In situ ester–amide exchange reaction between polyamide 6 and ethylene‐vinyl acetate rubber during melt blending

Abstract

AbstractThe ester–amide exchange reaction between polyamide 6 (PA6) and ethylene‐vinyl acetate rubber (EVM) with dibutyltin oxide (DBTO) as a catalyst took place during melt blending, leading to the formation of PA6‐grafted EVM copolymer (EVM‐g‐PA6) and acetamide‐terminated PA6. The exchange reaction extent, expressed by the percentage content of the acetate groups taking part in the exchange reaction, was 5.9 mol %, and the yield of EVM‐g‐PA6 copolymer was 6.8 wt % for PA6/EVM/DBTO (60/40/1) blend at 230°C for 60 min. The number‐average molecular weight of PA6 branches in EVM‐g‐PA6 was ∼278 g/mol as evaluated from nuclear magnetic resonance spectra. The reaction kinetic parameters were calculated according to a second‐order reversible reaction mechanism. The rate constant was dependent on the catalyst concentration, PA6/EVM ratio, and shearing conditions. In this article, the characterized ester–amide exchange reaction between PA6 and EVM will guide the fabrication of novel EVM‐based graft copolymers and high‐performance PA6/EVM thermoplastic elastomers for engineering applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40272.