Tuning of nanotube/elastomer ratio for high damping/tough and creep resistant polypropylene/SEBS-g-MA/HNT blend nanocomposites

Abstract

Polypropylene (PP)/maleic anhydride grafted polystyrene-b-poly (ethylene/butylene)-b-polystyrene (SEBS-g-MA)/organophilic halloysite nanotube clay ternary nanocomposites were produced by using HNT/SEBS-g-MA masterbatches at different nanotube loadings (1 wt%, 3 wt%, and 5 wt%). The masterbatches with different ratios of HNT/SEBS-g-MA (1/1, 1/2, and 1/3) were prepared via a revolution/rotation type mixing-assisted masterbatch process. All nanocomposites showed higher storage moduli and damping at low temperatures as compared to neat polypropylene. The nanocomposites having HNT/SEBS-g-MA ratio of 1/3 were found to act as effective dampers with their relatively higher damping values. In terms of short-term creep performance, 1 wt% and 3 wt% organophilic halloysite nanotube loaded systems with low amount of SEBS-g-MA (<9 wt%) enhanced dimensional stability of polypropylene with their lower creep strain and permanent deformation values. More specifically, among the nanocomposites, 3 wt% organophilic halloysite nanotube loaded nanocomposite with HNT/SEBS-g-MA ratio of 1/3 and co-continuous like morphology not only exhibited an effective damping over a wide range of temperature (from −70℃ to 50℃) but also showed relatively higher storage moduli at low temperature region together with lower permanent creep deformation as compared to neat polypropylene. As a result, the HNT/SEBS-g-MA masterbatch in 1/3 ratio was found to be the most suitable in polypropylene blend nanocomposites. It may be advantageous for polypropylene nanocomposite based applications where high damping/toughness at low temperature conditions and high dimensional stability under load are desired.