Limiting Properties of Isotactic Polypropylene

Limiting Properties of Isotactic Polypropylene

Stať ve sborníku v databázi WoS či Scopus

Morphology is answered for physical - mechanical properties of semicrystalline polymer. Generally, crystallinity is parameter that characterizes polymer morphology. The following conventional analyses are used for assessment of polymer's crystallinity: i) Differential Scanning Calorimetry, ii) X-ray spectroscopy, iii) Infrared spectroscopy, iiii) Density. Each of these methods gives different result of crystallinity. It is known, crystallinity is semiquantitative comparative parameter and it depends on method of assessment. In this present paper, the crystallinity of semicrystalline polymers is characterized via pulsed 1H-NMR. This method distinguishes sequences of macromolecules with different relaxation behavior. A large difference in mobility of the strongly coupled proton pairs within the two phases is expected. Actually, the Solid Phase Content (SPC) is called fast relaxing phase instead of the crystallinity. A direct model fit to the observed FID signal may determine the SPC. It is paid attention to use efficient analytical functions for FID signal fitting. In the end, SPC is correlated with physical - mechanical properties. Czech Company Chemopetrol Litvínov supplied the study polymer specimens for all measurement reported in this work. The main object of this presentation is to emphasize the potential use of the pulsed 1H-NMR analysis technique to characterize semicristalline polymers.

Morphology is answered for physical - mechanical properties of semicrystalline polymer. Generally, crystallinity is parameter that characterizes polymer morphology. The following conventional analyses are used for assessment of polymer's crystallinity: i) Differential Scanning Calorimetry, ii) X-ray spectroscopy, iii) Infrared spectroscopy, iiii) Density. Each of these methods gives different result of crystallinity. It is known, crystallinity is semiquantitative comparative parameter and it depends on method of assessment. In this present paper, the crystallinity of semicrystalline polymers is characterized via pulsed 1H-NMR. This method distinguishes sequences of macromolecules with different relaxation behavior. A large difference in mobility of the strongly coupled proton pairs within the two phases is expected. Actually, the Solid Phase Content (SPC) is called fast relaxing phase instead of the crystallinity. A direct model fit to the observed FID signal may determine the SPC. It is paid attention to use efficient analytical functions for FID signal fitting. In the end, SPC is correlated with physical - mechanical properties. Czech Company Chemopetrol Litvínov supplied the study polymer specimens for all measurement reported in this work. The main object of this presentation is to emphasize the potential use of the pulsed 1H-NMR analysis technique to characterize semicristalline polymers.

polypropylene, pulsed 1H-NMR, limiting properties

polypropylene, pulsed 1H-NMR, limiting properties

VILČ, L.; KRATOCHVÍLA, J.; KUČERA, J.

15.06.2005

Merseburg

3-928466-68-2

http://hdl.handle.net/