RING-OPENING POLYMERIZATION OF LACTONE IN THE PRESENCE OF BENZYL ALCOHOL CATALYZED BY ALIPHATIC TERTIARY AMINE

Abstract

In order to study the structure and the catalytic activity of aliphatic tertiary amines,the ring-opening polymerizations of trimethylene carbonate(TMC) and L-lactide(L-LA) were catalyzed by aliphatic tertiary amines,including triethylamine(TEA),N,N,N′,N′-tetramethylethylenediamine(TMEDA),1,1,4,7,7-pentamethyldiethylenetriamine(PMDTA) and 4-(dimethylamino)pyridine(DMAP),using benzyl alcohol as initiator in THF at 55℃.Studies revealed the catalytic activity of these tertiary amines was increased according to the order:TEA TMEDA≈PMDTA DMAP.The relationships of polymer molecular weight with the conversion of monomer were linear,which were consistent with a living polymerization character.Finally,the plausible polymerization pathway was through an alcohol-activating mechanism.Aliphatic tertiary amines which were abundant in source and cheap in price were suitable for catalyzing the ring-opening bulk polymerization of lactone in low temperature because of their low boiling point,being liquid under ordinary conditions and being easy to get rid of.