Showing papers on "SISAL published in 2006"
TL;DR: In this paper, the authors used sisal nanowhiskers as reinforcement to obtain nanocomposites with polyvinyl acetate (PVAc) as matrix phase.
Abstract: Sisal nanowhiskers were used as novel reinforcement to obtain nanocomposites with polyvinyl acetate (PVAc) as matrix phase. They are seen as attractive materials due to the widespread availability and low cost of the sisal source material. Statistical analysis of the sisal whisker length and diameter resulted in average values of 250 nm and 4 nm, respectively, resulting in an average aspect ratio in the upper range of reported cellulose nanowhisker values. The high aspect ratio ensures percolation, with resulting mechanical improvements and thermal stability, at lower fiber loads. Water uptake and thermal behaviour of the sisal whisker–PAVc composites were studied. Whisker addition was found to stabilize the nanocomposites with no benefit seen when increasing the whisker content beyond the percolation threshold: For all whisker contents studied above percolation, the water uptake stays constant, and the Tg does not vary with whisker content at a given relative humidity. The water diffusion rate however increases due to water accumulation at the whisker–PVAc interface. Below whisker percolation, stabilization is only noticed at low relative humidity, whereas high humidity results in disruption of whisker–PVAc interactions. This work shows the potential of cellulose nanowhiskers to stabilize polar polymers even at high humidity conditions with minimal reinforcement addition.
492 citations
TL;DR: In this article, the thermal conductivity, diffusivity and specific heat of polyester/natural fiber composites were investigated as function of filler concentration and for several fibre surface treatments.
285 citations
TL;DR: In this paper, natural rubber was reinforced with sisal and oil palm fibers and was subjected to dynamic mechanical analysis to determine the dynamic properties as a function of temperature, which is due to the increased stiffness imparted by the natural fibers.
Abstract: Natural rubber was reinforced with sisal and oil palm fibers and was subjected to dynamic mechanical analysis to determine the dynamic properties as a function of temperature. The storage modulus E′ was found to increase with weight fraction of fiber. This is due to the increased stiffness imparted by the natural fibers. Loss modulus increased with loading while the damping property was found to decrease. The fibers were subjected to alkali treatment of different concentrations namely 0.5, 1, 2, and 4% and the dynamic properties were studied. In the case of composites containing chemically modified fibers, storage modulus and loss modulus were found to increase. Scanning electron micrographs of tensile fracture surfaces of treated and untreated composites demonstrated better fiber–matrix bonding in the case of the former. POLYM. COMPOS., 27: 671–680, 2006. © 2006 Society of Plastics Engineers
272 citations
TL;DR: The degradation and biogas production potential of sisal fiber waste could be significantly increased by pre-treatment for reduction of particle size as mentioned in this paper, and the results confirmed that methane yield was inversely proportional to particle size.
264 citations
TL;DR: In this article, fracture toughness of natural fibers/castor oil polyurethane composites was investigated and the best fracture toughness performance was displayed by the sisal fabric composite, which has been attributed to the fibrillation process occurring under the severest condition of the alkaline treatment.
216 citations
TL;DR: In this article, Sisal fibers were modified by either mercerization (NaOh 10%), esterification (succinic anhydride), or ionized air treatment (discharge current of 5 mA) to evaluate how modifications applied on sisal fibers influence their properties and those of the composites reinforced with tem, mainly thermal properties.
