Search Results (83)

Industrial hemp (Cannabis sativa L.) is gaining renewed interest as a sustainable source of natural fibres, particularly in regions like Belgium, where well-established flax processing infrastructure exists. However, region-specific data on varietal performance for long fibre production remain limited, hindering large scale adoption by both farmers and processors. This study aimed to assess the agronomic performance of early- and late-flowering hemp varieties under temperate maritime conditions through a three-year field trial at two sites in Flanders (Belgium). The evaluation focused on key parameters including emergence rate, plant morphology, long fibre yield and quality. Results showed that successful crop establishment is critical, as poor emergence influenced stem diameter (increasing with decreasing emergence) and leads to reduced long fibre yields by up to 50% between tested sites. Significant yield differences between trial years were present at both sites, with the biomass yield ranging from 10.7 to 14.5 and from 7.8 to 9.6 t ha⁻¹ for Bottelare and Beitem, respectively. Under favourable conditions, long fibre yields reached up to 2.4 t ha⁻¹ for late-flowering and 2.1 t ha⁻¹ for early- and mid-late-flowering varieties. In Western Europe, early to mid-late flowering varieties are generally favoured. Among these, the mid-late flowering variety Bialobrzeskie demonstrated strong yield potential. Overall, fibre quality across varieties was comparable to that of flax. Full article

This study evaluates the thermal conductivity of hemp-based insulation materials, focusing on loose bulk mixtures of hemp fibre and hurd. Transient Plane Source (TPS) measurements were employed to assess the thermal conductivity of these materials, with a controlled variation in the fibre-to-hurd ratio and bulk density. Samples from various suppliers, including those with different fibre diameters and hurd contents, were tested. The results indicate thermal conductivities ranging from 0.055 to 0.065 W/mK, demonstrating good insulation performance. This study also highlights the influence of sample compression on thermal conductivity, with higher compression leading to both increased bulk density and thermal conductivity. When compared to the conventional insulation materials glass wool and polystyrene, hemp-based materials exhibited approximately double the thermal conductivity. However, the same thermal resistance (R-value) could be achieved by increasing the thickness of the hemp-based insulation. Full article

According to the global strategy of Green course, the production of sustainable textiles using different biodegradable fibres has immense potential for the development of sustainable products. Using one of the most sustainable biobased pure hemp and polylactide fibers yarns, four new biodegradable three-layer weft knitted fabrics with good thermal comfort properties were developed. The inner layer (worn next to the skin) and the middle layer of the knits were formed of hydrophobic polylactide fibers, the outer layer of different amounts (36–55%) of hydrophilic natural hemp fibers. Biodegradable polylactide fiber yarns were used as a replacement for conventional petroleum-based synthetic fibers. Natural hemp fibers are one of the most sustainable fibers derived directly from Cannabis sativa L. plants. The properties of the knitted fabrics were analysed and compared under thermoregulatory-moisture management, thermal resistance, air and water vapour permeability-properties. The results showed that all newly developed knits are ascribed to ‘moisture management’ fabrics according to the summary grading of all indices of moisture management parameters. In addition, it was found that the highest overall moisture management capability is related to the quantity of natural hemp fiber composition in different knitting structures. Based on the overall moisture management capacity (OMMC) index and thermal resistance values of developed knitted fabrics, the performance levels for these materials contacting the skin and intended for the intermediate layer were determined. Full article

Processing hemp seeds into foods generates several by-products that are rich in nutrients and bioactive phytochemicals. This paper presents a thorough plant metabolite analysis and a comprehensive assessment of the nutrient content of 14 hemp seed-based foods and by-products and evaluates their feasibility to deliver dietary needs and daily recommendations. The protein-85-product was the hemp food and hemp fudge the hemp by-product with the highest content of protein, 93.01 ± 0.18% and 37.66 ± 0.37%, respectively. Hemp seed-hull flour had the richest insoluble non-starch polysaccharide content (39.80 ± 0.07%). Linoleic acid was the most abundant fatty acid across all the hemp seed-based samples (ranging from 53.80 ± 2.02% in the protein-85-product to 69.53 ± 0.45% in the hemp cream). The omega-6 to omega-3 fatty acid ratio varied from 3:1 to 4:1 across all hemp seed-based samples. The majority of hemp seed-based samples were rich sources of potassium, magnesium, and phosphorus. Gentisic acid, p-coumaric acid, and syringaresinol were the most abundant plant metabolites measured and found mainly in bound form. Hemp seed by-products are valuable sources of nutrients capable of meeting dietary needs and, therefore, should be re-valorized into developing healthy food formulations to deliver a truly zero-waste hemp food production. Full article

