Functional group effect on flame retardancy, thermal, and mechanical properties of organophosphorus-based magnesium oxysulfate whiskers as a flame retardant in polypropylene

• DOI: 10.1039/c7ra02863f
• Publication Date: 2017-04-18T13:24:56Z
• Authors: Li Dang; Xueying Nai; Yaping Dong; Wu Li
• Keywords: Limiting oxygen index; Thermal Stability; Polypropylene

In this paper, magnesium oxysulfate whiskers (MOSw) were reacted with dodecyl dihydrogen phosphate (DDP) to prepare DDP functionalized MOSw (DDPMOSw). The morphology and structure of DDPMOSw characterized by scanning electron microscopy (SEM), transmission (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron (XPS). Then respectively incorporated into polypropylene (PP) obtain hybrid composites via the melt mixing method. SEM results showed that distributed more evenly within PP matrix than MOSw, resulting in improved thermal stability, nominal strain at break, impact toughness PP/DDPMOSw comparison PP/MOSw. flammability was investigated using limiting oxygen index (LOI) cone calorimetry (CC) tests. introduction further increased LOI, meanwhile, reducing heat release rate (HRR), smoke production (SPR) CO CO2 release. energy dispersive (EDS) analyses char residues implied two reasons for efficient flame-retardant properties PP/MOSw: (i) thoroughly decomposed nonflammable gases absorb during combustion process (gas-phase effect); (ii) induced formation carbonaceous residue, leading a compact coherent based on MgO backbone (condensed-phase effect). Besides, FTIR indicated phosphorous compound layer condensed phase also acted as protective shield.