Synergists for Hexaphenoxycyclotriphosphazene in Cast PA6

Carbon fiber reinforced (CFR) anionic polyamide 6 (APA6) is a light and at the same time very strong material. Therefore CFR APA6 components are of interest as lightweight construction materials e.g. for aircraft manufacturing. Like many other organic polymers APA6 is flammable and thus it is mandatory to protect the polymer matrix by adding flame retardants (FRs). However, an suitable process for production of CFR APA6 materials such as thermoplastic resin transfer molding (T-RTM) process is highly sensitive to presence of polymer additives such as FRs. E.g. commonly used FRs interrupt the anionic ring opening reaction of e-caprolactam to form PA6 or are filtered out by the fiber fleece. With hexaphenoxycyclotriphosphazene (HPCTP) we discovered an incorporable FR for CFR APA6.