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Technology for the transformation of waste feathers to quality regenerated filaments has been developed. Regardless of superior properties of natural keratin materials, previously developed regenerated materials from keratin had tensile properties much lower than their natural counterparts due to backbone hydrolysis and inefficient reconstruction of disulfide crosslinkages. In this work, tough keratin filaments have been regenerated from white duck feathers via efficient restoration of disulfide crosslinkages using a dithiol reducing agent. Dithiol substantially reserves free thiol groups in the extraction and formed lengthy intermolecular crosslinkages in regenerated keratin filaments. Due to the high degree of intermolecular reconstruction of disulfide bonds and formation of lengthy crosslinkages via dithiol chain-extension, the keratin filaments exhibited considerable improvements in mechanical properties, especially for ductility and water stability. The tenacity and elongation at break were 160.7 MPa and 14%, respectively. The filaments retained about 80% of the tenacity of natural feathers at either dry or wet conditions and demonstrated stretchability 150% higher than natural feathers. The fiber regeneration technology makes it possible to substitute primary fiber sources by renewable poultry feathers. Successful filament substitution or addition can bring more than 88-billion-dollar revenue. The technology not only contributes to a sustainable fiber and poultry industry but adds substantial values to poultry feathers., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Chicken feather, a potential source of keratin, is often disposed as waste material. Although some methods, i.e., hydrolysis, reduction, and oxidation, have been developed to isolate keratin for composites, it has been limited due to the rising environmental concerns. In this work, a green solvent N-methylmorpholine N-oxide (NMMO) was used to extract keratin from chicken feather waste. Eighty-nine percent of keratin was extracted using 75% NMMO solution. However, the result from size exclusion HPLC showed that most of the keratin degraded into polypeptide with molecular weight of 2189 and only 25.3% regenerated keratin was obtained with molecular weight of 14,485. Analysis of amino acid composition showed a severe damage to the disulfide bonds in keratin during the extraction procedure. Oxidization had an important effect on the reconstitution of the disulfide bonds, which formed a stable three-dimensional net structure in the regenerated keratins. Besides, Raman spectra, NMR, FT-IR, XRD, and TGA were used to characterize the properties of regenerated keratin and raw chicken feather. In the end, a possible mechanism was proposed based on the results.

In this research, keratin was extracted from the disposable chicken feather using l-cysteine as reducing agent. Then, it was re-dissolved in the sodium carbonate-sodium bicarbonate buffer, and the pure keratin membrane and fiber were fabricated by doctor-blade casting process and wet spinning method, respectively. Scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to characterize the chemical and physical properties of resulting powder, membrane and fiber. Compared with the raw chicken feather, the regenerated keratin materials retain its chemical structure and thermal stability, their relative crystallinity is a little different depend on the shaping method, which leads to the difference in moisture regain. The mechanical results show that tensile strength of the keratin membrane researches 3.5MPa, have potential application in biomedical fields. However, the keratin fiber presents low tenacity, i.e. 0.5cN/dtex, this problem should be solved in order to apply the new fiber in textile and material science., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This research demonstrated the feasibility of using bio-thermoplastics developed from chicken feathers grafted with acrylates and methacrylates as scaffolds for tissue engineering. Keratin, the major protein in feathers, is a highly crosslinked biopolymer that has been reported to be biocompatible. However, it is difficult to break the disulfide bonds and make keratin soluble to develop materials for tissue engineering and other medical applications. Previously, keratin extracted from feathers using alkaline hydrolysis has been made into scaffolds but with poor water stability and mechanical properties. In this study, thermoplastic films were compression molded from chicken feathers grafted with 6 different acrylate monomers. The influence of the concentration and structures of grafted monomers on grafting parameters and the tensile strength, water stability and cytocompatibility of grafted feathers compression molded into films were investigated. It was found that the grafted feather films were water stable and had good strength and better supported cell growth than poly(lactic acid) films. Grafted feathers demonstrated the potential to be used for fabrication of biomaterials for various biomedical applications., (Copyright © 2013 Elsevier B.V. All rights reserved.)

