Effects of fiber loadings and lengths on mechanical properties of Sansevieria Cylindrica fiber reinforced natural rubber biocomposites

© 2023 The Author(s). Published by IOP Publishing Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/In this present investigation, Sansevieria cylindrica fiber was used as a reinforcement in a natural rubber matrix. Various biocomposite samples with different fiber contents (lengths and loadings) were fabricated, using compression molding process and vulcanizing technique by maintaining the temperature around 150 °C. From the results obtained, mechanical properties: tensile strength, modulus elongation at break and tear strength of 10.44 MPa, 2.36 MPa, 627.59% and 34.99 N respectively, were obtained from the optimum composite sample with length and loading of 6 mm and 20 wt% composition, respectively. The maximum hardness was observed at 76.85 Shore A from the composite sample of 6 mm and 40 wt%. The optimum properties can be attributed to the presence of strong interfacial adhesion between the Sansevieria cylindrica fiber and the natural rubber matrix. The mechanisms of failure of the biocomposites at their interfaces were examined and analyzed, using scanning electron microscopy (SEM). The micrographs obtained from SEM further confirmed that the Sansevieria cylindrica fibers were surrounded with more amount of natural rubber which can exhibit strong interfacial bonding between fiber and matrix. The optimal composites of this work can be used in general, abrasion resistant conveyor belt.Peer reviewe

Physical, Chemical, and Mechanical Characterization of Natural Bark Fibers (NBFs) Reinforced Polymer Composites: A Bibliographic Review

The specific interest for the use of bark in materials, instead than for energy recovery, is owed to circular economy considerations, since bark fibers are normally byproducts or even waste from other sectors, and therefore their use would globally reduce the amount of refuse by replacing other materials in the production of composites. For the purpose of promoting their application in polymer composites, mainly under a geometry of short random fibers, bark fibers are extracted and treated, normally chemically by alkali. Following this, investigations are increasingly carried out on their chemical composition. More specifically, this includes measuring cellulose, hemicellulose, and lignin content and their modification with treatment on their thermal properties and degradation profile, and on the mechanical performance of the fibers and of the tentatively obtained composites. This work aims at reviewing the current state of studies, trying to elicit which bark fibers might be most promising among the potentially enormous number of these, clarifying which of these have received some attention in literature and trying to elicit the reason for this specific interest. These can be more thoroughly characterized for the purpose of further use, also in competition with other fibers not from bark, but from bast, leaves, etc., and pertaining to developed production systems (cotton, hemp, flax, jute, etc.). The latter are already widely employed in the production of composites, a possibility scantly explored so far for bark fibers. However, some initial works on bark fiber composites and both thermoplastic and thermosetting are indicated and the importance of some parameters (aspect ratio, chemical treatment) is discussed

Effect of Alkali Treatment on the Properties of Acacia Caesia Bark Fibres

As possible substitutes for non-biodegradable synthetic fibre, ligno-cellulosic fibres have attracted much interest for their eco-friendliness; a large number of them are already used for the production of green polymer composites. The search for further green candidates brings into focus other fibres not previously considered, yet part of other production systems, therefore available as by-products or refuse. The purpose of this study is to explore the potential of alkali treatment with 5% sodium hydroxide (NaOH) to enhance the properties of bark-extracted Acacia Caesia Bark (ACB) fibres. The microscopic structure of the treated fibres was elucidated using scanning electron microscopy (SEM). Moreover, the fibres were characterised in terms of chemical composition and density and subjected to single-fibre tensile tests (SFTT). Following their physico-chemical characterisation, fibre samples underwent thermal characterisation by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and their crystallinity was assessed using X-ray diffraction (XRD). This level of alkali treatment only marginally modified the structure of the fibres and offered some improvement in their tensile strength. This suggested that they compare well with other bark fibres and that their thermal profile showed some increase of degradation onset temperature with respect to untreated ACB fibres. Their crystallinity would allow their application in the form of fibres with an average length of approximately 150 mm, even in thermoplastic biocomposites

Biowaste management: Comparison of banana (Musa acuminata) and bamboo (Bambusa vulgaris) fibers

