The Effect of the Solvent on the Molecular Dynamics and Structure in Blended Composites of Polyurethane and a Copolymer of Styrene with Acrylonitrile

Abstract

By spin-probe electron paramagnetic resonance spectroscopy, IR spectroscopy, and study of the elastic strength properties (Instron), an investigation was made of the effect of solvents tetrahydrofuran (THF), methyl ethyl ketone (MEK), ethyl acetate (EA), and acetone (A) on the structure and molecular dynamics of blended composites based on polyurethane (PU) and a styrene acrylonitrile (SAN) copolymer. The molecular mobility (τ), degree of crystallinity (χ), and elastic modulus (E) undergo large changes in blended composites from 100% PU to 50% PU and 50% SAN, and only with a higher SAN content in the composite are sharp changes observed in the structural dynamic parameters, irrespective of the solvent. Increase in τ, χ, and E in blended composites as a function of the solvent was observed in the order THF, MEK, EA, and A, which is due to the thermodynamic affinity of the solvent and dissolved substance.