Green Coconut Fiber Research Articles

Absorção de água, solubilidade em água, propriedades mecânicas e morfológicas de compósitos de glúten de milho e poli(hidroxibutirato-co-valerato) (PHBV) reforçados com fibras de coco verde

Neste estudo, fibras de coco verde foram incorporadas em uma matriz composta de gluten de milho (GM) e poli(hidroxibutirato-co-valerato) (PHBV). As composicoes foram processadas por extrusao, onde o teor maximo de gluten adicionado a matriz para obter misturas com viscosidade suficientemente baixa para o processamento foi de 50% (em peso) em relacao ao teor de PHBV. O teor de fibras nos compositos variou de 5 a 20% por peso em relacao ao peso total dos polimeros. Os plastificantes usados foram acetil tributil citrato (ATBC) e glicerol. Os materiais extrudados foram moldados por compressao a quente para obtencao de corpos de prova para a caracterizacao das propriedades de absorcao de agua, solubilidade em agua, resistencia mecânica, alem de propriedades termo-dinâmico-mecânicas (DMTA) e morfologicas. Foi observado que as matrizes apresentaram duas transicoes vitreas (Tg's) uma para cada componente, indicando que as mesmas sao compostas de duas fases (GM) e PHBV. A adicao do PHBV ao gluten favoreceu ao aumento da rigidez e houve diminuicoes significativas na absorcao de agua e na solubilidade em agua, enquanto a presenca das fibras provocou, em algumas composicoes, um aumento no modulo de elasticidade e na resistencia a tracao.

Green coconut fiber: a novel carrier for the immobilization of commercial laccase by covalent attachment for textile dyes decolourization

Commercial laccase formulation was immobilized on modified green coconut fiber silanized with 3-glycidoxypropyltrimethoxysilane, aiming to achieve a cheap and effective biocatalyst. Two different strategies were followed: one point (pH 7.0) and multipoint (pH 10.0) covalent attachment. The influence of immobilization time on enzymatic activity and the final reduction with sodium borohydride were evaluated. The highest activities were achieved after 2 h of contact time in all situations. Commercial laccase immobilized at pH 7.0 was found to have higher activity and higher affinity to the substrate. However, the immobilization by multipoint covalent attachment improved the biocatalyst thermal stability at 50 °C, when compared to soluble enzyme and to the immobilized enzyme at pH 7.0. The Schiff's bases reduction by sodium borohydride, in spite of causing a decrease in enzyme activity, showed to contribute to the increase of operational stability through bonds stabilization. Finally, these immobilized enzymes showed high efficiency in the continuous decolourization of reactive textile dyes. In the first cycle, the decolourization is mainly due to dyes adsorption on the support. However, when working in successive cycles, the adsorption capacity of the support decreases (saturation) and the enzymatic action increases, indicating the applicability of this biocatalyst for textile wastewater treatment.

Testing the Use of Coconut Fiber as a Cushioning Material for Transport Packaging

In spite of being a raw material of virtually unlimited availability due to the massive consumption of the highly popular coconut water, fiber produced from green coconut is much less used than the dried coconut fiber. The objective of this study was to investigate the performance of green (white) coconut fiber as a cushioning material for use in packaging systems. The mechanical performance of both green coconut fibers in their natural state as well as those molded into the shape of cushioning pads were evaluated by shock absorption tests. The results showed that the fibers without agglutination agents exhibited the best performance when submitted to increasing static loads by presenting the greatest capacity to reduce impact acceleration. In addition, green coconut fiber presented behavior similar to that of cellulosic cushioning materials and in certain situations can be considered effective in protecting products that are considered fragile.

