Narendra Reddy | University of Nebraska Lincoln (original) (raw)

Papers by Narendra Reddy

Cellulose, 2013

Two plant proteins, soyprotein and wheat gluten, and chicken feathers used to size cotton substra... more Two plant proteins, soyprotein and wheat gluten, and chicken feathers used to size cotton substrates provided sizing performance similar to starch and were also easily degraded in activated sludge. Sizing is an essential process to impart protection to warp yarns and increase weaving efficiency. Cotton yarns have traditionally been sized with starch, modified starch derivatives, CMC, poly vinyl alcohol (PVA), or a combination thereof along with quite a few other fiber binding ingredients. Although starch and starch derivatives are extensively used for sizing, there can be several limitations including less-than-satisfactory sizing performance and difficulties in desizing starch based size. Plant proteins such as wheat gluten, soyproteins and poultry feathers are available in large quantities at low cost and have limited industrial applications. However, these proteins are known to have excellent film-forming properties, a primary requirement for a warp size, and have also been used as adhesives. Using proteins as warp sizing agents on cotton yarns potentially could provide acceptable sizing performance and be cost-effective, as well. In this research, soypro-teins, wheat gluten, and chicken feathers were studied for exploring their feasibility for sizing, desizing, biodegradability, and ability to replace starch and PVA for sizing cotton yarns. It was found that all three proteins provided similar cohesion to fibers and abrasion resistance compared to starch. Protein sizes had significantly high BOD 5 /COD ratio compared to PVA, suggesting that the proteins are easily degradable in textile effluent treatment plants.

Industrial Crops and Products, 2012

We show that the wheat proteins gluten, gliadin and glutenin can be compression molded into therm... more We show that the wheat proteins gluten, gliadin and glutenin can be compression molded into thermoplastic films with good tensile strength and water stability. Wheat gluten is inexpensive, abundantly available, derived from renewable resource and therefore widely studied for potential thermoplastic applications. However, previous reports on developing thermoplastics from wheat proteins have used high amounts of glycerol (30-40%) and low molding temperature (90-120 • C) resulting in thermoplastics with poor tensile properties and water stability making them unsuitable for most thermoplastic applications. In this research, we have developed thermoplastic films from wheat gluten, gliadin and glutenin using low glycerol concentration (15%) but high molding temperatures (100-150 • C). Our research shows that wheat protein films with good tensile strength (up to 6.7 MPa) and films that were stable in water can be obtained by choosing appropriate compression molding conditions. Among the wheat proteins, wheat gluten has high strength and elongation whereas glutenin with and without starch had high strength and modulus but relatively low elongation. Gliadin imparts good extensibility but decreased the water stability of gluten films. Gliadin films had strength of 2.2 MPa and good elongation of 46% but the films were unstable in water. Although the tensile properties of wheat protein films are inferior compared to synthetic thermoplastic films, the type of wheat proteins and compression molding conditions can be chosen to obtain wheat protein films with properties suitable for various applications.

Journal of Materials Science, 2010

Industrial Crops and Products, 2011

Soyprotein–jute fiber composites developed using water without any chemicals as the plasticizer s... more Soyprotein–jute fiber composites developed using water without any chemicals as the plasticizer show much better flexural and tensile properties than polypropylene–jute composites. Co-products of soybean processing such as soy oil, soyprotein concentrate and soy protein isolates are inexpensive, abundantly available and are renewable resources that have been extensively studied as potential matrix materials to develop biodegradable composites. However, previous attempts

Journal of Agricultural and Food Chemistry, 2007

Zein with a higher intrinsic viscosity and phosphorus content, similar protein content, lower yel... more Zein with a higher intrinsic viscosity and phosphorus content, similar protein content, lower yellowness, and at potentially much lower cost than commercially available zein was obtained from distillers dried grains with solubles (DDGS). A novel extraction method using acidic conditions in the presence of a reducing agent has been used to obtain about 10% aqueous ethanol soluble zein from DDGS. The optimum pH, time, temperature, and amount of reducing agent that can produce zein with high quality and yield have been developed. In addition to the zein, about 17% oil based on the dry weight of DDGS has also been obtained during zein extraction. The zein obtained from this research is expected to be suitable for use as fibers, films, and binders and in paints.

