Hemp, flax and other plant fibres

The natural lignocellulosic and protein fibres are very well known to the mankind from earlier times than 7000–8000 BCE. They are renewable, sustainable and completely biodegradable. They are characterized by important properties: good thermal isolation, air permeability, proper hygroscopicity and the moisture transfer, not releasing substances harmful to the body, not causing an allergic effect. Natural fibres behave safer in fire conditions in comparison with man-made fibres. Most of lignocellulosic fibrous materials such as cotton, flax, hemp, jute, kenaf, ramie, curaua, pineapple, bamboo, coir and also protein—wool and silk—can be extracted, processed, modified, functionalized and applied in the production of textiles (woven, knitted, nonwoven, technical and 3D textiles) and can be used as reinforcing materials in biocomposites and polymer composites. Special treatment and functionalization, such as enzymatic, ultrasound, plasma, corona, liquid ammonia, flame retardant treatments and protection against biodeterioration, provided new promising future of all natural fibres. The production of natural fibres is stable and the level of production is about 38 million tonnes per year. The new emerging potential (still disputable) of genetically modified natural fibres provided better performance, including the yield of major products and enhancing their quality. Results of research conducted at the Institute of Natural Fibers indicate that flax and hemp can also be used for the extraction of the following heavy metals: Pb, Cu, Zn, from the polluted soil, after the cultivation of these plants on the degraded land. In agriculture, hemp cultivated in European climatic conditions does not need any plant protection chemicals to grow thanks to the allelopathy phenomena.