Influence of Co-Catalysts and Polymerization Conditions on Properties of Poly(anhydride-altepoxide)s from ROCOP Using Salen Complexes with Different Metals

Cyclohexene oxide (CHO) and phthalic anhydride (PA) have been reacted in the presence of commercial salen-type complexes with di ff erent metals Cr (1), Al (2), and Mn (3) in combination with 4-(dimethylamino) pyridine (DMAP), bis-(triphenylphosphorydine) ammonium chloride (PPNCl) and bis-(triphenylphosphoranylidene) ammonium azide (PPNN3) as co-catalysts to obtain alternating poly(PA-alt-CHO) s by ring-opening copolymerization (ROCOP). The e ff ect of di ff erent reaction conditions (pre-contact between catalyst and co-catalyst, polymerization time) on the productivity, molecular weight and glass transition temperature has been evaluated. By using a 24 h pre-contact, the aliphatic polyesters obtained were characterized by high molecular weight (Mn > 15 kg / mol) and glass transition temperature (Tg) up to 146 ffi C; the more sustainable metals Al and Mn in the presence of PPNCl give comparable results to Cr. Moreover, biodegradability data of these polyesters and the study of the microstructure reveal that the biodegradability is influenced more by the type of chain linkages rather than by the molecular weight of the polyesters.