Journal of Materials Science-materials in Medicine, 2008

For the first time, protein fibers with excellent mechanical properties and water stability have ... more For the first time, protein fibers with excellent mechanical properties and water stability have been produced from gliadin for potential use in tissue culture and other medical applications. Biomaterials developed from plant proteins such as zein and soyproteins are preferred for several medical applications over synthetic polymers such as polylactic acid. However, the plant protein based biomaterials developed so far have poor mechanical properties and hydrolytic stability even after crosslinking. This study aims to develop biomaterials from gliadin with excellent mechanical properties and water stability without using any crosslinking agents. A novel gliadin fiber production method was used to self crosslink the fibers and obtain high strength and water stability. Gliadin fibers have high strength (120 MPa) and elongation (25%) compared to similar collagen fibers that were crosslinked with glutaraldehyde (strength of about 44 MPa and elongation of 14%). The fibers show 100% strength retention after being in pH 7 water at 50 °C for 40 days and also have better water stability than PLA in acidic conditions at high temperatures. Gliadin fibers are suitable for cell growth and promote the attachment and proliferation of bovine turbinate fibroblasts.

Journal of Agricultural and Food Chemistry, 2007

For the first time, sorghum leaves and stems have been used to produce natural cellulose fibers w... more For the first time, sorghum leaves and stems have been used to produce natural cellulose fibers with properties suitable for composite, textile, and other high-value fibrous applications. The leaf and stems fibers produced are multicellular and have similar cellulose contents. The breaking tenacity and elongation of the fibers are similar to that of natural cellulose fibers such as kenaf and cornstalk fibers. However, the sorghum fibers have a modulus of about 113 g/denier (15 GPa) similar to the modulus of cornstalk fibers but higher than that of cotton and cornhusk fibers. At least 7 million tons of natural cellulose fibers can be produced by using the sorghum stems and leaves available as byproducts every year. Using the sorghum byproducts as a source for cellulose fibers will help to add value to the sorghum crops and also make the fiber industry more sustainable.

Journal of Agricultural and Food Chemistry, 2007

Long natural cellulose fibers with properties suitable for textile and composite applications hav... more Long natural cellulose fibers with properties suitable for textile and composite applications have been obtained from wheat straw. This study aims to understand the potential of using wheat straw as a source for long natural cellulose fibers for textile, composite and other fibrous applications. The presence of wax on the outer layer of the straw and a unique zip-like structure that locks individual fibers makes it difficult to obtain fibers from wheat straw using the common methods of fiber extraction. A novel pretreatment with detergent and mechanical force followed by an alkaline treatment was used to obtain high quality fiber bundles. The structure and properties of the fibers are reported in comparison to common cellulose fibers, cotton, linen, and kenaf. Wheat straw fibers have coarser (wider width) single cells and lower crystallinity than cotton, linen, and kenaf. The breaking tenacity (force at break) of wheat straw fibers is similar to kenaf but lower than that of cotton and linen, % breaking elongation is similar to linen and kenaf but lower than cotton, and Young's modulus of the fibers is similar to cotton but lower than that of linen and kenaf.

Polymer, 2005

We have developed a fiber extraction method that produces fibers from cornstalks with mechanical ... more We have developed a fiber extraction method that produces fibers from cornstalks with mechanical properties similar to that of the common textile fibers. The fiber extraction method developed results in partial delignification and produces fibers from cornstalks that are suitable for textile and other industrial applications. The structure of the fibers obtained was investigated using X-ray diffraction and scanning electron microscope. The structure and composition of the natural cellulose fibers obtained from cornstalks are different than that of the common bast fibers such as flax and kenaf. Tensile properties of the fibers were studied using an Instron tensile tester. This study found that cornstalk fibers have relatively lower percent crystallinity but similar microfibrillar angle as that of the common bast fibers. The structure and properties of cornstalk fibers indicate that the fibers are suitable for producing various textile products.

Bioresource Technology, 2009

This paper reports the development of natural cellulose technical fibers from soybean straw with ... more This paper reports the development of natural cellulose technical fibers from soybean straw with properties similar to the natural cellulose fibers in current use. About 220 million tons of soybean straw available in the world every year could complement the byproducts of other major food crops as inexpensive, abundant and annually renewable sources for natural cellulose fibers. Using the agricultural byproducts as sources for fibers could help to address the concerns on the future price and availability of both the natural and synthetic fibers in current use and also help to add value to the food crops. A simple alkaline extraction was used to obtain technical fibers from soybean straw and the composition, structure and properties of the fibers was studied. Technical fibers obtained from soybean straw have high cellulose content (85%) but low% crystallinity (47%). The technical fibers have breaking tenacity (2.7 g/den) and breaking elongation (3.9%) higher than those of fibers obtained from wheat straw and sorghum stalk and leaves but lower than that of cotton. Overall, the structure and properties of the technical fibers obtained from soybean straw indicates that the fibers could be suitable for use in textile, composite and other industrial applications.

