Natural Reinforcement Research Articles

Morphological and physico-mechanical properties of mycelium biocomposites with natural reinforcement particles

Mycelium biocomposites represent a potential sustainable lightweight alternative materials due to their low energy consumption and lack of pollution to the environment. However, the low compression strength of mycelium biocomposites limits its application. In this study, three fungal strains (Pleurotus ostreatus, Oudemansiella radicata, and Acremonium sp.) were incubated in substrates (cotton stalk, wheat bran, and natural reinforcement particles (NRPs)) to obtain mycelium biocomposites. The physico-mechanical properties, morphological properties, and thermogravimetric analysis were examined. The colonization periods of the mycelium biocomposites varied with the different fungi, and adding NRPs to the substrates obviously improved the physico-mechanical properties of the mycelium biocomposites. The Pleurotus ostreatus biocomposites with 37.5% NRP had the highest UCS strength of 508 kPa and Young’s modulus of 38.5 MPa, which satisfies the requirements of backfill materials in geotechnical engineering, and its cohesion and internal friction angle were 178 kPa and 21.8°, respectively, based on triaxial tests. Moreover, although the addition of NRP will increase the density of the material, the density of mycelium biocomposites with NRP (0%–37.5%) only ranged from 0.310 g/cm3 to 0.413 g/cm3. The water absorption characteristics of the mycelium biocomposites with NRP were similar to those without NRP. The permeability coefficient decreased slightly with increasing NRP content, and the decreased percentage was related to the mycelium growth. All mycelium biocomposites showed lower thermal stability but a higher residue mass than EPS (expanded polystyrene). The results illustrate that the mycelium biocomposites proposed in this study could be used as lightweight backfill materials that are widely needed in geotechnical engineering.

Theoretical Study of the Effect of Thermal Stress on Transversal Damage of Hybrid Biocomposite Materials Flax-hemp/Polyethylene

Background: The objective of sustainable development in the field of materials necessitates and demands the substitution of the basic constituents of a composite material (carbon, glass, etc.) by natural reinforcements, which have a very important role in the protection of the environment and to subsequently have new materials with good properties compared to socalled traditional materials. Objective: In this context, we have investigated using genetic modeling based on probabilistic models the effect of thermal stress on transversal damage of a bio-composite hybrid Flax- Hemp/PE material. Methods: Our model genetic is based on probabilistic models of Weibull and the different values of the thermal stress were calculated by the Lebrun equation. To validate our theoretical calculations, we used the nonlinear parameter β in the Hoock law of the nonlinear acoustic technique to trace the curves of the damage under the mechanical and thermal stress. Results: The results obtained with a genetic simulation are in good agreement with the results found by Clément Gourier and Raphaël Kueny, who have shown that flax and hemp fibers (bark/Liberian fibers) are good reinforcements of the Polyethylene matrix; we found also found that our hybrid biocomposite material Flax-Hemp/PE is resistant in particular, a part of this material is of plant origin and gives us environmental benefit. Conclusion: It should be noted that the results obtained by the genetic simulation are in good agreement with the results obtained by the nonlinear acoustic technique mentioned by the green curve in all the figures. In perspective, it would be interesting to see, later, the effect of humidity on the damage of the matrix fiber interface of a hybrid biocomposite.

Fourier-Transform Infrared Spectroscopy and Thermal Investigation of Hybrid Banana/Sisal Fiber Reinforced Polyester Matrix Composite

The key focus of this work was to examine the effect of hybrid fiber reinforcement on thethermal properties of particulate based natural fiber-reinforced hybrid composites. Banana and sisal fiberswere selected as natural fiber reinforcements for the polyester matrix based composites, which wereproduced by mechanical stir mix technique. Thermo-Gravimetric Analysis (TGA) and Fourier-TransformInfrared Spectroscopy (FTIS) were conducted in accordance with American Society for Testing andMaterials (ASTM) standards for the characterization of the hybrid composites. The FTIS result shows thedisappearance of 1735 cm-1 peak, a notable evidence of NaOH treatment. The thermal analysis showedthat the hybridization significantly affected the high temperature stability of the composite, with 70%Sisal/30%Banana found to have the lowest high temperature mass loss at a temperature of 300–520oC, thushighest high temperature stability. Derivative Thermogravimetry (DTG) results shows a minor mass lossrate at a temperature range of 50–150oC as well as a major mass loss rate due to pyrolysis of key fiberconstituents such as cellulose, hemicellulose and lignin between 260 and 350oC. Also it was observed thatas the percentage of banana in the hybrid fiber increases the speed of high temperature mass loss reduces.

