Influence Of Cocatalysts And Polymerization Conditions On Properties Of Polyesters From ROCOP Of Epoxides And Cyclic Anhydride

Aliphatic polyesters (PEs) are an appealing class of polymers used in a range of applications such as biomedical devices and bulk packaging owing to their excellent properties and general biocompatility. Alternating ring-opening copolymerization (ROCOP) of epoxides and cyclic anhydrides (Figure 1) is becoming an attractive method for the synthesis of PEs. However, one of the major challenges faced with ROCOP is that the PEs synthesized via this technique are typically of low number average molecular weight (Mn) that leads poor mechanical and thermal properties and thus limits their applications. In recent years, numerous organometallic catalysts have been developed for the epoxide/anhydride copolymerization, many of which showed markedly higher activity with the addition of a nucleophilic co-catalyst . The influence of co-catalysts and polymerization conditions to obtain alternating polyesters with Mn > 10000 g/mol and Tg > 80 °C by ROCOP polymerization with commercial catalysts have been investigated. Cyclohexene oxide (CHO) and Phthalic anhydride (PA) have been reacted in the presence of salen - type complexes of three different metals Cr (1), Al (2), and Mn (3) in combination with DMAP, PPNCl and PPNN3 as cocatalysts. The polyesters were characterized by size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). This research work offers access to PEs with good thermal and molecular weight properties suitable for practical applications. Moreover, the percentage of biodegradation of selected polyesters have been determined according to ISO 14851.