Nettle Fibre Research Articles

A Characterization Study on Toughening Vinyl Ester Composites Using Annealed Vinyl Silane Functionalized Biosilica from Foxtail Millet Husk and Nettle Fibre

A Characterization Study on Toughening Vinyl Ester Composites Using Annealed Vinyl Silane Functionalized Biosilica from Foxtail Millet Husk and Nettle Fibre

Influence of silane functionalized heat treated biosilica on mechanical, wear, and dynamic load–bearing properties of nettle fibre–reinforced vinyl ester composites

Influence of silane functionalized heat treated biosilica on mechanical, wear, and dynamic load–bearing properties of nettle fibre–reinforced vinyl ester composites

Nonwoven acoustic panels from Himalayan nettle (Girardinia diversifolia L.) fibre

Sound absorption panels are being used extensively to mitigate the problem of noise pollution in buildings. Conventional materials used for sound absorption include glass wool, rock wool, mineral wool, asbestos, melamine, and polyurethane foam. However, recent studies show these materials can cause respiratory and skin problems. This has led to the search for natural and ecofriendly alternatives for sound absorbing materials. Lignocellulosic materials are cheap, renewable, biodegradable, and abundantly available and thus provide a viable option for use as sound absorbing materials. In this study, fibres extracted from the bark of Himalayan Nettle (Girardinia diversifolia L.) were used to prepare nonwoven webs using needle punching technique. Punch density was varied to create webs with variable properties. The effect of punch density on acoustic properties was studied. A positive correlation was observed between sample thickness and the Noise Reduction Coefficient. Samples having punch density of 75needles/cm2 showed the highest Noise Reduction Coefficient, attributable to their greater porosity and lower compactness. The study demonstrates that the morphological traits of the Himalayan nettle fibre, that is, a rough surface, flat elliptical cross-section, and a hollow core, make it an excellent sound absorption material. The acoustic properties can be tuned by varying the properties of the nonwoven web.

Stinging nettle fibres extraction and characterization using chemical retting method and influence of tensile properties

The tensile strength properties of stinging nettle fibres treated with sodium hydroxide and sodium chlorite solutions have been studied in this research. The fibre in stinging nettle bark is related to jute, hemp and flax, and it has a lot of potential in the green textile industries. Nettle fibres are naturally derived high-strength nettle yarn for the production of home textiles, handicrafts, and ropes. It is a high fibre-yielding plant that grows naturally in the Himalayan areas, Nagaland. In this study, nettle fibre samples were soaked in 4 % sodium hydroxide (NaOH) and 1% sodium chlorite (NaClO2) solutions at a 100 °C temperature for 90 min. The nettle fibre samples were prepared and tested as detailed in the ASTM D3822 standards. So that, the average tensile strength of treated nettle fibres was increased by 27.17 % compared with untreated fibre. The mild alkali treatment increases tensile strength, cellulose content and decrease elongation break acts to be due to fibre extraction and degradation of non-cellulosic materials such as hemicellulose, lignin, and pectin. Compared to untreated nettle fibre, the average Young's modulus of sodium hydroxide-chlorite treated fibre was increased by 26.79 %. Moisture sorption analysis, Fourier transform infra-red spectroscopy (FTIR), single fibre tensile strength, and physical properties were used to understand the properties of untreated and treated nettle fibres.

Optimizing the alkali treatment of cellulosic Himalayan nettle fibre for reinforcement in polymer composites

The Himalayan nettle plant can yield strong and long bast fibre. In this study, the extracted fibres were treated with 3, 5, 7, and 10 wt% alkali solution and characterised the raw and treated fibres for chemical, morphological, physical, mechanical, and thermal properties. The objective is to find the optimized alkali concentration for fibre surface treatment to use as reinforcement in polymer composites. Results revealed that alkali treatment removed waxes, lignin, and hemicellulose from the surface and enhanced the fibre properties to make it compatible with the polymer matrix. However, alkali concentration affected the fibre properties significantly. 5 % alkali treatment resulted in a maximum crystallinity index (79.1 %), average roughness (26.8 nm), tensile strength (296.97 MPa), activation energy (181.33/180.97 kJ/mol) and initial temperature for stage II degradation (311.2 °C). This investigation concludes that 5 % is the optimized alkali concentration for surface treatment of the nettle fibre.