Abstract: The study and development of polymeric composite materials, especially using lignocellulosic fibers, have received increasing attention. This is interesting from the environmental and economical viewpoints as lignocellulosic fibers are obtained from renewable resources. This work aims to contribute to reduce the dependency on materials from nonrenwable sources, by utilizing natural fibers (sisal) as reinforcing agents and lignin (a polyphenolic macromolecule obtained from lignocellulosic materials) to partially substitute phenol in a phenol-formaldehyde resin. Besides, it was intented to evaluate how modifications applied on sisal fibers influence their properties and those of the composites reinforced with tem, mainly thermal properties. Sisal fibers were modified by either (i) mercerization (NaOh 10%), (ii) esterification (succinic anhydride), or (iii) ionized air treatment (discharge current of 5 mA). Composites were made by mould compression, of various sisal fibers in combination with either phenol-formaldehyde or lignin-phenol-formaldehyde resins. Sisal fibers and composites were characterized by thermogravimetry (TG) and DSC to establish their thermal stability. Scanning electron microscopy (SEM) was used to investigate the morphology of unmodified and modified surface sisal fibers as well as the fractured composites surface. Dynamic mechnical thermoanalysis (DMTA) was used to examine the influence of temperature on the composite mechanical properties. The results obtained for sisal fiber-reinforced phenolic and lignophenolic composites showed that the use of lignin as a partial substitute of phenol in phenolic resins in applications different from the traditional ones, as for instance in other than adhesives is feasible.
152 citations
TL;DR: In this paper, the authors evaluated the relationship between fracture toughness and water absorption fatigue according to different polymer matrices such as epoxy and vinyl-ester composites and found that water uptake of the epoxy composites was found to increase with cyclic times.
148 citations
TL;DR: In this paper, the effect of the two most used fiber treatments: acetylation and alkaline-treatment and its variables: time and temperature for one constant concentration of catalyst, on the final properties of MaterBi-Y/sisal fiber composites was studied.
Abstract: In this work, the effect of the two most used fiber treatments: acetylation and alkaline-treatment and its variables: time and temperature for one constant concentration of catalyst, on the final properties of MaterBi-Y/sisal fiber composites was studied. It was demonstrated that this kind of treatments leads to several morphological changes like voids creation and fiber fibrillation. Acetylation for 1 h is an acceptable option when lower water uptake amount is let or high impact energy is required. On the other hand, alkaline treatment for two days at room temperature and 5% w/v NaOH leads to the highest flexural properties with high impact performance and low changes in the water uptake amount.
144 citations
TL;DR: In this paper, the degradation of short sisal fibres/Mater Bi-Y™ biocomposites during indoor burial experiments was analyzed, showing that composites absorbed less water than the matrix.
123 citations
TL;DR: In this article, natural rubber was reinforced with sisal and oil palm fibers and the dielectric properties of the composite were evaluated as a function of fiber loading, frequency and chemical modification of fibers.
Abstract: Natural rubber was reinforced with sisal and oil palm fibers. Biocomposites were prepared by varying the weight fraction of the fibers. The dielectric properties such as dielectric constant, volume resisitivity and dielectric loss factor of the biocomposites were evaluated as a function of fiber loading, frequency and chemical modification of fibers. The dielectric constant values were found to be higher for fiber reinforced system than the gum due to polarization exerted by the incorporation of lignocellulosic fibers. Chemical modification of fibers resulted in decrease of dielectric constant values and volume resisitivity values. The volume resisitivity of the composites was found to decrease with fiber loading due to increase of hydrophilicity imparted by the lignocellulosic fibers. The dissipation factor was found to increase with fiber content.
87 citations
TL;DR: In this paper, the mechanical behavior of high impact polystyrene (HIPS) reinforced with short sisal fibers was investigated under quasi-static and impact loading conditions, and the nonlinear elastic fracture mechanics was adopted to characterize fracture behavior in these materials.
Abstract: In this work the mechanical behavior of high impact polystyrene (HIPS) reinforced with short sisal fibers was investigated. Tensile and fracture tests were performed under quasi-static and impact loading conditions. From uniaxial tensile tests, an increasing trend of Young's modulus with fiber content was found, whereas tensile strength and deformation at break decreased. On the other hand, in fracture tests irrespectively of loading conditions, all materials exhibited non-linear load–displacement curves with stress whitened fracture surfaces. Hence, Non-Linear Elastic Fracture Mechanics was adopted to characterize fracture behavior in these materials. Higher values of quasi-static fracture toughness were exhibited by the composites in comparison to the plain matrix up to a fiber content of about 10 wt% sisal. Conversely, the addition of sisal fibers to the HIPS matrix led to inferior impact fracture properties.