Biotechnology and Bioengineering, 2007

We report the production and characteristics of natural cellulose fibers obtained from the leaves... more We report the production and characteristics of natural cellulose fibers obtained from the leaves and stems of switchgrass. In this paper, the composition, structure and properties of fibers obtained from the leaves and stem of switchgrass have been studied in comparison to the common natural cellulose fibers, such as cotton, linen and kenaf. The leaves and stems of switchgrass have tensile properties intriguingly similar to that of linen and cotton, respectively. Fibers were obtained from the leaves and stems of switchgrass using a simple alkaline extraction and the structure and properties of the fibers were studied. Fibers obtained from switchgrass leaves have crystallinity of 51%, breaking tenacity of 5.5 g per denier (715 MPa) and breaking elongation of 2.2% whereas the corresponding values for fibers obtained from switchgrass stems are 46%, 2.7 g per denier and 6.8%, respectively. Switchgrass is a relatively easy to grow and high yield biomass crop that can be source to partially substitute the natural and synthetic fibers currently in use. We hope that this research will stimulate interests in using switchgrass as a novel fiber crop in addition to being promoted as a potential source for biofuels. Biotechnol. Bioeng. 2007; 97: 1021–1027. © 2007 Wiley Periodicals, Inc.

Journal of Polymers and The Environment, 2007

The structure and properties of chicken feather barbs makes them unique fibers preferable for sev... more The structure and properties of chicken feather barbs makes them unique fibers preferable for several applications. The presence of hollow honeycomb structures, their low density, high flexibility and possible structural interaction with other fibers when made into products such as textiles provides them unique properties unlike any other natural or synthetic fibers. No literature is available on the physical structure and tensile properties of chicken feather barbs. In this study, we report the physical and morphological structure and the properties of chicken feather barbs for potential use as natural protein fibers. The morphological structure of chicken feather barbs is similar to that of the rachis but the physical structure of the protein crystals in chicken feather barbs is different than that reported for feather rachis keratin. The tensile properties of barbs in terms of their strength and modulus are similar but the elongation is lower than that of wool. Using the cheap and abundant feathers as protein fibers will conserve the energy, benefit the environment and also make the fiber industry more sustainable

International Journal of Biological Macromolecules, 2010

Silk fibers produced by undomesticated wild insects belonging to the Saturniidae family have uniq... more Silk fibers produced by undomesticated wild insects belonging to the Saturniidae family have unique properties compared to the commonly used silks. Insects belonging to the Saturniidae family are one of the largest moths found throughout the world, produce large cocoons and are easier to rear than B. mori. In this research, we have characterized the morphology and tensile properties of silks produced by eight wild insects that belong to the Saturniidae family. Fibers produced by Saturniidae insects such as C. hercuels have properties similar to that of B. mori silk whereas fibers produced by Copaxa multifenestrata have inferior properties than B. mori or the common wild silks. In addition, the tensile properties of the fibers vary considerably between insects. Fibers with fineness ranging from 1.5 to 7.8 denier and breaking tenacity ranging from 0.9 to 5 g per denier are produced by the Saturniidae insects. Identifying the unique properties of Saturniidae silks such as tensile properties, yield of silk from the cocoons and ability to grow under different environments will help to evaluate the potential of rearing the wild insects for commercial production of silk for textile, medical and other applications.

Biomacromolecules, 2007

Protein fibers with mechanical properties similar to those of wool and better than those of soypr... more Protein fibers with mechanical properties similar to those of wool and better than those of soyprotein and zein fibers have been produced from 100% wheat gluten. Wheat gluten is a low cost, abundantly available, and renewable resource suitable for fiber production. A simple production method has been developed to obtain high-quality wheat gluten fibers, and the structure and properties of the fibers have been studied. Wheat gluten fibers have breaking tenacity of about 115 MPa, breaking elongation of 23%, and a Young's modulus of 5 GPa, similar to those of wool. Wheat gluten fibers have better tensile properties than soyprotein- and casein-based biomaterials. In addition, the wheat gluten fibers have resistance similar to that of PLA fibers to water in weak alkaline and slightly lower resistance in weak acidic conditions at high temperatures.

