High strength, tough/damping and creep resistant EVA/HNT nanocomposites via help of EVA-g-MA compatibilizer

Abstract

Organophilic halloysite nanotube (Org-HNT) reinforced poly (ethylene-co-vinyl acetate) (EVA) nanocomposites were obtained with melt compounding technique with use of 10 wt% EVA-g-MA and Org-HNT. The use of EVA-g-MA in the nanocomposites provided a better distribution of the nanotubes as evidenced by the Scanning Electron Microscope (SEM) images. This is due to MA moiety of the EVA-g-MA interacting with the Org-HNT, which decreased its intertubular interactions, resulting in better nanotube in the EVA, that is consistent with the presence of large aggregates in the EVA/5H binary composite without EVA-g-MA. The highest tensile modulus was achieved with EVA/EMA-7H nanocomposite, which is about 40 % higher as compared to neat EVA, but its toughness and tensile strength values were found to be relatively lower compared to EVA/EMA-5H with 5 phr Org-HNT. It was explained with formation of highly reinforced/stiffened EVA and EVA-g-MA phases at higher nanotube loading. Among the composites, the EVA/EMA-5H nanocomposite appears to have the best composition, with the highest tensile strength and toughness as well as a tensile modulus that is about 30% higher than that of EVA. The nanocomposites had higher storage modulus values at 25°C and temperatures ranging from −50°C to 0°C when compared to neat EVA. The EVA/EMA-5H exhibited about 110 % higher storage modulus and higher damping parameter than neat EVA at 25°C. The same nanocomposite showed highest creep recovery rate with the lowest permanent deformation in accordance with its high dynamic modulus, indicating that the EVA/EMA-5H nanocomposite with a more optimal composition and elastic character, provides better hardness-toughness/damping balance.