Evaluation of flax accessions for high value textile end uses

Due to recent changes in EC subsidies for flax cultivation it has been difficult to grow short fibre flax profitably in the UK. The Texflax project aimed to demonstrate that high quality flax fibre can be produced and processed on short fibre cotton spinning systems. Initially 92 flax accessions were cultivated on test sites in the UK over three growing seasons to explore the range of fibre diameter found in fibre flax. The efficacy of applying a translocating herbicide at different stages of plant maturity for optimum fine fibre production was explored. A range of factors indicated that application at the midpoint of flowering stage is favourable for the desiccation of flax and onset of retting. Fibre was caustic extracted using a laboratory method developed at De Montfort University, and fibre evaluated in terms of diameter, length, consistency and cleanliness. At the end of the project five accessions from the original 92 were chosen as producing optimal quality fibre suitable for high value textile end uses. Improved agronomy and subsequent processing enabled yarns with a 50:50 cotton:flax blend to be spun at 26 N m yarn count, the normal blend ratio for this count being 70:30. The yarn properties show an improvement when compared to standard products and finer quality fabrics have been prepared using the yarns.     

汉麻温水沤法脱胶动态过程的观测

本文对汉麻温水沤法脱胶过程中的水体pH值和果胶酶活性,以及汉麻韧皮纤维中各组成成分(果胶、半纤维素、纤维素、木质素)的动态变化进行了测定,探明了汉麻温水沤法脱胶过程中水体pH值、果胶酶活性和韧皮纤维脱胶状态的动态变化规律。     

Comparison of composites made from fungal defibrated hemp with composites of traditional hemp yarn

Aligned epoxy-matrix composites were made from hemp fibres defibrated with the fungi Phlebia radiata Cel 26 and Ceriporiopsis subvermispora previously used for biopulping of wood. The fibres produced by cultivation of P. radiata Cel 26 were more cellulose rich (78%, w/w) than water-retted hemp due to more degradation of pectin and lignin. The defibrated hemp fibres had higher fibre stiffness (88–94 GPa) than the hemp yarn (60 GPa), which the fibre twisting in hemp yarn might explain. Even though mild processing was applied, the obtained fibre strength (643 MPa) was similar to the strength of traditionally produced hemp yarn (677 MPa). The fibre strength and stiffness properties are derived from composite data using the rule of mixtures model. The fibre tensile strength increased linearly with cellulose content to 850 MPa for pure cellulose. The fibre stiffness increased also versus the cellulose content and cellulose crystallinity and reached a value of 125 GPa for pure crystalline cellulose.     

Influence of agronomic factors on yield and quality of hemp (Cannabis sativa L.) fibre and implication for an innovative production system

Research and development of an innovative production system for hemp (Cannabis sativa L.) fibre for textile use requires the integration of multidisciplinary knowledge from cultivation technique to realization of end products. Research was carried out to study the effect of the agronomic factors cultivation year (2003–2004), genotype (Futura 75 and Tiborszallasi), plant population (120, 240 and 360 plants m⁻²) and harvesting time (beginning and full flowering) on fibre yield and quality in the whole hemp stem, and in the basal and apical stem portions separately. The study of separate stem portions was done to determine the effect on fibre quality of an innovative harvesting and processing system in which hemp stems are cut in two portions of approximately 1 m at harvest to enable processing on modern flax scutching lines.     

亚麻鲜茎雨露沤制技术的初步研究

雨露麻以其生产方式简单,成本低,不污染环境而被广泛应用,但传统的雨露麻采用人工收获,在多雨季节里原茎保存困难,常发生霉烂。给工农业均造成损失。鲜茎雨露沤麻技术的提出解决了这一问题,同时使沤麻时间提前10天左右,亚麻收获就开始沤制,充分利用了亚麻收获季节的高温和降雨。沤麻速度快,沤麻时间缩短,降低了生产成本,麻率相对提高0.5-1个百分点,纤维强度增加1.2—2.7kg。此项技术对我国雨露麻的发展具有一定的指导意义。     

Analysis of green hemp fibre reinforced composites using bag retting and white rot fungal treatments

The main objective of this project was to investigate two low cost treatment methods, namely bag retting and treatment with white rot fungi, which could be applied to hemp fibre with low environmental impact to improve its interfacial bonding with polypropylene. Wet chemical analysis, FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), zeta potential and single fibre tensile testing were used to characterise the effect of treatment on hemp fibres. It was found that all the treatments increased the tensile strength of composites. White rot fungi Schizophyllum commune (S.com) treated fibre composites had the highest tensile strength of 45 MPa, an increase of 28% compared to composites using untreated fibre.     

