Cotton fabric was coated with a ternary blend of sodium alginate, sugar, and natural rubber latex employing a knife-over-roll coating technique, followed by vulcanization with a sulphur curing system. The resulting coated fabric, when subjected to water treatment via a pad-dry technique, exhibited an appreciable moisture vapour transmission rate (MVTR) and water proofness, attributed to the formation of micropores within the waterproof coating. Optimal results in terms of 1850 g/m2/24 h of MVTR value and waterproofness, demonstrated by resisting the 90 cm water head test on a hydrostatic head tester and a 48 h cone test, were achieved for coating one side of fabric with a formulation comprising 100 PHR of natural rubber latex, 25 PHR-50 PHR of sodium alginate, and 20 PHR-30 PHR of sugar. Incorporation of only sodium alginate into the natural rubber latex moderately increased the MVTR of the coated sample, reaching up to 1176 g/m2/24 h. In contrast, incorporation of only sugar led to coagulation of the natural rubber latex, rendering it unsuitable for coating applications. However, sugar appeared to act as a dispersing agent, aiding the dispersion of sodium alginate evenly within the aqueous natural rubber latex system. Scanning electron microscopy (SEM) and pore size analysis revealed development of micropores ranging from 1.21 mu m to 1.72 mu m within the coating matrix, owing to leaching of water-soluble sugar. This porous structure allowed moisture vapour to pass through the coated cotton fabric while preventing liquid water to penetrate through it. Atomic force microscopy (AFM) of the coated fabric further supported the observation of erosion or loss of coating matrix due to sugar leaching thus supporting further the mechanism of formation of a microporous waterproof coated structure.

Plant fibres are promising reinforcements for bio-composites in additive manufacturing, but their use as long fibres remains limited, often reduced to short particles that underuse their potential. This study presents a customised yarn design that not only maintains fibre alignment parallel to the yarn axis but also ensures core resin impregnation. Commingling and wrap spinning techniques were used to produce four flax/PLA yarns with varying compositions. The manufacturing process and printing of unidirectional composite specimens are detailed. Tomography revealed up to 3.3 times lower intra-yarn porosity thanks to commingling, and tensile tests showed a modulus increase by a factor of 2.1 compared to similar previous works using conventional twisted yarns. These results pave the way for broader use of long flax fibres in 3D printing.

An alternative route to the traditional scutching and hackling processes was tested to produce hemp fibres suitable for load bearing composites. A classical approach consisting of a succession of breaking roller and breaking card, was used. The morphology and mechanical properties of the fibres were characterised. The tensile properties after breaking card, extra finishing card and combing were comparable to those obtained from the traditional approach. This similarity may be attributed to the drawing process which serves to homogenise the fibre properties by mitigating the number and severity of structural defects. This, combined with the possibility of using a more flexible approach than scutching and hackling may present an opportunity to increase the European production of technical fibres for load bearing applications. This would satisfy industries seeking large quantities of high potential fibres, a demand that cannot be adequately met by the textile flax resources which are increasingly diverted to the garment industry.

Optimisation of textile preforms play a crucial role in the development of high-performance biobased composites materials. In this context, the main ambition of this work is to quantify and assess the mechanical properties and behaviour of biocomposite materials made from unidirectional commingled preforms based on flax and poly(propylene) fibres. To the best of our knowledge, there is no literature examining the effect of the commingling process on the ultrastructure and the mechanical properties of flax fibres. At the scale of the elementary fibre, fibre mechanical properties are observed to be stable after commingling. However, repeated drawing in the commingling process leads to increased cellulose crystallinity and a larger fraction of elementary fibres exhibiting quasi-linear tensile behaviour. The composite materials produced with these commingled flax/poly-(propylene) preforms contain few cortical residues and show a remarkable degree of fibre individualisation. Moreover, they exhibit high Young's modulus and a stress at break of 24 GPa and 194 MPa, respectively, for a fibre volume fraction of 36 %. A substantial drop in properties is however noted at high fibre fractions due increased heterogeneity of the materials. Remarkably, the biocomposites achieved unprecedented transverse modulus and stress at break of 2.3 GPa and 16.5 MPa, respectively. Our results validate the potential and interest in commingling processes for designing a new family of plant fibre composite materials.

