Auteur ; Zhangwei Wang, Auteur ; Peiyi Wu, Auteur . - 2012 . - pp. 9365-9375. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 27 (Juillet 2012) . - pp. 9365-9375 Mots-clés : Diffusion Résumé : Tri-2-ethylhexyltrimellitate (TOTM) is one of the commercially used plasticizers for poly(vinyl chloride) (PVC). In this work, the diffusion behavior of TOTM in PVC films is investigated through real-time ATR-IR spectroscopy at 25, 40, and 70 °C, and the ratio changes of three C═O structures of TOTM are plotted as a function of diffusion time. TOTM itself is composed of two types of C═O structures: one C═O structure represents a free state and the other represents an aggregated C═O state formed by dipolar–dipolar interactions, as confirmed by the second derivative of FTIR and density functional theory (DFT). Furthermore, another new band related to C═O groups of TOTM was observed during diffusion experiments in PVC at different temperatures, which can be assigned to dipolar–dipolar interactions between TOTM and PVC (interacting C═O structure). These results show that the diffusion coefficients of TOTM in PVC increase with temperature. Conversely, the equilibrium concentrations of TOTM in PVC films decrease significantly with temperature due to rapid molecular movements and less interacting C═O structures. Moreover, it is also found that free C═O structures more easily interact with C–Cl groups of PVC at 25 °C, while aggregated C═O structures show prior contribution at 40 °C, which is effectively confirmed by two-dimensional (2D) correlation infrared spectroscopy. At 70 °C, however, free and aggregated C═O structures can reach an equilibrium much more quickly, but the content of interacting C═O structures has to keep a lower level because of higher temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26132273