Hemp Fibers Research Articles

Thermal and mechanical properties of high-performance polyester nanobiocomposites reinforced with pre-treated sunn hemp fiber for automotive applications

The objective of this study is to create high-performance nano biocomposites by utilizing unsaturated polyester resin (PE) reinforced with pre-treated short (2 cm) lengthened sunn hemp (SH) fibers and by incorporating 5 % nanoclay (hydrophilic bentonite) through the compression molding technique. The addition of 5 % nanoclay to the biocomposite significantly increased the flexural strength by approximately 165 % for H2O2-treated SH fiber and 148 % for KMnO4-treated SH fiber, when compared to untreated fibers. This enhancement was achieved through phase separation, intercalation, and exfoliation between the SH fibers, polyester resin (PE), and 5 % nanoclay. In particular, the H2O2-treated SH fiber nanobiocomposite exhibited a 43 % higher flexural strength compared to its corresponding biocomposite. The incorporation of nanoclay significantly decreased the water absorption of the bio-composites from 11.86 % in the untreated samples to a minimum of 2.76 % in the H2O2-treated SH/PE nanobiocomposite. The study suggests that short SH fiber/PE/nanoclay nanobiocomposites could be used as effective alternatives to synthetic composites in various applications, including the aerospace industry, household products, and automotive interior components such as side panels, seat frames, and central consoles. Additionally, they could be utilized in exterior parts like door panels and dashboards.

Flexural Fatigue Performance of Hemp Fiber–Reinforced Concrete Using Recycled Concrete Aggregates as a Sustainable Rigid Pavement

Flexural Fatigue Performance of Hemp Fiber–Reinforced Concrete Using Recycled Concrete Aggregates as a Sustainable Rigid Pavement

An overview of the effects of water and moisture absorption on the performance of hemp fiber and its composites

AbstractResearchers compare natural hemp fibers with synthetic fibers because of their distinct physical and mechanical properties, which have been well established over time. Hemp fibers are a versatile type of plant fiber commonly used in structural composites and have shown promise in various applications which include packaging, construction, and automotive parts. However, designing hemp‐based composite components presents challenges due to factors related to the plant's origin, growth conditions, age, stem position, separation methods, and the irregularity of fiber cross‐sections. This review aims to provide a comprehensive analysis of research on the performance of hemp fibers and their composites concerning moisture and water absorption. It reviews and analyzes important research on the water and moisture absorption properties of hemp fibers. The article also explains the critical properties of hemp fibers, the various factors affecting these properties, the role of hemp fibers in reinforcement composites, and how relative humidity and swelling characteristics impact hemp fiber composite components. Additionally, it highlights potential areas for future research.Highlights Effects of moisture on hemp fiber's structural properties. Mechanisms of water and moisture absorption in hemp fibers. Impact of moisture on hemp fiber reinforced composites. Key factors in selecting matrices for hemp fiber composites. Future prospects for hemp fiber composites in various applications.

Exploring the effect of hemp fibers’ addition on the properties of PLA/PPAd biodegradable blends

Poly(lactic acid) (PLA) is a compostable aliphatic polymer with enhanced strength and toughness, and it is a promising material for packaging products. Polymer blending is a financially feasible and easy way to upgrade its properties, such as its slow degradation and crystallization rates and its modest elongation, and thus, make it more adaptable. Furthermore, the use of natural fibers as fillers can reinforce the biobased character of the final composite materials and enhance their antioxidant activity values, a crucial property of polymers that are addressed for active packaging. Herein, the influence of the addition of hemp fibers (HF) on the features of poly(lactic acid)/poly(propylene adipate) blends containing 85/15 w/w PLA/PPAd, was investigated. The utilization of a poly(lactic acid)-co-poly(propylene adipate) block copolymer (cop) as a compatibilizer was also examined. The thermal, morphological and mechanical assets of the composite materials were evaluated with the implementation of multiple techniques. The addition of HF enhanced the hydrophobicity and biodegradation of the composites, render them as candidates for several applications. Furthermore, the introduction of the compatibilizer successfully increases the adhesion between the polymeric matrices and the HF, resulting in enhanced properties.

