Okra Fiber Research Articles

Study on the Physico-Mechanical Properties of Okra Fibre at Different Harvesting Time

Study on the Physico-Mechanical Properties of Okra Fibre at Different Harvesting Time

Thermal and Mechanical Characteristics of Okra (Abelmoschus esculentus) Fibers Obtained via Water- and Dew-Retting

In this research, fibers were extracted from different parts of the okra plant (Abelmoschus esculentus) via water- and dew-retting methods. The fibers were subjected to physical and thermal analyses. The fibers obtained from the upper part of the okra plant showed higher breaking strength and lower linear density. Fibers obtained via water-retting exhibited higher breaking strength, higher elongation at break rates, and lower linear density values. The paper also presents the results of thermogravimetric analysis of the okra fibers. Tests were carried out in oxygen and inert gas atmospheres. Slight differences were found in the thermal resistance of the tested fibers, which was confirmed by an analysis using the αs-αr methodology. The calculated activation energy showed a widespread range of values.

Effects of chemical treatments and degumming methods on physical and mechanical properties of okra bast and corn husk fibers

In this study, okra (Abelmoschus esculentus) bast fibers and corn (Zea mays L.) husk fibers were extracted via different degumming methods and subjected to different chemical treatments including alkalization, bleaching, maleic anhydrite and vinyl acetate treatments. Alkalization resulted in decrease of tensile stiffness and tenacity of the fibers while increasing elongation rate. Corn husk fibers were found to be more vulnerable to chemical treatments. Bleaching and vinyl acetate treatments led to the highest mechanical strength for okra bast and corn husk fibers, respectively. Okra fibers were found to be superior in terms of fineness and mechanical performance compared to corn husk fibers. The performance characteristics exhibited by the okra bast fibers are comparable to that of conventional bast fibers. Thus, okra bast fibers are promising for use in biocomposites as reinforcement elements, whereas cornhusk fibers may find use in non-load bearing applications like thermal insulation or noise control.

Improvement of the Mechanical Properties of Hibiscus Esculentus (Okra) Fiber Reinforced Polymer Composite

Natural fiber and their composites are the emerging trends in material science. They are speedily gaining grounds in the replacement of synthetic reinforcements. This is due to their low density, high specific mechanical strength, ultimate availability and disposability and less processing requirements. Most plant based fibers have become centers of research. This work is based on Okra fiber. Okra fiber was used as reinforcement in vinyl ester polymer matrix. Okra fiber was chemically treated using NaOH to clean fiber surface, modify the surface to increase the surface roughness and in general enhance bond strength between fiber and matrix. Reinforcement of the matrix using Okra fiber increases mechanical properties of the composite. But for optimal result, certain parameters were considered and varied. The two parameters considered were: fiber length, and proportion or volume fraction. Different variations of fiber length considered were: 10mm, 30mm and 50mm while the different fiber volume fractions considered are 10%, 30% and 50%. This work has analyzed how these parameters can be best combined for optimum values of tensile properties of the composite. The tensile strength of composite was highest at fiber length of 50mm and volume fraction of 10% at ultimate tensile strength of 214MPa.

Comparative Study of Jute, Okra and Pineapple Leaf Fiber Reinforced Polypropylene Based Composite

In this experimental studies, three types of fabric such as Jute, Okra and Pineapple Leaf Fiber (PALF) were selected and matrix material such as polypropylene (PP) was selected to manufacture composites. Jute/PP, Okra/PP, and PALF/PP based composites were prepared successfully by a conventional compression molding technique. The objective of this study is to compare the mechanical such as tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM), elongation at break (Eb%) and interfacial properties of the composites. Jute fiber (hessian cloth)-reinforced polypropylene matrix composites (45wt% fiber) were fabricated by compression molding. TS, TM, BS, BM, and IS of the composites were found to be 45 MPa, 2.2 GPa, 54 MPa, 4.1 GPa, and 16 kJ/m2, respectively. Then Okra and PALF fiber reinforced polypropylene-based composites (45 wt% fiber) were fabricated and the mechanical properties were compared with those of the jute-based composites. The result revealed that mechanical properties of PALF composite higher than jute and Okra fiber reinforced composites. Water absorption and elongation percentage at break showed different scenario and it was noticed from the experimental study that water absorption and elongation at break (%) of jute fabric was higher than other composites. Fracture sides of the composites were studied by scanning electron microscope (SEM), and the results revealed poor fiber-matrix adhesion for jute fiber-based composites compared to that of the other fiber-based composites (OF/PP and PALF/PP). KEY WORDS: Polypropylene, Jute Fiber, Okra Fiber, Pineapple Fiber, Mechanical Properties, Interfacial Properties, Composites. *Corresponding Address: dr.ruhul_khan@yahoo.com

