@article {Unger:2009:0003-7028:1034, author = "Unger, Miriam and Morita, Shigeaki and Sato, Harumi and Ozaki, Yukihiro and Siesler, Heinz W.", title = "Variable-Temperature Fourier Transform Infrared Spectroscopic Investigations of Poly(3-Hydroxyalkanoates) and Perturbation-Correlation Moving-Window Two-Dimensional Correlation Analysis. Part II: Study of Poly(-Caprolactone) Homopolymer and a Poly(3-Hydroxybutyrate)Poly(-Caprolactone) Blend", journal = "Applied Spectroscopy", volume = "63", number = "9", year = "2009", abstract = "In the present study, variable-temperature Fourier transform infrared (FT-IR) spectra of a poly(ε-caprolactone) (PCL) homopolymer and a poly(3-hydroxybutyrate) (PHB)-poly(ε-caprolactone) (PCL) blend were analyzed by generalized two-dimensional correlation spectroscopy (2DCOS) and perturbation-correlation moving-window two-dimensional (PCMW2D) correlation spectroscopy. The C=O stretching vibration bands of PCL and PHB were employed to explore the structural changes in the PCL homopolymer and the PHB-PCL blend during the heating process. For the melting of PCL homopolymer in the temperature range of 50 to 70 °C, we observed in the synchronous and asynchronous 2D correlation spectra one crystalline (1724 cm−1) and one amorphous (1737 cm−1) C=O stretching vibration band, which are also detectable in the one-dimensional FT-IR spectra. This result was also confirmed by PCMW2D correlation spectroscopy. During the heating process of the PHB-PCL blend in the temperature range 30-200 °C, the PCMW2D correlation analysis provided detailed information. Thus, in the synchronous PCMW2D correlation spectrum the melting of PCL was observed in the temperature region between 30 and 70 °C. The recrystallization of PHB in the blend in the temperature range 70-120 °C was accompanied by a shift of the C=O stretching band from higher wavenumber (1724 cm−1) corresponding to an imperfect crystalline state to the lower wavenumber (1721 cm−1) characteristic of a well-ordered crystalline state. In the temperature range 120-200 °C the melting process of PHB in the blend is captured by a sharp transition from the crystalline (1722 cm−1) to the amorphous (1747 cm−1) C=O stretching band.", pages = "1034-1040", url = "http://www.ingentaconnect.com/content/sas/sas/2009/00000063/00000009/art00015", doi = "doi:10.1366/000370209789379240", keyword = "POLY(3-HYDROXYBUTYRATE), PHB, POLY(EPSI-CAPROLACTONE), PCL, FOURIER TRANSFORM INFRARED SPECTROSCOPY, FT-IR SPECTROSCOPY, GENERALIZED 2D CORRELATION SPECTROSCOPY, 2DCOS, PERTURBATION-CORRELATION MOVING-WINDOW 2D CORRELAT, PCMW2D" }