The influence of different parameters in tribological characteristics of pineapple/sisal/TiO2 filler incorporation

In this experimentation hybrid composites using natural fibers and titanium oxide (TiO2) nano filler were fabricated using compression moulding technique. Pineapple (P) and Sisal (S) fibers were used as the natural reinforcements with epoxy as the matrix material. The mechanical results of flexural, impact and tensile properties found good improvement in the properties with SP fiber reinforcement (1:1 ratio) and TiO2 filler addition. The combination with 40 wt.% SP/5 wt.% TiO2 observed better mechanical results. The Taguchi optimization results showed lower Specific Wear Rate (SWR) by the incorporation of high TiO2 filler (5 wt.%) addition with the polymer-based composites. The filler substitutes replace the vacant space between fiber/matrix phase and add to the properties. The multi response optimization with TOPSIS proved that hybrid SP has the high influence in overall tribological properties of the natural fiber composites with rank 1 followed by filler incorporation. The results showed combination with 5 wt.% TiO2/20 wt.% SP Hybrid fiber/500 m Sliding distance/Sliding speed of 1 m/s and applied load of 5 N having optimized results.

Mechanical and durability properties of adobe blocks filled with date palm wastes

PurposeEarthen construction does not meet today’s requirements due to certain limitations such as low water resistance and its high vulnerability to cracking damage. The purpose of this study is to improve the mechanical properties and low durability of adobe blocks by incorporating date palm wastes as a natural reinforcement and lime as a stabilizer.Design/methodology/approachSoil from the region of Biskra in Algeria was mixed with sand and lime in suitable ratios. Then, date palm wastes were added to the previous mixture at different ratios (0.3%, 0.6% and 0.9%) by dry mix weight to manufacture adobes. Cubical and cylindrical specimens were prepared and tested in a laboratory to investigate the curing time, mechanical and durability characteristics of the formulated blocks. In addition, X-ray diffraction and scanning electron microscopy (SEM) tests were used to identify the materials.FindingsIt has been observed that the addition of lime to the soil is very beneficial for its stabilization, in particular for an optimum of 12%. The presence of date palm waste in the mixture (soil + lime) generated a significant improvement in tensile strength reaching a rate of about 67%. The same observation was made for the tests of resistance to dry abrasion, resistance to erosion, attack by external sulphate and wetting/drying. However, for cases of compressive strength, water absorption and swelling an unfavorable effect was recorded.Originality/valueBased on the above-mentioned findings, this paper presents a novel solution to increase the durability of adobe materials using date palm wastes with oven curing at 65°C for about nine days. Adopting such an approach would certainly encourage building durable mud housing on a large scale. This can contribute to solving the acute housing shortage, particularly in poor countries.

Effect of different chemical treatments and loadings of Arundo donax L. fibers on the dynamic mechanical, thermal, and morphological properties of bisphenol A aniline based polybenzoxazine composites

AbstractIn this research paper, bisphenol A aniline based benzoxazine (BA‐a) was reinforced with natural, inexpensive, and largely distributed cellulosic plant, namely Arundo donax L. (AD) at various loadings of 5, 15, and 25 wt%. AD fibers were initially subjected to three different chemical surface modifications using alkaline, silane, and combined alkali‐silane solutions. The main purpose of this work was to investigate the dynamic mechanical properties, morphological stability, and thermal stability of the as‐prepared composites by pointing out the effects of natural reinforcements treated in different ways at different loadings. Dynamic mechanical analysis of the prepared composites revealed an enhancement in storage modulus (E′) and loss modulus (E″) to higher values, especially for composites reinforced by alkali‐ or combined‐treated fibers due to the strong effect of alkaline solution to remove noncellulosic matters. Composite loaded at 25% of alkali‐silane treated AD exhibited a glass transition temperature (Tg) of 217°C, while pure polymer had a Tg of 188°C. The enhanced properties are a great indicator of the high fiber–matrix adhesion and compatibility. This conclusion is strengthened by scanning electron microscopy images. The thermal stability and degradation of the different biocomposites are also investigated by thermogravimetric analysis, revealing that the nature of the employed chemical treatment affected considerably the thermal behavior and the char yield of the composites.