Effect of Surface Chemical Treatment of Himalayan Nettle and Investigation of Surface, Physical and Mechanical Characteristics in Treated Nettle Fibre

Effect of Surface Chemical Treatment of Himalayan Nettle and Investigation of Surface, Physical and Mechanical Characteristics in Treated Nettle Fibre

Transcriptomic Changes in Internode Explants of Stinging Nettle during Callogenesis.

Callogenesis, the process during which explants derived from differentiated plant tissues are subjected to a trans-differentiation step characterized by the proliferation of a mass of cells, is fundamental to indirect organogenesis and the establishment of cell suspension cultures. Therefore, understanding how callogenesis takes place is helpful to plant tissue culture, as well as to plant biotechnology and bioprocess engineering. The common herbaceous plant stinging nettle (Urtica dioica L.) is a species producing cellulosic fibres (the bast fibres) and a whole array of phytochemicals for pharmacological, nutraceutical and cosmeceutical use. Thus, it is of interest as a potential multi-purpose plant. In this study, callogenesis in internode explants of a nettle fibre clone (clone 13) was studied using RNA-Seq to understand which gene ontologies predominate at different time points. Callogenesis was induced with the plant growth regulators α-napthaleneacetic acid (NAA) and 6-benzyl aminopurine (BAP) after having determined their optimal concentrations. The process was studied over a period of 34 days, a time point at which a well-visible callus mass developed on the explants. The bioinformatic analysis of the transcriptomic dataset revealed specific gene ontologies characterizing each of the four time points investigated (0, 1, 10 and 34 days). The results show that, while the advanced stage of callogenesis is characterized by the iron deficiency response triggered by the high levels of reactive oxygen species accumulated by the proliferating cell mass, the intermediate and early phases are dominated by ontologies related to the immune response and cell wall loosening, respectively.

Applications of Nettle Fibre in Textile: A Brief Review

Applications of Nettle Fibre in Textile: A Brief Review

Physico-chemical properties and toxicological effects on plant and algal models of carbon nanosheets from a nettle fibre clone

Carbon nanosheets are two-dimensional nanostructured materials that have applications as energy storage devices, electrochemical sensors, sample supports, filtration membranes, thanks to their high porosity and surface area. Here, for the first time, carbon nanosheets have been prepared from the stems and leaves of a nettle fibre clone, by using a cheap and straight-forward procedure that can be easily scaled up. The nanomaterial shows interesting physical parameters, namely interconnectivity of pores, graphitization, surface area and pore width. These characteristics are similar to those described for the nanomaterials obtained from other fibre crops. However, the advantage of nettle over other plants is its fast growth and easy propagation of homogeneous material using stem cuttings. This last aspect guarantees homogeneity of the starting raw material, a feature that is sought-after to get a nanomaterial with homogeneous and reproducible properties. To evaluate the potential toxic effects if released in the environment, an assessment of the impact on plant reproduction performance and microalgal growth has been carried out by using tobacco pollen cells and the green microalga Pseudokirchneriella subcapitata. No inhibitory effects on pollen germination are recorded, while algal growth inhibition is observed at higher concentrations of leaf carbon nanosheets with lower graphitization degree.

