Construction of an epoxidized, phosphorus-based poly(styrene butadiene styrene) and its application in high-performance epoxy resin

In modern industries, the demand of multifunctional, transparent epoxy resin (EP) combining superior dielectric, mechanical, and fire-safety performances is gradually increasing. However, it was difficult to realize such a performance portfolio in current research. Herein, we fabricated an epoxidized, phosphaphenanthrene-containing poly(styrene butadiene styrene) (ESD) for advanced fire-safe EP. ESD maintains the high transparency of EP and improves the UV-blocking property. 10 wt% ESD makes EP/DDM/10ESD pass a limiting oxygen index (LOI) of 36.0 % and a UL-94 V-0 rating. EP/DDM/10ESD displays improved mechanical properties because of intramolecular cavities and rigid P-based groups in ESD, as reflected by 79.2 %, 68.9 %, and 67.6 % increases in impact strength, tensile strength, and fracture toughness (KIC) relative to EP/DDM. Compared with EP/DDM, EP/DDM/10ESD shows obviously-decreased dielectric constant and loss. EP/DDM/10ESD outperforms many fire-safe epoxy resins due to its superior comprehensive performances. Thus, this work delivers an effective method for developing multifunctional flame-retardant epoxy resin.