Green epoxy resin/date stone flour biocomposites: Effect of filler chemical treatments on elastic properties

AbstractThis work aims to study the effect of chemical treatments of date stone flour (DSF) as a filler on the elastic properties of biocomposites based on green epoxy resin (GER) used as a matrix. The main disadvantages of natural reinforcements in biocomposites are the poor compatibility between the reinforcement and the matrix as well as the relatively high moisture sorption. Different chemical treatments using soda (alkaline), benzoyl chloride, and potassium permanganate were applied to the DSF filler. Then, the filler was incorporated into the matrix at 30 wt% to obtain GER/DSF biocomposites. The elastic properties of the biocomposites, namely, longitudinal modulus, shear modulus, bulk modulus, Young's modulus of elasticity, acoustic impedance, Poisson's ratio, and ultrasonic microhardness, were determined using ultrasonic through‐transmission method. In addition, the morphology was studied using microscopy analysis. The results obtained revealed a decrease of the elastic properties of the pretreated‐filler biocomposite compared to the pure GER. On the other hand, the chemical treatment of the filler leads to an improvement of the elastic properties of GER/DSF biocomposites. The permanganate treatment is the most suitable for GER/DSF biocomposites. The morphology analysis through optical microscopy and scanning electron microscopy showed that chemical treatments enhance the interfacial adhesion between the DSF filler and the GER matrix.

Tribological characteristics of AA7075 composites reinforced with rice husk ash and carbonized eggshells

This paper investigates dry sliding friction and wear behavior of AA7075 composites reinforced with rice husk ash and carbonized eggshells. Composites with varying weight percentages of rice husk ash and carbonized eggshells in the range of 0–5 wt.% were fabricated through stir-casting technique. Density, porosity content, and microhardness were computed before tribological testing. Friction and wear tests were conducted on pin-on-disc type tribometer at room temperature. The samples were tested at different loads (10–50 N) with constant speed of 1 m/s and constant sliding distance of 1500 m. Samples were also tested at different sliding speeds (3 and 5 m/s) with constant normal load of 30 N. The addition of natural reinforcements decreased the density of composites. Microhardness of sample having 5 wt% rice husk ash increased by 15.08% over base composition. Maximum wear resistance was shown by sample with 5 wt% rice husk ash. Highest coefficient of friction was shown by sample with 3.75 wt% rice husk ash and 1.25 wt% carbonized eggshells. Wear loss varied directly with increasing load and sliding speeds for all composites, whereas coefficient of friction increased with increasing load and decreased with increasing sliding speed for all composites. Delamination and ploughing are dominant wear mechanisms at low speed whereas ploughing is the dominant wear mechanism at high speed as depicted by scanning electron microscopic images of worn surfaces. Composites with improved wear-resistant properties can be used for different tribological applications particularly in automotive industry.

Extrusion and injection moulding induced degradation of date palm fibre - polypropylene composites

The use of date palm fibres, which are an abundant by-product of agriculture, as natural reinforcement in polypropylene (PP) was studied. Because odour emissions are one of the major challenges for natural fibre-based composites, the emission of Volatile Organic Compounds (VOC) generated at different processing steps was analysed online. The severest degradation on the date palm fibre morphology was observed at the injection moulding step, but even when degradation occurred date palm fibres were an effective reinforcement of PP and increased the Young's modulus significantly. Generation of odorous compounds caused by thermal degradation of date palm fibres such as furfural alcohol or methyl furfural was astonishingly low during the twin-screw extrusion and granulation process. In coherence with the evolution of the fibre morphology, the most critical processing step was the injection process. In conclusion, date palm fibres are a promising natural fibre for the production of natural fibre-based composites. Adapted twin-screw extrusion conditions allow for minimizing VOC emissions, but particular attention needs to be given to the optimization of the injection process.