Application of Natural (Plant) Fibers Particularly Hemp Fiber as Reinforcement in Hybrid Polymer Composites - Part III. Investigations of Physical and Mechanical Properties of Composites Reinforced with Hemp Fibers

ABSTRACT The article is the third part of a multi-directional analysis of the possibilities, advisability and validity of using natural plant fibers (NPFs) as a reinforcement for polymer structural composites that can be used in the shipbuilding industry in Poland. As a result of the analysis of macroeconomic indicators and natural and non-natural factors regarding NPFs, a representative selection of hemp (Cannabis sativa L.) was made as the raw material to be used to reinforce these composites. Methods and test results are presented enabling comparison of the physical and mechanical properties of the new pro-ecological construction material–hemp fiber reinforced polymer (HFRP), reinforced with fabric made of unmodified and chemically modified hemp fibers.

Fabrication of Green Composite Materials Using the Weight Sum Method (WSM) Method

The quest for sustainable materials the investigation into natural fibers for composite materials has been prompted by this development., aiming to reduce the environmental impact of traditional synthetic composites. In this study, we investigate the potential of flax, hemp, jute, kenaf, and ramie fibers as reinforcements in green composites fabricated using the Water Soaking Method (WSM). The evaluation parameters considered include density (g/cm3), fiber diameter (μm), tensile strength (MPa), Young’s modulus (GPa), and elongation at break (%). Through meticulous experimentation and analysis, it is revealed that jute emerges as the frontrunner among the alternatives, exhibiting superior performance across multiple evaluation parameters. Jute-based green composites demonstrate commendable strength and stiffness properties, coupled with a moderate density, making them promising candidates for various structural applications. Conversely, kenaf fiber-based composites exhibit the lowest performance in terms of evaluated parameters, indicating potential limitations in its suitability for high-performance applications. The comparative assessment underscores the significance of material selection in composite fabrication, emphasizing the diverse mechanical properties exhibited by different natural fibers. Furthermore, the utilization of the WSM method showcases its effectiveness in producing green composites with desirable characteristics, signifying its potential as a viable manufacturing technique for sustainable materials. eco-friendly composites, highlighting the importance of considering multiple factors such as fiber type and fabrication method in achieving optimal performance and environmental sustainability in composite materials. Further research may delve into refining fabrication techniques and exploring novel fiber combinations applications.

Development of Fiber-Reinforced Polymer Composites for Additive Manufacturing and Multi-Material Structures in Sustainable Applications

This study investigates the mechanical properties of carbon and natural fiber-reinforced Polylactic Acid (PLA) and Polyethylene Terephthalate Glycol (PETG) composites produced via Additive Manufacturing (AM), focusing on Material Extrusion (MEX). The performance of filaments made from pre-consumer recycled PLA (rPLA) and PETG, with varying weight percentages of hemp and jute short fibers, was evaluated through tensile testing. Comparisons were made between the original filaments (PLA, carbon fiber-reinforced PLA [CF–PLA], and PETG) and their recycled versions. Multi-material compositions—neat PLA and PETG, single-graded (PLA + CF–PLA, PETG + CF–PETG), and multi-gradient (PLA + CF–PLA + PLA, PETG + CF–PETG + PETG)—were analyzed for mechanical properties. Optical microscope images of multi-material specimens were captured before and after fracture to assess failure mechanisms. The results indicate that the original CF–PETG filaments achieved a tensile strength of 50.14 MPa, which is higher than rPLA, PLA, and CF–PLA by 2%, 70%, and 6.7%, respectively. The re-manufactured PLA filaments reinforced with 7 wt% hemp fibers exhibited a tensile strength of 38.8 MPa, representing a 29% increase compared to the original PLA filaments and a 26% improvement over recycled PLA. Additionally, incorporating 7% jute fiber into PETG resulted in a tensile strength of 62.38 MPa, reflecting a 12% improvement over the original PETG filaments and a 15% increase compared to the recycled PETG filaments. Among specimens produced by AM, CF–PLA and rPLA demonstrated the highest tensile and compressive strengths. However, multi-material composites showed reduced mechanical performance compared to neat PLA and PETG, highlighting the need for improved interlayer adhesion. This study emphasizes the importance of optimizing material combinations and fiber reinforcement to enhance the mechanical properties of composites produced through AM.

