Singlewall carbon nanotubes covered with polystyrene nanoparticles by in‐situ miniemulsion polymerization

Abstract

This work is to make carbon nanotubes dispersible in both water and organic solvents without oxidation and cutting nanotube threads. Polystyrene‐singlewall carbon nanotube (PS‐SWNT) composites were prepared with three different methods: miniemulsion polymerization, conventional emulsion polymerization, and mixing SWNT with PS latex. The two factors, crosslinking and surface coverage of PS are important factors for the mechanical and electrical properties, including dispersion states of SWNT in various solvents. The PS‐SWNT composite prepared via a conventional emulsion polymerization showed SWNT bundles entirely covered with PS, whereas the PS‐SWNT composite prepared via a miniemulsion polymerization showed SWNT partially covered with crosslinked PS nanoparticles. The method of mixing SWNTs with PS latex did not show the well dispersed state of carbon nanotubes because PS was not crosslinked and was dissolved in a solvent, and nanotubes separated from PS precipitated. So the PS nanoparticle‐SWNT composite had lower electrical resistance, and higher mechanical strength than the other composites made by the latter two methods. As the amount of SWNT increases, the bare surface area of SWNT increases and the electrical conductivity increases in the composite made by the miniemulsion polymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 573–584, 2006

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

“…Barraza et al [35] produced SWNT composites by miniemulsion polymerization utilizing cetyltrimethylammonium bromide (CTAB) as the surfactant, and achieved some improvement in electrical and mechanical properties. A more recent paper [36] compared both miniemulsion and normal emulsion polymerization of polystyrene in the presence of SWNTs. The focus was on dispersability after drying of the mixture rather than the mechanical properties of the solids.…”

Adaptation of polystyrene/multi‐wall carbon nanotube composite properties in respect of its thermal stability

“…As can be seen, the diameter of the beads (cross-linked PS nanospheres prepared during polymerization) is about 30 nm. The cross-linking was assured by divinylbenzene, and its purpose was to avoid possible PS elution from the tubes (i.e., complete extraction by benzene [23]) in the following steps in PS matrix melt or solution. Additional TEM analyses shows good adherence of PS beads onto MWCNT surface, Fig.…”

“…The supposed mechanism of microemulsion polymerization in the presence of CNT has been described by Ham et al [23]. In this case, the method was oil-in-water free radical type of microemulsion polymerization stabilized by an anionic surfactant (sodium dodecyl sulfate) and a co-surfactant (1-penthanol).…”

“…An example of the first one can be CNT and polymer in situ polymerization, which is often used to ensure chemical bonding between the two components, and thus, to improve the composite properties [21,22]. A noncovalent method was shown in [23][24][25], where polymeric material in the form of nanospheres was adsorbed onto the surface of CNT through microemulsion polymerization technique. Also here the aim was the same-better dispersion of the filler and stronger CNT/polymer interface.…”

Characterization of Carbon Nanotube Based Polymer Composites Through Rheology

“…Other efficient way to improve CNT dispersion in the polymeric matrix is chemical or chemical-physical modification (functionalization) of the CNT surface. The non-covalent method represents for example microemulsion polymerization technique in the presence of CNT material when polymeric material in the form of nanospheres is adsorbed onto the surface of CNT [13,14]. Chemical functionalisation of CNT then represents creation of covalent bonds between organic molecules or polymeric fragments and CNT surface.…”