Showing papers on "SISAL published in 2017"

Hybridization Effect of Sisal/Glass/Epoxy/Filler Based Woven Fabric Reinforced Composites

Abstract: Development of the Polymer based Composites from both natural and synthetic fibers is a sustainable alternative material for some engineering fields like automotive and aerospace. This work is aimed to incorporate the sisal and E-glass fabrics with the epoxy matrix and by adding silicon carbide filler to the sisal fabrics. Five different composite laminates were prepared by hand layup combined with vacuum bagging method as per laminate sequences. The physical and mechanical properties of composite laminates were evaluated according to ASTM. Results show that incorporation of E-glass and silicon carbide filler can reduce the voids and enhance the physical properties. As the amount of E-glass fibers slightly grows, tensile properties of composites grow. Effect of filler can enhance the flexural properties. Failure of composites mainly occurs due to the poor interfacial bonding between fabrics and matrix, fabrics pull out and fracture occurs in fabrics or matrix when load is applied.

Mechanical properties of a polyurethane hybrid composite with natural lignocellulosic fibers

Abstract: Several low-cost hybrid composites composed of polyurethane and renewable natural fibers were developed and analyzed for their mechanical and physical properties. Composites were fabricated by replacing up to 20% w/w of the polyethylene glycol present in conventional polyurethane foams with one and the mixture of three natural fibers: sugarcane bagasse, sisal or rice husk. Prior to composite production, fibers were mercerized with sodium hydroxide and hydrogen peroxide to remove lignin and hemicellulose. A simplex-centroid mixture design model was used to evaluate the effects of the added fibers on composite properties such as resilience, elastic modulus and deformation under permanent compression. Obtained hybrid composites demonstrated up to 32% of resilience, 0.1 GPa of elastic modulus, and 7.32% of permanent deformation. In order to optimize these properties, fiber amounts were adjusted using a quadratic mathematical model, indicating that formulations containing only the rice husk or an 82/18 (% w/w) rice husk/sugarcane bagasse mixture will perform best. The obtained composite is a unique low cost material because is environmentally friendly and has a high potential for applications in shock absorption and padding materials, due its proven good resilience and elastic modulus.

Sisal (Agave sisalana) fibre and its polymer-based composites: A review on current developments:

Abstract: Nowadays, it has been global demand to overcome the abundant use of synthetic fibres with respect to save the environment. Sisal fibre is one of the widely used natural fibre and being used as rein...

Processing of PLA/sisal fiber biocomposites using direct- and extrusion-injection molding

Abstract: The processing strategy adopted to develop biocomposites plays a significant role in determining their characteristics. The present experimental investigation explores the feasibility of using direct-injection molding (D-IM) process for processing of sisal fiber (3 mm and 8 mm) reinforced poly-lactic acid biocomposites with a fiber weight fraction of 30%. For a comparative analysis, mechanical and morphological behavior of biocomposites developed using D-IM process is compared with biocomposites developed using extrusion-injection molding (E-IM) process. The mechanical behavior in terms of tensile, flexural and impact properties is compared and discussed in relation to extracted fiber morphology and fiber orientation as well as dispersion within the developed biocomposites. Morphological investigation of extracted fibers revealed severe fiber attrition and fiber length variation during E-IM process as compared with D-IM process. However, short sisal fiber (3 mm) reinforced biocomposites developed ...

Characterization of sisal/cotton fibre woven mat reinforced polymer hybrid composites:

Abstract: The present research work addressed the results of experimental investigation on the mechanical properties and free vibration behaviours of sisal/cotton fabric reinforced polyester hybrid composites. Influence of fibre content and changing layer pattern (CLP) on the mechanical properties and free vibration characteristics are analysed. Hybrid composites are fabricated with simple hand lay-up method followed by compression moulding process. Natural frequency and modal damping values of hybrid composites are analysed by experimental modal analysis. Mechanical properties of composites are measured according to ASTM standards. It is found that an increase in the lamina content in the composite increase the mechanical and damping properties. The maximum mechanical properties are obtained for 40% fibre volume fraction (Vf) in sisal and cotton direction. Maximum natural frequency is found at 40% fibre Vf. By CLP, mechanical properties and damping characteristics are found intermittence of sisal and cotton direct...