亚麻种植、雨露沤制、初加工一体化生产配套技术

本文在研究亚麻重迎茬发病规律及防治方法、除草技术、雨露沤制技术研完的基础上，提出了亚麻种植、雨露沤制、初加工一体化生产配套技术。200l-2002年对谈技术进行了示范推广，推广面积5373公顷，取得了良好的经济效益。     

Physical and chemical properties of flax fibres from stand-retted crops desiccated at different stages of maturity

Dessication of flax at the mid-point of flowering, followed by stand-retting and high-speed decortication, yielded finer, stronger fibres with lower acid-insoluble lignin content and lighter colour than desiccation at later timings of two weeks after mid-flower and six weeks after mid-flower. Although fibres from all desiccation timings could be carded and blended with wool for spinning on woollen or worsted spinning systems, only the fine fibre from the earliest desiccated flax was suitable for carding, drawing, blending with cotton and spinning on cotton-processing systems.It was concluded that the lower lignin content at mid-flower allowed more complete retting of fibre bundles to give a higher yield of fine elementary fibres. This cotton-compatible fibre was produced at a competitive cost compared with cotton. It is suggested that further optimisation of desiccation timing may permit increased yields of cotton-compatible fibre.     

南方亚麻微生物脱胶技术及其理论研究Ⅲ．麻茎特性对亚麻脱胶效果的影响

在天然水浸脱胶条件下，对影响亚麻脱胶效果的麻茎特性及其作用机制进行了初步探讨。结果表明，麻茎上带有脱胶能力较强的微生物，能加速亚麻脱胶进程；麻茎的部位、粗细、麻龄等不同，其纤维及胶质的组成和分布也有差异，对亚麻的脱胶速度均产生不同程度的影响；机械破损能够破坏麻茎的表皮结构，增大脱胶酶的侵袭面积，能加快亚麻的脱胶速度。     

亚麻／大豆蛋白纤维转杯纺纱产品的开发与研制

介绍了亚麻和大豆蛋白纤维的性能，结合生产实践，通过工艺试验，探讨了亚麻／大豆蛋白纤维转杯纱的一些工艺参数，为提高成纱质量提供参考依据。     

南方亚麻微生物脱胶技术及其理论研究——Ⅰ．亚麻天然水沤法脱胶动态过程的观测

本文对亚麻天然水沤麻过程中的脱胶微生物数量，果胶酶、木聚糖酶、纤维素酶的活性，以及水体的pH、还原糖、含氮量、COD的动态变化进行了测定，探明了亚麻天然水沤麻过程中微生物类群与数量、脱胶酶活性、水体特征的动态变化规律。     

亚麻快速生物脱胶技术研究：Ⅰ．亚麻快速脱胶菌株的选育

通过广泛采集菌样、初筛、复筛和诱变育种等手段，获得了1株(编号为Ym68′)亚麻快速脱胶菌株；并对该菌株进行了规模为100kg的亚麻快速脱胶试验。结果表明：Ym68′在实验室条件下16h内可完成亚麻脱胶；与传统脱胶工艺相比，其脱胶周期缩短79％以上、综合出麻率提高7．3个百分点、纤维强力和长度分别提高50％和3．3％、COD降低17％左右，具有脱胶周期短、纤维产量高、品质好和环境污染轻等特点。     

Lignin content and briquette quality of different fibre hemp plant types and energy sunflower

