Advancing Sustainable Plastics through the Optimization of Glycerolplasticized Gluten as a Renewable Polymer Alternative

[EN] This study investigates the development of gluten-based samples through extrusion and injection molding, focusing on optimizing extrusion conditions to enhance material properties. During the extrusion process, the combined effect of shear and heat induces protein denaturation, promoting the formation of ß-sheets as confirmed by chemical characterization. Variations in extrusion parameters affect the torque evolution throughout processing, revealing their influence on structural behavior. A statistical analysis identified extrusion temperature, time, and screw speed as significant factors determining the mechanical performance of the samples. Thermal and thermo-mechanical analyses revealed that increasing extrusion severity resulted in an increase in tensile strength (from 2.80 to 4.14 MPa) and stiffness (from 133 to 280 MPa), along with an increase in elongation at break (from 11.7 to 29.8%). Additionally, the denaturation peak shifted from 93.1 °C to 78.2 °C, with a reduction in enthalpy from 170.6 to 57.2 J/g. Dynamic mechanical analysis showed an increase in storage modulus (from 30.2 to 45.1 MPa). Despite extensive prior research indicating that processing variables significantly influence protein denaturation and the resulting material characteristics, the distinct and synergistic impacts of critical extrusion parameters on thermoplastic gluten systems remain insufficiently understood. The present analysis underscores that precise regulation of extrusion conditions plays a fundamental role in modulating both the mechanical behavior and thermal stability of gluten-derived materials, thereby enabling the optimization of their functional performance.