Delamination in Drilling of Sisal/Banana Reinforced Composites Produced by Hand Lay-Up Process

Abstract: Natural fiber composites are presently replacing the synthetic fiber in many fields. The present research work study is an attempt to manufacture and test the sisal/banana fiber reinforced polymer composites. Composite have been manufactured using banana and sisal fiber along with epoxy resin as reinforcement. With these composites drilling has been carried out to study the factors and combination of factors that influence the delamination of drilled unidirectional sisal-banana fiber reinforced composites. Drilling experiments were performed based on the L9-Taguchi method. Delamination factor evaluated for the selected parameters spindle speed, feed and diameter of the drill tool with the help of signal to noise ratio, ANOVA analysis and to obtain the conditions for minimum delamination.

Cassava starch-based nanocomposites reinforced with cellulose nanofibers extracted from sisal

Abstract: Cellulose nanofibers were extracted from sisal and incorporated at different concentrations (0–5%) into cassava starch to produce nanocomposites. Films' morphology, thickness, transparency, swelling degree in water, water vapor permeability (WVP) as well as thermal and mechanical properties were studied. Cellulose nanofiber addition affected neither thickness (56.637 ± 2.939 µm) nor transparency (2.97 ± 1.07 mm−1). WVP was reduced until a cellulose nanofiber content of 3.44%. Tensile force was increased up to a nanocellulose concentration of 3.25%. Elongation was decreased linearly upon cellulose nanofiber addition. Among all films, the greatest Young's modulus was 2.2 GPa. Cellulose nanofibers were found to reduce the onset temperature of thermal degradation, although melting temperature and enthalpy were higher for the nanocomposites. Because cellulose nanofibers were able to improve key properties of the films, the results obtained here can pave the route for the development and large-scale production of novel biodegradable packaging materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44637.

Chemically extracted nanocellulose from sisal fibres by a simple and industrially relevant process

Abstract: A novel type of acetylated cellulose nanofibre (CNF) was extracted successfully from sisal fibres using chemical methods. Initially, a strong alkali treatment was used to swell the fibres, followed by a bleaching step to remove the residual lignin and finally an acetylation step to reduce the impact of the intermolecular hydrogen bonds in the nanocellulose. The result of this sequence of up-scalable chemical treatments was a pulp consisting mainly of micro-sized fibres, which allowed simpler handling through filtration and purification steps and permitted the isolation of an intermediate product with a high solids content. An aqueous dispersion of CNF could be obtained directly from this intermediate pulp by simple magnetic stirring. As a proof of concept, the dispersion was used directly for preparing a highly translucent CNF film, illustrating that there are no large aggregates in the prepared CNF dispersion. Finally, CNF films with alkali extracts were also prepared, resulting in flatter films with an increased mass yield and improved mechanical strength.

Bacterial cellulose production by Komagataeibacter hansenii ATCC 23769 using sisal juice: an agroindustry waste.

Abstract: In this study, we have optimized production of bacterial cellulose (BC) by Komagataeibacter hansenii ATCC 23769 in a static cultivation using sisal juice, an agroindustrial residue, as substrate. Optimization of fermentation parameters has been carried out using the one-variable-at-a-time method. Effect of initial sugar concentration, pH, nitrogen supplement, and cultivation time was evaluated. The influence of nitrogen source and quantity for bacterial cellulose production was studied using a central composite rotational design (CCRD).The highest production of BC (3.38 g/L) was obtained after 10 days of cultivation, using sisal juice (pH 5) at 15 g/L of sugars and supplemented with 7.5 g/L of extract yeast. The cellulose production yield in selected sisal culture conditions was three times higher than the yield in synthetic medium, indicating that sisal juice is a suitable substrate for BC production.

