Fabrication of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-decorated fullerene to improve the anti-oxidative and flame-retardant properties of polypropylene

Fullerene (C-60) is readily to capture chain radicals and delays the scission of macromolecular chains during the degradation or combustion of polymers, because of its high reactivity with free radicals. In this work, C-60 was functionalized with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), trying to combine their free radical-trapping effects both in gaseous phase and in condensed phase. Through an addition reaction between C-60 and DOPO, DOPO has decorated onto the surface of C-60 via P-H bond at the molar ratio of 1:1. From the images of transmission electron micrographs (TEM) and scanning electron microscopy (SEM), the introduction of DOPO onto C-60 surface prevented C-60 from clumping together and achieved a looser morphology. Thermogravimetry (TG), differential scanning calorimetry (DSC) and cone calorimetry measurements showed that compared with pristine C-60, DOPO-d-C-60 further increased the anti-oxidative properties and restrained the combustion process of polypropylene.