This paper presents the potential for an alternative use of structural polymer composite reinforcement, made from natural industrial hemp (Cannabis sativa L.) fibres, in the manufacture of selected products in the shipbuilding industry. This research used fabrics made from unmodified and chemically modified industrial hemp fibres. The primary research focus was on determining the impact strength of the new eco-friendly structural composites produced after long-term storage in representative aqueous environments. Also presented are the results of fire response tests of these composites in the context of their disposal by energy recycling. The tests carried out also referred to a well-defined glass fibre-reinforced polymer composite, from which a control slab of the actual product was realistically produced in the form of a representative section of a 34-foot boat hull plate below the waterline. The results of this basic research into these structural composites confirmed the validity of continuing, respectively, application and implementation research, aimed at producing composites dedicated to selected products of the shipbuilding industry. Full article

This study explores the potential use of mould biomass and waste fibres for the production of agrotextiles. First, 20 mould strains were screened for efficient mycelium growth, with optimized conditions of temperature, sources of carbon and nitrogen in the medium, and type of culture (submerged or surface). A method was developed for creating a biocomposite based on the mould mycelium, reinforced with commercial bleached softwood kraft (BSK) pulp and fibre additives (cotton, hemp). The best properties, including mechanical, water permeability, and air permeability, were shown by the biocomposites containing 10–20% Cladosporium cladosporioides mycelium grown in surface or submerged cultures, milled with BSK pulp, cotton, and hemp (10–20%). The mould mycelium was refined with cellulosic fibrous material, formed, pressed, and dried, resulting in a biomaterial with good mechanical parameters, low water permeability, and high air permeability. The biocomposite was fully biodegradable in soil after 10 days in field conditions. The use of the biocomposite as a crop cover shortened the germination time and increased the percentage of germinated onion, but had no effect on parsley seeds. This study shows the potential of using mould mycelium for the production of biomaterial with good properties for applications in horticulture. Full article

Natural fibres have garnered substantial attention because of their eco-friendly attributes and versatility, offering a sustainable alternative to synthetic ones. This review surveys plant fibres, including flax, hemp, jute, banana, and pineapple, emphasizing their diverse properties and applications in nonwoven materials. This research also examines the use of synthetic polymer composites blended with natural fibres to create high-performance nonwoven materials. Furthermore, this review outlines the primary applications of nonwovens manufactured with plant fibres through needle-punching. These applications span geotextiles, automotive interiors, construction materials, and more. The advantages, challenges, and sustainability aspects of incorporating natural fibres in needle-punched nonwovens are discussed. The focus is on mechanical and thermal properties and their adaptability for specific applications. This research provides valuable insights for researchers and industry professionals aiming to leverage the benefits of plant fibres in needle-punched nonwovens across various sectors. Full article

Applying coatings of paraffins and other synthetic waxes is a common approach to impart hydrophobic properties to fibres and thus control their surface characteristics. Replacing these fossil-based products with alternatives derived from renewable resources can contribute to humankind’s transition to a sustainable bioeconomy. This study presents the coating of hemp fibres with waxes extracted from pine bark as an exemplar application. Two bio-based emulsifiers were used to prepare wax emulsions suitable for a dry blending process. The coatings on the fibres were characterised, quantified, and visualised using a combination of spectroscopic and microscopic techniques. Confocal fluorescence microscopy was an excellent tool to investigate the spatial distribution of the pine bark waxes on the fibre surfaces. While successful deposition was demonstrated for all tested formulations, coating homogeneity varied for different emulsifiers. Compounding the hemp fibres with a bio-based polyester resulted in the substantial improvement of the mechanical behaviour. However, the presence of a wax coating on the fibres did not lead to a significant change in mechanical properties compared to the controls with uncoated fibres. Optimising the composite chemistry or adjusting the processing conditions might improve the compatibility of the hemp fibres with the matrix material, resulting in enhanced mechanical performance. Full article