Bioresource Technology, 2008

Velvet leaf (Abutilon theophrasti) that is currently considered a weed and an agricultural proble... more Velvet leaf (Abutilon theophrasti) that is currently considered a weed and an agricultural problem could be used as a source for high quality natural cellulose fibers. The fibers obtained from the velvet leaf stems are mainly composed of approximately 69% cellulose and 17% lignin. The single cells in the fiber have lengths of approximately 0.9 mm, shorter than those in common bast fibers, hemp and kenaf. However, the widths of single cells in velvet leaf fibers are similar to the single cells in hemp and kenaf. The fibers exhibited breaking tenacity from 2.4 to 3.9 g/denier (325–500 MPa), breaking elongation of 1.6–2.4% and Young’s modulus of 140–294 g/denier (18–38 GPa). Overall, velvet leaf fibers have properties similar to that of common bast fibers such as hemp and kenaf. Velvet leaves fibers could be processed on the current kenaf processing machineries for textile, composite, automotive and other fibrous applications.

Journal of Applied Polymer Science, 2004

Starch acetate–corn fiber foams were prepared by extrusion. Corn starch was acetylated (DS 2) to ... more Starch acetate–corn fiber foams were prepared by extrusion. Corn starch was acetylated (DS 2) to introduce thermoplastic properties. Corn stalks were treated with sodium hydroxide to remove the lignin and to obtain purified cellulose fibers. Starch acetate was blended with treated fiber at concentrations of 0, 2, 6, 10, and 14% (w/w) and extruded in a corotating twin-screw extruder with 12 to 18% w/w ethanol content and 5% talc as a nucleating agent. The samples were extruded at 150°C and selected physical and mechanical properties were evaluated. Micrographic properties were analyzed using scanning electron microscopy to observe the interaction of fiber and starch. Fiber incorporation at the lower concentrations enhanced the physical properties of the foams. Fiber contents greater than 10% decreased expansion and increased density and shear strength. Good compatibility between starch and corn fiber was observed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2627–2633, 2004

Bioresource Technology, 2009

Natural cellulose fibers have been obtained from the bark of cotton stalks and the fibers have be... more Natural cellulose fibers have been obtained from the bark of cotton stalks and the fibers have been used to develop composites. Cotton stalks are rich in cellulose and account for up to 3 times the quantity of cotton fiber produced per acre. Currently, cotton stalks have limited use and are mostly burned on the ground. Natural cellulose fibers obtained from cotton stalks are composed of approximately 79% cellulose and 13.7% lignin. The fibers have breaking tenacity of 2.9 g per denier and breaking elongation of 3% and modulus of 144 g per denier, between that of cotton and linen. Polypropylene composites reinforced with cotton stalk fibers have flexural, tensile and impact resistance properties similar to jute fiber reinforced polypropylene composites. Utilizing cotton stalks as a source for natural cellulose fibers provides an opportunity to increase the income from cotton crops and make cotton crops more competitive to the biofuel crops.

Green Chemistry, 2005

... Properties and potential applications of natural cellulose fibers from cornhusks. Narendra Re... more ... Properties and potential applications of natural cellulose fibers from cornhusks. Narendra Reddy and Yiqi Yang Green Chem., 2005, 7, 190-195. DOI: 10.1039/B415102J , Paper. ...

Polymer Degradation and Stability, 2008

Polyblend fibers were produced from five ratios of polylactic acid/polypropylene (PLA/PP) in an e... more Polyblend fibers were produced from five ratios of polylactic acid/polypropylene (PLA/PP) in an effort to improve the resistance to hydrolysis and biodegradation, and to improve the dyeability of PLA. The inherent limitations of PLA such as its relatively poor resistance to hydrolysis have restricted the use of PLA. When made into polyblend fibers, the two polymers, PLA and PP, show partial compatibility and the mechanical properties of the blends are inferior compared to the pure PLA or PP fibers. However, PLA in the blends had substantially better resistance to biodegradation and hydrolysis, and dyeability with disperse dyes, resulting in a polyblend fiber with much better resistance to hydrolysis and similar dyeability to PLA. Blending PP with PLA could be a simple and effective method to create a new fiber with better resistance to hydrolysis and lower price than PLA, and better dyeability, sustainability and faster degradability than PP.