Hemp is a sustainable source of natural fibres that can contribute to meet the increasing demand for technical applications in the textile and the composite sectors. Continuous reinforcements can be produced using the existing flax machinery, initially developed for textile purposes. To achieve competitive and economically viable fibre yields and a fibre quality suitable for secondary processing and composite application, hemp needs to be adequately selected and prepared and the flax machinery and settings have to be adapted to the hemp specificities. In this context, this paper studies the influence of agronomic features and processing stages and settings on the effective tensile properties of fibres extracted from two hemp varieties determined using impregnated fibre bundle tests. Results show that the effective properties of fibres are maintained and even improved during processing, in particular during the hackling and stretching steps. Hemp can achieve properties comparable to high quality long flax fibres.

During past few decades, a growing interest has been observed in the use of thermoplastic polymers as a composite matrix over their thermoset counterparts. It is mainly due to the recyclability and other different advantages of the thermoplastic polymers. This chapter initially summarizes the advantages of the thermoplastic polymer as a composite matrix and then discusses some thermoplastic polymers which are mostly used for thermoplastic composite manufacturing. This discussion is further proceeded by various thermoplastic composite manufacturing techniques followed by different types of reinforcing structures used during thermoplastic composite manufacturing. Finally, the influence of various factors such as fibre length, fibre orientation, fibre volume, fibre-matrix distribution, fibre matrix interphase and void content on thermoplastic composite properties has been discussed.

Due to the ever-growing demand for bast fibres for technical and garment textiles, complementary sources to textile flax, whose cultivation in western Europe cannot really be extended, need to be proposed. In this study, the interest in harvesting and processing linseed flax straw is studied for geotextile applications. The main critical stages of fibre-to-yarn production for geotextiles were investigated. Different dew retting levels as well as different all-fibre extraction processes were investigated to achieve this objective. It was demonstrated that the fibres extracted from linseed flax stems subjected to 12 weeks of dew retting using breaking rollers, thresher and a breaking card exhibited the most suitable morphological and mechanical properties. The optimal fibres were converted into 100% linseed flax yarns using a flyer spinning machine, and the mechanical properties as well as the biodegradability of the linseed yarns were evaluated to understand their potential as geotextiles. These linseed flax yarns were further coated with linseed oil or chitosan to enhance their durability. It was observed that the linseed oil coating better preserved the yarn’s integrity and mechanical properties over time, and it permitted doubling their service life potential.

Following their mechanical extraction, the fibers coming from the banana pseudo-stem are coarse and the inter fiber cohesive substances need to be removed before their transformation into textile yarns/technical textiles. To reach this objective, dry-coarse banana fibers previously extracted using compressive rollers are treated using an oil-water-based emulsion. Various properties such as mechanical properties, thermal properties, surface morphology, chemical structure, crystallinity, color value, and moisture content of the banana fibers extracted through emulsion treatment have been evaluated and are compared with those of untreated banana fibers, and the fibers extracted through acetic acid treatment and alkali treatment, respectively. It is observed that the banana fibers extracted through oil/water emulsion treatment show higher crystallinity, tensile properties, thermal stability, moisture content, and brightness than that of untreated fibers and the fibers extracted through other treatments. Following oil-water emulsion treatment, the banana fibers possess suitable properties for recyclable thermoplastic composite manufacturing with technical-grade polymers, such as PP or PLA.

Thermally bonded roving (TBR) is a novel hybrid yarn in which the constituent fibres remain in a twist-free state and are held together by means of molten thermoplastic resin at the roving surface while the roving core remain unbounded. The influence of TBR structures on their bio-composite properties is discussed in this present chapter. Initially, the impact of TBR making process parameters such as the influence of processing temperature, degree of constituent fibre mixing etc. on TBR properties is discussed. Then the properties of TBR-based unidirectional composite and the TBR-based differently woven fabric laminate properties, such tensile, flexural and impact properties, are discussed. Finally, the properties of TBR-based flax-PP composites are compared with that of glass-PP composites. This comparison concludes that one can replace the glass-PP film stacked composites with TBR-based flax-PP laminates in cases of low and medium load bearing applications.

