Keratin bio-composites with polysiloxane thermoplastic polyurethane

A sustainable resource in the form of chicken feather derived keratin was used to enhance the thermomechanical properties of polysiloxane-polyurethane biocomposites. Two methods, solvent-casting-evaporation-compression molding, and solvent-precipitation- evaporation-compression molding were used to create new bio-composites incorporating 20 %·w/w of chicken feather fibers into a polysiloxane-polyurethane matrix and the results were compared. A molecular modelling visualization indicated the possible existence of hydrogen bonding between fibers and polyurethane molecules. The thermo-mechanical properties of both the polysiloxane polymer and feather reinforced bio-composites were assessed using thermogravimetry, dynamic mechanical analysis and stress-strain measurements with hysteresis loops. The dispersion uniformity of the keratin fibers in the plastic matrix was investigated via macro photography. Addition of chicken feather fibers to the polysiloxane matrix was found to decrease the recovery strain and mass loss of the composites (at lower temperatures) but increase the elastic modulus, storage modulus, and char level (at higher temperatures). The results demonstrate that keratin derived from what is currently a waste product from the poultry industry (with significant economic and environmental disposal costs) can improve the thermo-mechanical properties of the tested bio-composites simply and cheaply, with potentially large cost savings and environmental benefits.