Electrical Conductivity and Tensile Properties of Block-Copolymer-Wrapped Single-Walled Carbon Nanotube/Poly(methyl methacrylate) Composites

Poly(methyl methacrylate) (PMMA) composites containing raw or purified single-walled carbon nanotubes (SWCNTs) are prepared by in situ polymerization and solution processing. The SWCNTs are purified by centrifugation in a Pluronic surfactant, which consists of polyethyleneoxide and polypropyleneoxide blocks. Both the effects of SWCNT purity and non-covalent functionalization with Pluronic are evaluated. Electrical conductivity of PMMA increases by 7 orders of magnitude upon the integration of raw or purified SWCNTs. The best electrical properties are measured for composites made of purified SWCNTs and prepared by in situ polymerization. Strains at fracture of the SWCNT/PMMA composites are nearly identical to those of the neat matrix. A certain decrease in the work to fracture is measured, particularly for composites containing purified SWCNTs (-31.6%). Fractography and Raman maps indicate that SWCNT dispersion in the PMMA matrix improves upon the direct addition of Pluronic, while dispersion becomes more difficult in the case of purified SWCNTs. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41547.