Nanomechanical characterization of hemp fiber with atomic force microscopy

Nanomechanical characterization of hemp fiber with atomic force microscopy

Acoustical characterization and modelling of the effects of eco-friendly flame retardant treatments on hemp fiber stacks

Vegetal wools are a bio-based insulator which building applications are limited due to their flammability. To overcome this problem while respecting their bio-based nature, it seems relevant to identify and apply an environmentally friendly fireproof treatment. However, the impact of this treatment on the acoustic performance of the vegetal wools is not examined in the literature. The objective of this work is to evaluate the efficacy of two phosphorus-based fireproof treatment methods i.e., impregnation and pulverization, and their impact on the acoustic properties of hemp fiber stacks. To assess the efficacy of the fireproof treatment, the amount of phosphorus grafted and the thermal degradation of the hemp fibers were evaluated through inductive coupled plasma (ICP) and thermogravimetric analysis (TGA), respectively. On the acoustic side, the impedance tube test results showed that the treatment can negatively impact the acoustic performance of hemp fiber samples, by the reduction of the sound absorption coefficient. To better understand the effects of treatments on the porous structure characteristics of the samples, parameters such as porosity, resistivity, tortuosity, etc. are determined and the acoustic absorption of the stacks is simulated using the JCAL modelling method.

Sandwich structures in bio-composite material for sustainable acoustic solutions

The use of bio-based materials in acoustic applications has gained a lot of attention recently as a functional and environmentally friendly alternative for synthetic materials. This is because conventional synthetic fibers have a significant impact on the environment and the health risks of people. The focus is now on developing composite systems that minimize environmental harm by using energy and materials more efficiently, and by substituting synthetic or petroleum-based materials with more sustainable options, such as natural fibers. These natural fibers are favoured for their biodegradability, sustainability, and widespread availability, earning them the label of "green materials." Thus, this paper aims to investigate the soundproofing capabilities of a novel sandwich structure composed of hemp fibers and bio-epoxy resin, aiming to broaden the application field of natural fiber composite materials.

Effect of Phenolic Resin on the Friction Performance of Composites with Hemp Fiber for Automotive Brake Pads

Effect of Phenolic Resin on the Friction Performance of Composites with Hemp Fiber for Automotive Brake Pads

Mechanical Characterization of Flax and Hemp Fibers Cultivated in Romania.

This study examines the mechanical properties, specifically strength and stiffness, of technical hemp and flax fibers grown in Romania. Tensile testing was employed to determine stress-strain curves and the Young's modulus and to assess the failure strength of both fiber types. Although samples of various lengths were tested, no significant length-dependent variations were observed. However, a strong dependence on fiber diameter was noted, with the smallest diameters approaching the documented strength of elementary fibers. Due to the considerable variability in the experimental results pertaining to the characteristics of the reinforced fibers, a statistical analysis using a two-parameter Weibull distribution was employed. The analysis revealed three distinct stress-strain curve profiles, i.e., linear, bi-linear, and tri-linear patterns, with the average ultimate stress ranging from 412 to 566 MPa for hemp and 502 to 598 MPa for flax.

The Effect of Biocomposite Material Composition with Natural Fiber Reinforced Polyester Matrix on Mechanical and Physical Strength

This study was conducted with the aim of determining the effect of natural fiber composition in polymer composites on the flexural strength and density of bio-composites with polyester matrix reinforced with ramie fiber, giant false agave (GFA), bamboo, and sugar cane fibers. Mechanical testing was carried out in the form of flexural strength testing and calculating density as a physical test. The composition of the matrix with fiber reinforcement was set at 70% polyester and 30% natural fiber. The variables used in this study were to create a dominant composition of fiber types in the form of a measured weight amount so as to produce a comparison of which type of natural fiber has a better test value. From the results of the flexural strength test, it was found that the bio-composite dominated by sugar cane fiber had the largest flexural strength value of 261.66 kg/cm2 while the bio-composite dominated by ramie and GFA sequentially produced flexural strengths of 101.465 kg/cm2 and 185.89 kg/cm2. The results of the density calculation show that the highest density was achieved by the bio-composite material with a dominant composition of hemp fiber (70% Polyester: 20% hemp fiber, 5% GFA fiber: 5% sugar cane fiber) of 1.049 g/cm3.

