Study of the mechanism of the thermochemical reaction of polyimides with hydroxyl groups via vibrational-spectroscopy and quantum-chemistry methods

Rusakova, O. Yu.; Kostina, Yu. V.; Rodionov, A. S.; Бондаренко, Г. Н.; Alent’ev, A. Yu.; Мелешко, Т. К.; Kukarkina, N. V.; Yakimanskiĭ, A. V.

doi:10.1134/s0965545x11080074

Cited by 8 publications

(23 citation statements)

References 7 publications

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“…Nonetheless, it can be presumed that by applying the very high temperatures used to force the intramolecular rearrangement, both lactams and benzoxazoles could be formed, and that the final composition is greatly affected by the final temperature and the heating protocol. In this regard, it is to remark that there is a spectroscopic indication of polyimide persistence, apart from the merging of bands attributable to lactams, as the characteristic IR bands of imide at about 1778, 1720, 1550 and 725 cm -1 remained in the IR spectra reported by Kostina et al, and that is so also for most of the TR-PBOs prepared from ortho-esterpolyimides reported until now [26,46].…”

Section: Thermal Treatment Of Precursor Polyimidesmentioning

confidence: 79%

“…It is well documented that pyrolysis of methoxy aromatic compounds proceeds via the homolytic scission of the (H3C)-O linkage, with the subsequent loss of CH3 as methane or ethane and recombination of the phenoxy radical to phenol [37]. If this mechanism is accepted as a hydroxypolyimides at temperatures over 400 ºC [26,46]. They have postulated that the formation of rigid cyclolactams, and not only polybenzoxazoles, is responsible of the chain conformational changes which lead to the observed strong effects on physical properties, and particularly to the dramatic increase of fractional free volume and hence of gas diffusivity.…”

Section: Thermal Treatment Of Precursor Polyimidesmentioning

confidence: 99%

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Gas separation membranes made through thermal rearrangement of ortho-methoxypolyimides

et al. 2015

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SummaryOrtho-methoxypolyimides were prepared by the classical chemical imidization method and also by azeotropic imidization, using 3,3'-dimethoxybenzidine (DMAB) and hexafluoroisopropylidene diphthalic anhydride (6FDA) as monomers. High molecular weights were achieved by both methods, and the physical properties of the materials were investigated by spectroscopic and thermal analytical techniques. Polymers exhibited excellent thermal properties and film-forming ability, which allowed them to be tested as dense membranes for gas separation after a convenient treatment at high temperature (450 °C) to promote thermal rearrangement (TR). Spectroscopic evidences indicated that the final composition of the TR materials seemed not to correspond to TR-polibenzoxazoles, as it is the case when ortho-hydroxypolyimides are exposed to similar thermal treatments. A detailed study was carried out with the purpose of elucidating the actual mechanism of rearrangement, comparing ortho-

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Section: Thermal Treatment Of Precursor Polyimidesmentioning

confidence: 79%

Section: Thermal Treatment Of Precursor Polyimidesmentioning

confidence: 99%

Gas separation membranes made through thermal rearrangement of ortho-methoxypolyimides

et al. 2015

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“…PI I − III were synthesized and characterized in the Institute of Macromolecular Compounds of the Russian Academy of Sciences by the technique described by Rusakova et al . PI IV was synthesized using the method described by Jung and Lee and provided by Young Moo Lee (Department of Polymer Science and Engineering, Korea).…”

Section: Resultsmentioning

confidence: 99%

“…Interesting results concerning the influence of residual solvent on the properties of PI films were obtained for PIs containing hydroxyl groups in the diamine fragment in the ortho ‐position to the nitrogen atom of the imide group (Table ). These PIs are capable of intramolecular thermochemical reaction (ITR) with the elimination of CO 2 resulting in the formation of an insoluble polymer with a new structure and consequently with new physical and chemical properties …”

Section: Resultsmentioning

confidence: 99%

“…The presence of complex formation is proved by the changes in theoretical and experimental vibration spectra; further work can be devoted to analyzing the influence of the process of complex formation or destruction of hydrogen bonds on the conformational composition of polymer elementary units. Such an approach was developed in the articles …”

Section: Introductionmentioning

confidence: 99%

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Influence of residual solvent on physical and chemical properties of amorphous glassy polymer films

et al. 2013

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One of the most important areas of current research is the study of the influence of the prehistory of samples of amorphous glassy polymers on their physical and chemical properties. The study of structural changes by high temperature IR spectroscopy compared with of quantum chemical calculations allows for an understanding of the mechanism and nature of such processes. The changes in the structure of the polymer chain depending on the type of solvent used in the formation of the films are demonstrated using the examples of several different classes of polymers. In turn, the impact of such changes in the structure on the physical and chemical properties of the polymer films is demonstrated. © 2013 Society of Chemical Industry

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Synthesis and Characterization of Polybenzoxazinone and its Prepolymer Using Gas Separation

Pientka

Brožová

Pulyalina

et al. 2013

Macro Chemistry & Physics

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Polybenz‐3,1‐oxazinone‐4 (PBOZ) films are prepared via the thermal rearrangement of poly[(methylene‐bis‐anthranilamide) 4,4′‐diphenyloxidicarboxylic acid] (PAA) films by heating to 300 °C. PAA is synthesized by low‐temperature polycondensation. The PBOZ film exhibits excellent mechanical properties and a high glass‐transition temperature. Conversion of PAA to PBOZ leads to an increase in the fractional free volume as a result of thermal dehydration and cyclization during membrane formation and due to the removal of residual solvent. The excess free volume in the PBOZ film is approximately 3–4% of the total volume. The gas permeability and selectivity of the PBOZ film is higher than that of the PAA film. The thermal rearrangement of polymers is recognized as a suitable method to improve separation efficiency.

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Study of the mechanism of the thermochemical reaction of polyimides with hydroxyl groups via vibrational-spectroscopy and quantum-chemistry methods

Cited by 8 publications

References 7 publications

Gas separation membranes made through thermal rearrangement of ortho-methoxypolyimides

Gas separation membranes made through thermal rearrangement of ortho-methoxypolyimides

Influence of residual solvent on physical and chemical properties of amorphous glassy polymer films

Synthesis and Characterization of Polybenzoxazinone and its Prepolymer Using Gas Separation

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