Novel exploration of the flame retardant potential of bimetallic MXene in epoxy composites

As a graphene-like material, MXene , represented by Ti 3 C 2 T x , has been found to possess promising flame retardant potential in polymers due to their excellent thermal and catalytic actions, as well as lamellar barrier effect. Thus, it is of great significance to explore whether MXene with double transition metal components has a higher flame retardant efficiency. Herein, Ti 3 C 2 T x and bimetallic MXene (Mo 2 Ti 2 C 3 T x ) were fabricated by acid-etching method and then introduced into epoxy resin (EP) for the comparative investigation of their flame-retardant effect. The results indicated that MXenes were homogeneously dispersed in EP matrix, which can contribute to the improvements of thermal and flame retardant properties of EP composites. Upon the incorporation of 1 wt% Mo 2 Ti 2 C 3 T x MXene, the EP composites achieved a significantly reduced maximum mass loss rate (R max ) by 39.4%, superb over EP/Ti 3 C 2 T x composites. Moreover, Mo 2 Ti 2 C 3 T x MXene endowed EP composites with a notable downward trend in fire risk, reflected by the decreasing PHRR of 34%, PSPR of 32.7%, TSP of 57.7%, PCO of 30.8%, along with significantly reduced SF value by 72.7%, which was superior to EP/Ti 3 C 2 T x composites. The strong catalytic attenuation and charring effect of transition metal Mo–Ti elements for bimetallic Mo 2 Ti 2 C 3 T x MXene, as well as nanosheet structure, imparted excellent fire retardant performance to EP composites. This work provides new insights into the application of bimetallic MXenes in flame retardant polymer composites .