High‐Temperature and Chemically Resistant Protein Material with Electric Insulation Properties Comparable to Todays Fossil‐Based Plastics

ABSTRACT To address the global challenges of fossil fuel depletion and plastic pollution, promoting sustainable environmental development, we have explored the use of wheat gluten (WG) as a possible insulating material in electric applications. Inspired by previous work on whey protein foams, where a thermal treatment improved the mechanical integrity, WG was also here heat‐treated at 150°C in air, and films were produced with and without a plasticiser (glycerol, GLY). The overall properties depended on the composition, processing conditions, environment, and whether a heat‐treatment was used or not. At best, films exhibited an electric insulation competitive to fossil‐based plastics (7.2 × 10 ¹⁴ Ω·m), oil resistance, and a comparatively low moisture uptake. Quite unexpectedly, these films, prepared with glycerol, remained flexible even after 4 weeks at 150°C. These results suggest that thermally treated WG/GLY materials have the potential to be used in e.g. low‐voltage insulation parts in electric motors, achieving a balance between performance and sustainability in automotive applications.