Surface‐free energy analysis of hydrolyzed ethylene‐vinyl acetate copolymers

Ethylene‐vinyl acetate (E‐VA) copolymers containing 12, 28, and 40 wt% of vinyl acetate, ethylene‐vinyl acetate‐vinyl alcohol terpolymers obtained by partial hydrolysis of (E‐VA) copolymers and ethylene‐vinyl alcohol (E‐VOH) copolymers obtained by complete hydrolysis of (E‐VA) copolymers were investigated by one‐liquid contact‐angle method. The polar force component of surface‐free energy (γ   p SV ) of copolymers drastically increased by the substitution of the acetate groups with hydroxyl groups. The dispersion force component (γ   d SV ) of copolymers increased only slightly with the hydrolysis degree and deviated largely from the additivity law in regards of the surface area functions. The surface‐free energy analysis of the cross‐linked ethylene‐vinyl alcohol and surface‐hydrolyzed ethylene‐vinyl acetate copolymers was also carried out.