Quassinoids are highly oxygenated triterpenes, which were isolated as bitter principles from the plants of Simaroubaceae family. Their synthesis has attracted much attention because of the wide spectrum of their biological properties. The most prevalent quassinoids have C-20 picrasane skeleton, some known as bruceolides as they were isolated from the genus Brucea, which showed marked antileukemic and antimalarial activities.

Covalently functionalized carbon nanotubes (CNTs) wrapped in intumescent flame retardant were successfully fabricated and characterized. By adjusting the ratio of CNTs and flame retardant, the diameter of the functionalized CNTs was effectively controlled to 20-90 nm. Compared with pristine CNTs, the functionalized CNTs are better dispersed in polypropylene (PP) due to the in situ compatibilization reaction between the active groups of the intumescent flame retardant on the CNT surface and the maleic anhydride groups in the compatibilizer, maleic anhydride-grafted polypropylene (PPMA). Incorporating the functionalized CNTs could confer outstanding flame retardancy on PP/ PPMA, and considerably enhance the mechanical properties of the polymeric materials due to the improved interfacial adhesion and stress transfer. Therefore, use of intumescent flame-retardantwrapped carbon nanotubes and in situ compatibilization are promising strategies for simultaneously improving the flame retardancy and mechanical properties of polymeric materials.

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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.

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