Experimental study on mechanical behavior of natural hybrid composites filled with ground nut shell ash

Abstract Nowadays, natural fiber reinforced polymer composites are widely used because of their advantageous properties like minimum density, maximum specific strength, low cost and easy availability. Manufacturing of natural fiber composite is easy as compared to the conventional methods. In the present scenario, due to an increasing interest in environmental consciousness with greenhouse effect, various industries have initiated the use of eco-friendly materials and are replacing hazardous materials with such eco-friendly materials. The present work aims to determine the tensile strength of okra and jute fibers reinforced in Epoxy LY-556 and XIN-100IN Resins. Okra fibers are developed from the stem of the plant of the Malvaceae family. Their use as reinforcement in polymer composites requires the basic knowledge of their mechanical properties. Jute fibers are developed from the best jute plants. The conclusions are based on their mechanical properties and behavior.

Green alternative treatment for cellulosic fibers: ionic liquid modification of Abelmoschus esculentus fibers with methyl-tri-n-butyl ammonium methyl sulphate

In this research, Okra (Abelmoschus esculentus) fibers were treated with an ionic liquid, methyl-tri-n-butyl ammonium methyl sulphate, to modify surface of the fibers. The fibers were exposed to aqueous ionic liquid solutions at different concentrations such as; 2, 5, 10 and 20 w/v% at ambient temperature. Ionic liquid treatment led to enhanced surface hydrophobicity of the okra fibers by means of increase in surface carbon/oxygen ratio. The proportion of C–C and C–H bands in the okra fibers were increased as a result of the treatment. The untreated and treated okra fibers gave similar crystalline index (CI) values. The CI results varied between 61.12 and 65.92%. Thermal stability of the fiber deteriorated after the treatment. However, char yield values increased indicating possibly enhanced flame retardancy after the treatments. Scanning electron microscopy observation confirmed the existence of ionic liquid both in intercellular gaps and on the surface of the okra fibers.

Improvement of Physical, Mechanical and Thermal Properties of Okra Fiber/Polypropylene Composites by UV Radiation

In this study, polypropylene (PP) composites (50% fiber by weight) were prepared by reinforcing lignocellulosic okra fiber using compression molding technique. In order to improve the mechanical properties of the composites, virgin okra fiber and PP sheet were exposed to different intensities of UV radiation (25–200 UV dose) and found significant enhancement in the mechanical properties up to 75 UV dose. Chemical structural and microstructural change of irradiated and non-irradiated composites was characterized by Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) was used to examine the change of the surface of okra fiber due to irradiation. Thermal stability of the composites was measured by the thermogravimetric analysis (TGA/DTG) and found to be in between PP and okra fiber. Thermal stability, melting temperature and crystallinity (%) of the composites further increased by UV radiation due to improved mechanical interlocking between irradiated okra fiber and PP. In addition, water uptake behavior of the composites was also performed and the irradiated composites showed a sharp decrease in the water absorption compared to that of the non-irradiated composites.

