Rheological characterization of nanostructured material based on Polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS) block copolymer: Effect of block copolymer composition and nanoparticle geometry

Block copolymer (BCP) nanocomposite systems are of broad interest; however, reports on the role of nanoparticles on microphase separation behavior are rare. The goal of present study is to investigate the preparation of composite nanostructured materials containing Multi-Walled Carbon Nanotubes (MWCNTs) or graphene nanoplates. BCP nanocomposites based on the linear triblock copolymer, Polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS), with different morphological structure were prepared by melt mixing. The results of temperature sweep experiments showed an enhancing effect of both MWCNT and graphene nanosheets on increasing the microphase separation temperature as well as accelerating its kinetic, resulting from the confinement of BCP segments, with graphene nanosheets providing a more severely confined geometry for polystyrene segments in contrast to MWCNTs. Additionally, DMTA results indicated a promotion of the BCP microphase separation by incorporation of nanoparticles. Transient flow measurements followed by time sweep test suggested the existence of a special 3D network microstructure caused by nanoparticles/domain interactions.