The anionic ROP of CL is an attractive protocol to melting cast polyamide 6 (MC PA6) in industry owing to the shorter reaction time (10–30 min), lower reaction temperature (150–180 8C) and pressure (atm) [14–16]. The anionic polymerization was usually conducted by a two-component system of a catalyst and an N-acyllactam type activator. The growing chain ends are always corresponding to N-acyllactam and the number of the polymer chains should be equal to that of the N-acyllactam if there are no side reactions. Thus, non-linear PA6 could be theoretically fabricated by adding multifunctional N-acyllactam type activators [17,18]. Ashida et al. explored a tertiary amine centered trifunc-tional activator from Desmodur L-2291A and CL [6]. Santos et al. synthesized a star-like PA6-block-polyurethane copolymer using a tri-arm polyurethane activator with glycol as a core moiety [19]. They found that the star-like copolymer showed better mechanical properties compared with the linear ones. However, these multifunctional activators suffered from the tedious synthesis and toxic isocyanate reagent. There is a great need to systematically investigate simple and novel multifunctional activators and SPA6.