Crystallization of polylactide and its stereocomplex investigated by two-dimensional fourier transform infrared correlation spectroscopy employing carbonyl overtones

Applied Spectroscopy
Pakorn OpaprakasitPramaun Tangboriboonrat

Abstract

The band origins and transitions of weak vibrational modes developed in the 3500 cm(-1) region of polylactide (PLA) spectra during crystallization are investigated. The band assignment to the OH stretching mode of terminal hydroxyls is unlikely because the trace amount of chain-ends is negligible considering the long chain of high molecular weight polymer. The band intensity can be enhanced for quantitative study by increasing the sample film thickness. The results show that the transition patterns of these bands mimic those of C=O stretching modes. Therefore, these are assigned to C=O overtones. Two bands associated with crystalline and amorphous characteristics are revealed during cold crystallization. The crystalline C=O bands of PDLA and its stereocomplex counterpart are located at 3510 cm(-1) and 3482 cm(-1), respectively, indicating a weaker C=O bond in the latter crystal structure. Two-dimensional Fourier transform infrared (2D-FT-IR) correlation spectroscopy is then applied to study the correlation between C=O overtones and the crystalline characteristic band located near 900 cm(-1). The transitions of the two vibrational modes observed in crystallization of the stereocomplex are in-phase with each other. This reflects ...Continue Reading

References

Mar 13, 2002·Biomacromolecules·Yoshihiro KikkawaYoshiharu Doi
Mar 2, 2005·Clinical Orthopaedics and Related Research·Axel ProkopKlaus Emil Rehm
Mar 17, 2006·The Journal of Physical Chemistry. B·E MeaurioJ R Sarasua

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Citations

Jan 20, 2016·Advanced Drug Delivery Reviews·Hideto Tsuji
Apr 30, 2016·Advanced Drug Delivery Reviews·Hideto Tsuji

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