Synthesis and Characterization of Phosphorus-Containing Flame Retardant Polyamide 66

Polyamide 66 (PA66) benefits from excellent mechanical properties and good chemical resistance, which enabled wide application of this material in various industrial fields; however, it suffers from high flammability. Generally, preparation of a flame retardant PA from a reactive flame retardant involves a two-step process. In this study, the flame retardant PA66s (FRPA66s) are synthesized via a one-pot melt copolycondensation route by using a reactive phosphorus-containing flame retardant (FR-B). Then, molecular weight, some mechanical and thermal properties along with flame retardant properties of FRPA66s were investigated by gel permeation chromatography (GPC), instron material testing, differential scanning calorimetry (DSC), thermogravimetry (TG) analysis, vertical burning test (UL 94), and limiting oxygen index test (LOI) techniques. The experimental results confirmed that FRPA66s synthesized by the one-pot method have very similar properties compared to those obtained via the two-step process. Moreover, the prepared materials showed good non-flammability behavior with limiting oxygen index value of over 30% and a vertical burning test result of V-0 rating.