MONITORING OF THE STATE OF A 3-COMPONENT SYSTEM POLYMER-SOLVENT-PRECIPITANT BY MEASURING VISCOELASTIC PROPERTIES

A method is developed for the investigation of phase states and kineti cs of structural transformations in a three-component system polymer-s olvent-precipitant. The method consists in monitoring of the rheologic al (viscoelastic) properties of the system by measuring free-damping o scillations of a torsion pendulum. Using this technique, the dependenc e of the elastic modulus and the mechanical loss tangent on the time o f exposure to solvent and precipitant were studied for a super-high-mo lecular-mass polyethylene. The data are interpreted on the basis of an alysis of the phase state and structure of the system.