Darstellung und Eigenschaften von aus Vanillin und Syringaaldehyd erhältlichen Polyestern

From vanillic and syringic acid, which are obtainable from the oxidation products of harwood lignins, polyesters were prepared by two procedures. By procedure A the respective phenolic acid was reacted with ethylene oxide to the corresponding hydroxyethyl ether, which itself was polycondensated in a second stage. By procedure B the phenolic acid was etherified with ethylene dibromide to a dibasic acid. In further stages the dibasic acid was esterified with ethylene glycol and then polycondensated. The glass transition points, melting points and molecular weights of the polyesters obtained were determined. As the results show, the polyesters differ in their melting points. The polyesters from vanillic acid exhibit relatively high melting points above 200°C, the polyesters from syringic acid are largely amorphic products.