Design and Characterization of Sustainable Bio-Composites from Waste Chicken Feather Keratin and Thermoplastic Polyurethane Firoozeh Pourjavaheri, 1 Oliver A.H. Jones , 2 Michael Czajka , 1 Isaac Martinez-Pardo, 1 Ewan W. Blanch, 1 Robert A. Shanks 1 1 School of Science, RMIT University, Victoria 3001, Australia 2 Australian Centre for Research on Separation Science, School of Science, RMIT University, Victoria 3001, Australia A polyurethane-based polymer, and a sustainable, nat- ural resource in the form of chicken feather (keratin) fibers were combined to form a bio-composite via sol- vent–casting–evaporation at 0, 10, 20, 30, 40, 50, 60, and 70%w/w. The thermo-mechanical properties of the composites were assessed using thermogravime- try, dynamic mechanical analysis, and stress–strain measurements with hysteresis loops. The uniformity of the dispersion of the feather fiber in the polyurethane matrix was investigated via macro-photography. Scan- ning electron microscopy of fracture surfaces was used to verify that the adhesion between fiber and polymer was effective. A molecular modeling visualiza- tion predicted the existence of hydrogen bonding between fibers and polyurethane molecules and this result was supported by Fourier transform infrared analysis of the final composites. Addition of chicken feather fibers to the polyurethane matrix was found to decrease the glass transition temperature, recovery strain and mass loss of the composites, but increase the elastic modulus, storage modulus and char level. 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 effectively and cheaply improve the thermo-mechanical properties of composite mate- rials, with potentially large environmental benefits. POLYM. COMPOS., 00:000–000, 2018. V C 2018 Society of Plas- tics Engineers INTRODUCTION Millions of tons of feathers are generated annually as a by-product of the poultry industry. These feathers, partic- ularly those from chickens, pose a significant (and costly) waste disposal problem since, at present, they are mostly either incinerated or sent to landfill. One solution to this problem is to find uses for waste feathers. Polymers reinforced with natural fibers, commonly named “bio-composites”, have started to be industrially applied in the automotive and building sectors as well as consumer goods. Green composites are a specific class of bio-composites where a bio-based polymer matrix such as a biodegradable polyurethane is reinforced by natural fibers such as keratin [1, 2]. Bio-based polymers have also been defined to include synthetic or machine- processed organic macromolecules derived from biologi- cal resources [3, 4]. The term bio-polymer polyurethane, or thermoplastic polyether–polyurethane (TPU-polyether) covers a large class of polymers with diverse physical and chemical properties, suitable for many biomedical or industrial applications [1]. Bio-based TPU polymers (e.g., Pearlth- ane ECO) are made up of block copolymers consisting of a sequence of polyol soft segments and hard polyurethane segments. While ether-based polyurethanes are an excel- lent choice for applications involving water their use in many other areas is often not practical due to poor heat resistance and mechanical properties [5, 6]. Development of TPU-polyethers with enhanced thermo-mechanical properties can be accomplished via the incorporation of reinforcing materials (the main aim of this study) and would be beneficial to a range of plastic-using industries. Biological material, in the form of feathers, has the poten- tial to fulfill this reinforcing fiber role and has the added benefit of utilizing a resource that would otherwise go to landfill or be incinerated. Chicken feather fibers (CFFs) are an interesting candi- date for the development of new plastic bio-composites due to their low density (0.89 gcm 23 ), low toxicity and abrasiveness (and associated machine wear), as well as high: thermal insulation, flame resistance, sustainability, Correspondence to: Oliver A.H. Jones; e-mail: oliver.jones@rmit.edu.au DOI 10.1002/pc.24794 Published online in Wiley Online Library (wileyonlinelibrary.com). V C 2018 Society of Plastics Engineers POLYMER COMPOSITES—2018