Recently, a rapid growth in the use of natural fibre as a composite reinforcement has been observed. However, the natural fibre as thermoplastic polymer reinforcement has some drawbacks. Among those shortcomings, non-uniform fibre-resin distribution and control of reinforcing fibre orientation in the composite structure are among the prime ones. Natural fibres in hybrid towpreg forms are often used during composite manufacturing to overcome the above-mentioned drawbacks of the natural fibre reinforced thermoplastic composite. The influence of hybridization and the use of hybrid towpregs during composite fabrication on various bio-composite properties is discussed in this chapter. Further, different manufacturing techniques of natural fibre-based twist-less towpreg and their influence on bio-composite properties are summarized. Finally, different characteristics and the evaluation techniques of the hybrid towpreg are discussed in the present chapter.

Linseed flax is an oilseed producing crop but its stems are rich in high potential fibers. However, linseed flax is not highly promoted for fiber application purposes. It is mainly due to the lack of technical knowledge regarding good quality fiber extraction from linseed stems. In this study, a fiber extraction device has been used to extract fiber from the randomly aligned linseed stems. Linseed fibers extracted using the above device are further refined in a gill drawing mini system having six different drawing passages. The extracted fibers are then evaluated at different stages of fiber extraction and are compared with industrial hackling tow textile flax fibers. It is observed that the extracted linseed flax fibers are long and fine enough for various textile yarn manufacturing. Their mechanical properties are also very high and are comparable to good quality textile flax fibers. Thus, these fibers can be considered as a complement to textile flax for the production of composite reinforcement fabrics, technical textiles, or garments.

Retting of fibrous plants such as flax is an essential step in the extraction of fibre bundles and their transformation into textiles and reinforcement fabrics for use in garments and composites. Dew-retting is traditionally performed from Northwest France to the Netherlands, as the climate is highly favourable for this process. Hemp is a plant that can be grown almost all over Europe with a low environmental impact. A retting step is also required to facilitate the separation of the hemp fibres before their transformation into textiles for garments or for 1D to 3D reinforcement composites, which requires thoroughly separated fibres. Dew-retting is currently used in flax production zones. The present work demonstrates that dew retting can be conducted under different climates on different soils, from dry Mediterranean environments up to the cooler regions of eastern France. If the ternary combination of moisture, temperature and solar radiation is appropriate, field retting (dew-retting) can be as short as about three weeks. In less favourable conditions, such as in dryer areas or when retting is performed late in the season after seed maturity (cooler temperatures), it lasts longer, but it can reach suitable levels. When conducted with care and with proper monitoring of the retting level, the dew-retting process does impact neither the tensile properties of elementary hemp fibres (by degrading crystalline cellulose I) nor the tensile properties of unidirectional and injected composite materials. Consequently, if extracted with a suitable process such as scutching and hackling, fibres suitable for load-bearing composites can be produced from dew-retted hemp stems produced in a wide range of climates and locations, therefore not limited to the conventional "dew retting zone" of flax production areas.

Increasing the production of high-performance natural fibres that minimise their impact on the environment is a challenge that flax (Linum usitatissinum L.) cannot address alone. In flax traditional production territories, hemp (Cannabis sativa L.) can be a complementary source of high added value fibres if their yield of long line fibres can be maximised to levels equivalent to the one of flax. The objective of the present work was to establish process parameters maximising the long line fibre yield using flax dedicated scutching and hackling devices. A lab-scale scutching/hackling device was used to establish sets of process parameters which best improve the long fibre scutching yield and as a consequence minimise the production of tow fibres. Decreases in straw processing transfer and beating speeds during scutching were necessary so that to be less aggressive on the straw and fibres. Very high long fibre yields were obtained after scutching and hackling at the laboratory scale (18 % of the hemp straw mass). These very high results, combined to high straw yield production in the field indicate that hemp can be a very productive source of high-performance fibres as these ones showed tensile properties completely suitable for a textile use as well as for load bearing composite materials. If the potential of high production yields and high mechanical and morphological properties was demonstrated at the lab-scale, this one should be improved at the industrial scale. Suggestions to reach this goal are provided to prevent too high transformation of long fibres into tows and to keep the mechanical potential maximum. When using optimised parameters and a lab-scale scutching/hackling device, it was demonstrated that hemp has the potential for providing equivalent amounts of long fibres per hectare than flax with tensile properties about 20 % lower than the ones of flax.

