Enhancement of the flame retardant properties of PPS-based composites via the addition of melamine-coated CaAl-LDH fire-retardant filler

Abstract

Addressing the global energy crisis and its environmental implications has become a critical challenge, prompting a growing interest in electric vehicles (EVs) as an alternative to fossil fuel-dependent vehicles. Engineering plastics (EPs), with their lightweight and cost-effective properties, are attractive candidates for various applications, including automotive components. However, certain drawbacks, such as poor thermal conductivity and fire resistance, have limited their widespread adoption. In this study, we focus on polyphenylene sulfide (PPS) as a promising super-engineering plastic with high thermal stability and mechanical properties but low thermal conductivity. To enhance its properties, we explore the incorporation of CaAl layered double hydroxide (CaAl-LDH) as a fire-retardant filler, with melamine coating to improve thermal stability. When fabricating composites at high filler ratio (over 30 %), the CaAl-LDH filler thermally decomposes and loses its flame retardant performance. To prevent this, our group attempted to provide thermal stability through melamine coating. The resulting PPS/GF/40 m-CaAl-LDH composites exhibited improved thermal conductivity of 0.37 W/m•K which is almost twice that of the PPS/GF composite, and mechanical properties, along with exceptional flame-retardant behavior, achieving a UL94 V-0 rating and limited oxygen index of 52.74 %. After a fire test, PPS/GF/40 m-CaAl-LDH composites shows improved tensile strength due to the molten m-CaAl-LDH wrapped the entire surfaces protecting from the flames. This research presents a promising strategy for developing high-performance PPS-based materials with applications in diverse industrial fields, including the automotive industry.