Hybrid biocomposites with high thermal and noise insulation from discarded wool, poultry feathers, and their blends

•Wool and poultry feathers have unique structure and properties.•Waste wool and discarded poultry feathers are available in large quantities at low cost.•Wool enhances water resistance and feather provides low density and also good thermal and acoustic resistance.•Wool and feather reinforced polypropylene composites are sustainable, alternative to gypsum tiles. Sheep wool and poultry feathers have unique properties that provide excellent noise and thermal insulation, and flame resistance when used as reinforcement for poly propylene. Discarded wool and poultry feathers are not only available in large quantities at low cost but have distinct characteristics that make them ideal to develop composites for various applications. In this study, we have studied the changes in tensile properties, thermal conductivity, sound absorption, and flame resistance of composites fabricated using wool and poultry feathers individually and as blends in various proportions. Reinforcing with sheep wool provided higher tensile and flexural strength compared to feathers. Compared to neat PP, higher tensile strength and modulus were obtained with 70% sheep wool as reinforcement but the flexural strength and modulus of the individual wool or feather and hybrid composites were considerably lower. When equal proportions of wool and feathers are used, the strength and modulus decreased compared to using the reinforcements individually. However, combining wool and feathers in 50/50 ratio and with 80% reinforcement, the composites had high sound absorption co-efficient of 0.55 with peak sound absorption found throughout the 1000 to 6000 Hz range depending on the proportion of wool and feathers. A flame resistance rating of V1 and thermal conductivity of 0.630 W/mK was obtained for the composites. Biocomposites with desirable properties could be obtained by blending sheep wool and poultry feathers for specific applications, particularly where acoustic, thermal and flame resistance is necessary.