Bast fibres

Cotton and Other Cellulosic Fibres. The dominant natural cellulosic fibre is cotton, the other natural cellulosic fibres, or bast fibres, include flax, linen, jute and ramie. The so-called regenerated fibres, which include viscose, modal fibres and lyoceU (Tencel), are made by various chemical treatments of cellulosic substrates. The dyeing and printing of cellulosic fibres and materials is carried out using, in decreasing order of scale and importance, reactive, direct and vat dyes. ... 

Hemp. This is obtained from the bast fibres of Cannabis sativa. Under the microscope these fibres, which are usually joined in bundles, have a bruised cylindrical appearance and a diameter greater than that of flax fibres (Fig. 74, Plate VII). They are irregular as regards thickness and there are many longitudinal striations, which are sometimes so marked as to render difficult the observation of the internal channel, the latter being about one-third as wide as the fibres. Transverse striae are also observed often these do not traverse the whole width of the fibre and they arc not so regular in appearance as with flax. At the ends the fibres are usually rounded and sometimes slit down for a short distance. 

Ramie. This includes the bast fibres obtained from certain Urti cacecs, cultivated mostly in the Far East owing to their whiteness, lustre and strength they are the best textile fibres furnished by the vegetable kingdom. 

During spinning and weaving of textiles (cotton, wool, bast fibres, etc.) breakdown of the textile yarn is frequently observed17. This has an influence not only on the quality of the textile product but also on the production cost, since the machines have to be stopped every time that the yarn is broken. To avoid or reduce the incidence of these harmful consequences, the textile yarn is strengthened with a layer of cellulose. Less than 5% of the breakages that occur with an untreated yarn still occur when the yarn is treated with cellulose. 

Ramie (Boehmeria nivea) is one of the oldest fibre crops, principally used for fabric production, even mummy cloths, because of the non-fibrous material with antifungal and antibacterial properties. It is a bast fibre, and the part used is the bark (phloem) of the vegetative stalks. Unlike other bast crops, ramie requires chemical processing to de-gum the fibre (up to 25% mass loss). 

Certain plant-fibres—for example jute, the bast-fibre of Cor-... 

Pectinase Aspergillus niger Scouring of vegetable or bast fibres like jute, hemp, flax, remie etc. 

Bast fibres like linen and remie are multiple cellular systems, in contrast to cotton, which consists only of a single cell. Multicellular fibres contain natural gums and resins that keep the cell together. Crystallinity indices of cotton, linen, remie and viscose fibres do not change after the enzymatic hydrolysis, nor does accessibility to moisture [39]. Consequently, neither the ratio of crystalline to amorphous material nor the DP of the residue changes significantly [40]. 

Further tests for damage on regenerated cellulosic fibres, such as iodine absorption, core/sheath differentiation, peeling methods, detection of traces of sulphur or copper as well as some hints for investigations on bast fibres are given in the literature. ... 

Turner, A. J., VIII. The Long Vegetable Fibres (1) Bast Fibres Jute, Hemp,... 

Vegetable fibre, those derived from the seed, stem, wood, bark (bast fibres), leaf, or fruit of plants. They are composed chiefly of cellulose (up to 90%), the remainder being primarily lignin, hemicellulose, and pectins. 

Jute, bast fibre from the inner bark of the round or long pod Jute plant Tiliaceae) and from other closely related plants such as kenaf... 

Cellulose fibres originate from the seed of the plant (cotton), its stem (bast fibres) or its leaves (sisal, alfa), having, as a consequence, different percentages of cellulose, lignin and hemicellulose. Basically, any plant may be used as a source of cellulose fibres, and it is a matter of historical development, availability and abundance that cotton, hemp and linen (flax) are today the most used cellulosic fibres. 

Bast fibres are obtained from the stems of the corresponding plants hemp is a variety of Cannabis saliva L (diflfering from marijuana by having a considerably low content of A-9-tetrahydrocannabinol, the narcotic substance), and flax is obtained from the plant Linium usitatissimum. The fibres contain 70-75% cellulose, with about 4% lignin, 17% hemicellulose and 6% pectin in hemp and... 

Compared to cotton the cultivation of bast fibres is much more sustainable. Although not botanically related, both plants grow well in a moderately cool, temperate climate and can be grown in almost any country in the world. The plants are resistant to pests and do not require pesticides. 

The bleaching process also has peculiarities depending on the type of fibre which is treated. The most common and environmentally friendly bleaching agent used for fibres is hydrogen peroxide. Cotton is also partly bleached while scouring, under the action of sodium chlorite. Some yellow wools or bast fibres may require a harsher bleaching, for which reason sodium dithionite or sodium formaldehyde sulphoxylate (for wool) and sodium chlorite (for bast fibres) are also used. 

Cotton and bast fibres fabric dimensions are set by mercerizing and sanforizing. 

Natural fibres can be subdivided into plant, animal, and mineral fibres. All plant fibres (cotton, jute, flax, hemp, etc.) are made of cellulose animal fibres are made of protein (wool, silk, hair). Based upon their origin, plant fibres are subdivided into bast and hard fibres. Bast fibres are derived fix)m the stems or stalks of plants hemp, jute, ramie, and flax, for example, belong to this category. Hard fibres, on the other hand, are derived from leaves, leaf sheaths, or fruit sisal and coconut belong to this category ... 

S.H. Aziz, M.P. Ansell, The effect of alkalization and fibre alignment on the mechanieal and thermal properties of kenaf and hemp bast fibre composites part 1-polyester resin matrix. Compos. Sci. Technol. 64(9), 1219-1230 (2004)... 

From the bark of the hemp stems, bast is obtained. The bast fibres are separated mechanically from the woody parts modern separation methods employ enzymes or steam pressure, surfactant or ultrasound processes. The best hemp fibres are obtained from the male plants being very durable. They are used for the manufacture of ropes, cords, nets, strings, yarn, carpets, textiles and sailcloth. The wood is used for the manufacture of insulating material, but it is also well suited for the production of paper, cardboard and cartons, since its lignin content amounts to only 10% (compared to 20-25% from trees). 

Inventory of major potential bast fibre sonrces for the year 2000/2001 [2]... 

Artificial retting [25] involves warm-water or canal retting and produces homogeneous and clean fibres of high quality in 3-5 days. Plant bundles are soaked in warm water tanks. After sufficient retting, the bast fibres are separated from the woody parts. The sheaves or hurds are loosened and extracted from the raw fibres in a breaking or scotching process. 

---