TL;DR: In this paper, the effect of chemical modifications on the structure and morphology of sisal fibers has been studied by 13 C VACP-MAS NMR in solid state, and SEM.
01 Jan 2006
TL;DR: In this article, a dynamic mechanical study of sisal/oil palm hybrid fiber reinforced natural rubber composites (at frequency 1 Hz) with reference to the role of silane coupling agents was conducted.
Abstract: This paper deals with the dynamic mechanical study of sisal/oil palm hybrid fiber reinforced natural rubber composites (at frequency 1 Hz) with reference to the role of silane coupling agents. Composites were prepared using sisal and oil palm fibers subjected to chemical modifications with different types of silane coupling agents. The silanes used were Silane F8261 [1,1,2,2-perfluorooctyl triethoxy silane], Silane A1100 [y-aminopropyltriethoxy silane] and Silane Al 51 [vinyl triethoxy silane]. It was observed that for treated composites, storage modulus and loss modulus increased while the damping property was found to decrease. Maximum E was exhibited by the composite prepared from fibers treated with silane F8261 and minimum by composites containing fibers treated with silane A 151. This was attributed to the reduced moisture absorbing capacity of chemically modified fibers leading to improved wetting. This in turn produced a strong interfacial interface giving rise to a much stiffer composite with higher modulus. Surface characterization of treated and untreated sisal fibers by XPS showed the presence of numerous elements on the surface of the fiber. Scanning electron micrographs of tensile fracture surfaces of treated and untreated composites demonstrated better fiber-matrix bonding for the treated composites.
TL;DR: In this paper, the effects of fiber surface treatment on fiber tensile strength and fiber-matrix interface characteristics were determined by using tensile and single fiber pullout tests, respectively, and the short beam shear test was also employed to evaluate the interlaminar shear strength of the composite laminates.
Abstract: Sisal-fiber-reinforced composites, as a class of eco-composites, have attracted much attention from materials scientists and engineers in recent years. In this article, the effects of fiber surface treatment on fiber tensile strength and fiber-matrix interface characteristics were determined by using tensile and single fiber pullout tests, respectively. The short beam shear test was also employed to evaluate the interlaminar shear strength of the composite laminates. Vinyl ester, epoxy, and high-density polyethylene (HDPE) were chosen as matrix materials. To enhance the interfacial strength, two kinds of fiber surface-treatment methods, namely, chemical bonding and oxidisation, were used. The results obtained showed that different fiber surface-treatment methods produced different effects on the tensile strength of the sisal fiber and fiber-matrix interfacial bonding characteristics. Hence, valuable information on the interface design of sisal fiber–polymer matrix composites can be obtained from this study.
TL;DR: It was found that the dissolution of celluloses and degree of substitution of cellulose derivatives depends on a fine adjustment of the dissolution/derivatization conditions, as well as on the origin (sisal or linters) of cellulosing.
TL;DR: In this paper, mercerized and nonmercerized coconut, jute and sisal fibers were combined with a matrix of gluten/starch/glycerol to produce composite materials.
Abstract: Mercerized and nonmercerized coconut, jute and sisal fibers were combined with a matrix of gluten/starch/glycerol to produce composite materials. All nonmercerized fibers improved the mechanical properties of the composites. After mercerization of the fibers, the composite reinforced with sisal fibers exhibited lower values of Young's modulus and ultimate tensile strength than composite with nonmercerized sisal fiber, whereas these properties were improved in the composites reinforced with mercerized coconut and jute fibers.
TL;DR: In this article, a fiber-reinforced cement composites were produced in Brazil using blast furnace slag cement reinforced with pulped fibers of sisal originated from agricultural by-products.
