A novel oligomeric phosphorous-nitrogen-containing intumescent flame retardant poly (4,4diaminodiphenylmethane-O-bicyclicpentaerythritol phosphate-phosphate) (PDBPP) is synthesized, and subsequently fullerene (C 60 )-decorated oligomeric intumescent flame retardant, C 60 -d-PDBPP, is fabricated via chemical grafting reaction and characterized. The grafting degree of C 60 is as high as 70 wt%, and C 60 -d-PDBPP nanoparticles can homogeneously disperse in polypropylene matrix since the grafting process may prevent the aggregation of C 60 particles. Upon incorporating C 60 -d-PDBPP, thermal oxidation degradation of polypropylene is considerably delayed. When the concentration of C 60 -d-PDBPP reached 2 wt%, the initial degradation temperature (T 5 : the temperature where 5wt% mass loss occurred) and maximum weight loss rate temperature (T max ) display an increase of about 72 C and 80 C, respectively. Moreover, C 60 -d-PDBPP can remarkably reduce the peak heat release rate (PHRR) values of polypropylene, and consequently slow down the combustion process of nanocomposites. Additionally, to some extent it prolongs the time to ignition (t ign ) and time to peak heat release rate (t PHRR ), all of which are very important parameters for evaluating the fire retardancy of a polymeric material.

Multi-walled carbon nanotubes were decorated with fullerene (C(60)) via a three-step chemical functionalization, with the goal of combining their unique physical and chemical characteristics and simultaneously improving the solubility of CNTs in organic solvents. C(60) molecules, about 0.67% by molecule, were homogeneously bonded onto the surface of the CNTs. Electron microscopy clearly shows that C(60) molecules are introduced onto the surface of the CNTs, and this is also evidenced by their UV-VIS absorption spectra. Cone calorimetry measurements showed that compared with pristine CNTs, fullerene-decorated CNTs further reduced the flammability of polypropylene, which may be due to the free-radical-trapping effect of C(60) and the barrier effect of the CNT network.

Carbon nanotubes (CNTs) wrapped with layered double hydroxide (LDH-w-CNTs) were facilely obtained through in situ introduction of CNTs into the hydrothermal reaction system of LDH, with the goal of combining their unique physical and chemical characteristics to meet new advanced applications. Morphological observations indicated that LDH lamellae enwrapped the surface of CNTs and the wrapping degree was dependent on the functionalization of CNTs. Zeta-potential measurements showed that the interaction between the positive charge of LDH and the negative charge of CNTs was the main driving force of the wrapping process. Both hybrids led to a reduction in the peak heat release rate (PHRR) of polypropylene, indicating that they could confer better flame retardancy on polypropylene with respect to LDH and CNTs.