The utilisation of Himalayan Nettle (Girardinia diversifolia) plant for development of UV protective textiles: A new perspective of a traditionally used plant

The Himalayan nettle ( Girardinia diversifolia) plant has been traditionally used to make various fibre-based products such as sack, rope etc. but with this fast-moving technological era, new developments and researches are required to meet the demand of present so that it could also be made commercially viable. Presently UV radiation causes various skin problems including skin cancer. The present study explores the fabric properties of woven fabrics made of Himalayan nettle ( Girardinia diversifolia ) fibre for new end uses to protect the skin from harmful UV radiation. Nettle Yarn was procured from Kraftloom Overseas Private Limited, Dehradun. Twill and crepe weave fabric were prepared using handloom at Kumaon woollens, Haldwani. Physical properties and Ultraviolet Protection Factor (UPF) of the developed woven fabric were studied at textile testing lab of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand. Based on results it was found that properties of nettle woven fabric like thickness, weight, thread count and cover factor affected the UPF of the nettle fabric. It was also found that ultraviolet protection properties of nettle woven fabric could be enhanced through weave variation. Ultraviolet protection properties of fabric made of nettle fibre were explored and reported for the first time which could be utilised for different UV protection products such as curtains, blinds and jackets. Further natural dyeing of developed fabric was also done in another part of the study to maximise the UV protective properties of the fabric.

Effect of hydrochloric acid treated neetle fibre on oil absorbency

Hydrochloric acid (HCl) treatment on nettle fibres has been performed to improve the oil absorbency. Box-Behnken experimental design is used to study the influence of parameters, such as treatment time, treatment temperature and concentration on oil absorbency. It is observed that the maximum oil absorbency of 15.39 g/g of nettle fibres is achieved at 2 % of HCl concentration, 75°C of treatment temperature and 60 min of treatment time. Scanning electron microscopic study reveals that the raw nettle fibre surface exhibits waxy and protruding parts, and on HCl treatment the surface becomes rougher. The influence of other parameters such as stirring speed, environmental temperature and reusability on oil absorbency is also studied. Oil sorbed nettle fibres are also subjected to soil burial tests and burning tests. In conclusion, the raw nettle fibres only show an oil absorbency of 9.25 (g/g), whereas HCl treated nettle fibres show a maximum oil absorbency of 15.39 g/g.

Determination of Static Fracture Toughness of Nettle Fibre (Urtica Dioica)/Polymethyl-methacrylate Composites Using Different Fracture Methods

In this study, the breaking behaviour of polymethylmethacrylate reinforced with nettle fibre was investigated experimentally. Single edge notched bending (SENB) and compact test(CT) specimens were produced to include notches in various ratios. The Mode I fracture behaviour of samples were determined utilizing static frac-ture toughness experiments such as the Three Point Bend-ing (TPB) and Compact Tensile tests. The fracture tough-ness (KIC) was investigated using the TPB Test (Compli-ance and Initial notch method), and Compact Tension test. The bending module and bending stresses were also determined. It was found that nettle-fibre reinforcement improves the bending strength of the composite by 60% and improves the fracture toughness more than two-fold.

Examining the Mechanical and Thermomechanical Properties of Polymethylmethacrylate Composites Reinforced with Nettle Fibres

The aim of this study was to determine the mechanical and thermomechanical properties of nettle fibre-reinforced polymethylmethacrylate composites. The polymethylmethacrylate composites reinforced with nettle fibres were manufactured using nettle fibres obtained using the natural methods. The nettle fibre contents were 0, 2.5, 5, 7.5, and 10 Vf %. The composites so formed were characterized in terms of their mechanical and thermomechanical properties. The mechanical properties of nettle-reinforced composites were characterized in terms of bending stress, bending modulus, impact strength, and fracture toughness tests, whilst their behaviour was determined by heat deviation temperature and Vicat softening temperature. The micro-mechanisms underlying the toughening and fracture processes were observed in the light of studies of the microstructure of fractures. From the mechanical properties of composites reinforced with 10% nettle fibres, an increase of 75% in bending stress, 40% in impact strength, and 106% in fracture toughness was recorded. The findings show that nettle fibres can be used as an important reinforcement material for environmentally friendly composite applications.

