Environmental Friendly Intumescent Flame Retardant Gives Epoxy Resin Excellent Fire Resistance and Mechanical Properties

To reduce the fire hazard of epoxy resin (EP), PA-CS-M (where PA = phytic acid, CS = chitosan, M = Cu 2+ , Co 2+ , Al 3+ , Zn 2+ , Mn 2+ ) environmental friendly flame retardant is prepared by a simple and green method. By comparing the data after cone calorimetry test (CCT) of various composites, it is found that when 5 wt% PA-CS-Mn is added to EP, it has good flame retardant and smoke suppression performance. The peak heat release rate (pk-HRR) decreased by 38% and the smoke production rate (SPR) decreased by 33%. In addition, some toxic smoke such as CO has been significantly inhibited. The structures and morphologies of the materials were investigated by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). When combined with expandable graphite (EG), it is found that when the ratio of PA-CS-Mn to EG is 1:5, the pk-HRR value and SPR value decreased by 69.8% and 66.6%, respectively. More importantly, the mechanical properties of the EP composites have also been greatly improved. The flexural modulus reaches 5.04 GPa, which is 52.3% higher than pure EP, and the flexural strength increases to 79.4 MPa, which also shows an increase of 41.4% as to the matrix.