Effect of sisal fiber filler on thermal properties of bio-based polyurethane composites

Abstract: This work is mainly focused on study of thermal and thermomechanical properties of obtained bio-based polyurethane (coded as bio-PU) composites via using different types of bio-components (bio-glycol, modified soybean oil and sisal fiber) in the procedure. The chemical structure, morphology and mechanical properties were also investigated and described in this manuscript in order to know more perfect characterization of produced composites. The bio-based polyurethane matrix of composites was synthesized via prepolymer method. Bio-PU composites were produced by dispersing 5 and 15 mass% of sisal fibers into the polyurethane matrix during their synthesis. To investigate the thermal stability of sisal fibers and bio-PU composites, the thermogravimetric method (TG) was used. Thermomechanical tests were performed by means of dynamic mechanical analysis (DMA). Based on the results of thermomechanical analysis, it was found that the sisal fibers amount has the impact on storage and loss modulus. Chemical structure was confirmed by FTIR spectra. Mechanical results and scanning microscopy images of the composites showed good interfacial adhesion between sisal fibers and the bio-based PU matrix.

Synergic effects of cellulose nanocrystals and alkali on the mechanical properties of sisal fibers and their bonding properties with epoxy

Abstract: Cellulose nanocrystal (CNC), as a new promising nanomaterial, has attracted considerable attention in recent years. In this research, electrophoretic deposition (EPD) was employed to modify sisal fibers with CNCs. Sisal fibers were treated with alkali before CNCs were deposited on their surface. The synergic effects of alkali and CNCs on the mechanical properties of sisal fiber and its interfacial properties with epoxy resin over a range of temperatures were investigated. The results showed that a 62% increase in tensile modulus of sisal fibers was obtained. At room temperature, the CNCs coating did not show any obvious effect on the interfacial shear strength (IFSS) between sisal fiber and epoxy while changing the debonding mode with an increased debonding frictional force. In the case of being at elevated temperatures, the CNCs modification significantly reduced the inverse effect of temperature on IFSS owing to the formation of an interphase with improved thermo-mechanical stability.

Development of fire retardant sisal yarn

Abstract: For the first time flame retardant functionality was imparted in sisal (leaf fibre) yarn using N-methylol dimethylphosphonopropionamide (MDPA) based formulation. MDPA formulations were applied to sisal yarn in various concentrations by the dipping method followed by drying and curing. The formulation was optimized on the basis of tensile strength of the treated yarns. Flame retardancy of the treated yarn was evaluated by limiting oxygen index (LOI) and vertical burning behavior testing with measurement of the char length. The LOI value of the treated sisal yarn was found to increase by 1.5 times after an application of 450 gpl MDPA formulation. Thermo-gravimetry and char morphology analysis of the control and the treated sisal yarn were analysed to understand the fire retardancy mechanism of treated sisal yarn. Further, washing durability of the treatment was also evaluated.

Enhancement on Mechanical and Thermal Properties of PLA Biocomposites Due to the Addition of Hybrid Sisal Fibers

Abstract: Hybrid sisal fibers (HSFs) were made by mixing untreated sisal fibers (USFs) with alkali treated sisal fibers (ASFs), and blended with PLA matrix to make PLA/HSFs composite. It was found that the reinforced effect of HSFs was better than that of ASFs. Impact strength and crystallinity of PLA/HSFs had obvious improvements. β crystal of PLA was found from the XRD graph of PLA/HSFs, which may lead to an enhance in the impact strength and thermal stability.

