High-Performance Thermoplastic Elastomers/Carbon Nanotubes Nanocomposites: Mechanical Behavior, Rheology, and Durability

Advanced polystyrene-b-polybutadiene-b-polystyrene (SBS) based nanocomposites containing bare carbon nanotubes (CNTs) and CNTs bearing hydroxyl functional groups (CNTs-OH) have been formulated and fully characterized. In particular, the reinforcement effect of CNTs and CNTs-OH on SBS was deeply investigated through mechanical and dynamical thermo-mechanical analysis and the rheological response of SBS-based nanocomposites was investigated and discussed. The mechanical properties of SBS/CNTs and even more of SBS/CNTs-OH nanocomposites are substantially superior to those of neat SBS, due to the uniformly dispersed nanofillers throughout the polymeric matrix. The presence of -OH groups onto CNTs promotes the stress transfer from polymer to CNTs, strengthening the overall performance of the nanocomposite. Moreover, the durability of SBS-based nanocomposites was monitored through mechanical, dynamic mechanical, and rheological analysis. SBS-based nanocomposites showed a significant improved photo-stability with respect to the neat matrix, due to the presence of CNTs that are able to stabilize efficiently SBS because of their acceptor-like electron properties. The presence of -OH groups onto CNTs enhance the protection ability of CNTs due to the larger amount of surface defects, that improves their radical scavenging activity. Furthermore, CNTs-OH can act as chain-breaking electron donor, becoming responsible for radical termination during SBS degradation. (C) 2015 Society of Plastics Engineers