© 2024, The Authors.Both developed and developing countries around the world are increasingly utilizing biodegradable products and bio-based materials. This is required to curb rampant environmental pollution caused by synthetic materials and their by-products. In this study, banana and bamboo fibers were prepared from agricultural and industrial wastes, respectively. Banana and bamboo fibers were obtained with aid of mechanical and waste extractions, respectively. Both fibers were subjected to a retting process for 24 hours, using normal warm water at a room temperature (27 ± 3 °C) to remove the impurities. Then, a comparative investigation and analysis was conducted concerning their properties and applications. The biomass level, physical, and chemical properties, structure, experimental analysis, and moisture regain behaviors of the plant materials were studied. Additionally, the antibacterial property of the samples was discussed. The biomass level was measured per hectare for banana (36.1 tons) and per plant for bamboo (65%), and the physical and chemical properties were identified via some basic testing techniques. The molecular, crystalline, and morphology structures were observed using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Finally, the industrial applications were elucidated to establish the possibility of using both fibers as promising sustainable, renewable, recyclable, and eco-friendly materials.Peer reviewe

Glass FRP-Reinforced Geopolymer Based Columns Comprising Hybrid Fibres: Testing and FEA Modelling

This study seeks to evaluate the effectiveness of glass-FRP-reinforced geopolymer concrete columns integrating hybrid fibres (GFGC columns) and steel bar-reinforced geopolymer concrete columns incorporating hybrid fibres (SFGC columns) under eccentric and concentric loadings. Steel fibre (SF) and polypropylene fibres (PF) are two types of fibres that are mixed into hybrid fibre-reinforced geopolymer concrete (HFRGC). Eighteen circular concrete columns with a cross-section of 300 mm × 1200 mm were cast and examined under axial loading up to failure. Nine columns were cast with glass-FRP rebars, whereas the other nine were cast with steel rebars. Using ABAQUS, a nonlinear finite element model was established for the GFGC and SFGC columns. The HFRGC material was modelled using a simplified concrete damage plasticity model, whereas the glass-FRP material was simulated as a linear elastic material. It was observed that GFGC columns had up to 20% lower axial strength (AST) and up to 24% higher ductility indices than SFGC columns. The failure modes of both GFGC and SFGC columns were analogous. Both GFGC and SFGC columns revealed the same effect of eccentricity in the form of a decline in AST. A novel statistical model was suggested for predicting the AST of GFGC columns. The outcomes of the experiments, finite element simulations, and theoretical results show that the models can accurately determine the AST of GFGC columns

Mechanical Property and Morphological Analysis of Polyester Composites Reinforced with Cyperus pangorei Fibers

In the present work, polyester composites reinforced with a newly identified Cyperus pangorei fiber (CPF) were developed by compression moulding technique. The effects of varying fiber content and fiber length on the mechanical properties of the Cyperus pangorei fiber reinforced polyester composites (CPFCs) such as tensile, flexural, and impact properties were studied. Mechanical strength of the CPFCs increased with fiber length up to 40 mm beyond which a reverse trend was observed. Based on the test results, it was concluded that the critical fiber length and the optimum fiber weight percentage were 40 mm and 40 wt% respectively. The maximum increase of 164% and 117% were found for the tensile and flexural strength of the composite with 40 mm fiber length and 40 wt% fiber content, respectively. On the other hand, a 64% increase in impact strength was noticed for the optimum case. The increasing contact surface between the fiber and the polyester matrix in optimum condition can restrict the probability of fiber pullout and in turn can make the composite carry more load. The chemical structure of CPF was also analyzed using Fourier-Transform Infrared Spectroscopy (FTIR) spectrum. The morphological analysis of fractured samples was performed using Scanning Electron Microscopy (SEM) to understand the interfacial bonding between CPFs and polyester matrix. The optimal composite can be a suitable alternative in the field of structural applications in construction and automobile industries

Wear Properties and Post-Moisture Absorption Mechanical Behavior of Kenaf/Banana-Fiber-Reinforced Epoxy Composites

The contribution of natural lignocellulosic fibers to the reduction in wear damage in polymer resins is of interest, especially when two of these fibers can combine their respective effects. Wear properties of hybrid kenaf/banana epoxy composites have been investigated using three different total amount of fibers, 20, 30 and 40 wt.%, at loading forces up to 30 N and to sliding distances of up to 75 m. This demonstrated that the introduction of the highest level of fibers proved the most suitable for consistency of results and containment of wear with increasing load, as was also found from the morphological evaluation of wear degradation using scanning electron microscopy (SEM). Subsequently, tensile, flexural and impact properties of as-received and post-water-saturation hybrid composites were examined. The tests revealed a limited reduction in tensile and flexural strength, not exceeding 10% of the initial values, which were very high compared to similar materials, almost reaching 140 MPa for tensile strength and exceeding 170 MPa for flexural strength. In contrast, a higher standard deviation of values was found for impact strength, although the decrease in average values was only slightly above 10%. The results suggest the availability of these hybrids for wear-resisting applications in high-moisture environments, and the even more limited water absorption conferred by banana fibers added to kenaf ones