Antiviral textiles are one of the most promising areas of protective textiles. Antiviral textiles are important in the field of health and hygiene. They become an essential part of our daily-life when a pandemic situation arises. The present paper critically analyses and summarizes various researches of the production of antiviral textiles. Different classes of the virus, how the virus transmits and replicates, various antiviral agents for textiles and their working mechanism, and the application procedure of various synthesized and bio-based antiviral compounds on textiles have been discussed in this paper. Finally, the present paper compares the existing antiviral finishing on textiles in terms of its effectiveness, durability and skin-friendliness and, following that, discusses the possibilities of using antiviral textiles in various sectors.

Recycling of thermoplastic composites has drawn a considerable attention in the recent years. However, the main issue with recycled composites is their inferior mechanical properties compared to the virgin ones. In this present study, an alternative route to the traditional mechanical recycling technique of thermoplastic composites has been investigated with the view to increase mechanical properties of the recycled parts. In this regard, the glass/polypropylene laminate offcuts are cut in different grain sizes and processed in bulk form, using compression moulding. Further, the effect of different grain sizes (i.e., different lengths, widths and thicknesses) and other process-related parameters (such as mould coverage) on the tensile properties of recycled aggregate-reinforced composites have been investigated. The tensile properties of all composite samples are tested according to ISO 527-4 test method and the significance of test results is evaluated according to Student’s t-test and Fisher’s F-test respectively. It is observed that the tensile moduli of the recycled panels are close to the equivalent quasi-isotropic continuous fibre-reinforced reference laminate while there is a noteworthy difference in the strengths of the recycled composites. At this stage, the manufactured recycled composites show potential for stiffness-driven application.

Flax-PP based thermally bonded roving (TBR) has a unique structure where the flax fibres remain twist-free and fully aligned along the roving axis. The present study describes an experimental investigation on the low velocity impact (LVI) behaviour of the TBR based woven fabric composites and compares the same with plain woven glass fabric reinforced PP composites (GRPC). Two different fabric architectures namely plain woven (PW) and unidirectional (UD) are fabricated using flax/PP based TBR. These TBR based woven fabrics and the glass fabric/PP sheets are consolidated in a compression moulding machine and the resultant composite-laminates are tested for their LVI behaviour. The impact test results revealed that the glass/PP composites absorb more energy and exhibit a higher peak load than both TBR based PW and UD fabric composites. However, the specific load and energy of all flax/PP composites are higher than the glass/PP composite. The damage tolerance of all composite laminates are evaluated by comparing their flexural strength before and after the impact. It is observed that the proportionate loss in flexural strength due to impact thrust is larger in case of glass/PP composites than all flax-PP composites.

In the current context of environmental contamination due to disposal of textile-manufacturing waste, substitution of synthetic dyes and chemicals with bio-colour or bio-extract is a big confront. Thus, the need of the hour is to develop green chemicals or dyes for sustainable textile processing with an eco-friendly approach. In light of above, a bio-colour has been extracted from Bauhinia vahlii bark and applied on the degummed and bleached silk fabric along with a bio-acid (citric acid). Dyed silk fabrics were tested for their color strength and fastness properties like color fastness to washing, water crocking and light and found satisfactory results. Banana peduncle extract (BPE) is also applied on the dyed fabric to improve the fastness properties and enhance the functional properties like flame retardant by pad-dry-cure method. Dyed and BPE treated silk fabric was tested and analysed for their color fastness properties and mechanical properties, like thickness, bending length, flexural rigidity and crease recovery and the results were recorded. Notably, evaluation of dyed and BPE treated silk fabric was carried out for flame retardancy according to ASTM D1230 standards and promising result was obtained.

Resistance to impact thrust is one of the most important requirement along with many others for defining suitable applications of any composite materials. In this present work, the influence of composite architecture and composite interfacial bonding strength on the impact performance of flax reinforced PP composites have been investigated. In this regard two different composite architecture through conventional film stacking method and through DREF (DR. E. Fehrer open-end friction spinning process) yarn consolidation method have been produced and to alter the fibre–matrix interfacial bonding the flax fibres are treated with MAgPP (Maleic Anhydride grafted Polypropylene). Finally, the notch Izod impact behaviour of all composite samples are evaluated and compared.