Imide-DOPO derivative endows epoxy resin with excellent flame retardancy and fluorescence without losing glass transition temperature

The aggregation and plasticizing of most 9,10-dihydro-9-oxa-10-phosphaphenanthrene -10-oxide (DOPO) derived additives often result in deteriorating the glass transition temperature and mechanical properties of epoxy resins (EP). To address this issue, an imide-DOPO derivative (BMP) with bulky aromatic structure was successfully synthesized. Benefitting from the space hindering and intermolecular interaction (pi-pi stacking) of BMP, it does not lead to the loss of glass transition temperature, and only a minor damage of tensile and impact strengths is caused. Additionally, with only 0.78 wt% loading of phosphorus (10 wt% BMP), the EP/BMP10% achieves UL-94 V-0 and high LOI value of 35%. Simultaneously, both the heat release rate and total smoke production are markedly reduced. More excitingly, BMP exhibits aggregation-induced emission enhancement of fluorescence in the N, N-dimethylformamide/water mixed solution as well as epoxy resin. This work provides a new insight in simultaneously imparting flame retardancy and fluorescence to epoxy resins without losing glass transition temperature.

Automated summary

A bulky aromatic structure imide-DOPO derivative (BMP) successfully imparts flame retardancy and fluorescence simultaneously to epoxy resins. BMP, benefiting from space hindering and intermolecular interactions, maintains the glass transition temperature of the epoxy resin with minor impact on mechanical properties.