Characterization of spin-coated films of biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymers by two-dimensional correlation spectroscopy

Principal component analysis-based two-dimensional (PCA2D) correlation spectroscopy combined with the eigenvalue manipulating transformation (EMT) technique by lowering the power of a set of eigenvalues associated with the original data was applied to the temperature-dependent infrared-reflection absorption (IRRAS) spectra of spin-coated films of biodegradable P(HB-co-HHx) (HHx = 3.8, 7.2, and 10.0 mol%) copolymers. The PCA2D correlation spectra for P(HB-co-HHx) (HHx = 10.0 mol%) copolymer is completely different from those for P(HB-co-HHx) (HHx = 3.8 and 7.2 mol%) copolymers. In the synchronous PCA2D correlation spectra, the intensity changes of the bands at 1136 and 1282 cm(-1) changed greatly as HHx mol% of P(HB-co-HHx) copolymers increases. Furthermore, EMT technique accentuates the contribution of intensity of band enhanced the minor PCs, seems to preferentially emphasizes the behavior of amorphous components of during the heating process. (C) 2008 Elsevier B.V. All rights reserved.