We often come across fibrous materials in everyday life. The fibers may be subdivided into natural ones like cellulose, hemp or asbestos and artificial ones like polyester or viscose [1] (figure 1). The artificial mineral fibers comprise crystalline fibers such as carbon fibers and silicon carbide but also amorphous fibers like glass wool or rock wool. Glass-like fibers are commonly used as insulating wool or as an additive in construction materials to enhance stability, toughness and durability.