Immobilization of commercial laccase onto green coconut fiber by adsorption and its application for reactive textile dyes degradation

► Coconut fiber was successfully used to immobilize commercial laccase by adsorption. ► The immobilization improved the operational and thermal stabilities of free enzyme. ► A high decolourization of practically all reactive textile dyes studied was obtained. An effort has been made to find a cheaper, easily available and simple alternative for the immobilization of enzymes and subsequent utilization at large scale in textile wastewater treatment. Commercial laccase was immobilized for the first time on an agroindustrial residue, green coconut fiber, by physical adsorption. The effect of the immobilization conditions (enzyme concentration, contact time and pH value) on the properties of the biocatalyst was determined. Then, the immobilized enzyme characterization was performed and kinetic parameters were obtained. Thermal and operational stabilities were improved compared with free commercial laccase showing its potential for continuous applications. Finally, the performance of immobilized laccase for the continuous degradation of various reactive textile dyes and of a mixture of them in batch reactors was evaluated. Two phenomena were observed: decolourization of the solutions due to dyes adsorption on the support and due to the enzyme action. A high decolourization percentage of practically all dyes in the first two cycles and an effective decolourization of the dye mixture were obtained, showing the suitability of the immobilized commercial laccase for continuous colour removal from textile industrial effluents.

Preparation and characterization of biodegradable composites based on Brazilian cassava starch, corn starch and green coconut fibers

Increasing search for new materials with high premium on eco-friendliness, new trend is emerging in materials development such as composites, which are well established for a wide variety of applications. With growing interest and importance of renewable bioresources has led to more stress on the use of locally available materials. This paper presents preliminary results on the preparation and characterization of composites based on Brazilian coconut fibers and starches of cassava and corn. The raw materials were characterized for their morphology, chemical composition, and thermal properties and X-ray diffraction studies. Coir fibers were also tested for their tensile properties showing increasing strength and Young's modulus with decreasing diameter, while the % elongation remaining constant. Lignin content of coir was found to be 35%. Structure and properties of composites containing 0, 5 10, 15% fibers in both the matrices and prepared by compression molding would be compared. For the 2 types of starch, there was an increase in the tensile strength by the increasing proportion of fiber. The effect of moisture in the composite stress affects the strength and percentage elongation. The water absorption was higher in the composites made from cassava starch.

Effect of chemical treatments on properties of green coconut fiber

Green coconut fiber, a lignocellulosic material native from Brazilian northeast coast, was chemically treated by three methods: NaOCl, NaOCl/NaOH or H 2O 2. The effect of these treatments on the structure, composition and properties of fibers was studied using SEM, FTIR, XPS, TGA and other analyses. SEM showed that treatment with H 2O 2 is the most efficient in terms of waxy and fatty acid residues removal but it does not modify the surface chemical composition, that it can be seen by FTIR and wettability results. The chemical composition and FTIR analyses revealed a reduction of the hemicelluloses content in the fibers treated with NaOCl/NaOH and, consequently, this fiber showed a greater exposure of cellulose and a reduction in thermal stability. The fiber surface treated with NaOCl is morphologically similar to the natural fiber surface, have the element Cl on your surface and it is a little more hydrophilic than the natural fiber.

Preparation and characterizations of polycaprolactone/green coconut fiber composites

AbstractThe mechanical, thermal, and morphological properties of polycaprolactone (PCL) and green coconut fiber (GCF) composites were evaluated. Blends containing acrylic acid‐grafted PCL (PCL‐g‐AA/GCF) exhibited noticeably better mechanical properties due to better compatibility between the two components. The dispersion of GCF in the PCL‐g‐AA matrix was significantly more homogeneous due to the creation of branched and cross‐linked macromolecules via reactions between carboxyl groups in PCL‐g‐AA and hydroxyl groups in GCF. The tensile strength of the PCL‐g‐AA/GCF composites at break was considerably greater than that of PCL/GCF composites. In addition, the PCL‐g‐AA/GCF blend was more easily processed due to lower melt viscosity. Biodegradation tests were performed with each composite in an Acinetobacter baumannii BCRC 15556 environment. The mass of both composites was reduced by the GCF content within 4 weeks. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Immobilization of Candida antarctica lipase B on NaOCl/NaOH treated green coconut fiber by adsorption