Macromolecular Materials and Engineering, 2007

Cellulose, 2013

Two plant proteins, soyprotein and wheat gluten, and chicken feathers used to size cotton substra... more Two plant proteins, soyprotein and wheat gluten, and chicken feathers used to size cotton substrates provided sizing performance similar to starch and were also easily degraded in activated sludge. Sizing is an essential process to impart protection to warp yarns and increase weaving efficiency. Cotton yarns have traditionally been sized with starch, modified starch derivatives, CMC, poly vinyl alcohol (PVA), or a combination thereof along with quite a few other fiber binding ingredients. Although starch and starch derivatives are extensively used for sizing, there can be several limitations including less-than-satisfactory sizing performance and difficulties in desizing starch based size. Plant proteins such as wheat gluten, soyproteins and poultry feathers are available in large quantities at low cost and have limited industrial applications. However, these proteins are known to have excellent film-forming properties, a primary requirement for a warp size, and have also been used as adhesives. Using proteins as warp sizing agents on cotton yarns potentially could provide acceptable sizing performance and be cost-effective, as well. In this research, soypro-teins, wheat gluten, and chicken feathers were studied for exploring their feasibility for sizing, desizing, biodegradability, and ability to replace starch and PVA for sizing cotton yarns. It was found that all three proteins provided similar cohesion to fibers and abrasion resistance compared to starch. Protein sizes had significantly high BOD 5 /COD ratio compared to PVA, suggesting that the proteins are easily degradable in textile effluent treatment plants.

Industrial Crops and Products, 2012

We show that the wheat proteins gluten, gliadin and glutenin can be compression molded into therm... more We show that the wheat proteins gluten, gliadin and glutenin can be compression molded into thermoplastic films with good tensile strength and water stability. Wheat gluten is inexpensive, abundantly available, derived from renewable resource and therefore widely studied for potential thermoplastic applications. However, previous reports on developing thermoplastics from wheat proteins have used high amounts of glycerol (30-40%) and low molding temperature (90-120 • C) resulting in thermoplastics with poor tensile properties and water stability making them unsuitable for most thermoplastic applications. In this research, we have developed thermoplastic films from wheat gluten, gliadin and glutenin using low glycerol concentration (15%) but high molding temperatures (100-150 • C). Our research shows that wheat protein films with good tensile strength (up to 6.7 MPa) and films that were stable in water can be obtained by choosing appropriate compression molding conditions. Among the wheat proteins, wheat gluten has high strength and elongation whereas glutenin with and without starch had high strength and modulus but relatively low elongation. Gliadin imparts good extensibility but decreased the water stability of gluten films. Gliadin films had strength of 2.2 MPa and good elongation of 46% but the films were unstable in water. Although the tensile properties of wheat protein films are inferior compared to synthetic thermoplastic films, the type of wheat proteins and compression molding conditions can be chosen to obtain wheat protein films with properties suitable for various applications.

Journal of Materials Science, 2010

Industrial Crops and Products, 2011

Soyprotein–jute fiber composites developed using water without any chemicals as the plasticizer s... more Soyprotein–jute fiber composites developed using water without any chemicals as the plasticizer show much better flexural and tensile properties than polypropylene–jute composites. Co-products of soybean processing such as soy oil, soyprotein concentrate and soy protein isolates are inexpensive, abundantly available and are renewable resources that have been extensively studied as potential matrix materials to develop biodegradable composites. However, previous attempts

Journal of Agricultural and Food Chemistry, 2007

Zein with a higher intrinsic viscosity and phosphorus content, similar protein content, lower yel... more Zein with a higher intrinsic viscosity and phosphorus content, similar protein content, lower yellowness, and at potentially much lower cost than commercially available zein was obtained from distillers dried grains with solubles (DDGS). A novel extraction method using acidic conditions in the presence of a reducing agent has been used to obtain about 10% aqueous ethanol soluble zein from DDGS. The optimum pH, time, temperature, and amount of reducing agent that can produce zein with high quality and yield have been developed. In addition to the zein, about 17% oil based on the dry weight of DDGS has also been obtained during zein extraction. The zein obtained from this research is expected to be suitable for use as fibers, films, and binders and in paints.

