The program COST Action 847 Textile Quality and Biotechnology (2000-2005) has given an excellent chance to review the possibilities of the research, aiming at development of the industrial application of enzymes for bast fibrous plant degumming and primary processing. The recent advancements in enzymatic processing of bast fibrous plants (flax, hemp, jute, ramie and alike plants) and related textiles are given. The performance of enzymes in degumming, modification of bast fibres, roving, yarn, related fabrics as well as enzymatic bonding of lignocellulosic composites is provided.

In this article the review of the methods of lignocellulosic plants

Hemp grown for textile applications must be sown at high densities (60-80 kg/ha) and harvested early to obtain fiber of high quality, and the interest in cultivating industrial hemp used for non-textile applications is growing. Broadening the use of hemp as a raw material for specific industrial products and obtaining maximum yields calls for revision of current sowing densities and harvest dates. Therefore, two experiments (A + B) have been carried out in 2004-2006 at the INF Experimental Farm in Petkowo, Poland, near 1roda Wielkopolska. In experiment A, four sowing densities of hemp grown for biomass, straw, panicles, and seed were tested (30, 40, 50, 60 kg/ha). In experiment B, lower sowing densities were compared for hemp grown for seed, panicles, and straw (5, 10, 15, 20 kg/ha). In both experiments, plants were harvested at three periods: beginning of panicle forming, full bloom, and full seed maturity. Panicles were harvested for essential oils. Results of field and laboratory testing confirmed a hypothesis that maximum yields of biomass, straw, cellulose, and fiber can be obtained at lower sowing densities (30 kg/ha) harvested at full bloom. When growing hemp for seed or panicles, the highest yields were obtained when hemp was sown at 10-20 kg/ha and harvested at full maturity of panicles. Following the results of the study, the norms for sowing hemp for non-textile applications used in agricultural practices require verification to increase yields of raw materials from 1 ha and to improve competitiveness of industrial products.

This article presents an evaluation of bast fiber properties conditioned by the selection of a retting method in terms of meeting requirements for the final application of the fibers as composite reinforcement. Two different methods of fiber extraction were used in the experiment: dew retting and osmotic degumming. The fibrous material was extracted from flax (Modran variety) and hemp (Bialobrzeskie variety). In addition, retted kenaf fibers (from China) were evaluated for the comparison of fiber properties. The properties of the retted and degummed fibers were evaluated according to relevant valid standards regarding color, linear mass, breaking tenacity, aspect ratio, microscopic images and chemical composition, which included the determination of wax and fat, cellulose, hemicellulose, lignin and pectin content and the thermogravimetric analysis coupled with Fourier transform infrared spectroscopy technique. The Attenuated Total Reflection FTIR spectroscopic technique was used for the characterization of the fibers. Also, fogging and volatile organic compound (VOC) emissions were tested in order to evaluate the suitability of the bast fiber for composite formation. The results of the study proved that osmotic degumming applied for bast fiber extraction improves significantly the fiber quality in terms of color, odor, aspect ratio and VOC emission. The aspect ratio of osmotically degummed flax fibers increased by about 46% and hemp fibers by about 22% in comparison with dew-retted fibers. VOC emission of osmotically degummed hemp decreased by about 35%, but in the case of flax fibers, increasing of VOC has been observed. For this reason, osmotically degummed fibers can be recommended as more suitable for composite reinforcement.

This paper presents results of studies on a new physical-mechanical method of degumming of flax fibers in order to determine optimal parameters of the process for obtaining high-quality fiber.The study was carried out on an experimental device where lengthwise and crosswise flow of the liquid through a straw batch was applied and where the following process parameters were controlled: temperature, flow velocity, and time of the process. The pH was maintained at a stable neutral level. The degumming process was evaluated by measurement of the mass loss of the straw during the process, by physical-chemical tests of the process liquid, by metrological and chemical tests of the obtained fiber, and by statistical analysis of the results. The results of the study, compared with the results of traditional warm water retting, indicate that by proper selection of physical factors of the process, it can be intensified resulting in obtaining high-quality fiber, superior to the fiber obtained in the traditional retting technique.Keywords physical-mechanical degumming of fibrous plants, physical factors, flax fiber, diffusion, lengthwise and crosswise liquid flow, process optimization Bast fibers are enjoying a renaissance because of the development of new applications, which are in accordance with the principles of sustainable growth. The European Technology Platform for the Future of Textiles and Clothing regards bast fibers of flax and hemp as raw materials of special importance for Europe, the so-called ''Textile Flagship for Europe'', that is, a factor that has a strong effect on the attractiveness of the market, with potential to cope with societal and economic challenges of European industry. However, in order to meet the objectives of European Flagship, flax fibers must be characterized with a completely new quality and become an alternative for the fiber obtained in the traditional way. The application of flax fiber in the clothing sector, which makes use of its beneficial effect on physiological parameters of human body, 1,2 and in technical applications as reinforcement for structural composites 3-7 requires high quality that will guarantee obtaining final products with new desired competitive properties. Therefore, it is important to carry out studies on development of a method of obtaining high-quality bast fiber, the quality of which depends on the extraction method, the number of elementary fibers in the stem, distribution structure, and binding of fibers within bundles. Extraction of fibers from the plant relies on degumming of fibrous straw in an aqueous environment where biological, chemical, and physical processes occur. [8][9][10][11] Currently, a method commonly used in central Europe of separating ligneous parts of stems from fibers, extracting them and removing the non-cellulosic Downloaded from residues is the so-called dew retting, that is, retting of the fibrous plants on the fields. The retting process involves spreading the straw on the ground, where it is subjected to moisture and later to microbi...

No abstract

The commonly used flax process of decortication allows the mechanical extraction of fibre from plant stems without prior retting. The one-type fibre obtained in this process is characterised by very low quality, as it is poorly divided, has high linear mass and high amounts of impurities. This paper presents a description of a newly developed method of obtaining high quality flax cottonized fibre from low quality decorticated fibre by application of a wet degumming process for fibre. The experiment involved studying the parameters of flax fibres after each step of the technological process i.e. after decortication, wet degumming and final mechanical cottonisation. The study covered tests of the following fiber parameters: linear mass, length, impurities, chemical composition as well as thermogravimetric analysis, Fourier transform infrared spectroscopy analysis and scanning electron microscopy images. The results confirm the efficiency of the method applied for obtaining high quality fibre from decorticated flax fibre.

No abstract