We demonstrate a novel approach of developing thermoplastic films from feathers by alkaline hydrolysis and crosslinking with citric acid. Unlike previous approaches that used toxic chemicals, complicated and/or expensive methods to develop films, in this research, feathers were hydrolyzed using various concentrations of alkali and the hydrolyzed feathers were compression molded into films using glycerol as plasticizer and crosslinked with citric acid to improve water stability. Alkali hydrolyzed feathers could be compression molded into films with tensile strength of 5.9 MPa and elongation of 31.7% but had poor wet strength. Feather films crosslinked with citric acid had tensile strength of 1.9 MPa and elongation of 24.6% after being in 90% humidity at 21 °C for 24 hours. Alkaline hydrolysis and citric acid crosslinking provides an opportunity to develop inexpensive and biodegradable thermoplastics from the inexpensive, renewable and sustainable poultry feathers., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Poultry feathers are renewable resources, inexpensive and abundantly available, but have limited applications. Although keratin extracted from feathers has been chemically modified, there are no reports on the chemical modification or development of thermoplastics from poultry feathers. Acetylation is an inexpensive and environmentally friendly approach to make biopolymers thermoplastic. Several biopolymers have been acetylated and used to produce fibers, films, and extrudates. In this research, chicken feathers were acetylated, and the structure and properties of the acetylated feathers were studied. Acetylation conditions such as concentration of chemicals and catalyst and time and temperature of acetylation were optimized. Acetylation of feathers was confirmed using Fourier transform infrared (FTIR) and pyrolysis-gas chromatography-mass spectrometry (P-GC-MS). The acetylated feathers were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to understand their thermal behavior. Acetylated feathers were thermoplastic and could be compression molded to form transparent films despite the relatively low percentage of acetyl content.

Inexpensive and biodegradable thermoplastics were developed through graft polymerization of native chicken feather with methyl acrylate as a potential substitute for petroleum products. Poultry feathers are available in large quantities at a low price. However, natural chicken feathers have poor thermoplasticity, cannot be used to develop thermoplastic products, have very limited industrial applications, and are often considered as solid wastes. In this research, the effects of graft polymerization conditions, such as molar ratio of NaHSO(3) to K(2)S(2)O(8), initiator and monomer concentrations, pH, temperature and time of polymerization, on grafting parameters, that is, the conversion of monomer to polymer, grafting percentage, and grafting efficiency were evaluated. Methyl acrylate was found to be successfully grafted onto functional groups on the surfaces of the chicken feathers, and optimal graft polymerization conditions were also obtained. The feather-g-poly(methyl acrylate) developed showed good thermoplasticity, and feather films had substantially higher tensile properties than soy protein isolate and starch acetate films.

Tough keratin fibers from chicken feathers have been produced continuously via controlled assembly of secondary protein structures. Though research on utilization of keratinous wastes began decades ago, very few regenerated products with high quality were developed due to damage to the primary structures during extraction and poor recovery of the secondary structures in the regenerated materials. Fibers have the highest quality requirements among the regenerated keratin products, including high toughness and resistance to repeated laundering. Our group developed regenerated keratin fibers on a lab scale previously. However, the regenerated keratin had poor spinnability with low recovery of secondary protein structures. As a result, keratin fibers could not be produced continuously, and their properties, especially the wet strength, were not acceptable. In this paper, high drawing ratios of keratin fibers on a continuous line have been achieved via stepwise oxidation and drawing technology. This technology resulted in controlled assembly of disulfide crosslinkages, optimum recovery of the secondary structures, satisfactory mechanical properties and scalable production of keratin fibers. Furthermore, the use of inexpensive chemicals makes the continuous keratin fiber production developed in this work affordable for scale-up. The technology developed for continuous production of tough keratin fibers has high potential for the development of high quality regenerated products from other cysteine-containing protein materials. [ABSTRACT FROM AUTHOR]

Chicken feather, a potential source of keratin, is often disposed as waste material. Although some methods, i.e., hydrolysis, reduction, and oxidation, have been developed to isolate keratin for composites, it has been limited due to the rising environmental concerns. In this work, a green solvent N-methylmorpholine N-oxide (NMMO) was used to extract keratin from chicken feather waste. Eighty-nine percent of keratin was extracted using 75% NMMO solution. However, the result from size exclusion HPLC showed that most of the keratin degraded into polypeptide with molecular weight of 2189 and only 25.3% regenerated keratin was obtained with molecular weight of 14,485. Analysis of amino acid composition showed a severe damage to the disulfide bonds in keratin during the extraction procedure. Oxidization had an important effect on the reconstitution of the disulfide bonds, which formed a stable three-dimensional net structure in the regenerated keratins. Besides, Raman spectra, NMR, FT-IR, XRD, and TGA were used to characterize the properties of regenerated keratin and raw chicken feather. In the end, a possible mechanism was proposed based on the results. [ABSTRACT FROM AUTHOR]