Structural and Chemical Characteristics of Sisal Fiber and Its Components: Effect of Washing and Grinding

Abstract: This work covers the study of microstructural changes of natural sisal fibers induced by different conditioning pre-treatments: mechanical grinding, cryogenic grinding, and hot water washing. The aim of the work is to clarify the effects of the pre-treatments on crystallinity and infrared spectra of sisal. Scanning electron microscopy results allowed to identify morphological changes on the fiber surface. Deeper changes of chemical origin were studied by attenuated total reflectance/Fourier transform infrared spectroscopy (FTIR) and focused on the main components of cellular walls: cellulose, lignin, and xylan. The work was complemented with crystallinity index (Ic) data determined by two very different methods: the widely used for lignocellulosic fibers Segal equation based on X-ray diffraction measurements, and the other based on FTIR through the 1430/900 cm−1 band intensity ratio, which is mostly used with cellulosic samples.

Measuring fibre orientation in sisal fibre-reinforced, injection moulded polypropylene - Pros and cons of the experimental methods to validate injection moulding simulation

Abstract: In commercial injection moulding simulation software only tools for glass fibre-reinforced thermoplastics exist, but not for natural fibres. In our research, we adapted a simulation software for sisal fibre-reinforced polypropylene. To evaluate our simulation results, three experimental methods, to measure fibre orientation are compared to each other using injection moulded sisal fibre-reinforced polymer parts: terahertz spectroscopy, μ-CT and light microscopy measurements (LMM) of microtome sections. Terahertz spectroscopy determines the main orientation over the plate thickness, but it neglects variances of fibre orientation across the plate thickness. Using μ-CT and LMM allows measuring fibre orientation at different layers across the plate thickness and to detect a shell-core effect. Care has to be taken comparing results from μ-CT and LMM, due to their differences in the slice thicknesses. The orientation found with the μ-CT correlates well with the injection moulding simulation developed for sisal fibre-reinforced polypropylene.

Thermogravimetric characterization of polyester matrix composites reinforced with eucalyptus fibers

Abstract: The substitution of natural fibers for synthetic ones as reinforcement of polymer matrix composites is today not only the subject of investigation but also engineering applications. Natural fibers display environmental advantages in association with economic benefits related to comparatively lower cost as well as less energy consumption. Several natural lignocellulosic fibers (LCF's) extracted from worldwide cultivated plants, such as sisal, coir, cotton, flax, among others, are successfully being used in composites. A great number of other LCF's, especially from wood species, has a reinforcement potential waiting to be explored. Thus, the objective of this short communication is to evaluate the thermogravimetric (TG/DTG) behavior of polyester matrix composites reinforced with relatively higher volume fractions, 30, 40 and 50 vol%, of eucalyptus fibers. The incorporation of eucalyptus fibers slightly reduces the thermal stability of the polyester matrix by a small decrease in the onset of thermal degradation and the DTG peak temperature as compared to neat polyester. The limit for practical application of these composites could be set as 300 °C, before the onset of major weight loss.

In situ reactive interfacial compatibilization of polylactide/sisal fiber biocomposites via melt-blending with an epoxy-functionalized terpolymer elastomer

Abstract: The in situ reactive interfacial compatibilization and properties of polylactide/sisal fiber biocomposites made via melt blending with an epoxy-functionalized terpolymer elastomer, ethylene/methyl acrylate/glycidyl methacrylate (EGMA), were investigated. Scanning electron microscopy results showed that the introduction of EGMA improved the interfacial adhesion between the sisal fibers (SF) and matrix, which was ascribed to the improved interfacial compatibilization between the polylactide and fibers via in situ reaction with EGMA during the melt-blending processing. It was also observed that the EGMA tends to weld on the surface of the fibers, which is called a self-weld fiber structure. The interfacial reaction and microstructure of the composites were further investigated by FTIR characterization, and thermal and rheological analyses. The results demonstrated that the mobility of the polylactide molecular chain was restricted due to the enhanced interfacial interaction of the composites. The addition of EGMA improved the toughness of the polylactide/sisal fiber composites without much decline in the tensile strength. Polylactide/sisal fiber composites with a good stiffness-toughness balance were obtained.