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Okra bast fiber (OBF) is one of the underutilized natural bast fibers, extracted from the bark of the okra plant’s (Abelmoschus esculentus) stem. Globally, the okra crop is cultivated for its green immature fruit consumed as a vegetable. After fruit harvesting, the okra plants are treated as agro-waste. Worldwide, 62.11 lakh MT of green okra plant agro-waste is estimated annually. This agro-waste can be utilized to extract the technical bast fibers. The estimated production potential per hectare is 162 kg OBF and nearly 186 lakh kg OBF in the world. Extracted OBF has the potential to be utilized as commercial fiber-like jute fiber (JF). Therefore, the properties of extracted OBF were compared with those of JF in terms of linear density (tex), optical, tensile, and structural properties. OBF was extracted from the 120 ± 10 days old okra plant harvest waste through the water retting process (both flowing and stagnant water) in two different time intervals (17 and 25 days). Overall OBF showed better optical properties and similar or better tensile properties, while coarseness in its fineness than JF.

This paper focuses on the effect of okra bast fillers on biodegradation of poly(vinyl alcohol) composites. Fibers were obtained from okra plant stems via biological degumming and subjected to different chemical treatments such as scouring, alkalizing, maleic anhydride treatment, and vinyl acetate grafting. The fibers were ground and PVA-okra bast filler composites were produced at 20 wt% fiber load via the solution casting method. The obtained composites were tested in terms of mechanical properties and exposed to biodegradation in soil. Effects of okra bast filler addition and chemical treatments on changes in mass, breaking strength, elasticity modulus, and breaking elongation of composites upon soil biodegradation were determined. The composites can be considered for utilization in packaging and agricultural applications. [ABSTRACT FROM AUTHOR]

In this study, biologically degummed okra bast and corn husk fibers were subjected to alkalization processes. Alkalization treatments resulted in decrease of linear density of the biologically degummed fibers. Increment in alkali concentration resulted in an initial increase then a successive decrease in all tensile indicators: initial modulus, breaking tenacity and breaking elongation. 3 g/L NaOH-treated fibers showed the best tensile characteristics for both okra bast and corn husk fibers. The IR spectra analysis suggested elimination of extracellulosic materials upon alkaline treatment. The ranges for properties of the produced okra bast and corn husk fibers can be summarized in consecutive order as linear density of 9.7–12.3 and 20.0–24.3 tex; initial modulus between 1257-1897 and 156.4–354.6 cN/tex; breaking tenacity range in 28.0–46.8 and 6.37–15.2 cN/tex; and elongation in the range 2.0–2.5% and 8.7–19.9%. The properties of obtained okra bast fibers are found to be superior to corn husk fibers and comparable to that of conventional bast fibers.

Okra bast fiber (OBF) is one of the underutilized natural bast fibers, extracted from the bark of the okra plant's (Abelmoschus esculentus) stem. Globally, the okra crop is cultivated for its green immature fruit consumed as a vegetable. After fruit harvesting, the okra plants are treated as agro-waste. Worldwide, 62.11 lakh MT of green okra plant agro-waste is estimated annually. This agro-waste can be utilized to extract the technical bast fibers. The estimated production potential per hectare is 162 kg OBF and nearly 186 lakh kg OBF in the world. Extracted OBF has the potential to be utilized as commercial fiberlike jute fiber (JF). Therefore, the properties of extracted OBF were compared with those of JF in terms of linear density (tex), optical, tensile, and structural properties. OBF was extracted from the 120 ± 10 days old okra plant harvest waste through the water retting process (both flowing and stagnant water) in two different time intervals (17 and 25 days). Overall OBF showed better optical properties and similar or better tensile properties, while coarseness in its fineness than JF. [ABSTRACT FROM AUTHOR]

This paper focuses on preparation of poly(vinyl alcohol) (PVA)-based composite films reinforced with okra bast fibers at different percentages of 5, 10, 20% via solution casting method. Fibers obtained from different sections of okra plants were biologically degummed and scoured with Na2CO3. Selected fibers were bleached, treated with maleic anhydride or grafted with vinyl acetate. Mechanical, physical and biodegradational properties of the composites were investigated. The tensile strength of the produced composites ranges between 33.8 and 55.1 MPa, elasticity modulus from 1.8 to 2.6 GPa, elongation rate at break varies in 2.8-10%. Chemical treatments led to improved mechanical performance whereas increased fiber content reduces tensile strength, stiffness and elongation, as well as water absorption. Fiber addition significantly affected biodegradation in a complicated way: by decelerating mass loss but accelerating deterioration of mechanical properties. [ABSTRACT FROM AUTHOR]

In this study, biologically degummed okra bast and corn husk fibers were subjected to alkalization processes. Alkalization treatments resulted in decrease of linear density of the biologically degummed fibers. Increment in alkali concentration resulted in an initial increase then a successive decrease in all tensile indicators: initial modulus, breaking tenacity and breaking elongation. 3 g/L NaOH-treated fibers showed the best tensile characteristics for both okra bast and corn husk fibers. The IR spectra analysis suggested elimination of extracellulosic materials upon alkaline treatment. The ranges for properties of the produced okra bast and corn husk fibers can be summarized in consecutive order as linear density of 9.7–12.3 and 20.0–24.3 tex; initial modulus between 1257-1897 and 156.4–354.6 cN/tex; breaking tenacity range in 28.0–46.8 and 6.37–15.2 cN/tex; and elongation in the range 2.0–2.5% and 8.7–19.9%. The properties of obtained okra bast fibers are found to be superior to corn husk fibers and comparable to that of conventional bast fibers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper focuses on the effect of okra bast fillers on biodegradation of poly(vinyl alcohol) composites. Fibers were obtained from okra plant stems via biological degumming and subjected to different chemical treatments such as scouring, alkalizing, maleic anhydride treatment, and vinyl acetate grafting. The fibers were ground and PVA-okra bast filler composites were produced at 20 wt% fiber load via the solution casting method. The obtained composites were tested in terms of mechanical properties and exposed to biodegradation in soil. Effects of okra bast filler addition and chemical treatments on changes in mass, breaking strength, elasticity modulus, and breaking elongation of composites upon soil biodegradation were determined. The composites can be considered for utilization in packaging and agricultural applications., (© TÜBİTAK.)

The effect of chemical treatment i.e. bleaching, alkalization and graft copolymerization on the morphology changes of okra bast fiber has been investigated by means of infrared spectroscopy (IR), scanning electron microscopy (SEM), water absorption and tensile properties measurements. The graft copolymerization reaction of bleached fiber with acrylonitrile monomer (AN) has been carried out under the catalytic influence of K2S2O8 and FeSO4 redox system. The maximum graft yield (11.43 %) has been found at 70°C temperature, 3×10−2 mol/ l acrylonitrile, 5×10−3 mol/ l K2S2O8, 5×10−3 mol/ l FeSO4 and for 90 min. On the contrary, the fiber has been treated with 10 % NaOH solution, which is much effective to remove the impurities. Based on findings of water absorption, tensile properties and SEM micrograph, the AN-grafted fiber has been showed better properties than bleached and alkali treated fibers. The degree of modification of okra bast fiber by chemical treatment has been evaluated by IR measurement. [ABSTRACT FROM AUTHOR]