This work presents the extrusion-based preparation of new biocomposites from two plant fibres (namely Cannabis sativa L. and Opuntia ficus-indica Mill.) that are added to two different polymers (an ethylene–octene elastomer and polylactic acid), which act as matrices. Structural and morphological characterization (using X-ray diffraction and field emission scanning electron microscopy) have been used to correlate the interactions between the biomass and the polymers employed with the efficiency of the proposed approach. It was found that Opuntia-based composites can be easily formed in a range of biomass/polymer ratios. However, the interaction between hemp and the matrix means that only specific ratios can form tightly bound composites. The present communication thus paves the way for more complex and comprehensive studies on the formulation of biocomposites containing these matrices. Full article

Polysaccharides from hemp seeds exhibit antioxidant activities in vitro and in vivo. However, crude polysaccharide quality is often low owing to the presence of fibres and pigment impurities, which are difficult to eliminate in the hemp seed shell. In this study, crude polysaccharides from hemp kernels (HKP) were obtained by hot water extraction and separated by membrane ultrafiltration into eight fractions with different molecular weights. Total antioxidant capacity and free radical scavenging (DPPH) assays were performed to evaluate the antioxidant activities of HKP and the fractions in vitro. The structural characteristics of HKP were determined using various analytical techniques. The Fe³⁺-reducing power of HKP was 7.65 ± 0.22 μmol/g, and HKP possessed the highest DPPH radical-scavenging rates (94.30 ± 2.27%), similar to 5 mg/mL Vitamin C (Vc), which had a rate of 95%. The HKP was an acidic polysaccharide with a low molecular weight (4.21 ± 0.12 kDa). The monosaccharide composition indicated that HKP primarily comprised mannose, ribose, glucuronic acid, galacturonic acid, glucose, galactose, arabinose, and fucose in a molar ratio of 0.96:1.95:8.27:0.98:9.46:1.69:6.10:2.82. The molar mass of HKP was distributed widely in a triple helical conformation. This study provides a scientific basis for further research on the use of hemp polysaccharides. Full article

This paper examines the water-vapour diffusion resistance (Z-value) of vapour versus wind barriers by determining their Z-value ratio in exterior wood-frame walls thermally insulated with six different materials to prevent mould growth. Using WUFI Pro, the water-vapour diffusion resistance requirements were determined for thermal insulation using mineral wool and biogenic materials: wood fibre, straw, flax, grass, and hemp. Hygrothermal simulations determine the minimum Z-value ratio between these materials with vapour versus wind barriers in temperate and cold climates. Wind barriers with Z-values between 1 and 8 GPa s m²/kg were used in walls with U-values of 0.15 and 0.10 W/m² K. The indoor moisture load was defined from classes of 1 to 5 with a U-value of 0.15 W/m² K and classes of 2 and 3 were used for a U-value of 0.10 W/m² K. The Z-value ratio depends on the Z-values of the wind barrier and thermal insulation material, moisture load class, and U-value. The required Z-value ratio declines with an increased wind-barrier Z-value. The vapour-barrier Z-value approaches a fixed threshold for wind-barrier Z-values approaching lower values (1 GPa s m²/kg) and those approaching higher values (8 GPa s m²/kg), depending on the thermal insulation material. This parameter study examines wind barriers with a Z-value ranging between 1 and 8 GPa s m²/kg, which characterises typical wind barriers used in Denmark For the water-vapour diffusion resistance requirement of the vapour barrier, the Z-value increases for increased moisture load classes and thermally insulated walls with lower U-values. The conversion between the Z-value, the Sd-value, and the water-vapour resistance factor µ can be found in DS/EN ISO 12572:2016. Full article

An open field experiment from November 2022 to May 2023 in Croatia, which is characterized by a continental humid climate, evaluated nonwoven mulches made from viscose, jute, and hemp fibres blended with PLA fibres. The blends of viscose and jute fibres (90:10, 80:20, and 70:30 ratios) were produced using mechanical web formation on cards with needle punching for bonding webs. Additionally, hemp fibres were blended with PLA fibres in a ratio of 80:20. Winter conditions caused significant structural changes in the mulches, including shrinkage, increased mass per unit area, thickness, and reduced air permeability. The amount of PLA fibre in the nonwoven mulch blends significantly affected nonwoven fabric structure change during exposure to winter conditions. After 180 days, the breaking force of all mulches increased by 30% to 277%. The soil beneath jute and hemp mulches maintained higher temperatures and moisture levels compared to viscose mulches. Soil organic carbon content varied with fibre type and was higher under jute and hemp mulches. K₂O content was significantly higher in soils covered by mulches. All mulches effectively suppressed weeds. The experiment results showed that the newly produced nonwoven mulches could replace the conventional agro foil. Results also suggest that choosing biodegradable nonwoven mulches produced from fibres obtained from natural and renewable sources can influence soil fertility and the availability of nutrients, ultimately affecting plant growth and agricultural productivity. Full article

