Enhancing toughness, flame retardant, hydrophobic and dielectric properties of epoxy resin by incorporating multifunctional additive containing phosphorus/silicon

Developing epoxy resins with superior toughness, flame retardant and hydrophobic as well as dielectric properties remains a huge challenge. Herein, an epoxy additive (ETP) was prepared by grafting phosphorus-containing molecules into the skeleton of silicone resin through silicon hydrogen addition reaction. Through such a design, the obtained ETP imparted Bisphenol A epoxy resin (DGEBA) with excellent flexibility, fire safety, hydrophobicity and dielectrical property. When only 6 wt% of ETP was introduced into the DGEBA system, the resulting product (ETP-6) passed the V-0 level in the UL-94 test with a high limiting oxygen index of 29.8 %, which could be ascribed to the presence of phosphorus and silicon element. Meanwhile, compared with neat DGEBA, the peak heat releases and smoke emissions of ETP-6 were reduced by 32.7 % and 37.8 % during the combustion. Additionally, ETP also imparted the cured product with excellent hydrophobic and dielectric properties, as well as superior toughness (114.5 % increase in impact strength) due to its “rigid and flexible” silicone skeleton and good dispersion. This work opens up a new strategy for developing high-performance and multifunctional epoxy resin additives with potential versatile applications.