Journal of Materials Science-materials in Medicine, 2008

For the first time, protein fibers with excellent mechanical properties and water stability have ... more For the first time, protein fibers with excellent mechanical properties and water stability have been produced from gliadin for potential use in tissue culture and other medical applications. Biomaterials developed from plant proteins such as zein and soyproteins are preferred for several medical applications over synthetic polymers such as polylactic acid. However, the plant protein based biomaterials developed so far have poor mechanical properties and hydrolytic stability even after crosslinking. This study aims to develop biomaterials from gliadin with excellent mechanical properties and water stability without using any crosslinking agents. A novel gliadin fiber production method was used to self crosslink the fibers and obtain high strength and water stability. Gliadin fibers have high strength (120 MPa) and elongation (25%) compared to similar collagen fibers that were crosslinked with glutaraldehyde (strength of about 44 MPa and elongation of 14%). The fibers show 100% strength retention after being in pH 7 water at 50 °C for 40 days and also have better water stability than PLA in acidic conditions at high temperatures. Gliadin fibers are suitable for cell growth and promote the attachment and proliferation of bovine turbinate fibroblasts.

Journal of Agricultural and Food Chemistry, 2007

For the first time, sorghum leaves and stems have been used to produce natural cellulose fibers w... more For the first time, sorghum leaves and stems have been used to produce natural cellulose fibers with properties suitable for composite, textile, and other high-value fibrous applications. The leaf and stems fibers produced are multicellular and have similar cellulose contents. The breaking tenacity and elongation of the fibers are similar to that of natural cellulose fibers such as kenaf and cornstalk fibers. However, the sorghum fibers have a modulus of about 113 g/denier (15 GPa) similar to the modulus of cornstalk fibers but higher than that of cotton and cornhusk fibers. At least 7 million tons of natural cellulose fibers can be produced by using the sorghum stems and leaves available as byproducts every year. Using the sorghum byproducts as a source for cellulose fibers will help to add value to the sorghum crops and also make the fiber industry more sustainable.

Journal of Agricultural and Food Chemistry, 2007

Long natural cellulose fibers with properties suitable for textile and composite applications hav... more Long natural cellulose fibers with properties suitable for textile and composite applications have been obtained from wheat straw. This study aims to understand the potential of using wheat straw as a source for long natural cellulose fibers for textile, composite and other fibrous applications. The presence of wax on the outer layer of the straw and a unique zip-like structure that locks individual fibers makes it difficult to obtain fibers from wheat straw using the common methods of fiber extraction. A novel pretreatment with detergent and mechanical force followed by an alkaline treatment was used to obtain high quality fiber bundles. The structure and properties of the fibers are reported in comparison to common cellulose fibers, cotton, linen, and kenaf. Wheat straw fibers have coarser (wider width) single cells and lower crystallinity than cotton, linen, and kenaf. The breaking tenacity (force at break) of wheat straw fibers is similar to kenaf but lower than that of cotton and linen, % breaking elongation is similar to linen and kenaf but lower than cotton, and Young's modulus of the fibers is similar to cotton but lower than that of linen and kenaf.

Polymer, 2005

We have developed a fiber extraction method that produces fibers from cornstalks with mechanical ... more We have developed a fiber extraction method that produces fibers from cornstalks with mechanical properties similar to that of the common textile fibers. The fiber extraction method developed results in partial delignification and produces fibers from cornstalks that are suitable for textile and other industrial applications. The structure of the fibers obtained was investigated using X-ray diffraction and scanning electron microscope. The structure and composition of the natural cellulose fibers obtained from cornstalks are different than that of the common bast fibers such as flax and kenaf. Tensile properties of the fibers were studied using an Instron tensile tester. This study found that cornstalk fibers have relatively lower percent crystallinity but similar microfibrillar angle as that of the common bast fibers. The structure and properties of cornstalk fibers indicate that the fibers are suitable for producing various textile products.

Bioresource Technology, 2009

This paper reports the development of natural cellulose technical fibers from soybean straw with ... more This paper reports the development of natural cellulose technical fibers from soybean straw with properties similar to the natural cellulose fibers in current use. About 220 million tons of soybean straw available in the world every year could complement the byproducts of other major food crops as inexpensive, abundant and annually renewable sources for natural cellulose fibers. Using the agricultural byproducts as sources for fibers could help to address the concerns on the future price and availability of both the natural and synthetic fibers in current use and also help to add value to the food crops. A simple alkaline extraction was used to obtain technical fibers from soybean straw and the composition, structure and properties of the fibers was studied. Technical fibers obtained from soybean straw have high cellulose content (85%) but low% crystallinity (47%). The technical fibers have breaking tenacity (2.7 g/den) and breaking elongation (3.9%) higher than those of fibers obtained from wheat straw and sorghum stalk and leaves but lower than that of cotton. Overall, the structure and properties of the technical fibers obtained from soybean straw indicates that the fibers could be suitable for use in textile, composite and other industrial applications.

