Hansen solubility parameter: from polyethylene and poly(vinyl acetate) homopolymers to ethylene-vinyl acetate copolymers

The Hansen solubility parameters (HSPs) of two ethylene-vinyl acetate (EVA) copolymers (with 18 and 33 wt% of vinyl acetate) and their corresponding homopolymers (polyethylene, PE, and poly(vinyl acetate), PVAc) have been studied at various temperatures, employing the previously obtained Flory-Huggins parameters. From these latter values, a procedure based on the Hansen solubility spheres theory was employed to determine the HSPs, as well as the radius of interaction. The procedure was validated with literature data, with deviations of around 3%. The HSP values (dispersion, polar and association terms, respectively, all in MPa1/2) at 333.15 K are 14.84, -3.88 and 1.78 for PE, 17.65, -1.24 and 2.76 for EVA410 (with 18 wt% of vinyl acetate), 17.52, 0.15 and 3.61 for EVA460 (with 33 wt% of vinyl acetate) and 19.45, 10.59 and 5.76 for PVAc. The main characteristic of the obtained HSP values is that the high polar term of PVAc tends to increase the solubility character of the pure PE, and thus the EVA copolymers, allowing them to solubilize dispersion and polar compounds. Finally, it was also demonstrated that it is possible to predict the HSPs of EVA copolymers using the vinyl acetate content and the HSPs of pure PE and PVAc as input data. (c) 2017 Society of Chemical Industry