THE STRUCTURE OF A STYRENE-ACRYLONITRILE BUTADIENE POLYMER STUDIED BY2D-IR SPECTROSCOPY/

2D-i.r. spectroscopy involving mechanical excitation is employed to st udy the mechanical relaxation phenomena in a styrene-acrylonitrile/but adiene (ABS) sample, revealing detailed information regarding the mole cular segments involved in macroscopic mechanical relaxation. From the temperature dependence of the dynamic signals it is corroborated that in the ABS sample the polybutadiene (PB) rubber relaxes entirely inde pendently from the styrene-acrylonitrile (SAN) matrix, and thus is pre sent as a separate phase in the material. The rapid-scan variation dev eloped to perform 2D-i.r. experiments offers a significantly reduced m easurement time in comparison with the step-scan mode of operation. In particular, in relation to research in the polymer field, in which ca se stress relaxation is expected to occur during the 2D-i.r. experimen t, this presents a major advantage. (C) 1997 Elsevier Science Ltd.