Abstract: Fiber-reinforced cement composites were produced in Brazil using blast furnace slag cement reinforced with pulped fibers of sisal originated from agricultural by-products. Thin pads were produced by slurring the raw materials in water, followed by de-watering and pressing stages. Studies of mechanical behavior included observations of stable crack growth behavior under monotonic loading (resistance-curve behavior), followed by scanning electron microscopy (SEM) analysis of the fracture surfaces. Reinforcement with cellulose fibers resulted in improved fracture toughness, even after 9 months in laboratory environment. Microscopic analysis indicated a considerable incidence of crack bridging and fiber pull-out in the composite. The shielding contributions from crack bridging are estimated using a fracture mechanics model, before comparing with the measured resistance-curve behavior.
TL;DR: In this article, the effect of chemical modification of sisal fabric on moisture uptake was analyzed and the mechanism of diffusion in the composites was found to be fickian in nature.
Abstract: Textile biocomposites were prepared by reinforcing natural rubber with woven sisal fabric. Sisal fabric was subjected to various chemical modifications like mercerization, silanization, and thermal treatment. The moisture uptake of the textile composites was found to depend upon fiber content as well as architecture. The mechanism of diffusion in the composites was found to be fickian in nature. The effect of chemical modification of sisal fabric on moisture uptake was also analyzed. Mercerization was seen to increase the water uptake in the composites while thermally treated fabric reinforced composites exhibited lower water uptake. The influence of temperature on water sorption of the biocomposites is also analyzed. The thermodynamic parameters of the sorption process were also evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 416–423, 2006
TL;DR: In this article, the rubber/fiber interface is improved by the addition of a resorcinol-hexamethylene tetramine system to the rubber matrix and the swelling index parameter is evaluated.
Abstract: Textile composites are prepared by reinforcing natural rubber with woven sisal fabric. Sisal fabric is subjected to various chemical modifications like mercerization, silanation, and heat treatment, and its influence on the mechanical properties is analyzed. Tensile strength is seen to decrease with all chemical modifications except for composites prepared with heat-treated sisal fabric. The rubber/fiber interface is improved by the addition of a resorcinol-hexamethylene tetramine system to the rubber matrix. Equilibrium swelling experiments are carried out to assess the extent of interfacial adhesion. The swelling index parameter is evaluated. The hardness of the textile composites is analyzed. Scanning electron microscopic (SEM) studies are conducted to evaluate fiber/matrix interface.
TL;DR: In this paper, composites of an EVA polymer matrix and short sisal fiber were characterized, and the physical-morphological and chemical interactions between EVA and sisal were investigated.
Abstract: In this work, composites of an EVA polymer matrix and short sisal fiber were characterized. The physical- morphological as well as chemical interactions between EVA and sisal were investigated. When the samples were prepared in the presence of dicumyl peroxide, the results suggest that crosslinking of EVA as well as grafting between EVA and the sisal fibers took place. Morphological changes were studied by scanning electron microscopy (SEM). Re- sults from Hg-porosimetry, SEM, Fourier transform infrared spectroscopy, surface free energy, and gel content strongly indicate grafting of EVA onto sisal under the composite preparation conditions, even in the absence of peroxide. The grafting mechanism could not be confirmed from solid-state 13 C NMR analysis. The grafting had an impact on the ther- mal and mechanical properties of the composites, as deter- mined by differential scanning calorimetry and tensile test- ing. Thermogravimetric analysis results show that the com- posites are more stable than both EVA and sisal fiber alone. The composite stability, however, decreases with increasing fiber content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1607-1617, 2006
TL;DR: In this article, the stress relaxation characteristics of sisal/oil palm hybrid fiber reinforced natural rubber composites were analyzed with special reference to fiber loading and chemical modifications, and the kinetics of thermal degradation was also analyzed.