Fibre hemp and energy sunflower are potential energy crops for production of solid biomass as renewable energy. The current study estimated (i) the lignin content of fibre hemp and energy sunflower plants grown on different nitrogen treatments and (ii) the quality of the briquettes made from different plant types of fibre hemp (i.e. monoecious and dioecious), energy sunflower and the combination of fibre hemp and energy sunflower. The monoecious and dioecious fibre hemp cultivars (Chameleon, Finola and Santhica-27, USO-31, respectively) and the energy sunflower cultivar Wielkopolski were grown in the experimental field in 2008-2010 on Stagnic Luvisol soil. The plants were grown on N treatments of N0, mineral nitrogen (100 kg N ha⁻¹), cattle slurry (100 kg N ha⁻¹), sewage sludge (100 kg N ha⁻¹) and vetch (100 kg N ha⁻¹). Calorific values (16.6-17.4 MJ kg⁻¹) of briquettes pressed from different materials did not differ significantly and had relatively low sulphur (<0.05%) and chlorine content (0.03-0.37%). Briquettes with higher compactness were made from the sunflower and the dioecious hemp. Dioecious hemp had significantly higher lignin content. The dioecious hemp needs lower GDD values for maturating, its stems lignin content was higher than of monoecious hemp by harvest time and therefore this plant type is more suitable for briquetting in Nordic climatic conditions. Comparison of the different N treatments indicated that application of sewage sludge decreased the emergence and density of the fibre hemp plants and the lignin content per kg of DM.     

Pilot plant for processing flax fiber

A flax fiber pilot plant is needed to process small samples of flax straw into fibers to facilitate research on retting and fiber properties. Our objective was to develop and test a modular design for a flax processing pilot plant based on a commercial line that was capable of cleaning fiber and seed flax straw from unretted, dew-retted, and enzyme-retted samples. The USDA Flax Fiber Pilot Plant (Flax-PP), which is the only research facility of this type in the United States, was designed according to the commercial ‘Unified Line’ (Czech Flax Machinery), but smaller and constructed in four individual modules. The modules and their order for processing were as follows: 9-roller calender, top shaker, scutching wheel, top shaker, 5-roller calender, and top shaker. Illustrations and diagrams of the operating modules are presented. Unretted ‘Neche’ linseed flax, dew-retted ‘Natasja’, and enzyme-retted ‘Jordan’ fiber flax were processed, and the cumulative weight loss of material at successive processing steps was determined to assess the effectiveness of cleaning. Fiber strength, fineness, and elongation were determined for the retted samples after cleaning through all the steps in the Flax-PP. A yield of fine fiber from the retted stems processed through the Flax-PP was acquired from further cleaning and refining by passage through a Shirley Analyzer. The various samples behaved differently at different stages of processing and the resulting fibers had different properties. The dew-retted Natasja fibers were stronger and finer than the enzyme-retted Jordan flax after pilot plant processing, but the Jordan fibers appeared cleaner and better retted. The Flax-PP effectively processed samples of diverse characteristics and will facilitate integrated research on retting methods for fibers with tailored properties.     

Bio-accumulation and distribution of heavy metals in fibre crops (flax,cotton and hemp)

Flax, hemp and cotton, grown in industrially polluted region, were included in the present research. The experimental plots were situated at different distances (0.5 and 15 km) from the source of pollution—the Non-Ferrous-Metal Works (MFMW) near Plovdiv. We investigated the level of pollution and the way heavy metals enter the fibre crops, by taking soil and plant samples. The contents of heavy metals in plant materials (roots, stems, leaves, seeds, flowers) were determined after the method of the dry mineralization. The quantitative measurements were carried out with inductively-coupled plasma (ICP).A clearly distinguished species peculiarity exists in the accumulation of heavy metals in the vegetative and reproductive organs of flax, hemp and cotton. Flax is the crop that most strongly absorbs and accumulates heavy metals from the soil, followed by hemp and cotton. The distribution of the heavy metals along the plant axis of the studied crops seems to be selective, therefore their contents in flax and hemp are decreasing in the following order: roots>stems>leaves>seeds, while in cotton: leaves>seeds>roots>stems. A strongly exhibited tendency towards decrease of the contents of heavy metals in the fibre crops is observed as the distance from the NFMW increases.Flax and hemp are cultures, suitable for growing in industrially polluted regions—they remove considerable quantities of heavy metals from the soil with their root system and can be used as potential crops for cleaning the soil from heavy metals.     

