Materiales compuestos termoplásticos cargados con residuos biogénicos de base proteínica: influencia del tamaño de partícula

Chicken feathers are cheap, available and a ubiquitous renewable waste material resulting from the massive production of chicken meat from the aviary industry which is estimated in 925.000 ton/year in EU. Consequently, its abundance and properties suggest that this waste can be re-used as an alternative material versus those natural fibres utilized nowadays such as cellulose based fibres. For these reasons, chicken feathers can be used in some cases in order to develop more environmentally friendly composite materials. The present work proposes a preliminar study regarding the re-valorization of chicken feathers waste (Plu) for the preparation of thermoplastic microcomposite materials with matrixes of High Density Polyethylene (HDPE), Polypropylene (PP) and Ethylene Vinyl Acetate (EVA). Specifically, the effect of the particle size of the fibrous keratinic waste on mechanical, physical, morphological and thermal properties was studied in composite materials including a 20%v/v of chicken feathers in random distribution. The waste, once clean and disinfected, was ground and sieved in order to obtain five fractions with different particle size (<100 µm, 100-250 µm, 250-500 µm, 500-1000 µm and 1000 µm). These fractions were used to prepare sheets of composite materials of (160 x 160 x 2 mm3) at pre-established conditions of temperature, time, mixing speed and pressure. Obtained results show that production of composite materials by this process is feasible for all the sizes. On the other hand, mechanical properties of the composite materials HDPE/Plu, PP/Plu y EVA/Plu decrease significantly compared with the values of the neat matrixes. Only Young’s Modulus increases slightly, especially for EVA/Plu composites with a particle size of 100 µm because they present the best adhesion at feather-matrix interface as it has been corroborated by Scanning Electronic Microscopy images. Anyway, in general terms, the study shows a low compatibility between the components what is consistent with the physic-chemical properties of the residue. However, this compatibility could be improved by using proper coupling agents. The composite materials are lightweight materials; their density has not increased, being similar to that of the matrices. Dimensional stability decreases with the size of the feather particles especially for EVA/Plu composites, which show higher water absorption