Application of soda-AQ pulping to agricultural waste (okra stalks) from Sudan

Abelmoschus esculentus okra as whole stalks was examined for its suitability for pulp and paper production. It’s, fiber dimensions, morphological and chemical characteristics were reported. The pulping trials with soda- Anthraquinone (AQ,) at different chemical charges. Application of 21% as NaOH with 0.1% AQ gave good results in degree of delignification, mechanical properties. Utilization of okra pulps and blender is recommended due to good pulp properties. Evaluation of general characteristics of okra stalks in terms of fiber dimensions morphological indices, chemical components, Soda-AQ cooking and to study their suitability for paper production. Okra Fiber dimension evaluation done after maceration with a mixture of 30% hydrogen peroxide and acetic acid (1:1) for core and bark parts separately and was carried out under microscope staining with aqueous safranin. The Soda-AQ cooks at different active alkali levels were calculated as NaOH on oven dry raw material. The fibers from okra stalks studied (core and bark) were in the range of hardwood fibers, with short fiber length, especially the core with more or less moderate walls, narrow lumen and fiber width. The fiber width of bark was medium –narrow with medium wall thickness. The ash content was rather high whereas the silica content was comparatively high The hot water extractives from okra stalks was (4.1%), cold water (0.4) ethanol/ cyclohexane (1.1), ethanol extractives (1.2%) and 1% NaOH (27.6%) were rather high. The cellulose (Kurschner-Hoffer) was (48.5%) The lignin content was (15.3%) which was relatively moderate. The use of 0.1% AQ enhanced the delignification in the three trials applied. The screened yield increase with increase of chemical dose applied while the rejects decrease. When 21% NaOH was applied, the screened yield was 32.2% with negligible amount of rejects, however with lower alkali charge 18% the screened yield was decreased to 28% with very low rejects 1.5%. on the other hand rejects were increased to 7% when 15% NaOH was applied with very low screened yield 19%.The pulps produced from okra soda-AQ are suitable for production of printing and writing papers and it is advisable to use them in blending due to good papermaking properties.

Comparative Study of Physico-Mechanical Properties Between Okra and E-glass Fiber-Reinforced Polypropylene-based Composites

Okra fiber (OF) reinforced polypropylene (PP) matrix composites (45 wt% fiber) were fabricated using a compression molding technique. To fabricate the composite treated Okra fiber were used. Tensile strength (TS), tensile modulus (TM), elongation at break (Eb%), bending strength (BS), bending modulus (BM), impact strength (IS) and hardness of the composites were found to be 38.5 MPa, 0.68 GPa, 8.2%, 72.5 MPa, 5.56 GPa, 22.87 kJ/m2, and 97 (Shore-A), respectively. Then E-glass fiber (woven)-reinforced polypropylene-based composites (45 wt% fiber) were fabricated and the mechanical properties (TS, TM, Eb%, BS, BM, IS, hardness) were found 80 MPa, 5 GPa, 11%, 81 MPa, 10 GPa, 32 kJ/m2, and 97 (Shore-A), respectively. After that compared E-glass fiber/PP based composites mechanical properties with those of the OF/PP based composites mechanical properties. It was observed that E-glass fiber-based composites showed almost double mechanical properties compared to OF/PP based composite. Water absorption and elongation percentage at break showed different scenario and it was noticed from the experimental study that water absorption and elongation at break (%) of was higher than E-glass based composites. After the flexural test, fracture surfaces of the E-glass/PP and OF/PP composites were investigated using scanning electron microscope (SEM) and the results revealed that E-glass fiber reinforced based composites matrix adhesion less than the E-glass fiber reinforced based composites.

Microwave Assisted Surface Treatment of Okra Fibers

All over the world, the importance of the sustainable and biodegradable materials is increased very fast. The use of agricultural stem waste as a technical textile material can be made a huge contribution for save the environment. The aim of this research was to pre-treat the okra fibers with microwave energy. The fibers were obtained from Marmara Region agricultural waste by use a specially designed machine. They were microwave- assisted surface treated with 7 % sodium bisulphate and 10 % acetic acid. The results of tensile strength, fiber diameter, SEM and X-Ray analyses were compared to the conventionally treated fiber samples. Finally, microwave-assisted treatments were quite good. Bisulphate treatment was more effective than treatments with acetic acid. When the SEM images was investigated, a lot of porosity was observed on the surface of acetic acid treated fiber and the tensile strength values increased bisulphate treatment.

Evaluating the performance of gamma irradiated okra fiber reinforced polypropylene (PP) composites: comparative study with jute/PP

