Calculation of the mutual packing of poly(4,4′-oxydiphenylene) pyromellitimide chains

Lukasheva, N. V.; Зубков, В. И.; Milevskaya, I.S.; Baklagina, Yu. G.; Strunnikov, A.Yu.

doi:10.1016/0032-3950(87)90398-4

Cited by 4 publications

(1 citation statement)

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“…Specific inter-chain interactions leading to the creation of ordered regions and in the extreme—to a semicrystalline structure—for PI, which has only para -substituted aromatic cycles in the elementary unit at Ph–O–Ph′ fragments (Kapton) are described previously. A method for selecting an optimal conformation of the macromolecule in the crystalline region was developed for it, and variants of polymer chains packing were calculated [ 24 , 25 ]. In these works, it was shown that the para -substituted aromatic rings at the Ph–O–Ph′ nodes in Kapton are “hinges” that are characterized by a variety of conformers.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Conformation Order on Gas Separation Properties of Polyetherimide Ultem Films

et al. 2020

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Changes of the spectral characteristics of absorption bands depending on the films’ treatment method were registered for polyetherimide Ultem films. The possibility of selection of structural criteria (the ratio of the functional groups absorption bands intensities) showing all conformational changes in elementary unit with metrological processing of the results is shown. It is demonstrated that film formation from chloroform solution leads to elementary unit fragments, Ph–O–Ph′, which have an effect on macromolecule conformation and result in increasing of space between fragments of macromolecules (local polymer matrix packing loosening). Desorption of residual chloroform from films by ethanol or supercritical CO2 leads to a change of conformers set in Im–Ph–Im′ units. Quantum chemical modeling showed the possibility of convergence of these fragments in neighboring macromolecules, and consequently of interchain π–π interaction (local densification of chain packing of the polymer matrix). After annealing at a temperature higher than glass transition temperature, the polyetherimide film exhibits the most disordered (amorphous) state at all of the fragments. It is demonstrated that the results, obtained by the combination of theoretical and experimental vibrational spectroscopy methods, are in good agreement with data of chain packing ordering found by analysis of gas separation parameters.

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Section: Resultsmentioning

confidence: 99%