This research demonstrates that chicken feathers can be used as matrix to develop completely biodegradable composites with properties similar to that of composites having polypropylene (PP) as matrix. Feathers are ubiquitous and inexpensive but have limited industrial applications. Feathers have been preferably used for composite applications due to their low density and presence of hollow structures that facilitate sound absorption. However, previous approaches on using feathers for composites have used the whole feather or the feather fractions as reinforcement with synthetic polymers as matrix resulting in partially degradable composites. In addition, the hydrophilicity of the feathers and hydrophobicity of the synthetic matrix results in poor compatibility and therefore less than optimum properties. Although it has been shown that feathers can be made thermoplastic and suitable to develop films and other thermoplastics, there are no reports on using feathers as matrix for composites. In this research, chicken feathers were used as matrix and jute fibers as reinforcement to develop completely biodegradable composites. Tensile, flexural and acoustic properties of the feather-jute composites were compared to PP-jute composites. Utilizing feathers as matrix could enable us to develop low cost 100 % biodegradable composites containing feathers or other biopolymers as the reinforcement. [ABSTRACT FROM AUTHOR]

High- density polyethylene (HDPE) in used plastic bags was reinforced with chicken feathers to develop composites in an effort to add value and reduce the amount of the plastics and feathers disposed in landfills. Feathers are biodegradable, derived from renewable resource, and are inexpensive and HDPE in plastic bags is mostly discarded in landfills. Utilizing feathers as reinforcement for HDPE composites will provide an opportunity to develop environmentally friendly composites. In this research, HDPE plastic bags were reinforced with chicken feathers and the flexural, tensile and acoustic properties were studied. It was found that incorporating feathers substantially improved the flexural properties and tensile modulus. At the optimum condition, the HDPE-feather (50/50) composites had flexural strength of 13.9 MPa and stiffness of 0.45 N/mm compared to 9.8 MPa and 0.29 N/mm for 100% HDPE. The 50/50 HDPE-feather composite had similar tensile strength but more than twice the tensile modulus of neat HDPE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

[Display omitted] • Green, sustainable and continuously spun keratin fibers finer and tougher than wool. • The toughness through enhanced molecular entanglement and conformation organization. • Enhanced protein unfolding and conformation controlled by amine-tuned chitin. • Excellent processibility of composite fibers throughout the entire garment-making process. We utilize chitin nanoparticles with controlled deacetylation and develop novel wet-spun keratin/chitin fibers on a pilot scale with strong interactions between keratin fibers and chitin nanoparticles. There is an urgent need to develop sustainable and degradable materials as alternatives to the current nondegradable textile fibers. Regenerating feather wastes into high-quality protein fibers promotes the sustainable development of the fiber industry. However, inferior properties of keratin fibers, resulting from insufficient protein unfolding, molecular entanglements, and recovery of secondary protein structures, hindered their large-scale commercialization. Inspired by chitin-protein interaction in crab shells, we reported the development of wet stable keratin composite fibers with similar fineness to silk and better toughness than wool. On the continuous spinning line, small amount of chitin nanoparticles with controlled amine content enhanced keratin molecular entanglement, improved fiber drawability, induced the formation of ß-sheet conformation, and incorporated external crosslinkages. As a result, keratin composite fibers with chitin nanoparticles had fineness, tenacity, breaking elongation, and toughness, and wet properties from 2.1 to 0.9 denier, 1.1 to 2.2 g/den, 11 % to 19 %, 21 to 50 J/cm3, and 0.6 to 1.2 g/den, respectively. We further fabricated the continuously spun keratin composite fibers into filament yarns and a sweater. Keratin composite fibers exhibited excellent processibility throughout the entire garment-making process. The green conversion from feather wastes to tough and wet stable composite fibers had a high potential for practical and sustainable applications in the textile industry. [ABSTRACT FROM AUTHOR]

Abstract: This paper demonstrates that etherification can be used to develop thermoplastic films from chicken feathers. Feathers are inexpensive, abundantly available and renewable resources but have limited applications mainly due to their non-thermoplasticity. However, it has been shown that chemical modifications such as grafting can make feathers thermoplastic. Etherification provides better thermoplasticity to biopolymers compared to chemical modifications such as acetylation. In this research, chicken feathers were etherified using acrylonitrile and various concentrations of catalyst. Even at low weight gain (3.6%), cyanoethylated feathers were thermoplastic and showed a melting peak at 167°C. Films compression molded from the cyanoethylated feathers had strength ranging from 1.6 to 4.2MPa and elongation ranging from 5.8 to 14% depending on the extent of cyanoethylation. Feathers modified by cyanoethylation had good thermoplasticity and could be useful to develop various thermoplastics. [Copyright &y& Elsevier]