Characterization of Natural Reinforcements and their Composites

In this study, the mechanical properties of flax, jute and jute/carbon woven fabrics, and their composites were investigated and compared with 3K carbon fabric composites. Mechanical properties of yarn, fabric and composites were separately investigated and compared for each scales. In addition, yarn and fabric structures were characterized. It was found that, fabric structure, yarn physical properties and fiber cross-section and fiber molecular structure parameters of reinforcement have seriously effect on the composite mechanical properties. It can be concluded that fabric tensile strength attribute to composite tensile strength, but there was not a direct relation between fabric tensile strength and composite tensile strength. The tensile strength of natural fiber fabrics were determined to be significantly reduced depending on the temperature increasing. This condition should be considered as a important limitation for composite applications of natural fibers. Mechanical test results are proved that natural fiber composites not to be an important alternative to conventional composites.

Characterization of the Bioplastic Cups from Cassava Starch (Manihot esculenta Crantz) with the Addition of Coconut Fiber Powder

The accumulation of plastic waste in Indonesia has increased from year to year. This plastic waste is in the form of single-use plastic bags, plastic cups, plastic bottles, plastic straws, styrofoam from restaurants, packaged drinks, snack packaging, and so on. Therefore, efforts are made to synthesize the raw materials for making plastics or polymers that can be properly degraded by soil microorganisms called biodegradable plastics. Starch is a potential raw material for making bioplastics. However, the use of starch as a material for making bioplastics is considered fragile so it needs a natural reinforcement, namely a coconut fiber powder. This study aims to see the effect of adding coconut fiber powder to bioplastic glass. Bioplastic cups are made from cassava starch and glycerol with the addition of coconut fiber powder as a reinforcement. The research methode used a completelyrandomized design using 1 factor, namely the addition of coconut fiber powder with 4 levels of treatment. The results showed that, in testing the solubility of bioplastic glass experienced the greatest weight reduction in treatment P3 with a value of 0.85%, in testing the resistance to hot water, bioplastic glass experienced the greatest weight loss in treatment P0 with the weight loss value at 80 ° C was 0.55 % and at a temperature of 100 ° C of 1.66%, in the biodegredable test, the bioplastic glass experienced the greatest weight loss in treatment P1 with a value of 0.60%.

Tensile strength evaluation of glass/jute fibers reinforced composites: An experimental and numerical approach

Polymer-based composites have an exceptional perspective to replace traditional structural materials like steel and aluminium, owing to their low weight, high strength, and outstanding performance at elevated temperatures. However, the utilization of natural reinforcements for functional polymer composites is still in infancy. In this study, the tensile properties of natural and synthetic fiber-reinforced hybrid composites are reported. Glass-jute hybrid composites, prepared through hand layup technique, were used with different glass and jute fiber stacking sequences. The experimental results stipulate that the tensile properties of glass fiber reinforced polymer (GFRP) were merely affected at lower jute fiber concentration. The strength of composites consisting of single jute fabric lamina and four glass-fiber laminas were comparable with five-laminas GFRP composites. For validation of the experimental tensile testing results, a numerical simulation was also executed. Errors between experimental and numerical simulations were found for different stacking sequences due to non-uniformity in jute fiber diameter and the manufacturing process adopted for these hybrid composites. Fractographic analysis revealed the micro voids and adhesive failure at different joining layers of fibers as the primary cause of delamination.

Development and Characterization of Environmentally Friendly Wood Plastic Composites from Biobased Polyethylene and Short Natural Fibers Processed by Injection Moulding.