Biotechnology and Bioengineering, 2007

We report the production and characteristics of natural cellulose fibers obtained from the leaves... more We report the production and characteristics of natural cellulose fibers obtained from the leaves and stems of switchgrass. In this paper, the composition, structure and properties of fibers obtained from the leaves and stem of switchgrass have been studied in comparison to the common natural cellulose fibers, such as cotton, linen and kenaf. The leaves and stems of switchgrass have tensile properties intriguingly similar to that of linen and cotton, respectively. Fibers were obtained from the leaves and stems of switchgrass using a simple alkaline extraction and the structure and properties of the fibers were studied. Fibers obtained from switchgrass leaves have crystallinity of 51%, breaking tenacity of 5.5 g per denier (715 MPa) and breaking elongation of 2.2% whereas the corresponding values for fibers obtained from switchgrass stems are 46%, 2.7 g per denier and 6.8%, respectively. Switchgrass is a relatively easy to grow and high yield biomass crop that can be source to partially substitute the natural and synthetic fibers currently in use. We hope that this research will stimulate interests in using switchgrass as a novel fiber crop in addition to being promoted as a potential source for biofuels. Biotechnol. Bioeng. 2007; 97: 1021–1027. © 2007 Wiley Periodicals, Inc.

Journal of Polymers and The Environment, 2007

The structure and properties of chicken feather barbs makes them unique fibers preferable for sev... more The structure and properties of chicken feather barbs makes them unique fibers preferable for several applications. The presence of hollow honeycomb structures, their low density, high flexibility and possible structural interaction with other fibers when made into products such as textiles provides them unique properties unlike any other natural or synthetic fibers. No literature is available on the physical structure and tensile properties of chicken feather barbs. In this study, we report the physical and morphological structure and the properties of chicken feather barbs for potential use as natural protein fibers. The morphological structure of chicken feather barbs is similar to that of the rachis but the physical structure of the protein crystals in chicken feather barbs is different than that reported for feather rachis keratin. The tensile properties of barbs in terms of their strength and modulus are similar but the elongation is lower than that of wool. Using the cheap and abundant feathers as protein fibers will conserve the energy, benefit the environment and also make the fiber industry more sustainable

International Journal of Biological Macromolecules, 2010

Silk fibers produced by undomesticated wild insects belonging to the Saturniidae family have uniq... more Silk fibers produced by undomesticated wild insects belonging to the Saturniidae family have unique properties compared to the commonly used silks. Insects belonging to the Saturniidae family are one of the largest moths found throughout the world, produce large cocoons and are easier to rear than B. mori. In this research, we have characterized the morphology and tensile properties of silks produced by eight wild insects that belong to the Saturniidae family. Fibers produced by Saturniidae insects such as C. hercuels have properties similar to that of B. mori silk whereas fibers produced by Copaxa multifenestrata have inferior properties than B. mori or the common wild silks. In addition, the tensile properties of the fibers vary considerably between insects. Fibers with fineness ranging from 1.5 to 7.8 denier and breaking tenacity ranging from 0.9 to 5 g per denier are produced by the Saturniidae insects. Identifying the unique properties of Saturniidae silks such as tensile properties, yield of silk from the cocoons and ability to grow under different environments will help to evaluate the potential of rearing the wild insects for commercial production of silk for textile, medical and other applications.

Biomacromolecules, 2007

Protein fibers with mechanical properties similar to those of wool and better than those of soypr... more Protein fibers with mechanical properties similar to those of wool and better than those of soyprotein and zein fibers have been produced from 100% wheat gluten. Wheat gluten is a low cost, abundantly available, and renewable resource suitable for fiber production. A simple production method has been developed to obtain high-quality wheat gluten fibers, and the structure and properties of the fibers have been studied. Wheat gluten fibers have breaking tenacity of about 115 MPa, breaking elongation of 23%, and a Young's modulus of 5 GPa, similar to those of wool. Wheat gluten fibers have better tensile properties than soyprotein- and casein-based biomaterials. In addition, the wheat gluten fibers have resistance similar to that of PLA fibers to water in weak alkaline and slightly lower resistance in weak acidic conditions at high temperatures.