Abstract: Natural rubber was reinforced using two hybrid biofibers namely sisal and oil palm. The stress relaxation characteristics of sisal/oil palm hybrid fiber reinforced natural rubber composites was analyzed with special reference to fiber loading and chemical modifications. It was seen that the rate of relaxation decreased with fiber content and was found to be maximum in gum compound. Chemical modification of the fiber surface was found to affect the degree of adhesion and thereby the nature of relaxation. The thermal stability of the composites was also investigated with reference to loading and chemical treatment. The kinetics of thermal degradation was also analyzed. Activation energy was calculated from two methods: the Horowitz and Metzger method and the Coats-Redfern method.
TL;DR: In this article, the mechanical performance of unsaturated polyester/hybrid sisal-glass fabrics was determined as a function of fibre content and test direction, and the results showed enhanced properties with fibre content for all composites under investigation.
Abstract: Hybridization can alter both mechanical performance and cost of polymer composites, and novel composite materials can be obtained by the combination of both fibrous and mineral reinforcements. In the present work the mechanical performance of unsaturated polyester/hybrid sisal-glass fabrics was determined as a function of fibre content and test direction. Three different hybrid fabrics (30, 40 and 50% w/w glass content) with sisal strings in the warp and glass roving in the weft were hand weaved. Aligned fabric compression moulded composites were obtained at room temperature. The results showed enhanced properties with fibre content for all composites under investigation. Composites reinforced by fabrics with low glass fibre content exhibited lower properties when tested along the glass fibre direction than when tested along the sisal fibre direction and, at high glass fibre content the opposite trend was observed. These behaviours were associated with the low glass fibre content along the test direction and to the high sisal fibre diameter. At low glass fibre content the sisal fibres would act as inclusions or defects, thereby lowering the mechanical performance of the composite; at high glass fibre contents the superior mechanical properties of the glass would surpass the defects caused by sisal fibres.
TL;DR: In this paper, potato, sweet potato, and corn starch varieties were used as matrices of the biocomposites and natural fibers including jute, sisal, and cabuya was used as discrete reinforcement.
Abstract: This is the second part of a series of articles dealing with characterization of starch based biodegradable composites. Potato, sweet potato, and corn starch varieties were used as matrices of the biocomposites. Natural fibers including jute, sisal, and cabuya were used as discrete reinforcement. Water and glycols were used as plasticizers. Compression molded specimens were prepared and characterized by a variety of techniques. Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA) were used to characterize the thermal behavior of these composites. Processed specimens did not show the typical endothermic peak observed in DSC scans for native starch powder. No significant difference was observed for weight loss and decomposition due to fiber or plasticizer content among the different specimens. Attenuated Total Reflectance–Infrared Spectroscopy (ATR-IR) was used to characterize the starch compounds and the effect of plasticizers and reinforcing fibers. The spectra found for most specimens were ...
TL;DR: In this article, the effect of maleic anhydride esterified fiber composites was studied on absorption of steam and water at ambient temperature in wood polymer composites, and the results showed that maleic-anhydride (MA) treated fiber composite showed less absorption of water than the untreated fiber composite.
Abstract: In this work the fibers of banana, hemp, and sisal are employed as fillers for the formation of wood polymer composites with polystyrene in the different ratios of 40:60 and 45:55 (wt/wt), respectively. These fibers were esterified with maleic anhydride, and the effect of maleic anhydride was studied on absorption of steam and water at ambient temperature in wood polymer composites. Untreated fiber composites show more absorption of steam in comparison to maleic anhydride (MA)–treated fiber composites. The absorption of water increases with the increase in time from 2–30 h in all untreated fiber composites. The maximum absorption of water was found in hemp fiber composites and the minimum in sisal fiber composites. The maleic anhydride esterified fiber composites showed less absorption of water than the untreated fiber composites. Steam absorption in MA treated and untreated fiber composites is higher than the water absorption in respective fiber composites. The wood polymer composites containing low amou...
