Waste Wool Fibers Research Articles

Preparation and performance study of thermo-responsive P(NIPAM-AM-ABP)/keratin composite nanofiber membrane for bio-application

This paper describes a temperature-responsive composite nanofibrous membrane by blending of the P(NIPAM-AM-ABP) (PNAA) nanofiber and the wool keratin (WK) nanofiber. The photo crosslinkable PNAA with the LCST value of 38.1 °C was obtained by free radical copolymerization of the temperature sensitive N-Isopropylacrylamide (NIPAM) monomer, the hydrophilic monomer Acrylamide (AM), and the photo crosslinkable monomer 4-Acryloyloxybenzophenone (ABP). Keratin was extracted from waste wool fiber by reduction method. The PNAA nanofiber (PNAA-NF) and the keratin nanofiber (WK-NF) were electoral spun separately by two-needle parallel spinning, and the obtained composite nanofiber membrane was then crosslinked by UV irradiation and heat treatments to prepare the PNAA/WK nanofiber membrane (PNAA/WK-NFM) with good water tolerance. The result indicated that the photo cross-linkable temperature sensitive PNAA with the LCST of 38.1 °C was successfully synthesized. The obtained PNAA/WK-NFM has a good fibrous morphology and excellent water tolerance. The composite nanofiber membrane showed good reversible temperature sensitivity and temperature responsive drug releasing property due to the PNAA. By combining of the PNAA-NF and WK-NF, the mechanical property of the PNAA/WK-NFM was greatly enhanced in both dry and wet states, and the slow drug releasing property of the membrane was further improved. In-vitro cell culture experiments indicated that the PNAA/WK-NFM has a good biocompatibility with no cytotoxicity. These findings suggested that the PNAA/WK-NFM has a potential application in temperature responsive drug releasing biomaterials.

Upcycling Post-Consumer Paint Pail Plastic Waste.

The need for ending plastic waste and creating a circular economy has prompted significant interest in developing a new family of composite materials through recycling and recovery of waste resources (including bio-sourced materials). In this work, a family of natural fiber-reinforced plastic composites has been developed from paint pail waste recycled polypropylene (rPP) and waste wool fibers of different diameter and aspect ratio. Composites were fabricated by melt processing using polypropylene-graft-maleic anhydride as a compatibilizer. The internal morphology, interfacial and thermal characteristics, viscoelastic behavior, water sorption/wettability, and mechanical properties of composites were studied using electron microscopy, high-resolution synchrotron Fourier transform infrared microspectroscopy, thermal analysis, rheology, immersion test, contact angle measurement, tensile test and flexural test. The composite matrix exhibited an internal morphology of coalescent micro-droplets due to the presence of polyethylene and dry paint in the rPP phase. In general, the rheological and mechanical properties of the composites comprising higher-aspect-ratio (lower diameter) fibers exhibited relatively superior performance. About an 18% increase in tensile strength and a 39% increase in flexural strength were measured for composites with an optimal fiber loading of 10 wt.%. Interfacial debonding and fiber pull-out were observed as the main failure mechanism of the composites. The developed composites have potential for applications in automotive, decking, and building industries.

First Detection of Food-Derived Agricultural Chemicals Residues in Waste Wool Fibers by Ultrasound-Assisted Extraction-QuEChERS Cleanup-UPLC-MS/MS.

Food-derived agricultural chemical residues (FACRs) accumulate gradually in organisms and can damage their nervous system, endocrine system and reproductive system, posing significant harm. Currently, there is little literature on the detection of FACRs in waste wool fibers. In this paper, an ultrasound-assisted extraction-QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) cleanup-UPLC-Ms/Ms method was applied for the qualitative analysis and quantitative determination of trace FACRs in waste wool fibers with 0.2% formic acid-methanol as extraction solvent and multi-selective ion scanning. Using the external standard method, it was shown that the 13 target FACRs showed good linearity in the mass concentration range of 0.1-50μg/kg. The limits of detection were 1.0-10.0μg/kg and the limits of quantification were 4.0-40.0μg/kg. The recoveries of the 13 target FACRs ranged from 78 to 112.6% at the 5-, 10- and 20-fold detection limit spiked levels, and the intra- or inter-day relative standard deviations were 2.05-6.98% or 1.98-6.99%, respectively. This method satisfied the detection requirements and can be used in applications.