Bioresource Technology, 2008

Velvet leaf (Abutilon theophrasti) that is currently considered a weed and an agricultural proble... more Velvet leaf (Abutilon theophrasti) that is currently considered a weed and an agricultural problem could be used as a source for high quality natural cellulose fibers. The fibers obtained from the velvet leaf stems are mainly composed of approximately 69% cellulose and 17% lignin. The single cells in the fiber have lengths of approximately 0.9 mm, shorter than those in common bast fibers, hemp and kenaf. However, the widths of single cells in velvet leaf fibers are similar to the single cells in hemp and kenaf. The fibers exhibited breaking tenacity from 2.4 to 3.9 g/denier (325–500 MPa), breaking elongation of 1.6–2.4% and Young’s modulus of 140–294 g/denier (18–38 GPa). Overall, velvet leaf fibers have properties similar to that of common bast fibers such as hemp and kenaf. Velvet leaves fibers could be processed on the current kenaf processing machineries for textile, composite, automotive and other fibrous applications.

Journal of Applied Polymer Science, 2004

Starch acetate–corn fiber foams were prepared by extrusion. Corn starch was acetylated (DS 2) to ... more Starch acetate–corn fiber foams were prepared by extrusion. Corn starch was acetylated (DS 2) to introduce thermoplastic properties. Corn stalks were treated with sodium hydroxide to remove the lignin and to obtain purified cellulose fibers. Starch acetate was blended with treated fiber at concentrations of 0, 2, 6, 10, and 14% (w/w) and extruded in a corotating twin-screw extruder with 12 to 18% w/w ethanol content and 5% talc as a nucleating agent. The samples were extruded at 150°C and selected physical and mechanical properties were evaluated. Micrographic properties were analyzed using scanning electron microscopy to observe the interaction of fiber and starch. Fiber incorporation at the lower concentrations enhanced the physical properties of the foams. Fiber contents greater than 10% decreased expansion and increased density and shear strength. Good compatibility between starch and corn fiber was observed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2627–2633, 2004

Bioresource Technology, 2009

Natural cellulose fibers have been obtained from the bark of cotton stalks and the fibers have be... more Natural cellulose fibers have been obtained from the bark of cotton stalks and the fibers have been used to develop composites. Cotton stalks are rich in cellulose and account for up to 3 times the quantity of cotton fiber produced per acre. Currently, cotton stalks have limited use and are mostly burned on the ground. Natural cellulose fibers obtained from cotton stalks are composed of approximately 79% cellulose and 13.7% lignin. The fibers have breaking tenacity of 2.9 g per denier and breaking elongation of 3% and modulus of 144 g per denier, between that of cotton and linen. Polypropylene composites reinforced with cotton stalk fibers have flexural, tensile and impact resistance properties similar to jute fiber reinforced polypropylene composites. Utilizing cotton stalks as a source for natural cellulose fibers provides an opportunity to increase the income from cotton crops and make cotton crops more competitive to the biofuel crops.

Green Chemistry, 2005

... Properties and potential applications of natural cellulose fibers from cornhusks. Narendra Re... more ... Properties and potential applications of natural cellulose fibers from cornhusks. Narendra Reddy and Yiqi Yang Green Chem., 2005, 7, 190-195. DOI: 10.1039/B415102J , Paper. ...

Polymer Degradation and Stability, 2008

Polyblend fibers were produced from five ratios of polylactic acid/polypropylene (PLA/PP) in an e... more Polyblend fibers were produced from five ratios of polylactic acid/polypropylene (PLA/PP) in an effort to improve the resistance to hydrolysis and biodegradation, and to improve the dyeability of PLA. The inherent limitations of PLA such as its relatively poor resistance to hydrolysis have restricted the use of PLA. When made into polyblend fibers, the two polymers, PLA and PP, show partial compatibility and the mechanical properties of the blends are inferior compared to the pure PLA or PP fibers. However, PLA in the blends had substantially better resistance to biodegradation and hydrolysis, and dyeability with disperse dyes, resulting in a polyblend fiber with much better resistance to hydrolysis and similar dyeability to PLA. Blending PP with PLA could be a simple and effective method to create a new fiber with better resistance to hydrolysis and lower price than PLA, and better dyeability, sustainability and faster degradability than PP.

Macromolecular Materials and Engineering, 2007