SYNTHESIS OF NEW TELECHELIC OLIGOMERS AND MACROMONOMERS BY CONSTRUCTIVE DEGRADATION

Telechelic acrylic oligomers possessing terminal carboxylic acid, ketone, aldehyde or hydroxyl groups can be synthesised in good yields by the ozonolysis of free radical copolymers of the appropriate acrylic monomer with a small amount of a 1,3-diene, such as butadiene, 2,3-dimethyl-butadiene or 2,3-diphenyl-butadiene. The oligomers so-prepared have high end-functionalities (>98%), controllable average molecular weights, relatively narrow molecular weight distributions, and can be chain extended by a variety of means to give back high molecular weight polymers. Oligomers with perfect alpha-phenyl ketone-omega-carboxylic acid functionality can be prepared by ozonolysing copolymers containing low concentrations of units derived from phenyl acetylene. Photolysis of copolymers of an alkyl vinyl ketone with monomers such as styrene yield, directly, oligomers with polymerisable unsaturated end-groups, i.e. macromonomers.