Multifunctional role of an ionic liquid in melt-blended poly(methyl methacrylate)/ multi-walled carbon nanotube nanocomposites

Poly(methyl methacrylate) (PMMA)/multi-walled carbon nanotube (MWNT) nanocomposites with a homogeneous dispersion of MWNTs have been fabricated by a simple melt-mixing method in the presence of a room-temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6]. It has been found that the ionic liquid provided multiple functions in the preparation of the nanocomposites: (1) the ionic liquid acts as an effective compatibilizer to significantly improve the dispersion of MWNTs in the PMMA matrix; (2) the ionic liquid is an efficient plasticizer for the prepared nanocomposites, inducing a drastically reduced glass transition temperature in the PMMA matrix; (3) the ionic liquid acts as a processing aid for the melt processing of PMMA/MWNT nanocomposites; (4) the ionic liquid increases the electrical conductivity as a dopant. This strategy is free of solvents and compatible with industrial applications, which opens new avenues for the larger-scale fabrication of polymer/carbon nanotube nanocomposites. (paper)