Hyperbranched poly(ether ketones): Manipulation of structure and physical properties

Abstract

Hyperbranched poly(ether ketones), with a variety of chain end functional groups and controllable degrees of branching, are prepared by the polymerization of AB2, AB3, and AB4 monomers. It is found that the choice of A and B, or the incorporation of dendritic and linear units into the ABx monomer structure, dramatically affects the degree of branching. Depending on the structure of the monomer unit, degrees of branching ranging from 15 to 71% can be obtained. For determining the degree of branching for fluoro-terminated hyperbranched poly(ether ketones), a new technique based on 19F NMR has been developed. Evaluation of the physical properties of the hyperbranched poly(ether ketones) with different degrees of branching has shown that thermal properties are independent of macromolecular architecture but depend heavily on the nature of the chain end functional groups, with glass transition temperatures ranging from 97 to 290°C. The solubility of the hyperbranched poly(ether ketones) is also shown to depend heavily on the nature of the chain ends, and by varying the chain ends, poly(ether ketones) soluble in either hexane or aqueous solutions could be obtained. The water-soluble derivatives were shown to act as unimolecular micelles.