Thermodynamic interactions of EVA copolymer-solvent systems by inverse gas chromatography measurements

摘要

The solubility parameter and the Flory-Huggins interaction parameter of two EVA (ethylene-vinyl acetate) copolymers, each one with different vinyl acetate content, are calculated by using inverse gas chromatography technique. The influence of the vinyl acetate percentage is analyzed and indicates that the polymer-solvent interactions are stronger in the case of the copolymer with the highest vinyl acetate percentage. The results also point to the fact that the most favorable solvents for the studied materials are the aromatic-type ones. Finally, from the calculated values of the polymer solubility parameter (16.3 MPa~(0.5) for EVA 460 and 15.1 MPa~(0.5) for EVA410, at 50°C), it can be noticed that the solubility parameter of the EVA copolymer with the largest vinyl acetate content is the closest to the solubility parameter of pure vinyl acetate.