High flame-retardant polyether sulfone/carbon fiber/polyethylene terephthalate fiber hybrid composites with low density

Abstract

Polyether sulfone (PES) in filter material has been reported extensively. However, PES fibers have not yet been used in flame-retardant composites. This study systematically investigates the effect of PES/carbon fiber (CF)/polyethylene terephthalate (PET) fiber content, hot-pressing temperature, pressure, and duration on the flame-retardant property. The flame-retardant properties, tensile properties, morphology, and thermogravimetric analysis (TGA) have been studied. The results show that the optimum parameter is PES/CF/PET fiber content of 65/30/5 wt%, hot-pressing temperature of 270°C, hot-pressing pressure of 35 MPa, and hot-pressing duration of 50 min. The fiber hybrid composite has a 50% lower density compared to conventional CF composites. The sample successfully passes the vertical burning test (UL-94) V-0 flammability rating, and it can be immediately extinguished and no droplets are produced during the testing process. Further, the cone calorimeter results demonstrated that the composite also has a low heat release rate (the peak of the heat release rate is 47.226 kW/m2) and a low smoke density (the peak of the smoke production rate is 0.0107 m2/s). The carbon residue rate of the PES/CF/PET fiber hybrid composite reached 44.45% at 900°C. The carbonization of the benzene ring on the PES fiber backbone is the main mechanism of flame retardancy of the PES/CF/PET fiber hybrid composite.