Progressive damage analysis of green composite laminates subjected to in-plane crashworthiness

In this paper the initiation and propagation of delamination in thin-walled green composite structures were studied. In particular, laminates of flax and hemp fibers with epoxy resin were investigated from experimental and numerical points of view, using the finite element code LS-DYNA. First, an experimental campaign was conducted using DCB and 4ENF tests to obtain the values of the interlaminar fracture modes, required for the cohesive fracture modeling. In addition, in-plane crashworthiness tests were performed on composite plates to analyze the damage of the specimens, under both quasi-static and dynamic conditions. A trigger mechanism was considered to help delamination to start and to ensure the most progressive crushing possible. The predominant damage mode was splaying, but some ply fragmentation in the middle layers and some buckling phenomena were also observed. In general, more stable progressive crushing was observed under dynamic conditions than under quasi-static ones, even if a reduction in terms of absorbed energy was obtained by moving to the dynamic condition. The numerical predictions showed a good agreement with the experimental reference results, validating the current framework for crashworthiness analysis of green composite structures.

Mechanical Properties of Natural Composites: Hemp Fiber and Polypropylene Resin

Mechanical Properties of Natural Composites: Hemp Fiber and Polypropylene Resin

Development of sustainable flame-retardant bio-based hydrogel composites from hemp/wool nonwovens with chitosan-banana sap hydrogel

Flame retardant (FR) finishing is crucial for developing protective textiles, traditionally relying on halogen, phosphorus, and phosphorus-nitrogen chemistries, which have limitations like toxicity and fabric stiffening. Innovative approaches such as nanotechnology, plasma treatments, and natural resource-based finishes are being explored to achieve sustainable FR textiles. This study presents the development and comprehensive characterization of hydrogel composites made from nonwoven fabrics composed of various hemp/wool blends (70/30, 80/20, and 90/10). The nonwoven fabrics were treated with a chitosan hydrogel incorporating banana sap to enhance their properties. Scanning electron microscope (SEM) examined the surface morphology and structural integrity of the composites, while Fourier transform infrared spectroscopy (FTIR) identified chemical interactions and functional groups. Differential scanning calorimeter (DSC) revealed thermal properties, water absorbency tests demonstrated hydrophilicity, mechanical testing assessed tensile strength, and vertical flammability tests evaluated fire resistance. SEM and FTIR revealed a successful coating of chitosan hydrogel with banana sap inclusions onto the hemp/wool nonwoven fabric, forming a composite structure. DSC analysis suggests higher chitosan content and hemp fiber ratio (like 70/30) lead to increased thermal stability of hydrogel composites. Higher chitosan concentrations in the hydrogel significantly improve the flame-retardant properties of hemp/wool nonwoven fabrics by reducing char length and enhancing protective char layer formation, with banana sap further promoting charring. These results indicate that the developed composite can be effectively used in flame-retardant textiles.

Exploring mechanical properties of eco-friendly hybrid epoxy composites reinforced with sisal, hemp, and glass fibers

It is now widely accepted that various subsets of hybrid fiber composites reinforced with combined natural and synthetic fibers can significantly expand the applicability of composite-based materials in design and technology practice. The already existing unnatural circumstances on the planet put natural fibers far ahead of traditions in the field of materials thanks to their biodegradability characteristics, availability and over-term endurance and corrosion resistance. At the same time, composites are rapidly taking their place in many industries and sectors of the economy as metals in as much as it is economically and energetically justified. This study evaluates the mechanical properties of hybrid composites reinforced with glass, hemp, and sisal fibers. Using a hand lay-up method with epoxy resin, composite laminates were fabricated and tested for tensile, flexural, impact strengths and hardness test in accordance with ASTM standards. The experimental results revealed that glass-sisal fiber composites achieved the highest tensile strength of 69.1 MPa, while glass-hemp-sisal fiber composites exhibited superior flexural strength of 15.22 MPa and impact strength of 137.45 kJ/m2 while best hardness value was 24.73 HV for glass-sisal fibre composite. These findings underscore the potential of glass-sisal-hemp fiber-reinforced epoxy composites as viable alternatives to traditional synthetic fiber-reinforced materials in automotive industry where there are no structural loadings i.e. automobile interiors; offering enhanced mechanical performance and sustainability.