In this study, two bast fibers such as okra and jute were selected to manufacture composites taking polypropylene (PP) as matrix material by means of compression molding technique with maintaining 40% fiber content on the total weight of the composites. Investigation was done on tensile properties such as tensile strength (TS), tensile modulus (TM), elongation at break (EB%), bending properties such as bending strength (BS), bending modulus (BM) and impact properties like impact strength (IS) and hardness (Shore-A) of the composites. From analyzed data, it was found that Okra/PP composites showed very competitive mechanical properties to Jute/PP composites. Non-irradiated okra composite showed the value of TS, TM, BS, BM, IS and hardness to be 32.2 MPa, 602 MPa, 55.6 MPa, 3.6 GPa, 19.54 kJ/m2 and 95 (Shore-A), respectively, whereas that value for non-irradiated jute composite was 35.5 MPa, 629 MPa, 71.5 MPa, 4.5 GPa, 21.48 kJ/m2 and 96 (Shore-A), respectively. The composite samples were exposed to different intensities of gamma radiation (250‒1000 krad) at a dose rate of 330 krad/h and changes in mechanical properties were examined. Both irradiated composites (500 krad) showed significant improvement of mechanical properties compared to that of the non-irradiated composites. Maximum TS, TM, BS, BM and IS value were found to be 41.9 MPa, 685 MPa, 72 MPa, 4.7 GPa and 22.6 kJ/m2, respectively for irradiated okra composite and 45.3 MPa, 717 MPa, 88 MPa, 6.7 GPa and 24.3 kJ/m2, respectively for irradiated jute composite. Fourier transform infrared spectroscopy was used to identify the surface groups of the composites. Water absorption, degradation behavior of the composites under soil and heat medium were also performed. Degradation tests revealed that okra composite retained its original mechanical properties higher than that of jute composite. The morphology of the composites was inspected by scanning electron microscope.

Fabrication, Mechanical Characterization and Interfacial Properties of Okra Fiber Reinforced Polypropylene Composites

In this study, an attempt has been taken to manufacture okra fiber (OF) composites with varying the fiber content ranging from 25-65% on total weight of the composites and polypropylene (PP) was preferred as matrix material. To fabricate the composites untreated and mercerized fibers were selected. A systematic study was done to observe the mechanical behaviors of the composites such as tensile, impact and bending properties. It was found that treated (mercerized) fiber composites exhibited improved mechanical properties than that of untreated fiber composites. Maximum tensile strength (TS) and bending strength (BS) was examined 38.5 MPa and 72.5 MPa respectively, whereas the highest tensile modulus (TM) and bending modulus (BM) was observed 675 MPa and 5.4 GPa respectively. The optimum impact strength (IS) and hardness value was found to be 22.87 KJ/m2 and 97 (Shore-A) for mercerized fiber composites containing 45% fiber. The composite samples were exposed to different intensities of γ radiation (2.5 kGy–10.0 kGy) and found significant improvement in the mechanical properties up to 5.0 kGy dose. Water absorption, degradation properties due to heat and soil medium of the composites were also performed. The interfacial property was examined by Microscopic Projector and Scanning Electron Microscope (SEM) and found that the interfacial bonding between matrix material and fiber was enhanced due to the treatment of fibers which authenticate the found mechanical characteristics of the composites.

Synthesis of Nano-Cellulose from Okra Fibre and FTIR as Well as Morphological Studies on It

Nano-cellulose was extracted from Okra fiber by various chemical treatment such as alkali treatment, bleaching and then by acid hydrolysis. The final products were characterized by means of Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). FTIR results showed that the hemicelluloses and lignin were removed from the extracted nano-cellulose. On the other hand, SEM analysis showed that the surface morphology of raw fiber, bleached fiber, alkali treated fiber and nano-cellulosic fiber. The surface of raw fiber was rough, not plain and smooth but the surface of Crystalline Nano Cellolose (CNC) became plain, smooth and not rough for the removing of lignin and fatty and waxy materials from it and simultaneously there is a honey comb structure appeared which will be very helpful for producing nano composites with polymeric materials. Size of the okra fiber was cellulose reduced into nano-sized particles.

Nonwoven production from agricultural okra wastes and investigation of their thermal conductivities

Nowadays bio-based composite materials have been used in rising amounts and demanded widely in industrial uses, as they provide cost reduction and weight loss in the end use products. Agricultural cellulose based wastes can be a good alternative to synthetic fibers and can be used in natural fiber reinforced composite production, as there is a huge (more than 40 million tons) potential for natural cellulose production from agricultural wastes. Okra is one of the most grown vegetables around the world with stems left on the fields after harvest. When the similarity of mechanical properties of okra fibers with traditional bast fibers (flax, kenaf, hemp) are considered, from an economical and an environmental point of view this research emphasizes the potential of agricultural biomass for natural fiber production. In this study, okra stem wastes used for natural cellulosic fiber production and treated with 10% NaOH at 60°C for 10, 20, 30 and 40 minutes. By alkali treatment, decrease in fiber diameter and weight, and increase in tensile strength and elongation % have been observed. Nonwoven production has been done from both the fibers with and without surface treatments. Thermal conductivity properties of both nonwovens have been investigated.

