Studies on the reactive polysulfone-polyamide interface: interfacial thickness and adhesion

The reactive interface formed between an immiscible polymer pair, amorphous polyamide (aPA) and functionalized polysulfone (PSU), was studied by ellip sometry. Diblock copolymers were formed in situ by an interfacial reaction between the amine-terminated aPA and the end-functionalized PSU, whereas gr aft copolymers were formed between the amino-chain end groups of aPA and th e PSU functionalized in the middle of the chains. It was found that the int erfacial reaction significantly increased the interfacial thickness, even r eaching the size larger than the coil size of the copolymers formed at the interface. The interface structure and the properties were affected by the position and type of functional groups incorporated to the PSU. The reactiv e interface resulting in the graft copolymers tended to be thicker than tha t forming the block copolymers. However, the thinner interface demonstrated a superior adhesion to the thicker interface. (C) 1999 Elsevier Science Lt d. All rights reserved.