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•“Hybrid” composites were manufactured using PLA through extrusion and injection moulding.•Sisal and hemp fibres were hybridized to develop sustainable composites.•Mechanical and ...thermal properties of the hybrid composites were evaluated.
Natural polymers based composites offers significant advantages over synthetic fibre reinforced petroleum matrix based composites with regard to biodegradability, biocompatibility, design flexibility and sustainability. This work reports for the first time manufacturing of hybrid fibre reinforced biodegradable composites using sisal and hemp fibre with polylactic acid employing melt processing and injection moulding techniques. Granulated sisal and hemp fibres were blended and hybrid composites were manufactured using aliphatic polyester made up of lactic acid (PLA) through extrusion and injection moulding and their performance was evaluated. Experimental results revealed that density, elongation at break and water absorption capacity of hybrid composites were 1.14 ± 0.07 g/cm3, 0.93 ± 0.35% and 1.06 ± 0.18% respectively. The achieved mean tensile strength (46.25 ± 6.75 MPa), Young’s modulus (6.1 ± 0.58 GPa) and specific tensile strength (38.86 ± 5.0) of hybrid fibre reinforced PLA composites were improved compared to neat PLA. The flexural strength (94.83 ± 11.21 MPa), flexural modulus (6.04 ± 0.55 GPA) and specific flexural strength (79.76 ± 8.80) of hybrid fibre composites also showed better performance than those of neat PLA. Incorporation of sisal and hemp fibre with polylactide remarkably increased the impact strength of composites. Overall, the hybrid composites demonstrated good performance suggesting that they have great potential for use as an environmentally friendly alternative material in automotive, packaging, electronics, interiors and agricultural applications.
► Chemical treatments alter the contents of fibre constituents. ► Fibre constituents such as cellulose, hemicellulose and lignin were separated from the treated fibres. ► Chemical and thermal ...behaviour of fibre constituents were analysed. ► Hemicellulose was less thermally stable than the cellulose and lignin. ► Hemicellulose was primarily responsible for moisture absorption of the fibre.
In this study, hemp fibres were treated with alkali, acetyl and silane chemicals. Fibre constituents such as cellulose, hemicellulose and lignin constituents were separated from treated fibres. The chemical and thermal influences of these constituents on the treated fibres were examined by using scanning electron microscope (SEM), fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Experimental results revealed that, hemicellulose was degraded faster than that of cellulose and lignin. Cellulose exhibited better thermal stability and lignin was degraded in a wide range of temperatures. The hydrophilic nature of the fibres was predominantly caused by the presence of hemicellulose and then lignin constituents. Hemicellulose and lignin were mostly removed by the alkalisation with higher concentrations of NaOH, followed by acetylation. Silane treatment could not remove the hemicellulose and lignin, rather this treatment facilitated coupling with the fibre constituents.
The construction sector, responsible for over one-third of global carbon emissions, is increasingly focusing on hemp-based construction materials to alleviate the environmental impact in the built ...environment; however, the lack of information and streamlined processes hinder widespread adoption. By conducting a comprehensive review of state-of-the-art research, this study explores the vast potential of hemp-based materials across the built environment, encompassing building and transportation applications. In this study, the material properties and application of hemp lime concrete for buildings, along with hemp fibre in asphalt for highways, are discussed, and crucial research gaps and technical challenges are identified. Employing a holistic sustainability approach, the material evaluation considers economic, social, and environmental factors. Notable hemp construction projects are presented as case studies, emphasising their environmental carbon credentials. Furthermore, technoeconomic challenges are scrutinised, and effective solutions are proposed. Beyond its role as a wall material, hempcrete's significant application as building insulation material is highlighted due to its exceptional hygrothermal properties. The material also shows promise in enhancing asphalt mix for pavement construction. Evidence from life cycle analysis supports the claim that hempcrete can be considered a carbon-negative material. Moreover, the findings indicate that the hempcrete industry has the potential to yield various macroeconomic and socio-economic advantages, including job creation, enhancing energy access, alleviating cost of energy, and improved societal health and well-being.
