The synergistic action between anhydride grafted carbon fiber and intumescent flame retardant enhances flame retardancy and mechanical properties of polypropylene composites

摘要

The applications of polypropylene/carbon fiber (PP/CF) composite are hindered by the highflammability of PP substrate. This work reports a facile solvothermal method to modify CFthough grafting maleic anhydride (MAH) on its surface, with the goal of enhancing thecompatibility of intumescent flame retardant (IFR) with PP substrate, thus enhancingthe flame-retardant and mechanical performance of the resulting PP/CF/IFR composite.The effect of maleic anhydride-g-carbon fiber (MAH-g-CF) to IFR ratio on the overallperformance of the composite was assessed. The possible interactions between MAH-g-CFand IFR were characterized by dynamic thermomechanical analysis and Fourier-transforminfrared spectroscopy. Results show that when 3 wt% MAH-g-CF and 22 wt% IFR wereadded to the PP substrate, the composite exhibited a much lower heat release rate valueand smoke suppression ability. Meanwhile, the composites achieved 26.7 MPa in tensilestrength and 50.6 MPa in flexural strength. We propose that MAH on MAH-g-CF acts as acompatibilizer that improves the adhesion and cross-linking between CF and IFR, therebyenhancing mechanical strength and flame-retardancy of the PP/IFR/MAH-g-CF composite.