Composites of Single-Walled Carbon Nanotubes and Styrene-Isoprene Copolymer Latices

• Published in: Macromolecular chemistry and physics Vol. 208; no. 5; pp. 446 - 456
• Main Authors: Ha, Mai L. P., Grady, Brian P., Lolli, Giulio, Resasco, Daniel E., Ford, Warren T.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 05.03.2007; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; carbon nanotubes; Composites; dispersions; Exact sciences and technology; Forms of application and semi-finished materials; latices; nanocomposites; Polymer industry, paints, wood; rheology; Technology of polymers; Mixing; Electrical conductivity; rheology; Electrical properties; Emulsion copolymerization; Carbon nanotubes; Mechanical properties; Experimental study; nanocomposites; Latex; Singlewalled nanotube; Dynamic mechanical properties; dispersions; Morphology; Preparation; Concentration effect; Isoprene copolymer; Nanocomposite; Radical copolymerization; latices; Styrene copolymer
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.200600521

Composites of a styrene‐isoprene copolymer and SWNTs were prepared by emulsion and miniemulsion polymerization in the presence of SWNTs, as well as by mixing dispersed SWNTs with a styrene‐isoprene copolymer latex after polymerization. For the former, the surfactant was displaced from SWNTs to monomer droplets leading to SWNT aggregation. Mixing dispersed SWNTs with latex after reaction was able to preserve SWNT dispersion and gave a polymer composite with an electrical percolation threshold of 0.2%. Dynamic mechanical measurements of film samples in tension showed that the composites had a measurable modulus above Tg, indicating entanglement formation. The modulus above Tg was strongly temperature dependent, confirming shear measurements that have shown entanglements in SWNT/polymer composites both polymer and nanotubes.