Alkyd resins based on hyperbranched polyesters and PET waste for coating applications

Abstract Medium oil alkyd resins based on the glycolyzed PET waste and different generations of aliphatic hyperbranched polyesters with linseed and sunflower oil fatty acids, which are of interest to the coating industry, were investigated. Different resin compositions were synthesized and characterized by IR and 1 H NMR spectroscopy. The effect of oil fatty acid type, glycolyzed products, functionality of the polyols on thermal and film performance properties was studied. The onset of decomposition of all samples displayed at values above 200 °C which render them suitable for the processing requirements of most conventional coating applications. All films had good adhesion, bending, impact and ductility. The gloss and hardness increased with increasing the degree of branching and consequently, the molecular weight in the resin backbone. The presence of G3 as polyol enhanced the thermal stability and film properties of coatings.