Core-shell structured carbon nanotube/poly (methyl methacrylate) composite and its electrorheological characteristics

Multi-walled carbon nanotube (MWNT) adsorbed poly(methyl methacrylate) (PMMA) microspheres with a core-shell structure were prepared and their physical characteristics including electrorheology were examined. Initially, mono-dispersed spherical PMMA particles (D = 5 μ) as a core material were synthesized using a dispersion polymerization method. To improve adsorption of the MWNT onto the PMMA surface, amino-functional modification was applied to the MWNT to enhance grafting of the MWNT onto PMMA, in which the amino-functionalization was followed using thionyl chloride and hexamethylene diamine. Amino-functionalized MWNT (MWNT-NH₂) was dispersed into aqueous PMMA colloid solutions under sonication. Surface morphology of the MWNT/PMMA microspheres was observed by SEM, while FT-IR and TGA were used for examining chemical composition and thermal stability of the composites synthesized, respectively. MWNT was found to be densely and uniformly adsorbed onto the surface of polymeric microbeads. In addition, these MWNT-adsorbed PMMA microspheres were examined as electrorheological (ER) materials when dispersed in silicone oil.