Characterization of Mechanical and Thermal Properties of Poly(ethylene-co-vinyl acetate) with Differents Bentonites

In this study, poly(ethylene-co-vinyl acetate) (EVA) with different organophilic bentonites were prepared by melt-blended and evaluated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and the tensile properties. The results showed that the modification of bentonite with the two different surfactants presented distinct thermal and tensile behaviors of the samples containing natural bentonite. Both modifiers acted on the compatibility of the filler with the polymer matrix, obtaining injected-specimens that were visibly homogeneous. The samples containing the Cloisite (R) bentonite modified with ammonium salt-free surfactant (eBI-AM) presented a different behavior from the others, in that increased crystallinity, which was verified through DSC, due to the nucleating effect of the filler influenced the flexible character of the EVA materials, thus increasing the rigidity and decreasing elongation. Therefore, it was of utmost importance the use and the proposal of an ammonium salt-free modifier due to the low thermal stability that are caused by them in polymer/organophilic bentonite, as it has already been reported in the literature.