The effect of separation of blocks on the crystallization kinetics and phase composition of poly(butylene adipate) in multi-block thermoplastic polyurethanes

Gorbunova, M.A.; Komov, E.V.; Grunin, L.Y.; Ivanova, M.S.; Abukaev, A.F.; Imamutdinova, A.M.; Ivanov, D.A.; Anokhin, D.V.

Авторы: Gorbunova Marina A., Komov Evgenii V., Grunin Leonid Yu, Ivanova Mariya S., Abukaev Ainur F., Imamutdinova Arina M., Ivanov Dimitri A., Anokhin Denis V.
Журнал: Physical Chemistry Chemical Physics
Год издания: 2021
Издательство: Royal Society of Chemistry
Местоположение издательства: United Kingdom
DOI: 10.1039/D1CP04684E
Аннотация: The influence of the hard segment nature on the crystallization kinetics of multi-block thermoplastic polyurethanes containing poly(butylene adipate) (PBA) as a soft segment was investigated. Using a combination of FTIR spectroscopy, time-domain 1H nuclear magnetic resonance (TD-NMR), differential scanning calorimetry (DSC), fast-scanning calorimetry (FSC) and wide-angle X-ray diffraction (WAXS), it was shown that aliphatic, cycloaliphatic and aromatic diisocyanates affect the phase separation efficiency of soft and hard segments. The best phase separation efficiency was observed for a sample containing aliphatic diisocyanate due to the development of a hydrogen bond network. The thermal history, phase separation and the degree of ordering of the polyurethane determine the polymorphic behavior of melt-crystallized PBA. The formation of a partially-ordered mesophase of linear aliphatic polyurethane leads to an increase in the crystallization rate of PBA at room temperature and the formation of thermodynamically stable α-crystals. The presence of bulk cycloaliphatic and aromatic diol-urethane fragments prevents the phase separation of PBA, which crystallizes after slow cooling in a mixture of α- and β-crystalline forms. The new nanocalorimetry technique allows the identification of a direct correlation between the phase separation and crystallization kinetics of the melt-crystallized PBA in a wide range of cooling rates – from 2 to 30 000 K s−1. Particularly, ultra-fast cooling suppresses the nucleation of the β-phase of PBA resulting in slow crystallization of only α-modification at room temperature. The role of the polyurethane mesophase in the crystallization of the soft segment was discussed for the first time.
Добавил в систему: Иванов Дмитрий Анатольевич

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The effect of separation of blocks on the crystallization kinetics and phase composition of poly(butylene adipate) in multi-block thermoplastic polyurethanesстатья

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