Synthesis and characterization of star-branched polyamide 6 via anionic ring-opening polymerization with N,N′,N″-trimesoyltricaprolactam as a multifunctional activator

Star-branched polyamide 6 was prepared via anionic ring-opening polymerization of ε-caprolactam in the presence of a simple benzene-centered trifunctional activator of N,N′,N″-trimesoyltricaprolactam. A high polymer yields of above 95% were achieved at 160 °C for 15 min utilizing ε-caprolactam magnesium bromide as a catalyst. Compared with its linear counterpart, the resultant star-branched polyamide 6 showed smaller relative viscosity (1.51), decreased melting temperature (218 °C) and lower crystallinity (24.2%). The specific properties demonstrated the existence of a star-branched structure and provided potential advantages in engineering applications.