Immobilization of Candida antarctica lipase B on NaOCl/NaOH treated green coconut fiber by adsorption

Renewable resource-based composites of recycled natural fibers and maleated polylactide bioplastic: Characterization and biodegradability

The thermal properties of composite materials composed of polylactide (PLA) and green coconut fiber (GCF) were evaluated. Blends containing maleic anhydride-grafted PLA (PLA-g-MA/GCF) exhibited noticeably superior thermal properties due to greater compatibility between the two components. The dispersion of GCF in the PLA-g-MA matrix was highly homogeneous as a result of ester formation, and the consequent creation of branched and cross-linked macromolecules, between the carboxyl groups of PLA-g-MA and the hydroxyl groups in GCF. In addition, the PLA-g-MA/GCF blend was more easily processed due to a lower melt viscosity. Each composite was subject to biodegradation tests in a Burkholderia cepacia BCRC 14253 compost. The bacterium completely degraded both the PLA and the PLA-g-MA/GCF composite films. Morphological observations indicated severe disruption of the film structure after 9–12 days of incubation. The PLA-g-MA/GCF (10 wt%) films were not only more biodegradable than those made of PLA, but also exhibited lower molecular weight and intrinsic viscosity, implying a strong connection between these characteristics and biodegradability.

Solid State NMR Study of Polypropylene Composites Filled with Green Coconut Fiber

Dried green coconut fibers (GCF) consist of fibers of various length mixed with a fine powder. Both components can be separated by simple screening techniques, and the present paper summarizes an experimental study on the mechanical and molecular dynamic behaviors and the morphological aspect of green coconut fiber-reinforced polypropylene composites, with respect to the effects of content and granularity of the filler in the powder (0,841–0,500 mm) and fiber (10 mm) forms. All compounds were prepared in an internal mixer at 170°C, 60 rpm for 8 min. It was observed that the flexural modulus increases with increasing fiber content, either in powder or fiber forms. Impact tests show that fiber-filled composites have greater impact strength than powder-filled composites. The results obtained by low-field NMR show that the stiffness of composites decreases with higher fiber loading, due to the poor compatibility between fibers and matrix. The morphology of the system was studied by SEM analysis. In general, composites with fiber showed better properties than those with powder.

Characterization of Green Coconut Fiber Composites

Composites of polypropylene and green coconut fiber were prepared in an extruder with temperatures of 140°C in the first zone and 170°C in the other five zones. The screw speed varied from 60 to 140 rpm. Two fiber granulometries were used, X (0,500–0,250 mm) and Y (0,841–0,500 mm). The homogeneity and the effect of the strain history of these composites could be studied by rheological data of molten composites. Flexural modulus was improved by using an adequate fiber granulometry and extruder screw speed. Results showed that the composite with Y fiber, obtained at 140 rpm, was the better one.

Immobilization of Candida antarctica Lipase B by Adsorption to Green Coconut Fiber

An agroindustrial residue, green coconut fiber, was evaluated as support for immobilization of Candida antarctica type B (CALB) lipase by physical adsorption. The influence of several parameters, such as contact time, amount of enzyme offered to immobilization, and pH of lipase solution was analyzed to select a suitable immobilization protocol. Kinetic constants of soluble and immobilized lipases were assayed. Thermal and operational stability of the immobilized enzyme, obtained after 2 h of contact between coconut fiber and enzyme solution, containing 40 U/ml in 25 mM sodium phosphate buffer pH 7, were determined. CALB immobilization by adsorption on coconut fiber promoted an increase in thermal stability at 50 and 60 degrees C, as half-lives (t (1/2)) of the immobilized enzyme were, respectively, 2- and 92-fold higher than the ones for soluble enzyme. Furthermore, operational stabilities of methyl butyrate hydrolysis and butyl butyrate synthesis were evaluated. After the third cycle of methyl butyrate hydrolysis, it retained less than 50% of the initial activity, while Novozyme 435 retained more than 70% after the tenth cycle. However, in the synthesis of butyl butyrate, CALB immobilized on coconut fiber showed a good operational stability when compared to Novozyme 435, retaining 80% of its initial activity after the sixth cycle of reaction.