Environmentally friendly wood plastic composites (WPC) with biobased high density polyethylene (BioHDPE) as the polymer matrix and hemp, flax and jute short fibers as natural reinforcements, were melt-compounded using twin-screw extrusion and shaped into pieces by injection molding. Polyethylene-graft-maleic anhydride (PE-g-MA) was added at two parts per hundred resin to the WPC during the extrusion process in order to reduce the lack in compatibility between the lignocellulosic fibers and the non-polar polymer matrix. The results revealed a remarkable improvement of the mechanical properties with the combination of natural fibers, along with PE-g-MA, highly improved stiffness and mechanical properties of neat BioHDPE. Particularly, hemp fiber drastically increased the Young’s modulus and impact strength of BioHDPE. Thermal analysis revealed a slight improvement in thermal stability with the addition of the three lignocellulosic fibers, increasing both melting and degradation temperatures. The incorporation of the fibers also increased water absorption due to their lignocellulosic nature, which drastically improved the polarity of the composite. Finally, fire behavior properties were also improved in terms of flame duration, thanks to the ability of the fibers to form char protective barriers that isolate the material from oxygen and volatiles.

Assessment of Impact Energy, Wear Behavior, Thermal Resistance and Water Absorption Properties of Hybrid Bagasse Fiber/CaCO3 Reinforced Polypropylene Composites

Abstract To harness the inherent advantages of both synthetic and natural reinforcements, mercerized bagasse fibers (BF) and particulate calcium carbonate (CaCO3) were utilized as a complementing reinforcement for the fabrication of bagasse fiber/calcium carbonate (BF/CaCO3) polypropylene composites. Two sets of composites were produced – one with mercerized BF/CaCO3 and the other with unmercerized BF/ CaCO3. The effect of reinforcement loading on the impact energy, wear behavior, thermal resistance and water absorption properties of the composites were studied. Results showed that the mercerized BF/CaCO3 hybrid reinforced polypropylene composites exhibited significant increase in impact energy and offered better resistance to weight loss during wear test. Similarly, the thermal resistance of the mercerized composites was higher than their corresponding unmercerized composites. Additionally, water absorption in mercerized composites was highly resisted than in unmercerized samples. These results indicated that mercerization treatment and reinforcement hybridization improved the impact energy, wear, thermal resistance and water ingress resistance of hybrid fiber/ particulate reinforced polypropylene composites.

Experimental characterization of natural fibre\u2013soil interaction: lessons for earthen construction

Earthen construction materials are the subject of renewed interest due to the rising alarm about environmental pollution from the construction industry. Current research efforts are focused on improving the mechanical properties of earthen materials to make them modern and competitive. To increase strength and improve ductility fibres can be added to the soil mixture and if natural fibres are used one achieves stabilisation in an environmentally friendly way. Several previous studies have dealt with the behaviour of this composite material at a macroscopic level and on the general interaction between fibres and soil, but there is little published research on the interfacial mechanical interaction between natural fibre reinforcement and a soil matrix which is key to the former. This paper attempts to fill this gap by presenting and discussing laboratory results from a large campaign of pull-out tests conducted on composite earthen samples. The variables investigated here are the nature of the fibres (i.e. single or collections twisted together) and the use of fibre treatments such as PVA glue and baking soda. In the study both fibre–soil failure and soil-soil failure are investigated and the results lead to conclusions as to appropriate use of fibres to reinforce earthen construction materials.

Evaluation of Interface Shear Strength of Natural Kenaf Geogrid and Recycled Concrete Aggregate for Sustainable Pavement Applications

ABSTRACT In this research, a natural kenaf geogrid was used to reinforce recycled concrete aggregate (RCA) as a base/subbase material. The interface shear behavior of kenaf geogrid-reinforced RCA was investigated using a large-scale direct shear test (LSDT). The influence of aperture sizes of geogrid, gradations of RCA, and normal stress on the interface friction angle (δ) and adhesion (c a ) of kenaf geogrid-reinforced RCA was evaluated. The interface shear strength of kenaf geogrid-reinforced RCA were found to be dependent upon the gradation of RCA and the aperture size of kenaf geogrids (D). The higher D resulted in the higher δ, while exhibited less effect on c a of the large-sized RCA samples. Furthermore, it was found that the higher D resulted in the higher c a of the small-sized RCA samples and indicated less influence on the δ. A practical correlation between the interface shear strength coefficient (α) and D/F D ratio, where F D is RCA particles finer than D, is proposed for the rapid estimation of the interface shear strength between the kenaf geogrid and RCA. The outcome of this research will lead to the promotion of using kenaf geogrids as a natural reinforcement in waste RCA for sustainable pavement base/subbase applications.

