Acoustic evaluation of mycological biopolymer, an all-natural closed cell foam alternative

•Acoustic absorption material that is based solely on mycelium fruiting bodies.•Bio-polymer is grown in a newly devised system that grows a foam free from substrate material.•Performance of the myco-polymer was shown to have high acoustic absorption capabilities. This research examines the use of a novel new renewable resource in acoustic absorption applications that requires no glues or other artificial binders. Hence the proposed material provides a sustainable and environmentally friendly alternative to construction industry for acoustic absorption panels. The material being tested is an all-natural biopolymer that consists entirely of pure fungal mycelium that is cultured at elevated temperatures from 30 to 35 Cent. in an elevated carbon-dioxide rich environment, from three to seven percent, which in combination suppresses the fruiting bodies. This new biopolymer provides an alternative to closed cell foams and synthetic honeycombs that are suitable for a wide range of applications from fire-resistant bio-leather, textile support foams used in shoes and clothing, scaffolding for medical bio-organs and vegetarian meat. This study examines the acoustical absorption properties of this material over the frequency range from 350 Hz to 4 kHz. The results of the study indicate this new class of a pure mycelium foam provides a sustainable promising bio-based all-natural fiber alternative for acoustic shielding alternative to the traditional acoustic absorbers that are most commonly constructed with petroleum based glues and synthetic fibers.