Functional aliphatic polyesters were synthesised by melt copolymerization of succinic anhydride (SA) and allyl glycidyl ether (AGE) in the presence of benzyltrimethylammonium chloride (BTMAC) as a catalyst. The influence of the parameters of the process: AGE/SA feed ratio, duration of the reaction, amount of water and of the catalyst added on the reaction course and on characteristics of the products obtained has been examined. Tendency to gelation of the polyesters during some syntheses and increase of molecular weight after consumption of functional groups were observed. (C) 2000 Elsevier Science B.V. All rights reserved.