Dissertation•
01 Jul 2006
TL;DR: In this paper, a linear flow model based on Darcy's law was used in the experiment to measure the permeability of sisal textile and the Kozeny constant was calculated through experimental results.
Abstract: In this paper, a linear flow model based on Darcy's law was used in the experiment to measure permeability of sisal textile. The Kozeny–Carman equation was employed to predict the permeability of sisal textile and the Kozeny constant was calculated through experimental results. Both experimental and predicted permeability values of sisal textiles were compared. Effects of fiber surface treatments and fiber volume fraction on the permeability of sisal textile were also studied in this research. Comparisons of mechanical properties of sisal-textile-reinforced composites manufactured by different processing technologies were made.
TL;DR: AFM can detect heterogeneity in the wettability of sisal fibers with nanometer resolution and can be applied in the study of fiber-matrix adhesion in polymer composites.
Abstract: Atomic force microscopy (AFM) was used to study the nanoscale surface chemistry and morphological changes caused by chemical treatment of sisal fibers. Scanning Electron Microscopy (SEM) micrographs indicated that sisal in natura (bundle of fibers) is formed by fibers with diameters of approximately 10 microm. AFM images showed that these fibers consist of microfibrils with diameters varying from 250 to 600 nm, which are made up of nanofibrils of ca. 20 nm in diameter. The adhesion force (pull-off force) between the AFM tip and the fibers surface increased after benzylation, pointing to a decrease in the polar groups on the sisal fiber. The adhesion map measured over a scan range of 3 microm was heterogeneous in samples treated with 40% NaOH and the low adhesion sites disappeared after benzylation. Using an established mathematical model, it was possible to evaluate the increase in adhesion work and consequently in the interaction between the AFM tip and sisal fibers. These results indicated that AFM can detect heterogeneity in the wettability of sisal fibers with nanometer resolution and can be applied in the study of fiber-matrix adhesion in polymer composites.
TL;DR: In this article, a hammer mill was used to decorticate bast fibers, and measured data of the mechanical and thermal properties such as fineness, length distribution, strength, modulus of elongation, impurities, thermo-gravimetric and differential thermal analysis.
Abstract: The developed and tested hammer mill decorticates bast fibers effectively. The fibers processed are characterized by measured data of the mechanical and thermal properties such as fineness, length distribution, strength, modulus of elongation, impurities, thermo-gravimetric and differential thermal analysis. The data and parameter of the European bast fibers hemp, flax and linseed do not differ very much from the data of the tropical fibers sisal, jute, kenaf and ramie. Only the fruit fiber coir has essential diverging parameters. The results can be used for the technical application of natural fibers.
01 Sep 2006-International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship
TL;DR: In this paper, the authors analyzed and redesigned the various components of a previously designed sisal decorticator prototype and developed a working prototype to meet the needs of small-scale Kenyan sisal farmers.
Abstract: This project analyzed and redesigned the various components of a previously designed sisal decorticator prototype. The sisal plant is easily grown in the arid regions of Kenya and its fiber has widespread industrial and consumer applications. Competition from Brazilian and Chinese sisal growers has made it difficult for small-scale Kenyan sisal farmers to yield a profit. Decorticator machines strip the usable fiber from the sisal
leaves. A strong market exists in Kenya and beyond for an affordable and capable decortication device. Based on interaction with University of Nairobi students and faculty, design parameters were assessed and adapted to create a working prototype to meet these needs. Throughout the design process, affordability, energy consumption, transportability, reliability, on-site material and assembly constraints were taken into account. The designs chosen accomplished the project requirements by minimizing cost through material selection and ease of manufacture, and provided adjustable parameters in order to facilitate decortication quality testing. A vertical feed, small diameter decorticator with steel blades transportable via a steel frame with two wheels was determined to be the optimal solution. Testing with actual sisal and variable components enabled quality to be assessed as well as ensured that the designed prototype operated correctly and safely.