Title

Memory Effects in Supramolecular Networks of Diacids and Polyfunctional Pyridine Derivatives

Document Type

Article

Publication Date

6-5-2004

Department

Polymers and High Performance Materials

Abstract

Highly crosslinked networks were produced through a series of diacids and tetrakis pyridyls. These materials displayed complex crystallization behaviors over multiple heat/cool cycles. The shifting of crystallization behaviors with time in the melt phase seems to indicate that the materials move toward thermodynamically ideal structures. This behavior is suggestive of a type of memory in which the networks remember the morphological structure previous to the melt and improve upon that structure in the next cooling cycle. The network/memory phenomena observed in small molecule diacid/tetrapyridyl systems also appeared to exist when poly(ethylene terephthalate) (PET) polymer was used as the source of carboxylic acid functionalities. The same time-dependent behaviors, suggestive of sequential steps toward thermodynamically optimum states, were observed when the PET/tetrapyridyl systems were thermally cycled. It was also observed that complexation of tetrapyridyl with PET brought about a significant change in oxygen gas barrier properties; these changes were opposite to those obtained when covalent crosslinks were introduced into PET. (C) 2004 Wiley Periodicals, Inc.

Publication Title

Journal of Applied Polymer Science

Volume

92

Issue

5

First Page

3097

Last Page

3106