Sucrose synthase gene expression analysis in the fibre nettle (Urtica dioica L.) cultivar “clone 13”

The use and valorisation of fibre crops are sustainable solutions to reduce the world’s dependence on petroleum-derived products and fossil energy. Fibre crops have a relatively short growth cycle and provide high amounts of biomass used in different industrial sectors. Among fibre crops there is stinging nettle (Urtica dioica L.), a perennial herbaceous plant growing in temperate regions. Nettle phloem fibres (a.k.a. bast fibres) have a high cellulose content (ca. 80%) and low amount of lignin (ca. 4%); additionally, they are silky and have a high tensile strength. The gelatinous cell walls of bast fibres are primarily composed of cellulose. The biosynthesis of cellulose is dependent on the provision of uridine diphosphate glucose, which, besides being formed from glucose-1-phosphate through uridine diphosphate glucose pyrophosphorylase, can also be produced via the reaction catalysed by sucrose synthase (SUS). A regulation of SUS gene expression accompanying the developmental stages of the bast fibres is therefore likely to exist along the stem of nettle plants. The objectives of this study were: 1) to identify the SUS genes in nettle and 2) to analyse their differential expression in tissues of stem internodes sampled at different heights (i.e. top, middle and bottom). The gene expression analysis is accompanied by optical and confocal microscopy observations concerning cellulose and lignin distribution. The results here presented identify 6 SUS genes in nettle belonging to the three Angiosperm groups previously reported (groups I–III). Their gene expression analysis shows a differential regulation in the stem tissues sampled at different heights, which reflects the increase in cell wall thickness of bast fibres along the stem of nettle. In particular, 3 expression patterns of genes either more expressed in young/old stem regions or peaking at the middle internode are identified with the heat map hierarchical clustering. This is the first study on the expression of SUS genes in a nettle fibre variety and on the immunohistochemical analysis of U. dioica internodes sampled at different stem heights. This work will serve as a basis for future molecular studies on a neglected, yet potential multi-purpose plant.

Analysis of the morphometric variations in natural fibres by automated laser scanning: Towards an efficient and reliable assessment of the cross-sectional area

The development of natural fibres in engineering applications requires the reliable and accurate assessment of their dimensional characteristics and mechanical properties. Fibre cross-sectional area (CSA) obtained from lateral dimensional measurements should consider the specific cross-sectional shape of natural fibres and its wide lengthwise morphometric variations. In this study, a detailed dimensional analysis was conducted on a selected panel of natural fibres with contrasted morphometric characteristics belonging to various phylogenetic plant species with dissimilar functions in planta. An automated laser scanning technique was used, and geometrical models and filtering data method were developed for calculation of reliable CSAs adapted to each plant fibre species. Results show that CSAs of palm and sisal fibre bundles can be satisfactorily assessed by a circular model with minimal data processing, whereas hemp, flax and nettle fibre bundles require specific data filtering due to partial splicing, and can be better assessed by an elliptic model.

Effect of ecological surface treatment method on friction strength properties of nettle (urtica dioica) fibre yarns

Over the last few decades, more attention is given to lignocellulose based fibres as reinforcement material in the polymer composites owing to the environmental pollution caused by the extensive usage of synthetic and inorganic fibres. Developing new natural fibre reinforced composites is the focus of many researches nowadays. They are made from renewable resources and they have less environmental effect in comparison to inorganic fibre reinforced composites. The interest of consumers in eco-friendly natural fibres and textiles has increased in recent years. Unlike inorganic fibres, natural fibres present light weight, high strength/density ratio and are readily available, environmentally friendly and biodegradable. Many different types of natural fibres are exploited for the production of biodegradable polymer composites. The nettle (Urtica dioica L.) is a well-known plant growing on rural sites of Europe, Asia, and North America. Nettle plant contains fibre similar to hemp and flax. However, similar to other natural fibres, nettle fibres are poorly compatible with the thermoplastic matrix of composites, due to their hydrophilic character which reduces mechanical properties of nettle fibre reinforced thermoplastics. In order to improve the fibrematrix adhesion of the natural fibre reinforced composites, surface treatment processes are applied to the lignocellulose fibres. In this study nettle (urtica dioica) fibre yarns were treated with NaOH by using conventional, ultrasonic and microwave energy methods. After treatment processes tensile strength, elongation, friction strength and SEM observations of the nettle fibre yarns were investigated. All treatment processes were improved the tensile strength, elongation and friction strength properties of the nettle fibre yarns. Also higher tensile strength, elongation and friction strength properties were obtained from treated nettle fibre yarns which treated by using microwave energy method.

