Multifunctional coupling agents. Part 4: Block copolymers based on amino terminated polyamide-12 and carboxy terminated poly(butylene terephthalate)

A carboxy terminated poly(butylene terephthalate) (PBT) was obtained by quantitative reaction of a hydroxy terminated PBT with succinic anhydride. Subsequent melt mixing with an amino group terminated PA12 did not result in the formation of linking groups between the components. Instead, the formation of succinimide terminal groups on the polyamide-12 (PA12) chains was observed.The same conversion in presence of a bifunctional coupling agent possessing one oxazoline and one oxazinone group yielded PA12/PBT block copolymers in high extent. DSC and microscopic measurements showed that a phase separated morphology is predominant.