From fibers, to flowering, to metabolites: unlocking hemp (Cannabis sativa L.) potential with the guidance of novel discoveries and tools.

Cannabis sativa L. is an ancient crop whose agricultural adoption has been interrupted to prevent the use of marijuana as psychoactive drug. Nevertheless, hemp - the Cannabis sativa type with low concentrations of intoxicating Δ9-tetrahydrocannabinoid - is experiencing resurged interest thanks to loosened cultivation restrictions and its potential as multipurpose bio-based crop. In fact, hemp has valuable applications, including production of medicines from its non-intoxicating cannabinoids, food, medical, and industrial uses of its seed oil rich in poly-unsaturated fatty acids, and production of fibers for textiles and industry from its stems. Recently, several hemp genomic and genetic resources have been developed, allowing for a significant expansion of the genetic knowledge on major hemp traits, as cannabinoids, oil, and fibers synthesis, and regulation of flowering and sex determination. Still, hemp is an under-improved crop, whose advancement will depend on the ability to expand and collectively use the novel resources available in light of the fast advancements in bioinformatics and plant phenotyping technologies. This review discusses on the current genetic and genomic knowledge on the most important hemp traits, and provides a perspective on how to further expand such knowledge and tackle hemp improvement with the most up-to-date tools for plant and hemp research.

The Influence of Hemp Fibers (Cannabis sativa L.) on the Mechanical Properties of Fiber-Gypsum Boards Reinforcing the Gypsum Matrix.

The modern construction industry is looking for new ecological materials (available, cheap, recyclable) that can successfully replace materials that are not environmentally friendly. Fibers of natural origin are materials that can improve the properties of gypsum composites. This is an important issue because synthetic fibers (hardly biodegradable-glass or polypropylene fibers) are commonly used to reinforce gypsum boards. Increasing the state of knowledge regarding the possibility of replacing synthetic fibers with natural fibers is another step towards creating more environmentally friendly building materials and determining their characteristics. This paper investigates the possibility of manufacturing fiber-gypsum composites based on natural gypsum (building gypsum) and hemp (Cannabis sativa L.) fibers grown in Poland. The effect of introducing hemp fibers of different lengths and with varying proportions of mass (mass of gypsum to mass of fibers) into the gypsum matrix was investigated. The experimental data obtained indicate that adding hemp fibers to the gypsum matrix increases the static bending strength of the composites manufactured. The highest mechanical strength, at 4.19 N/mm2, was observed in fiber-gypsum composites with 4% hemp fiber content at 50 mm in length. A similar trend of increased strength was observed in longitudinal tension. Again, the composite variant with 4% fiber content within the gypsum matrix had the highest mechanical strength. Manufacturing fibers-gypsum composites with more than 4% hemp fiber content negatively affected the composites' strength. Mixing long (50 mm) hemp fibers with the gypsum matrix is technologically problematic, but tests have shown a positive effect on the mechanical properties of the refined composites. The article indicates the length and quantity limitations of hemp fibers on the basis of which fiber-gypsum composites were produced.

Physico-Mechanical Characteristics of Gypsum-Fiber Boards Manufactured with Hydrophobically Impregnated Fibers.

Although gypsum-based building materials exhibit many positive characteristics, solutions are still being searched for to reduce the use of gypsum or improve the physico-mechanical properties of board materials. In this study, an attempt was made to produce gypsum boards with hemp fibers. Although hemp fibers can be a specific reinforcement for gypsum-based board materials, they negatively affect the gypsum setting process due to their hygroscopic characteristics. Fibers impregnated with derivatives based on polyvinyl acetate, styrene-acrylic copolymer and pMDI (polymeric diphenylmethane diisocyanate) were used in this study. Gypsum-fiber boards produced with impregnated fibers showed approximately 30% higher mechanical properties as determined by the 3-point bending test. The positive effect of the impregnates on the hemp fibers was confirmed by FTIR (Fourier-transform infrared spectroscopy) and TG/DTA (thermogravimetric analysis/thermal gravimetric analysis) analysis.