Zinc Amido-Oxazolinate Catalyzed Ring Opening Copolymerization and Terpolymerization of Maleic Anhydride and Epoxides.

Muneer Shaik,Vamshi K Chidara,Guodong Du,Srinivas Abbina

doi:10.3390/molecules25184044

Abstract

Ring opening copolymerization (ROCOP) of epoxides and cyclic anhydrides has become an attractive approach for the synthesis of biodegradable polyesters with various compositions. Encouraged by the efficiency and versatility of a series of amido-oxazolinate zinc complexes, in this study they were shown to be active catalysts for the synthesis of unsaturated polyesters via ROCOP of maleic anhydride and various epoxides. The relative activity of epoxides in these reactions was observed to be styrene oxide > cyclohexene oxide > phenyl glycidyl ether, which could be correlated with the electronic and steric features of the substrate. To provide more structural possibilities for the polyesters, the difference in epoxide reactivity was exploited in an attempt to prepare block terpolymers from one anhydride and two epoxides. Terpolymerization was carried out in one or two steps in a single pot. The thermal characterization by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques suggested that the resulting materials were mostly random terpolymers.

Highlights

Polyesters are an important class of biodegradable and biocompatible polymers that possess various applications in drug delivery, orthopedic implants, artificial tissues, and commodity materials [1,2,3,4]
We focused on maleic anhydride (MA) and cyclohexene oxide (CHO), an aliphatic epoxide, to expand the substrate scope of the catalysis
Because CHO could undergo homopolymerization at elevated temperatures in the presence of a catalyst, the initial reaction conditions were varied in an attempt to minimize the formation of ether linkages in the Ring opening copolymerization (ROCOP) of CHO and MA

Summary

Introduction

Polyesters are an important class of biodegradable and biocompatible polymers that possess various applications in drug delivery, orthopedic implants, artificial tissues, and commodity materials [1,2,3,4]. Typical synthetic methods leading to polyesters involve step growth polycondensation or ring-opening polymerization (ROP) [5,6]. ROP of cyclic esters effectively produces polyesters with controlled structure and molecular weight, but the availability of cyclic monomers may be limited. Catalytic ring-opening copolymerization (ROCOP) of epoxides and cyclic anhydrides is another technique to produce polyesters that has gained increased attention in recent years [11,12]. This approach could possibly circumvent the limitations posed by the aforementioned methods while taking advantage of both. The increasing availability of bio-derived epoxides and cyclic anhydrides further enhances the attractiveness of the approach [14,15,16]

Methods

Results

Conclusion