Improvement of polyamide/thermoplastic polyurethane blends with polyamide 6‐polyurethane copolymer prepared via suspension polymerization as compatibilizer

Abstract The polyamide 6‐polyurethane copolymer (PA6‐ b ‐PU‐ b ‐PA6) was synthesized through anionic suspension polymerization and then mixed with polyamide 6/thermoplastic polyurethane (PA6/TPU) and polyamide 6, 6/thermoplastic polyurethane (PA66/TPU) blends using as the compatibilizer. The results show that the PA6‐ b ‐PU‐ b ‐PA6 copolymers powders several can be obtained through suspension polymerization using dimethicone as disperse medium. The average diameter of PA6‐ b ‐PU‐ b ‐PA6 copolymer powders decreased with the increasing of PU content. With the addition of PA6‐ b ‐PU‐ b ‐PA6, the TPU phase dispersed more uniformly in PA6 or PA66 matrix, and the size of TPU dispersed phase decreased obviously. The PA6‐ b ‐PU‐ b ‐PA6 copolymer with higher PU content shows better compatibilizing effect. Addition of PA6‐ b ‐PU‐ b ‐PA6 can improve both strength and toughness of the PA/TPU blends. When the amount of PA6‐PU25% copolymer was 5 phr, the tensile strength and notched impact strength of PA6/TPU/PA6‐PU25% blends increased 29 and 159.4%, respectively, compared to the PA6/TPU blend without compatibilizer.