SYNTHESIS AND CHARACTERIZATION OF RIGID-ROD POLYESTERS BEARING 3-HYDROXYPROPYL AND 3-ACETOXYPROPYL SIDE-GROUPS

A description of the syntheses of two structurally well-defined aromat ic polyesters having polar 3-hydroxypropyl or 3-acetoxypropyl side gro ups is given. The hydroxy derivative was prepared by reacting a solubl e precursor polyester bearing 2-propenyl substituents with 9-borabicyc lo-3.3.1!nonane, followed by an oxidative work-up procedure. The acet oxy-substituted polyester was obtained treating the hydroxy polymer wi th acetic anhydride. The reaction conditions for these steps were stud ied in detail by using model compounds to minimize cleavage of the est er bonds during the conversions. The analysis of the polyesters by NMR spectroscopy and osmometry proved that under suitable conditions almo st no degradation occurs during the conversions of the polyesters.