APPLICATION OF POLYPHOSPHONATE FLAME RETARDANTS IN TRANSPARENT ENGINEERING THERMOPLASTICS

摘要

Polyphosphonates and polyphosphonate-co-carbonates can be used to flame retard engineering thermoplastics for various applications,such as polyethylene terephthalate (PET) fibers for carpeting and textiles,and glass reinforced polycarbonate (PC) compounds for electronic equipment housings and covers.Moreover,these flame retardants also present a unique opportunity to make transparent polymer blends with resins like PET,PC,and thermoplastic polyurethane (TPU).This paper will present the different mechanisms involved in making transparent blends of polyphosphonate and its copolymers with these resins systems.In biaxial oriented PET films (BOPET),the reaction between polyphosphonate and PET was found critical to obtain blend transparency.While PC and polyphosphonate-co-carbonates blends are inherently miscible and transparent,PC and polyphosphonate homopolymer blends are only made miscible in twin screw extruders with the addition of compatibilizers.In TPU resin systems,the molecular composition of TPU,the molecular weight (MW) of polyphosphonate and its loading level play key roles in making clear blends.