•The vast potential of hemp-based materials across built environment is explored.•Its economic, social and environmental factors and impacts are evaluated.•UK hemp projects showcase eco-friendly, carbon-friendly credentials.•Hemp reinforcement shows promise in enhancing sustainable asphalt mixes.•Hempcrete industry has the potential to yield various socio-economic advantages.
The textile waste fibre reinforced composites are sustainable in terms of their environmental and economic benefits. However, these composites have not attracted the attention of composite ...manufacturers. This research report waste cotton composites loaded with reduced graphene oxide (rGO) nanoparticles and enzyme-treated hemp fibre (HF) microparticles as a filler to improve their mechanical properties. The cotton/epoxy composite loaded with 0.3 wt% of rGO shows a ~11% increment in tensile strength, ~20% increment in flexural strength, and ~30% increment in impact strength. The cotton/epoxy composite loaded with 3 wt% of HF particles show enhancement in tensile, flexural, and impact strength by ~20%, ~14%, and ~116%, respectively. All the composites are thermally stable enough. The developed composites are potential materials for interior furniture of trains and buses.
•Textile waste reinforced composites are environmentally and economically beneficial.•Filler particles improve the mechanical properties of the textile waste composites.•The developed composites are the potential replacement for wood and particleboards.
The bonding between the masonry unit and mortar plays very important role in strength of masonry. To improve the bond strength, we need to concentrate on the mortar properties. The present study ...focusses on the bond strength of masonry by adding reinforcement for the mortar. The hemp fibre and chicken mesh are used as a reinforcement for the mortar. For the test masonry triplets are used with mortar of proportion 1:4. The optimum dosage for hemp fibre is found to be 2% and chicken mesh is added along with mortar joints. The bond strength was tested in universal testing machine and the results have compared each other. From the study it was found that, the bond strength of hemp fibre reinforced triplets is found to be 27% higher than the chicken mesh reinforcement and 73% higher than the unreinforced mortar masonry.
Over the last several decades,
L. has become one of the most fashionable plants. To use the hemp potential for the development of a sustainable textile bio-product sector, it is necessary to learn ...about the effect of the processes creating hemp's value chain on fibre properties. This review presents a multi-perspective approach to industrial hemp as a resource delivering textile fibres. This article extensively explores the current development of hemp fibre processes including methods of fibre extraction and processing and comprehensive fibre characteristics to indicate the challenges and opportunities regarding
L. Presented statistics prove the increasing interest worldwide in hemp raw material and hemp-based bio-products. This article discusses the most relevant findings in terms of the effect of the retting processes on the composition of chemical fibres resulting in specific fibre properties. Methods of fibre extraction include dew retting, water retting, osmotic degumming, enzymatic retting, steam explosion and mechanical decortication to decompose pectin, lignin and hemicellulose to remove them from the stem with varying efficiency. This determines further processes and proves the diversity of ways to produce yarn by employing different spinning systems such as linen spinning, cotton and wool spinning technology with or without the use of the decortication process. The aim of this study is to provide knowledge for better understanding of the textile aspects of hemp fibres and their relationship to applied technological processes.
•We examined durability of NaOH treated hemp fibre fly ash alkali-activated mortars.•We tested mortars’ properties prior and after 10 wet/dry cycles.•NaOH fibres treatment separates fibre bundles and ...increases their roughness.•Treated fibres increase physical properties of mortars prior and after the cycles.•Treated fibres increase mechanical properties of mortars prior and after the cycles.
The conducted study investigates the influence of sodium hydroxide-treated hemp fibres on fibre reinforced fly ash-based alkali-activated mortars and their durability under wet/dry cycles, by examinating mortars’ physical and mechanical properties. This is the first study where the natural fibre reinforced alkali-activated materials under wet/dry cycles are examinated.
The sodium hydroxide treatment of hemp fibres leads to separation of fibre bundles and increases the fibres’ surface roughness. This leads to the mortar’s porosity and water absorption decrease, the mortar’s compressive and flexural strength increase and importantly energy absorption capacity increase, all prior and after wet/dry cycles.
