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

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.