A study on blend ratio-dependent Far-IR and low-frequency raman spectra and WAXD patterns of poly(3-hydroxybutyrate)/poly(4-vinylphenol) using homospectral and heterospectral two-dimensional correlation spectroscopy

Abstract

An intensive analysis of far-infrared (far-IR), low-frequency Raman, and wide angle X-ray diffraction (WAXD) data has been performed by two-dimensional correlation spectroscopy (2D-C0S) as a function of the blend ratio of poly(3-hydro\ybutyrate)/poly(4-vinylphenol) (PHB/PVPh). Honiospectral 2D-C0S revealed that a weak band at 128 cm-1 in the far-IR spectra appeared more clearly in the 2D correlation spectra. Heterospectral 2D-C0S (far-IR/Iow-frequency Raman and far-IRAVAXD) provided very important results that were hardly detected in the conventional 2D-COS. A far-IR peak at 130 cm-1 in the heterospectral 2D-COS had negative correlations with the peaks in the low-frequency Raman spectra at 81, 100, and 110 cm-1 and \\v\XD profile 8.78 and 11.01°. These results indicated that those peaks have different origins; the 130 cm-1 peak comes from the intermolecular C=0-H-0 hydrogen bond between PHB and PVPh, while those for low-frequency Raman and WAXD peaks are the features of PHB crystalline structure.