Effect of the fiber content and plasticizer type on the rheological and mechanical properties of poly(vinyl chloride)/green coconut fiber composites

AbstractA series of poly(vinyl chloride) (PVC)/green coconut fiber (GCF) composites, with dioctyl phthalate (DOP) or thermoplastic polyurethane (TPU) as a plasticizer, were prepared by melt mixing. Their properties were studied in the molten state with an advanced nonlinear harmonic testing technique; in the solid state, the hardness and impact resistance were evaluated, and scanning electron microscopy was used for fractured surfaces. The effect of the fiber loading was investigated, as well as the role of the plasticizer. PVC–GCF composites are heterogeneous materials that, in the molten state, exhibit essentially a nonlinear viscoelastic character, in contrast to pure PVC, which has a linear viscoelastic region up to 50–60% strain. The complex modulus increases with the GCF content but in such a manner that the observed reinforcement is at best of hydrodynamic origin, without any specific chemical (i.e., permanent) interaction occurring between the polymer matrix and the fibers. As expected, PVC offers good wetting of GCFs, as reflected by the easy mixing and the rheological and mechanical properties. Fibers can be incorporated into PVC up to a 30% concentration without any problem, with the PVC/plasticizer ratio kept constant. Higher GCF levels could therefore be considered. Replacing DOP in part with TPU gives some benefit in terms of impact resistance, likely because of the viscoelastic nature of the latter and the associated energy absorption effects. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Immobilization of Candida antarctica lipase B by covalent attachment to green coconut fiber

The objective of this study was to covalently immobilize Candida antarctica type B lipase (CALB) onto silanized green coconut fibers. Variables known to control the number of bonds between enzyme and support were evaluated including contact time, pH, and final reduction with sodium borohydride. Optimal conditions for lipase immobilization were found to be 2 h incubation at both pH 7.0 and 10.0. Thermal stability studies at 60 degrees C showed that the immobilized lipase prepared at pH 10.0 (CALB-10) was 363-fold more stable than the soluble enzyme and 5.4-fold more stable than the biocatalyst prepared at pH 7.0 (CALB-7). CALB-7 was found to have higher specific activity and better stability when stored at 5 degrees C. When sodium borohydride was used as reducing agent on CALB-10 there were no improvement in storage stability and at 60 degrees C stability was reduced for both CALB-7 and CALB-10.

Optimized Preparation Techniques for PVC–Green Coconut Fiber Composites

Composites of poly(vinyl chloride) (PVC) and green coconut fibers were prepared by two techniques: dry blending + extrusion and dry blending + mixing. The degree of homogeneity of the mixes was evaluated through dynamic modulus measurements in both the molten and the solid states. Dry blending + mixing was found to be most appropriate in the preparation of laboratory scale composites. In addition, results suggest that no physico-chemical interactions occur between the matrix and the fibers.

Fibra de coco e adubação foliar no crescimento e na nutrição de Cryptanthus sinuosus

Plantas de Cryptanthus sinuosus foram cultivadas em três substratos (mesocarpo de coco - MC; mesocarpo de coco lavado - MCL e xaxim-X), visando comparar o efeito da fibra de coco verde, como substrato, àquele da fibra de xaxim sobre o crescimento e teores de nutrientes das plantas, sob três níveis de adubação foliar: 50, 100 e 150% de solução contendo 210 mg L-1 de N, 31 mg L-1 de P e 234 mg L-1 de K. O experimento constou de um fatorial em delineamento de blocos ao acaso, com quatro repetições e três plantas por parcela, uma planta por vaso e conduzido em casa de vegetação. O número de folhas, diâmetro da roseta, massa da matéria seca (MS) de folhas e raízes e teores de nutrientes foram avaliados. As plantas cultivadas em X apresentaram valores de MS de folhas e de raízes mais altos que aquelas em MC, mas não diferiram estatisticamente daqueles observados nas plantas em MCL. As plantas cultivadas em MC e MCL apresentaram características semelhantes indicando que a alta condutividade elétrica encontrada no substrato MC não prejudicou o acúmulo de matéria seca. As plantas cultivadas em MC e MCL apresentaram menores teores foliares de N, P, S que as cultivadas em X, porém com coloração e arquitetura foliares mais atrativas. Os diferentes níveis de adubação utilizados não tiveram efeito diferenciado sobre as características de crescimento, nem sobre os teores de nutrientes nas plantas.

