Unexpected behaviour of multi-walled carbon nanotubes during “in situ” polymerization process: When carbon nanotubes act as initiators and control agents for radical polymerization

Abstract

Raw multi-walled carbon nanotubes (MWCNTs) were used, without an initiation agent, to initiate and self-control polymerization of poly(acrylic acid) and poly(methyl methacrylate) copolymers. To enhance the livingness of the radical polymerization, a stable nitroxide can be added to strongly reduce the rate energy of the macromolecular chains growth and their dispersion. During the auto-initiation and self-control processes of the radical polymerization, the grafting of the copolymers onto the MWCNTs surface has been observed and characterized by transmission electronic microscopy (TEM). In particular, the grafting can be achieved thanks to an “in situ” radical polymerization that can simultaneously lead to the grafting of the MWCNTs and improve the dispersion. This work represents a real insight and breakthrough because in one step, MWCNTs acting as chemical motors are grafted and the growth of copolymer chains is well controlled.