Two-Dimensional Fourier Transform Raman Correlation Spectroscopy Studies of Polymer Blends: Conformational Changes and Specific Interactions in Blends of Atactic Polystyrene and Poly(2,6-dimethyl-1,4-phenylene ether)

Abstract

Fourier transform (FT) Raman spectra have been measured for atactic polystyrene (PS), poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and their blends of different compositions: PS/PPE = 90/10, 70/30, 50/50, 30/70, 10/90. Composition-dependent spectral variations of the blends have been analyzed by generalized two-dimensional (2D) correlation spectroscopy to study the conformational changes and specific interactions in the blends. The FT-Raman spectra have been divided into two sets for the 2D correlation: set A of high PS contents (PS/PPE = 100/0, 90/10, 70/30) and set B of high PPE contents (PS/PPE = 50/50, 30/70, 10/90). The 2D synchronous correlation analysis discriminates between the bands of PS and those of PPE and detects bands that are not readily identifiable in the one-dimensional spectra of PS and PPE. The main chain conformation of PS undergoes a drastic change when mixed with PPE, as reflected in the abnormal behavior of bands at 1448 and 1329 cm-1 due to the backbone methylene vibrations and ...