Synthesis and Structure of Polyamide 6-block-Vinyl Polymer Prepared from Polyamide 6 Radical Initiator

The effects of reaction conditions, types and molecular weights of polyamide 6 (PA6) radical initiators (PA6ini) and a chain transfer agent on the structure of block copolymers were studied. For the polymerizations of methyl methacrylate (MMA) with PA6ini, the poly (MMA) contents, the molecular weights of poly (MMA) segments of the block copolymer and the initiator efficiency decreased with an increase of the ratio of azo group concentration to MMA concentration. Poly (MMA) segment molecular weight decreased with a decrease of the molecular weight of PA6ini, while the poly (MMA) content and the initiator efficiency increased. The initiator efficiency of azo group in the center of PA6ini molecular chain was lower than that of azo group at the terminal of PA6ini. Solvents, reaction times and reaction temperatures affected the structure of PA6-block-poly (MMA). The molecular weight of poly (MMA) segment was controlled by addition of a chain transfer agent. Molecular weights of poly (styrene) (St) segment of PA6-block-poly (St) obtained by heterogeneous polymerization were higher than those of block copolymers obtained from homogeneous polymerization. Thermal properties of block copolymers were measured by differential scanning calorimeter (DSC).