Achieving High Toughness Retention and Flame Retardancy in PC / ABS Alloys by the Synergistic AHP / DSPSi System With Reactive Compatibilization

Abstract

The flammability of polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) alloy limits its applications. To enhance flame retardancy while maintaining mechanical properties, we employed a reactive silicon‐containing polyphosphamide copolymer (DSPSi) and aluminum hypophosphite (AHP) as flame retardants, along with an ethylene‐maleic anhydride alternating copolymer (ZeMac) as a reactive compatibilizer. AHP and DSPSi synergistically promote the formation of a dense char layer during combustion. Through molecular design, DSPSi incorporates flexible siloxane segments, which alleviate the stress concentration caused by AHP agglomeration, thereby reducing the adverse impact on mechanical properties. ZeMac acts as an interfacial compatibilizer to improve component compatibility. With 2.5 wt% DSPSi and 5.0 wt% AHP, the limiting oxygen index (LOI) reaches 22.1% and achieves a UL‐94 V‐0 rating. Compared with unmodified PC/ABS, the peak heat release rate (PHRR) and peak smoke release rate (PSPR) decrease by 67.5% and 27.0%, respectively, while the elongation at break increases from 30.8% to 44.8%. Through the synergy of molecular design of the flame retardant and interfacial compatibilization, this work provides a new route to high‐performance flame‐retardant PC/ABS alloys.