Macrocycles for the synthesis of high molecular weight polymers

Abstract

Cyclic polymers have been a subject of interest for polymer chemists for many years. Most conventionally prepared, linear thermoplastic polymers contain small amounts of cyclic polymers, usually lower molecular weight oligomers. Using very high dilution conditions, high molecular weight cyclic polymers can also be prepared as the major product. High molecular weight cyclic polymers have proved to be of interest for a variety of purposes, including use as models for polymers with no end-groups, and for comparison of physical properties, such as solution and melt viscosity with linear molecules. Cyclic oligomers of many types of polymers have been isolated by extraction from the parent polymers, and authentic samples have been synthesized in many cases. Many examples of reconversion of the cyclic oligomers to high molecular weight linear polymer via ring opening polymerizations have also been reported (Equation 6.1).