The focus of this work was to produce short (random and aligned) and long (aligned) industrial hemp fibre reinforced polylactic acid (PLA) composites by compression moulding. Fibres were treated with ...alkali to improve bonding with PLA. The percentage crystallinity of PLA in composites was found to be higher than that for neat PLA and increased with alkali treatment of fibres which is believed to be due to the nucleating ability of the fibres. Interfacial shear strength (IFSS) results demonstrated that interfacial bonding was also increased by alkali treatment of fibres which also lead to improved composite mechanical properties. The best overall properties were achieved with 30
wt.% long aligned alkali treated fibre/PLA composites produced by film stacking technique leading to a tensile strength of 82.9
MPa, Young’s modulus of 10.9
GPa, flexural strength of 142.5
MPa, flexural modulus of 6.5
GPa, impact strength of 9
kJ/m
2, and a fracture toughness of 3
MPa
m
1/2.
New energy-efficient materials are increasingly used in architecture and civil engineering today. Many of these are based on the reuse of plants and plant residues from industry and agriculture for ...the production of bio-sustainable insulation materials, and as aggregates in concretes. This paper presents the results of our study of research into hemp concrete, an emerging material in the green building sector, since it first appeared about twenty-five years ago to the present day. The study centres on a growing bibliography over this period, emphasizing some fundamental parameters of hemp raw materials and related building materials, the binders used in the production of hemp aggregate concretes and assessments of different aspects of their performance. The most important properties of hemp concrete vary according to the quality of the plant aggregates, the choice of binders (typically aerial or hydraulic lime), the proportions of the raw materials and the application techniques. Organic aggregates are less stable than inorganic aggregates and are therefore more difficult to use in a concrete mix with both inorganic and organic binders. Among other reasons, this is due to the disproportionate amount of water required in the mixing of plant-based concretes and to the release of organic compounds, which can have serious effects on the hardening process. This problem was identified in scientific studies on the use of hemp concrete in sustainable, bioclimatic construction, whether applied as a semi-liquid mass or as a precast element. This new biomaterial offers excellent results in terms of its application on site and has important physical properties, such as high durability and easy conservation. This study seeks to provide a useful tool for future research into sustainable building materials, better use of available energy and plant-based resources and more efficient recycling of the waste produced by human activities.
•Smaller particle size responds with greater compressive and tensile strength.•Greater compressive strength behaves greater thermal conductivity.•Hemp concrete can be used both as construction and an insulation material.•The acoustic qualities of hemp concrete depend on its porous structure and particles size.•Systematic hemp research shows the great advantages in green construction.
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•Properties of cement mortars reinforced with hemp and Spanish broom fibers were compared.•pH-values of the treatment medium have a great influence on the degree of crystallinity ...within the fibers.•Natural fibers significantly increase the ductility of the mortar.•Mechanical properties of specimens with a lower proportion of natural fibers achieved better results.•The treatment with seawater is the most ecologically and economically acceptable method of fiber processing.
This paper presents experimental investigations into the behaviour of cement mortar micro-reinforced with natural hemp and Spanish broom fibres. The fibre treatment process was carried out with: alkali (2.5, 5, 6, 8, 10 and 15% NaOH solution, and 2.5 or 5% NaOH and 2% Na2SO3 mixed solution), seawater, and a combination of alkali (5% NaOH) and seawater. The changes in fibre structure caused by the chemical treatment were monitored by FTIR, TG/DTG and XRD analysis. Fibres were added to mortar specimens in amounts of 0.34, 0.5, 0.68 and 1 vol%. The flexural and compressive strengths were tested on mortar specimens after 56 days. The σ–δ diagrams are presented, and the specific fracture energy is determined based on the curve from the plot of load (N) vs. displacement (mm). The tensile strength of the fibres was determined on specimens treated in the same way. Treatment in different solutions showed that increased pH values of the treatment medium have a great influence on the increase in crystallinity, for both Spanish broom and hemp fibres. The results presented here showed that natural fibres do not have a significant influence on the mechanical properties of the mortar (compressive and flexural strengths), but do significantly increase its ductility. In addition, it has been shown that specimens with a lower proportion of natural fibres give better mechanical properties and higher ductility of the material. It was observed that both the mortar preparation and the method of fibre installation significantly affect the mortar properties. Seawater as a means of treating fibres was proven to be the most ecologically and economically acceptable treatment method. Spanish broom fibres showed large potential for reinforcing cement composites.
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