Synthesis and properties of macromer-grafted polymers for noncovalent functionalization of multiwalled carbon nanotubes

We prepared macromer-grafted polymers (MGPs) containing suitable polymer side chains for improving solubility and pyrene units for improving adsorption on multiwalled carbon nanotube (MWCNT) surfaces, and demonstrated that these MGPs act as MWCNT solubilizers that improve solubility of MWCNTs in typically poor solvents such as alkanes and that improve flowability of polymer/MWCNT composites. The polydimethylsiloxane (PDMS)-MGPs, synthesized using PDMS macromers and pyrene-containing monomers, improved solubility of MWCNTs not only in chloroform but also in hexane, which is a poor solvent for MWCNTs. Moreover, the addition of PDMS-MGP-adsorbed MWCNTs (MWCNT/PDMS-MGPs) to epoxy resin monomers or polybutylene terephthalate (PBT) drastically reduced the viscosity of the obtained epoxy resin monomer/MWCNT/PDMS-MGP mixtures and PBT/MWCNT/PDMS-MGP composites in comparison to the epoxy resin monomer/MWCNT mixtures and PBT/MWCNT composites, respectively. The viscosity of PBT/MWCNT/PDMS-MGP composites including ?1 vol% of MWCNTs, in particular, was almost equal to that of pristine PBT.