Study of the morphological characteristics and physical properties of Himalayan giant nettle (Girardinia diversifolia L.) fibre in comparison with European nettle (Urtica dioica L.) fibre

Development of sustainable fibres for high performance applications is challenging because of the high mechanical strength properties demanded by such fibres and the general lack of such properties in natural fibres. The mechanical properties of Himalayan giant nettle (Girardinia diversifolia L.) fibre are measured and compared to those for European nettle (Urtica dioica L.) fibre. The mean length of G. diversifolia fibre is substantially higher than U. dioica fibre, and the longest fibre length reported for any bast fibre. G. diversifolia and U. dioica fibres have similar cross-sectional area, but G. diversifolia fibre is a wider, flatter, oval shape with a significantly wider lumen. G. diversifolia fibres display a generally linear stress/strain curve. Ultimate stress value for G. diversifolia fibre is over twice that of U. dioica fibre, and the highest of any bast fibre reported. G. diversifolia fibre also displays greatest strain at failure of any bast fibre. Young's modulus for G. diversifolia and U. dioica fibre are similar. Himalayan giant nettle fibres display tensile properties that offer potential in high performance applications.

Nettle Fibre: Its Prospects, Uses and Problems in Historical Perspective

The stinging nettle plant (Urtica dioica L.) is perhaps best known as an abundant and perennial weed, but throughout history it has been used as a source of fibre in many parts of the world. This paper explores the potential uses of nettle fibre within a historical context and describes efforts made by the German and UK governments to cultivate and process the fibre for special war purposes during World War I and II. There has recently been a revival of interest in this fascinating fibre, and recent attempts to commercialise production are discussed.

Comparison of Enzymatically Separated Hemp and Nettle Fibre to Chemically Separated and Steam Exploded Hemp Fibre

Abstract Hemp (Cannabis sativaL.) and nettle (Urtica dioicaL.) are both attractive candidates for high fibre yields with little or no biocide requirement. Separation of fibre fine enough for quality yarns to make hemp fabric or blends has been achieved in Western Europe in the last decades only on a laboratory scale because process costs are high. In Hungary, Romania, the Ukraine and Poland a hemp processing industry has continued retting mainly by water processes. Search for a commercially and environmentally viable method led us also to explore enzymatic separation, which was initiated by various researchers in the late 1960s and 1970s. This involves the use of various enzymes that dissolve pectin and hemicellulose between the cell walls thus freeing the fibre bundles and fibres. We tested various commercial and non commercial products (Röhm Enzyme GmbH and Novozymes AS/Bayer AG) and methods and then measured our results against samples of fibre separated by other methods using a Stelometer to determine tensile strength of fibre bundle collectives and OFDA (Optical Fiber Diameter Analyzer) to analyze fibre bundle width. Our results showed enzymatic separation capable of producing comparably fine and strong fibre suitable for quality textiles. These studies open the way for sustainable and local production of high value fibre with low impact on the environment.

Recent Investigation of New Plant Fibres

AN investigation has been carried out by the Royal Botanic Gardens, Kew, in collaboration with the National Physical and Chemical Laboratories and the Imperial Institute, of the mechanical properties of the fibre from nettle stems (Urtica dioica) and other plants native to Great Britain, and of methods of extraction. The nettle fibre has been found to be suitable for the manufacture of high–grade paper, and possibly of textiles, while the leaves are commercially valuable for the extraction of chlorophyll. Arrangements were made for the extensive collection of this abundant raw material during 1941.