The current paper provides an overview to emphasize the role of functionalization of multiwalled carbon nanotubes (MWCNTs) in manipulating cure kinetics of epoxy nanocomposites, which itself determines ultimate properties of the resulting compound. In this regard, the most commonly used functionalization schemes, that is, carboxylation and amidation, are thoroughly surveyed to highlight the role of functionalized nanotubes in controlling the rate of autocatalytic and vitrification kinetics. The current literature elucidates that the mechanism of curing in epoxy/MWCNTs nanocomposites remains almost unaffected by the functionalization of carbon nanotubes. On the other hand, early stage facilitation of autocatalytic reactions in the presence of MWCNTs bearing amine groups has been addressed by several researchers. When carboxylated nanotubes were used to modify MWCNTs, the rate of such reactions diminished as a consequence of heterogeneous dispersion within the epoxy matrix. At later stages of curing, however, the prolonged vitrification was seen to be dominant. Thus, the type of functional groups covalently located on the surface of MWCNTs directly affects the degree of polymer‐nanotube interaction followed by enhancement of curing reaction. Our survey demonstrated that most widespread efforts ever made to represent multifarious surface‐treated MWCNTs have not been directed towards preparation of epoxy nanocomposites, but they could result in property synergism.
13 February 2018 in Journal of Materials Chemistry A
This paper presents investigations into the use of ionic liquids as sizing agents for carbon fibers in epoxy matrices. A variety of aqueous ionic liquid solutions was employed as the sizing bath, at concentrations relevant to industry standards. Of the ionic liquids used, the widely available and inexpensive BmimCl was found to give the optimal fiber-to-matrix adhesion improvements of 250% relative to control fibers in epoxy, and 66% improvement in polypropylene. Molecular dynamics simulations suggest that the diffusion of the ionic liquids into the polymer phase accompanied by self-agglomeration generates a plasticised interphase resulting in high shear tolerant materials.