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Reorganization of semicrystalline polymers on heating: Analyzing common misconceptions in the interpretation of calorimetric dataстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Martin Rosenthal, Melnikov Alexey P., Manfred Burghammer, Ivanov Dimitri A.
- Журнал: European Polymer Journal
- Год издания: 2017
- Издательство: Pergamon Press Ltd.
- Местоположение издательства: United Kingdom
- DOI: 10.1016/j.eurpolymj.2017.06.036
- Аннотация: In our recent article entitled “re-exploring the double-melting behavior of semirigid-chain polymers with an in-situ combination of synchrotron nanofocus X-ray scattering and nanocalorimetry” (European Polymer Journal 81 (2016) 598–606), we investigated complex thermal behavior of a typical semirigid-chain polymer, poly(trimethylene terephthalate), PTT. In the comment on our paper published by Furushima and colleagues (EUROPOL_2017_495), our interpretation of the multiple melting phenomenon was seriously questioned. In particular, it was argued that the main drawback in our paper was due to the fact that the critical heating rate above which the PTT structure does not reorganize after isothermal melt crystallization at 180 °C should be 2000 °C/s, i.e. higher than the rate of 1000 °C/s used in our experiments. It is noteworthy that the authors of the Comment performed all their experiments on a different grade of PTT, which makes quantitative comparison with the recrystallization rates in our experiments problematic. In the present paper, we employ a combination of X-ray scattering with fast single-photon-counting X-ray detection and custom-built ultrafast chip calorimeter to show that the claims of Furushima and colleagues are not relevant to our case and, therefore, cannot be generalized. Indeed, even for a PTT sample melt-crystallized at 150 °C, which recrystallizes on heating much faster than the sample crystallized at 180 °C, the critical heating rate is safely below 500 °C/ s. To further clarify the issue, we discuss on a general misconception in the literature concerning the interpretation of double melting peaks in DSC traces as being indicative of a melting/ recrystallization process. Since many works in the field including the discussed one are based entirely on calorimetric data, the direct information on the structure is simply missing. Therefore, such interpretations of the thermal behavior evoking the so-called “single crystal population” are clearly inadequate. By contrast, on the basis of on-time X-ray scattering recorded simultaneously with ultrafast chip calorimetry we unambiguously show that even in the absence of reorganization processes a uniform population of PTT crystals formed at isothermal conditions exhibitsdouble melting. In agreement with our earlier publications (Macromolecules 41 (2008) 9224–9231) this is explained by strong interactions between amorphous and metastable crystalline regions, which are very characteristic for the semirigid-chain polymer family.
- Добавил в систему: Иванов Дмитрий Анатольевич