Wear Properties and Post-Moisture Absorption Mechanical Behavior of Kenaf/Banana-Fiber-Reinforced Epoxy Composites

The contribution of natural lignocellulosic fibers to the reduction in wear damage in polymer resins is of interest, especially when two of these fibers can combine their respective effects. Wear properties of hybrid kenaf/banana epoxy composites have been investigated using three different total amount of fibers, 20, 30 and 40 wt.%, at loading forces up to 30 N and to sliding distances of up to 75 m. This demonstrated that the introduction of the highest level of fibers proved the most suitable for consistency of results and containment of wear with increasing load, as was also found from the morphological evaluation of wear degradation using scanning electron microscopy (SEM). Subsequently, tensile, flexural and impact properties of as-received and post-water-saturation hybrid composites were examined. The tests revealed a limited reduction in tensile and flexural strength, not exceeding 10% of the initial values, which were very high compared to similar materials, almost reaching 140 MPa for tensile strength and exceeding 170 MPa for flexural strength. In contrast, a higher standard deviation of values was found for impact strength, although the decrease in average values was only slightly above 10%. The results suggest the availability of these hybrids for wear-resisting applications in high-moisture environments, and the even more limited water absorption conferred by banana fibers added to kenaf ones

Properties of Biocomposite Films From PLA and Thermally Treated Wood Modified with Silver Nanoparticles Using Leaf Extracts of Oriental Sweetgum

The technological, thermal, and antimicrobial properties of biocomposite films produced from polylactic acid (PLA) and thermally treated wood flour with in situ generated nanosilver particles (AgNPs) using a bio-reduction method. The extracts of fresh leaves of the phenolic-rich Oriental sweetgum (Liquidambar orientalis) tree were used as the reducing agent for silver ions. Six different formulations of the mixed raw materials were extruded in the co-rotating twin screw extruder. The PLA bicomposite films at the 5 and 10 wt% loading levels of wood flour were produced by a hot press method from the following six formulations: (a) thermally treated wood + leaf extract + AgNO3, (b) untreated wood + leaf extract + AgNO3, (c) thermally treated wood + AgNO3, (d) untreated wood + AgNO3, (e) thermally treated wood, (f) untreated wood, and (g) neat PLA. All biocomposite films produced with the untreated/treated wood flour at 5 and 10 wt% loading levels of wood flour showed better tensile modulus than the neat PLA specimens. In general, the tensile strength of the biocomposites was negatively affected by the increased content of the wood flour. The spectra obtained from scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) showed the silver nanoparticles in the wood particles. The results showed that the biocomposite films produced with PLA and wood flour modified using silver nitrate and leaf extract had the highest tensile modulus. It was observed that the leaf extract treatment had a positive effect on the tensile properties of the biocomposite films at 10 wt% content of wood flour. The remarkable antimicrobial results was obtained by the prepared biocomposites treated with gram positive and gram negative clinical pathogens at maximum zone of clearance 2.6 mm treated with E.coli bacteria

Mechanical and Thermo-Mechanical Behaviors of Snake Grass Fiber-Reinforced Epoxy Composite

Snake grass fiber was used as a supporting material in an epoxy matrix. The goal was to develop a lightweight structural material. To enhance the interfacial bonding between the snake grass (Sansevieria ehrenbergii) fiber and polymer matrices, the fiber underwent chemical treatment with NaOH. Samples were prepared with both neat and treated fibers mixed with epoxy at various volume percentages. The mechanical properties of snake grass fiber exhibited improvement with increasing fiber length and fixation, reaching optimal values at 20 mm length and 20% v/v fixation. Dynamic mechanical analysis (DMA) demonstrated superior energy absorption by the composite up to 140 °C, irrespective of repetition. Thermogravimetric analysis (TGA) indicated rapid degradation of untreated fiber with a residue level of 0.2%, while the snake grass composite (25% v/v) exhibited stable residue content at 11%. Microscopic evaluation using a scanning electron microscope provided insights into the morphology of the fiber surface