Effect of nitrogen and oxygen doped carbon nanotubes on flammability of epoxy nanocomposites

Abstract

To overcome the flammability of epoxy resins, novel nitrogen (CN x ) and oxygen (CO x ) doped CNT were synthesized via CVD method and epoxy nanocomposites at 2 wt.%. constant loading were prepared by three roll milling and cured. The structures of the nanotubes were confirmed by XRD, XPS, SEM and Raman and it was found a very high aspect ratio especially for CO x . Thermal degradation as well as glass transition temperatures and elastic moduli were measured by TGA, DSC and DMTA. The flammability of epoxy nanocomposites was studied by microscale combustion calorimetry (MCC) and limiting oxygen index (LOI) determination. Results showed that the fire retardant properties of nanocomposites improved significantly specially for CO x , which presented a very high LOI (35%) and a homogeneous and uniform surface after burning. This effect was tentatively attributed to the very high aspect ratio of CO x tubes.

Thermo-mechanical properties of epoxy nanocomposites incorporating amino acid and acid functionalized multi-walled carbon nanotubes

“…Several studies have also reported the decline in thermal stability through incorporating MWCNTs. They argued that it happens because thermal conductivity increases within the nanocomposite 41 and MWCNTs act as a catalyst. 42 MWCNTs as a catalyst could be explained based on DSC results suggesting that in the case of adding different MWCNTs to the epoxy resin, the completion of the curing reaction is quickened.…”

Evaluating the biological risk of functionalized multiwalled carbon nanotubes and functionalized oxygen-doped multiwalled carbon nanotubes as possible toxic, carcinogenic, and embryotoxic agents

“…Defects in nanotubes are any alteration of the graphitic lattice, including exohedral, endohedral, and in-plane doping; they are common in the CNTs synthetized by the present method 38 and have been well characterized elsewhere. [39][40][41]52 An atomistic difference between MWNTs and COxs is difficult to appreciate by SEM and TEM, since, as discussed by Botello-Méndez et al, 39 Shabestari et al, 40 and González et al, 52 the meaning of oxygen doping is the formation of different atomic alterations in the graphene layers as carbon-oxygen bonds (eg, by the use of X-ray photoelectron spectroscopy) 52 present the percentage of carbon atoms in graphitic or aliphatic bonds or as part of functional groups such as alcohol, lactones, and carboxyl. This functional group makes COx slightly more reactive than nondoped or MWCNTs.…”

“…Functionalization is another process where the as-grown CNTs are subjected to a series of chemical processes. 38 In previous biological reports, oxygen-doped MWCNTs (COxs) 39,40 have been used due to the presence of carbonyl, hydroxyl, and oxygenated functional groups enhancing their chemical reactivity, in addition to their higher water solubility 25 Prior to considering MWCNTs as biological scaffolding for grown MSCs in future cardiac protocols, in this study, we aim to evaluate the possible adverse effects on cells and cardiac tissues, using two kinds of CNTs, such as acid functionalized MWCNTs (fMWCNTs) and functionalized oxygen-doped multiwalled CNTs (fCOxs). The objective is to study the effect of fMWCNTs and fCOxs at different concentrations in two biological models with the following purposes: first, on rat MSCs focusing on their growth, proliferation, cell cycle, and possible cell transformation processes to cancer cell and, second, using an in vivo chicken model to study the cardioembryotoxicity.…”

A green self-assembled organic supermolecule as an effective flame retardant for epoxy resin

“…8,9 In solving these problems, environmentally friendly ame retardants have become a topic of considerable research interest at present. [10][11][12] Currently, several halogen-free ame retardants, such as graphene, [13][14][15] layered double hydroxide (LDH), 16,17 boron nitride (BN), 18,19 MoS 2 , 20 and carbon nanotubes, 12,21 have been rapidly developed. A small amount of nanoller added into the polymer matrix can result in excellent ame retardancy while simultaneously maintaining or enhancing the other properties of the composites.…”