Investigating polypropylene–green coconut fiber composites in the molten and solid states through various techniques

AbstractA series of polypropylene (PP)–green coconut fiber (GCF) composites were prepared by melt mixing and their properties studied in the molten state using an advanced nonlinear harmonic testing technique, and in the solid state using standard mechanical testing and scanning electron microscopy (SEM). The effect of fiber loading as well as the role of maleated polypropylene as compatibilizing agent was investigated. PP–GCF composites are heterogeneous materials that, in the molten state, are found to exhibit essentially a nonlinear viscoelastic character, in contrast with the pure PP, which has a linear viscoelastic region up to 50–60% strain. Complex modulus increases with GCF content but in such a manner that the observed reinforcement is at best of hydrodynamic origin, without any specific chemical interaction occurring between the polymer matrix and the fibers. The addition of maleated polypropylene improves the wetting of fibers by the molten polymer but the effect is so small that specific chemical reactions could hardly be considered as occurring. Flexural modulus data confirm the reinforcing effects of the fiber and an improvement is noted when some maleated polypropylene is used, with an optimum level of around 1% (or the PP content). SEM microphotographs clearly show that maleated polypropylene imparts a better wetting of GC fibers by PP, but chemical interactions are unlikely to occur between the polymer and GCF. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1922–1936, 2006

Poly(vinyl chloride)–green coconut fiber composites and their nonlinear viscoelastic behavior as examined with fourier transform rheometry

AbstractUsing a purposely modified torsional dynamic rheometer with a closed cavity, I investigated composites of poly(vinyl chloride) (PVC) and green coconut fibers (GCFs) with Fourier transform (FT) rheometry, a new dynamic test technique that resolves the complex dynamic response of materials submitted to harmonic strain into their main and harmonic components. Because of instrument limitations in the low‐strain region, torque signal harmonic components had to be corrected to yield results that suited established theoretical considerations. The preparation method of the composites had major effects on their linear and nonlinear viscoelastic responses; essentially, no homogeneous material could be prepared by dry blending plus extrusion, in contrast to dry blending plus mixing, which is the recommended technique; this was likely because PVC plasticization was then achieved. One of the most important rheological characteristics of the PVC–GCF composites was the quasidisappearance of the linear viscoelastic behavior. Nevertheless, an easy extrapolation technique was used to extract linear modulus data from the FT results, which led me to the conclusion that the reinforcing effect of the GCFs was essentially hydrodynamic with little, if any, interfacial interaction between the polymer matrix and the fibers. The results gathered from nonlinear viscoelastic properties, as obtained through FT rheometry, supplement this conclusion. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3638–3651, 2006

Caracterização mecânica e morfológica de compósitos de polipropileno e fibras de coco verde: influência do teor de fibra e das condições de mistura

Compósitos de polipropileno com 10, 20 e 30% em volume de fibra de coco verde foram obtidos em câmara de mistura Haake, tendo como variáveis a temperatura de processamento e a velocidade de cisalhamento. O módulo de flexão e as características morfológicas dos diferentes compósitos obtidos foram avaliados e comparados com o polipropileno puro. Foi observado que a temperatura de 170 °C, a velocidade do rotor de 60rpm e o teor de fibra de coco verde de 30% forneceram o melhor desempenho quanto à flexão. Essas observações foram comprovadas pela análise da morfologia.