Effect of bio-friendly conditioning agents on jute fibre spinning

From early times, jute fibre has been generally conditioned for easy spinning by adding oil and water in the form of an emulsion. The commonly used oil consists of C₁₂–C₃₁ fractions of mineral oil that sometimes impart different intensities of oily (kerosene) or fishy smell to the end product. In the present work, efforts have been made to find a suitable sustainable substitute of mineral oil based conditioning agent for spinning of jute yarn and for this, three types of vegetable oil (rice bran oil, palmolein oil and castor oil), a silicone emulsion, a mixed enzyme system and glycerine have been used separately or in combinations as conditioning agents for jute fibre before its mechanical processing for making yarn in jute spinning machines. Considering comparable mechanical process performance for spinning of jute fibre (viz., fibre loss as droppings during processing, moisture retention prior to spinning stage and spinning end breakage rate), tensile properties of yarn, and lower yarn hairiness, it may be suggested to use 2.5% castor oil alone, or 2% castor oil in combination with 0.1–0.5% glycerine in the form of oil-in-water emulsion as the most suitable alternatives to conventional mineral oil-based jute conditioning agent to spin ordinary jute yarn.     

南方亚麻微生物脱胶技术研究 2.麻茎特性对亚麻脱胶的影响

在天然水体条件下 ,对亚麻不同株龄、粗细、部位、含水量及霉变程度的麻茎进行了脱胶试验 ,结果表明 :麻茎越老熟、越粗者 ,脱胶越难 ,反之 ,脱胶速度越快 ;鲜茎经刹青处理后 ,脱胶速度较快 ,其完成脱胶的时间分别较鲜茎、干茎缩短 6 h和 1 2 h;麻茎发生霉变后 ,脱胶速度明显变慢 ,整株霉变的脱胶时间长达 82 h,较未霉变的延长 2 8h,且纤维质量变劣。     

Extraction of lipids from flax processing waste using hot ethanol

The cuticle of flax stems contains lipids that provide a protective barrier to pathogens and control moisture loss. These lipids include wax esters and long chain fatty alcohols or policosanols. Cuticle fragments generated during several different fiber processing operations retain these lipid compounds that represent a potential co-product. Samples of flax shives (i.e., lignified core tissues), processing dust, and cuticular fractions recovered from enzyme retting waste water were extracted on a laboratory scale with hot ethanol to remove the lipid compounds. Ethanol extracts were analyzed by gas chromatography to determine the amount and type of lipids recovered. The results demonstrated that hot ethanol effectively extracted the lipid compounds from cuticle fragments in all these samples. When the extract was cooled, the longer chain wax esters (i.e., chain length of 44 carbon atoms or larger) precipitated and could be separated from the shorter chain lipid components (i.e., fatty alcohols and aldehydes less than 44 carbons). Similar results were obtained using absolute ethanol or 95% ethanol (aqueous). This technique provides a very economical method to recover lipid fractions as potential value-added co-product from flax processing waste.     

The effects of yarn number and liquid ammonia treatment on the physical properties of hemp woven fabrics

The effects of yarn number and liquid ammonia (L/A) treatment on the physical properties of woven fabrics prepared with pure hemp spun yarns were investigated. As a result of L/A treatment, the crystal structure of hemp fiber was changed from cellulose I to the mixtures of cellulose III and cellulose I and its crystallinity was slightly decreased by 13 %. The crease recovery of hemp fabric treated with L/A was improved upto 78 %. The washing shrinkage of hemp fabric treated with L/A decreased significantly to less than 0.4 %, while the washing shrinkage of hemp fabric prepared with the fined yarn was superior to that of hemp fabric prepared with the coarsed yarn. Especially, the wicking speed and drying ratio of hemp fabrics treated with L/A were higher than those of the untreated as yarn number increased. However, it was found that there is no significant effect on the UV protection of the L/A treated hemp fabrics.     

Effect of sowing date and plant density on the cell morphology of hemp (Cannabis sativa L.)

A range of papers report a major effect of agronomic procedures on the growth, biomass, fibre yield and fibre quality of hemp. The aim of this paper is to examine the influence of sowing date, seed density and year on histological characteristics of hemp (size of the different layers in the cross section of the stem, area of primary fibre cells and their cell lumen, size of fibre cell wall). It was realised that a higher seed density resulted in a reduction of almost all layers in the cross section of the stem. A similar effect was caused by the drought 1998, whereas the sowing date had almost no influence on the size of the various layers. The area of primary fibre cells was smaller in 1998. Sowing date and seed density did not affect the fibre cell area and area of cell lumen in the way mentioned above during the 2 years of the trial. During this period the size of cell wall was mainly determined by climatic conditions. Higher elongation and higher tensile strength of hemp planted at higher seed density is probably caused by differences in primary cell morphology.