Synthesis of low-VOC unsaturated polyester coatings for electrical insulation

The objective of this research is to develop an unsaturated polyester (UPE) varnish with low-volatile organic compounds (VOCs). Instead of using a solvent, the solvent-free varnish incorporates a reactive diluent to reduce viscosity and a catalyst to accelerate curing. To achieve this, vinyl toluene and 1,4-butanediol dimethacrylate were employed as curing agents. Sebacic acid (SA) and fumaric acid were utilized to create UPE coatings for electrical insulation. Various tests and measurements were made to evaluate the physical, thermal, and chemical structure determination, and electrical properties of the synthesized resins. Given the increasing demand for eco-friendly and low-VOC products, gas chromatography was employed to determine VOC levels. The study demonstrated that the electrical volume resistance of cross-linked coatings containing FA was 1.58 × 1015 Ω·cm, whereas coatings containing SA exhibited a measurement of 6.96 × 1011 Ω·cm. VOC levels in the UPE coatings were found to be in the range of 2.10–3.60%.