Development of advanced bamboo stem derived chemically designed material

The present work reports a novel process for developing advanced chemically designed materials by utilizing both bamboo stem and fly ash's inherent chemical and complementary properties. The process involves forming unique heterogeneous tailored precursor material using treated bamboo stem and Class F-fly ash to develop advanced chemically designed material in a Panel form. In the process, the bamboo stem plays a dual role by helping in the in-situ formation of chemicals like sodium silicates; sodium lignates etc. which are essential for the formation of geo polymeric moieties during the reaction processing in the developed product. The other is the so formed cellulosic derived fibers are used as natural reinforcement fibres.

Improvement of the impact resistance of natural fiber–reinforced polypropylene composites through hybridization

AbstractPolypropylene (PP) hybrid composites were prepared by the combination of natural reinforcements and poly(ethylene terephthalate) (PET) fibers. Wood, flax, and sugar palm fibers were used to increase stiffness and strength, while PET fibers served to improve impact resistance. Interfacial adhesion was increased by using a maleated PP (MAPP) coupling agent. The hybrid composites containing 20 wt% of the natural fibers were homogenized in a twin‐screw compounder and then injection molded into standard tensile specimens. The amount of PET fibers was changed from 0 to 40 wt% in the composites. Tensile and impact testing, acoustic emission measurements, and scanning electron microscopy (SEM) were used for the characterization of the composites as well as to follow deformation and failure processes. The results proved that the concept of using PET fibers to improve impact resistance works with all natural fibers. Local deformations, the debonding or pullout of the PET fibers, initiate the plastic deformation of the matrix, which consumes considerable energy. The fracture of PET fibers might also contribute to energy absorption. The type of natural fiber does not influence the effect; the amount of PET fibers determines fracture resistance. The improvement of interfacial adhesion by coupling increases strength and slightly improves impact resistance. The overall properties of the hybrid composites prepared are acceptable, sufficiently large stiffness and impact resistance being achieved for a large number of structural applications.

About the Mechanical Properties for a Type of Green Composites with Hybrid Dammar/Sandarac Matrix and Natural Reinforcements

AbstractThis paper presents the mechanical properties for sandwich core strips with a 60% sandarac combination core and 40% Resoltech 1050 epoxy resin with 1055 hardener, and the upper and lower layers reinforced with cotton, silk and linen fabric, and the matrix is a combination of 60% dammar resin and 40% Resoltech 1050 epoxy resin with 1055 hardener. For these materials, there is determined: static mechanical properties from tensile stress (Young elastic modulus, yield strength, breaking strength) and chemical composition by energy dispersive spectroscopy analysis with an scanning electron microscope. It is observed that the dammar resin, in all the cases, has increased mechanical characteristics compared to sandarac. Also, the samples reinforced with cotton show better mechanical properties compared to the ones reinforced with flax and silk.

Mechanical properties and sustainability aspects of coconut fiber modified concrete

Coir fiber has been examined for their suitability as reinforcement of concrete. Mechanical properties and sustainability aspects of concrete composites were estimated after 7. 14, and 28 days of curing. Natural reinforcement of 0.46 and 0.62% by weight of coir fiber was added. Fibers were analyzed by means of scanning electron microscope (SEM). Besides, an Eco-audit tool has been used to estimate energy and carbon emission of material, manufacturing, transportation, and disposal phases. It was found that fibers additions lowered the compressive strength compared to plain concrete. However, failures of the composites exhibited good post-cracking behavior. The use of vegetable fibers affects positively the life cycle of the material. Eco-audit results indicate that there is a potential to reduce between 9.15% and 13.35% of embodied energy and between 9.61% and 13.94% of CO2 during the material production phase. These suggest that coir fibers could be useful from the environmental view, although more studies regarding their durability are needed.