Natural fibres (NFs), hairlike structures, originated from animals (hairs, wools, silks, etc.), plants (bast, leaf and husk fibres, seed hairs, etc.), or geological processes. These can be used as a component of composites, nonwoven fabrics e.g. felt or paper or, altered into yarns, into woven cloth. The NFs have many advantages in different aspects e.g. environmental pollution, health, etc. over artificial fibres. These NFs are renewable, carbon-neutral, biodegradable and also produce waste that is either organic or can be used to generate electricity or make ecological housing material towards the achievement of UN Sustainable Development Goals (# 12 Responsible Production and Consumption). The demand for commercial use of the NFs and fibre-based composites in various industrial sectors e.g., textile, pulp, automotive interior linings (roof, rear wall, side panel lining), furniture, construction, packaging, and shipping pallets, etc. for their better physicochemical and physicomechanical properties [1]. The quality and use of a natural fibre may vary due to inherent variabilities in its natural components such as fibrous nature, fibre morphology, cellulosic, and non-cellulosic content, and key properties such as fibrous structure, spinnability, strength, fineness, dyeability, and the ability to react with acid or alkali [2].
Hemp (Cannabis sativa L.; Cannabaceae) and flax (Linum usitatissimum L.; Linaceae), two of the oldest cultivated fibre plants, fibres are singly or combined used for clothing and household textiles [3]. Hemp has also various traditional uses in the Indian subcontinent such as fibre and roasted seeds eaten as a food. In Bangladesh, the hemp plant was cultivated for manufacturing three narcotic products called Ganja, Charas and Bhang [4]; there are disagreements over the use of hemp fibres. According to O’Malley, hemp was cultivated on 8,000 acres (approx. 3,250 ha) of land of Sitakund on the banks of the Sangu River and in the southeast of Satkania on the banks of Tankabati for producing hemp fibre [5]. Milburn initially mentioned that hemp has been cultivated in Bengal from time immemorial for intoxication [6]; but is never used by natives for cordage or cloth, as in Europe. However, he also pointed out later that when hemp is intended for cordage, the natives sow it very thin and afterwards transplant the young plants, placing them at a considerable distance from each other, often 2.75 or 3.0 m. The history of commercial hemp cultivation in Bangladesh has been discussed [7]. Hemp fibres are used in rope, textiles, garden mulch, the assortment of building materials and animal beddings, to fabricate different composites, and processed to form yarn or bundles [1]. The history of linen production and use dates back to 12000 BC (Vedic age) to 1500 CE (Medieval period) in the Indian subcontinent, including India, Pakistan and Bangladesh < https://agropedia.iitk.ac.in/content/history-linen-indian-subcontinent>. Edible flaxseed dominated India’s production rather than fibre flax; because other fibre species, such as hemp, were already in wide use [8]. Flax fibres are used in furniture materials, textiles bed sheets, linen, interior decoration accessories, composite reinforcement, etc. [1, 9].
The nutritional aspects of both hemp and flax seeds and different plant parts were reported in different publications [10–15]. Although the physical properties of hemp and flax fibres are known to us [1], hitherto, no information on the proximate composition of fibres Bangladeshi genotypes of these two important fibre-yielding crops is available. The constituent fibre properties influence application of textiles in many fields e.g., composites, automotive, marines, aerospace, electronics, civil construction, nanotechnology, biomedical, as well as the apparel or clothing industry [2]. We have, therefore, reported the proximate composition and thermogravimetric analysis data of 3 hemp and 6 flax genotypes here.