Straightforward Synthetic Protocol to Bio-BasedUnsaturated Poly(ester amide)s from Itaconic Acidwith Thixotropic Behavior.

Lazaros Papadopoulos,Dimitrios N Bikiaris,Marcel Kluge,Tobias Robert

doi:10.3390/polym12040980

Abstract

In the field of polymer chemistry, tremendous efforts have been made over the last decade to replace petrochemical monomers with building blocks from renewable resources. In this respect, itaconic acid has been used as an alternative to acrylic acid or maleic acid in unsaturated polyesters for thermal or UV-curing applications. However, examples of poly(ester amide)s from itaconic acid are scarce. Under standard polycondensation reactions, the presence of free amines leads to aza-Michael addition reactions at the α,β-unsaturated double bond of the itaconic acid and isomerization reactions to mesaconic acid. Both reactions make the resulting materials useless as UV-curing polymer resins. To avoid these undesired side reactions, we herein report the use of preformed, well-defined diols containing internal amide bonds. The resulting unsaturated poly(ester amide) resins were analyzed before and after UV-induced crosslinking. Viscosity measurements revealed a strong thixotropic behavior induced by the amide groups, which is usually not detected in structurally similar polyester resins.

Highlights

Over the last years, polymers from renewable resources have attracted considerable attention from both industry and academia in an effort to limit the environmental impact arising from the excessive use of polymeric materials derived from fossil resources [1,2,3,4]
One of the main objects of this work was the introduction of amide moieties into the backbone of a bio-based unsaturated polyester resin derived from itaconic acid
We report the synthesis of bio-based unsaturated poly(ester amide)s, trying to overcome aza-Michael additions and isomerization reactions that usually take place when itaconic acid and primary diamines are reacted under polycondensation conditions

Summary

Introduction

Polymers from renewable resources have attracted considerable attention from both industry and academia in an effort to limit the environmental impact arising from the excessive use of polymeric materials derived from fossil resources [1,2,3,4]. A viable way to achieve the latter is the utilization of bio-based monomeric building blocks, which are not economically accessible from petrochemical pathways These can be used to produce novel polymeric structures that in turn can lead to materials with new properties [7,8,9]. In this context, itaconic acid (IA) has lately drawn considerable attention as it exhibits a promising structure and is available at competitive prices (80.000 t/a) via the fermentation of sugars with the fungi aspergillus terreus [11,12,13]

Methods

Results

Conclusion