DEGRADATIVE ROUTES TO TELECHELIC OLIGOMERS AND MACROMONOMERS

A variety of telechelic oligomers with terminal aldehyde, hydroxyl, ke tone or carboxylic acid end groups can be synthesized by ozonolyses of suitable free radical copolymers containing small amounts of randomly distributed C=C bonds. These bonds can be introduced using either a d iene or an acetylene as comonomer. The average molecular weights of th e oligomers are controlled by the C=C content, and the nature of the e nd groups by the choice of diene or acetylene and by the procedures us ed to work up the ozonides. Potentially macromonomeric oligomers can b e synthesized by the photolysis of copolymers containing small amounts of alkyl vinyl or aryl vinyl ketone units. Telechelic oligomers can b e chain-extended by a variety of means, including by Michael additions , depending on the nature of the end groups.