New insights into the mechanism of interaction between CO2 and polymers from thermodynamic parameters obtained by in situ ATR-FTIR spectroscopy

New insights into the mechanism of interaction between CO2 and polymers from thermodynamic parameters obtained by in situ ATR-FTIR spectroscopy Full article

Journal

Physical Chemistry Chemical Physics
ISSN: 1463-9076 , E-ISSN: 1463-9084

Output data

Year: 2016, Volume: 18, Number: 9, Pages: 6465-6475 Pages count : DOI: 10.1039/c5cp06431g

Authors

Gabrienko Anton A. ^1,2 , Ewing Andrew V. ¹ , Chibiryaev Andrey M. ^2,3 , Agafontsev Alexander M. ^3,4 , Dubkov Konstantin A. ² , Kazarian Sergei G. ¹

Affiliations

1	(Данные Web of science) Univ London Imperial Coll Sci Technol & Med, Dept Chem Engn, South Kensington Campus, London SW7 2AZ, England
2	(Данные Web of science) Russian Acad Sci, Siberian Branch, Boreskov Inst Catalysis, Prospekt Akad Lavrentieva 5, Novosibirsk 630090, Russia
3	(Данные Web of science) Novosibirsk State Univ, Fac Nat Sci, Pirogov St 2, Novosibirsk 630090, Russia
4	(Данные Web of science) Russian Acad Sci, Siberian Branch, Vorozhtsov Inst Organ Chem, Prospekt Akad Lavrentieva 9, Novosibirsk 630090, Russia

This work reports new physical insights of the thermodynamic parameters and mechanisms of possible interactions occurring in polymers subjected to high-pressure CO2. ATR-FTIR spectroscopy has been used in situ to determine the thermodynamic parameters of the intermolecular interactions between CO2 and different functional groups of the polymers capable of specific interactions with sorbed CO2 molecules. Based on the measured ATR-FTIR spectra of the polymer samples subjected to high-pressure CO2 (30 bar) at different temperatures (300-340 K), it was possible to characterize polymer-polymer and CO2-polymer interactions. Particularly, the enthalpy and entropy of the formation of the specific non-covalent complexes between CO2 and the hydroxy (-OH), carbonyl (C=O) and hydroxyimino (=N-OH) functional groups of the polymer samples have been measured. Furthermore, the obtained spectroscopic results have provided an opportunity for the structure of these complexes to be proposed. An interesting phenomenon regarding the behavior of CO2/polymer systems has also been observed. It has been found that only for the polyketone, the value of enthalpy was negative indicating an exothermic process during the formation of the CO2-polymer non-covalent complexes. Conversely, for the polyoxime and polyalcohol samples there is a positive enthalpy determined. This is a result of the initial polymer-polymer interactions requiring more energy to break than is released during the formation of the CO2-polymer complex. The effect of increasing temperature to facilitate the breaking of the polymer-polymer interactions has also been observed. Hence, a mechanism for the formation of CO2-polymer complexes was suggested based on these results, which occurs via a two-step process: (1) the breaking of the existing polymer-polymer interactions followed by (2) the formation of new CO2-polymer non-covalent interactions.

Gabrienko A.A. , Ewing A.V. , Chibiryaev A.M. , Agafontsev A.M. , Dubkov K.A. , Kazarian S.G.
New insights into the mechanism of interaction between CO2 and polymers from thermodynamic parameters obtained by in situ ATR-FTIR spectroscopy
Physical Chemistry Chemical Physics. 2016. V.18. N9. P.6465-6475. DOI: 10.1039/c5cp06431g WOS Scopus

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