High impact strength of aliphatic polyketone/polyamide 6 blends induced by a chemical reaction

Compatibility and physical properties of aliphatic polyketon (PK)/polyamide 6 (PA6) blend were investigated. The PK and PA6 showed high adhesion strength and thus impact strength of PK/PA6 blends was very high. It was observed that PK-PA6 copolymers are formed by a chemical reaction between the two polymers and the copolymers act as a reactive compatibilizer in the PK/PA6 blends. The presence of the PK-PA6 copolymer was confirmed by FTIR analysis. The adhesion strength between PK and PA6 was very high compared to a typical incompatible polymer pair. PA6 investigated herein has two end groups, NH2 and carboxylic acid. We also adopted end-capped PA6 that has two carboxylic acid end groups. The adhesion strength and impact strength of the PK/end-capped PA6 blends was much lower than that of PK/PA6 blends. More importantly, the PK-PA6 copolymer was not formed in the PK/end-capped PA6 blends. Thus, it was concluded that the chemical reaction occurs between the carbonyl of PK and the primary amine end group of PA6. Due to the high impact strength of PK/PA6 blends, possible applications could be automotive parts where higher impact strength is required.