This study describes the production of a new biobased epoxy thermoset and its use with long hemp fibres to produce high-performance composites that are totally biobased. The synthesis of BioIgenox, an epoxy resin derived from a lignin biorefinery, and its curing process have been optimised to decrease their environmental impact. The main objective of this study is to characterise the rheology and kinetics of the epoxy system with a view to optimising the composite manufacturing process. Thus, the epoxy resin/hardener system was chosen considering the constraints imposed by the implementation of composites reinforced with plant fibres. The viscosity of the chosen mixture shows the compatibility of the formulation with the traditional implementation processes of the composites. In addition, unlike BPA—a precursor of diglycidyl ether of bisphenol A (DGEBA) epoxy resin—BioIgenox and its precursor do not have endocrine disrupting activities. The neat polymer and its unidirectional hemp fibre composite are characterised using three-point bending tests. Results measured for the fully biobased epoxy polymer show a bending modulus, a bending strength, a maximum strain at failure and a T_g of, respectively, 3.1 GPa, 55 MPa, 1.82% and 120 °C. These values are slightly weaker than those of the DGEBA-based epoxy material. It was also observed that the incorporation of fibres into the fully biobased epoxy system induces a decrease in the damping peak and a shift towards higher temperatures. These results point out the effective stress transfers between the hemp fibres and the fully biobased epoxy system. The high mechanical properties and softening temperature measured in this work with a fully biobased epoxy system make this type of composite a very promising sustainable material for transport and lightweight engineering applications. Full article

In the current work, the performance properties of natural-fibre-based thermal insulation materials were examined. For this purpose, three different compositions of natural fibres were prepared: pure sheep wool (SW), wool and industrial hemp (SW/HF) fibres, and pure industrial hemp (HF) fibres. Low-melt bicomponent polylactide (PLA) fibres were used as a binding material. For specimens prepared from natural fibres, the dependence of the thermal conductivity, the tensile strength along and across the direction of product formation, and the short-term water absorption on the density of the specimens and the flammability parameters were determined. In addition, to reduce the water absorption and flammability, the specimens were coated with hydrophobic agents and flame retardants. The obtained research results were also statistically processed. The analysis of the results showed that the thermal conductivity of natural-fibre-based thermal insulation materials varied within the range of 0.0333 ÷ 0.0438 W/(m·K), the tensile strength varied from 2.5 to 130 kPa, the short-term water absorption varied from 0.5 to 8.5 kg/m², and the water vapour diffusion resistance factor varied from 2.537 to 2.667. It was additionally determined that all the studied products were flammable. The water absorption and flammability values were significantly reduced by the use of hydrophobic agents and flame retardants. Full article

There are two key areas of development across wind turbine blade lifecycles with the potential to reduce the impact of wind energy generation: (1) deploying lower-impact materials in blade structures and (2) developing low-impact blade recycling solution(s). This work evaluates the feasibility of using natural fibres to replace traditional glass and carbon fibres within state-of-the-art offshore blades. The structural design of blades was performed using Aeroelastic Turbine Optimisation Methods and lifecycle assessment was conducted to evaluate the environmental impact of designs. This enabled the matching of blade designs with preferred waste treatment strategies for the lowest impact across the blade lifecycle. Flax and hemp fibres were the most promising solutions; however, they should be restricted to use in stiffness-driven, bi-axial plies. It was found that flax, hemp, and basalt deployment could reduce Cradle-to-Gate Global Warming Potential (GWP) by around 6%, 7%, and 8%, respectively. Cement kiln co-processing and mechanical recycling strategies were found to significantly reduce Cradle-to-Grave GWP and should be the prioritised strategies for scrap blades. Irrespective of design, carbon fibre production was found to be the largest contributor to the blade GWP. Lower-impact alternatives to current carbon fibre production could therefore provide a significant reduction in wind energy impact and should be a priority for wind decarbonisation. Full article