Mechanical Properties Characterization of Okra Fiber Based Green Composites & Hybrid Laminates

The research towards the development of composites has been around for many years. But rising concerns about the global warming, waste generation & management, increasing environmental consciousness, growing pressure on the resources of fossil fuels has led to the development of green composites.Furthermore, there are some natural fibers where the properties can be good in comparison with the synthetic fibers which have contributed to this development. In this paper the experimental characterization of mechanical properties of okra fiber reinforced epoxy composite has been performed. finite element analysis (FEA), analytical study was performed to characterize the properties of banana and kenaf fiber reinforced epoxy composites. A number of inter - lamina hybrid laminates of different configurations were designed using these composite laminas and their mechanical properties were found and compared.

Okra as a drag reducer for high Reynolds numbers water flows

The capability of a mixture of okra fiber and mucilage as drag reducer in high Reynolds number flows through a pipeline, in which the flux is maintained by a centrifugal pump with controlled rotation, is analyzed. A DR close to the maximum drag reduction asymptote, which is obtained for polymeric additives, was achieved when concentrations around 1600 ppm were used. The loss of efficiency of the solution over the number of passes through the system was almost the same of that observed for rigid materials like Xanthan Gum and Guar Gum, which suggest that the main cause of a decreasing drag reduction is the de-aggregation instead of mechanical degradation, commonly observed in flexible polymers. As expected, the material degrades biologically, but it seems that it is not a great problem for open systems, since such a degradation is perceptible only after 24 h. We strongly believe that this new bio-drag reducer can be an alternative to synthetic polymers or other biopolymers, since it is extremely cheap and easy to be obtained.

Characterization, modification and use of biomass: okra fibers

In the present study, fibers were extracted from different parts of okra stem and branches by way of biological retting. The extracted fibers were subjected to chemical and enzymatic treatments. The effects of the treatments on the fibers’ physical, mechanical, chemical and morphological aspects were investigated. The dyeability of the fibers with industrial green mate (Paraguayan tea) waste was studied. The heavy metal ion adsorption capability of okra bast fibers from aqueous systems was examined. The ranges for properties of the produced okra bast fibers can be summarized as linear density of 14·7–26·9 tex (g/km), initial modulus of 862–1358 cN/tex, breaking tenacity of 24–35 cN/tex, elongation of 2·5–3·2% and water absorption of 67·2–84·8%. As a mordant, iron sulfate resulted in higher color strength (K/S) for fibers dyed with the green mate tea waste compared to potassium aluminum sulfate (alum). Use of okra bast fibers resulted in iron (III), copper (II) and chromium (III) ion concentration decreases, as high as 71–98%, in aqueous solutions for pH values under 7.

Isolation and characterization of lignin from okra (Abelmoschus esculentus) fibre and stick

The okra (Abelmoschus esculentus) plant consists of bast fiber and core (stick). The bast fibre of okra plant was characterized with high ?-cellulose (56.7%) and low lignin (12.6%) and stick withlow ?-cellulose (34.3%) and high lignin (25.2%) content. Lignin was isolated from the fiber and stick by acidolytic dioxane method and characterized for elemental analysis, methoxyl analysis and FTIR and 1H-NMR spectroscopy. The C9 formulas for okra stick and fibre lignin were C9H9.61O4.63(OCH3)1.24 and C9H8.61O4.66(OCH3)1.49, respectively. Both of the lignins were of the guaiacyl-syringyl type. The bands of FT-IR spectrum at 1327 cm-1, 1122 cm-1 and 837 cm-1 associated with syringyl unit was higher in okra fibre lignin than in the okra stick lignin. The structural analysis revealed that the average numbers of proton of ?-O-4 (H? & H?) per C9 unit in okra stick and fibre lignin were 1.53 and 1.20, respectively. The ?-O-4 units in these lignins had predominately erythro stereochemistry type.Bangladesh J. Sci. Ind. Res. 50(4), 257-262, 2015

Mechanical Performance of Hybrid Okra Fibre Reinforced Polyester Composites—Part I: Reinforced with Fresh and Long Time Dried Fibres

Mechanical Performance of Hybrid Okra Fibre Reinforced Polyester Composites—Part I: Reinforced with Fresh and Long Time Dried Fibres