Influence of Solvent and Organophilic Clay Content on the Properties of EVA Nanocomposite Films.

This study investigates the combined influence of solvent type and organophilic clay (Cloisite 20A) content on the properties of EVA nanocomposite films with a view to improving mechanical and barrier performance. EVA (vinyl acetate) films were obtained by solvent evaporation, using chloroform (CHCl3) or tetrahydrofuran (THF) as the solvent, and with 0, 3, and 5% clay as reinforcement. XRD, FTIR, SEM, TGA, DSC, contact angle, water vapor transmissibility, and tensile testing were used to characterize the samples. Structural and morphological analyses indicated good lamella dispersion and heterogeneous morphology throughout the thickness. The incorporation of clay increased thermal stability (lower mass loss up to ∼ 300 °C) and low-temperature melting enthalpy, suggesting a higher crystalline fraction and greater rigidity. The Young's modulus of the ETC3% film (THF + 3% clay) was more than twice that of ETC0 %. THF-based films showed lower elongation at break, while those produced with chloroform were more ductile. Clay increased the contact angle and reduced water vapor permeability; the ECHC3 % film showed a ∼37% reduction, and the ETC3 % film showed a ∼15% reduction compared to the respective pure films, highlighting the relevance of the solvent as a design parameter in EVA/organoclays films.