Otto H. York Department of Chemical and Materials Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.
Bolt Threads Inc., San Francisco, California 94114, United States.
ACS Appl Bio Mater. 2024 Oct 21;7(10):6441-6450. doi: 10.1021/acsabm.4c00586. Epub 2024 Oct 9.
Leather is a product that has been used for millennia. While it is a natural material, its production raises serious environmental and ethical concerns. To mitigate those, the engineering of sustainable biobased leather substitutes has become a trend over the past few years. Among the biobased materials, mycelium, the fungal "root" of a mushroom, is one of the promising alternatives to animal leather, as a material with tunable physicomechanical properties. Understanding the effect of humidity on mycelium-based leather material properties is essential to the production of durable, competitive, and sustainable leather products. To this end, we measured the water sorption isotherms on several samples of mycelium-based leather materials and investigated the effects of water sorption on their elastic properties. The ultrasonic pulse transmission method was used to measure the wave speed through the materials while measuring their sorption isotherms at different humidity levels. Additionally, the material's properties were mechanically tested by performing uniaxial tensile tests under ambient and immersed conditions. An overall reduction in elastic moduli was observed during both absorption and immersion. The changes in the measured longitudinal modulus during water sorption reveal changes in the elasticity of the test materials. The observed irreversible variation of the longitudinal modulus during the initial water sorption can be related to the material production process and the presence of various additives that affect the mechanical properties of the leather materials. Our results presented here should be of interest to material science experts developing a new generation of sustainable leather products.
皮革是一种已经使用了几千年的产品。虽然它是一种天然材料，但它的生产却引发了严重的环境和伦理问题。为了减轻这些问题，过去几年来，工程学领域已经开始设计可持续的生物基皮革替代品。在生物基材料中，菌丝体是蘑菇的真菌“根”，是一种具有可调节物理机械性能的有前途的动物皮革替代品之一。了解湿度对基于菌丝体的皮革材料性能的影响对于生产耐用、有竞争力和可持续的皮革产品至关重要。为此，我们测量了几种基于菌丝体的皮革材料的水分吸附等温线，并研究了水分吸附对其弹性性能的影响。超声脉冲传输法用于在不同湿度水平下测量材料的吸附等温线的同时测量其波速。此外，通过在环境和浸泡条件下进行单轴拉伸试验对材料的性能进行了机械测试。在吸收和浸泡过程中都观察到弹性模量的整体降低。在水分吸附过程中测量的纵向模量的变化揭示了测试材料弹性的变化。在初始水分吸附过程中观察到的纵向模量的不可逆变化可能与材料的生产过程以及影响皮革材料机械性能的各种添加剂的存在有关。我们在这里提出的结果应该会引起开发新一代可持续皮革产品的材料科学专家的兴趣。
