Sustainable manufacture of renewable materials without compromising performance remains a challenge to material scientists. Biomass material is acknowledged as a cost-effective approach to alleviate the situation. In this work, carbonized silk fiber (average 5 μm diameter) mats were derived from silkworms through degumming and subsequent one-step carbonization process at high temperature. It is demonstrated that the resultant mats are able to show great flexibility and high-efficiency microwave attenuation performance by optimizing the annealing process. At the optical carbonization temperature of 650 °C, the carbonized silk fiber mat/silicone composite could exhibit a minimal reflection loss (RL) value of −70 dB at 17.6 GHz and 2.5 mm thickness. At 3.2 mm thickness, an effective absorption bandwidth (EAB, RL < −10 dB) as wide as 8.7 GHz (9.3–18 GHz) is achieved. Such a broad bandwidth is mainly attributed to the long fiber length and well-connected conductive network in the mat, which leads to promoted permittivity at a low filling ratio (5 wt %). Combining the great flexibility, broad bandwidth, lightweight, and low cost with a simple fabrication process, the established carbonized silk fiber mat could be an environmentally friendly alternative to currently existing traditional absorber materials for microwave attenuation in electromagnetic compatibility applications.

中文翻译：

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碳化丝纤维毡：一种灵活的宽带微波吸收器，以及长度效应

在不影响性能的情况下可持续制造可再生材料仍然是材料科学家面临的挑战。生物质材料被认为是缓解这种情况的一种具有成本效益的方法。在这项工作中，碳化丝纤维（平均直径为 5 μm）垫是从蚕中通过脱胶和随后的高温一步碳化过程获得的。结果表明，通过优化退火工艺，所得垫能够显示出极大的灵活性和高效的微波衰减性能。在 650 °C 的光学碳化温度下，碳化丝纤维毡/硅胶复合材料在 17.6 GHz 和 2.5 mm 厚度下可以表现出 -70 dB 的最小反射损耗 (RL) 值。厚度为 3.2 mm 时，有效吸收带宽 (EAB, RL < -10 dB) 高达 8.7 GHz (9. 3–18 GHz) 实现。如此宽的带宽主要归因于垫子中的长纤维长度和连接良好的导电网络，这导致在低填充率（5wt%）下提高了介电常数。将极大的灵活性、宽带宽、重量轻和低成本与简单的制造工艺相结合，已建立的碳化丝纤维垫可能是目前现有的传统吸收材料的环保替代品，用于电磁兼容应用中的微波衰减。