Intumescent Flame-retardant Modification of Polypropylene/Carbon Fiber Composites

To improve the flame resistance of polypropylene(PP)/carbon fiber(CF) composite materials,triazine char-forming agent (TCA) was compounded with ammonium polyphosphate (APP) or modified APP (CS-APP) in a 2:1 ratio to prepare intumescent flame retardant (IFR) and the modified intumescent flame retardant (CS-IFR) in this paper.Flame retardancy and thermal degradation behaviors of the composites modified by IFR and CS-IFR were characterized by Fourier Transform Infrared (FTIR),contact angle measurement,oxygen index (OI),vertical burning tests (UL-94),thermogravimetric analyer (TGA),and thermogravimetric analyzer coupled with Fourier transform infrared (TG-FTIR).It was found that 25.0 phr of IFR and 24.0 phr of CS-IFR could improve the LOI value of PP/CF composites to 28.3% and 28.9%,respectively.At the same time,a UL-94 V-0 rating was achieved.The experimental results show that the IFR and CS-IFR prepared could effectively improve the flame retardancy and thermostability of PP/CF composites,and they would greatly expand the application range of PP/CF composite materials.