NH2-UiO-66 (Zr) modified waste wool fibers for efficient adsorption of dye from water

Developing low-cost and stable adsorbent is urgent and attractive to remove hazardous dye from water. In this study, zirconium based metal-organic framework (NH2-UiO-66) was grown on waste wool fibers and the fabricated composite adsorbent (NH2-UiO-66/wool) was used to remove anionic dye methyl orange (MO). After characterizing the adsorbents, we determined the effect of pH and initial concentration of MO on adsorption performance. Moreover, adsorption kinetics and isotherms were conducted to reveal the adsorption mechanism. The results showed that NH2-UiO-66/wool achieved the highest adsorption capacity at natural pH with the maximum adsorption of 61.0 mg/g adsorbent, which is higher than most biomass based adsorbents. Moreover, NH2-UiO-66/wool enabled a broad range of pH (3−11) and initial concentration of MO (10–50 mg/L). Adsorption kinetics and isotherms of NH2-UiO-66/wool fitted well with pseudo-second-order model and Langmuir mode, respectively. NH2-UiO-66/wool presented 40.3 times higher of kinetics constant than that of original wool in the presence of initial MO concentration of 10 mg/L due to the positive nature of NH2-UiO-66. Ultimately, NH2-UiO-66/wool presented excellent regeneration ability with 500 mg/L NaCl solution and regeneration efficiency remained 98% after 10 cycles. Overall, this work may provide new insights into the development of MOFs/wool adsorbents for enhanced dye removal.

Physicochemical Behavior of Superfine Wool Powder Dyed with Reactive Dye

ABSTRACT Superfine wool powder is obtained from waste wool fiber by physical grinding. Its physicochemical properties are different from those of wool fiber, and it is widely used in industry. In order to clarify the dyeing behavior of wool powder, C. I. Reactive Yellow 145 dye was used to dye wool powder, and the adsorption kinetics and thermodynamics were systematically studied in this work. The adsorption kinetics of reactive dye on wool powder was found to adhere to a pseudo-second-order kinetic model. At 60, 80 and 95°C, the half-dyeing time (t 1/2) and diffusion coefficient were 2.37, 1.56 and 1.00 min, and 0.2045, 0.1611 and 0.1368 cm2·min−1, respectively. And the diffusion activation energy was −11.82 kJ·mol−1. A Langmuir-type adsorption isotherm was obtained. At 60, 80 and 95°C, the standard affinity was 18.17, 20.06 and 20.82 kJ·mol−1, respectively. And the dyeing enthalpy change and dyeing entropy change were 7.27 kJ·mol−1 and 0.077 kJ·mol−1·K−1, respectively. In addition, the specific surface area, morphology and dyeing properties of wool fiber were compared. Through the study on the dyeing physicochemical properties of wool powder, it provides a theoretical basis for people to understand and use wool powder.

Identification of Wool and Cashmere Fibers by Preparation of Hollow-like Carbon Tubes after Carbonization

ABSTRACT Identification of wool and cashmere has attracted considerable attention in various research fields due to the outstanding properties of fibers. Herein, the hollow-like carbon tubes were facilely prepared by carbonization using the waste wool fibers, which were further characterized by elemental analysis and scanning electron microscope (SEM). After carbonization, hollow-like structures were observed in wool, while cashmere still presented in solid shapes at cross-sectional morphologies. Furthermore, the medulla existed in wool can be pyrolyzed after the carbonization process, which may be an effective way to distinguish the cashmere from wool by their obvious differences in fiber shapes, fiber sizes and residual weights. The effects of temperature on the properties of wool and cashmere were also analyzed. The proportions of hollow wool tubes increased with the rise of temperature, reaching more than 90% at 500°C. Apart from that, the mean diameter of treated wool (16.022 μm) was larger than treated cashmere (8.399 μm), which both shrunk nearly 50% than pristine fibers, and the residual weight of cashmere (68.95%) was higher than wool (62.98%). This method could be extended for identifying specialty fibers like fine yak fiber and yak hair, paving the way for distinguishing protein fibers in multiple areas.

Sound absorption and thermal insulation characteristics of fabrics made of pure and crossbred sheep waste wool

Waste wool fiber is a potential source for thermal and acoustical applications due to its natural properties. This work aims to investigate the potential of crossbreeding for the engineering of the sound absorption and thermal insulation properties of the waste wool. At first, a crossbreeding strategy was performed on the local sheep called Ghezel (Gh) thick-wool with Arkharmerino (Ar) fine-wool, and the procedure was continued up to two races (ArGh1 and ArGh2). Afterward, the wool fibers were collected from all four breeds, and the short fibers were removed as the waste. The chemical and morphological analyses were carried out on the fibers. The waste fibers were then spun and used as weft yarns to weave the woolen fabrics. The sound absorption and thermal insulation properties of the fabrics were also investigated. Additionally, the frequency-dependent sound absorption coefficient (SAC) of samples was predicted using the Mechel model.The results showed that the crossbreeding of Gh with Ar results in improvement of fiber fineness, which in turn positively affects the sound absorption behavior of the fabrics. There was a good adoption between the experimental and predicted results, indicating the high accuracy of the Mechel model for the woolen woven fabrics. The results also indicated that fabrics made from coarser fibers show better thermal insulation performance. The results indicated that waste wool as an environmentally friendly thermal insulation material has comparable acoustical and thermal characteristics to mineral/wools and glass fiber-based materials, with the advantage of being ecological and simultaneously economical, biodegradable, and abundant.

Preparation of antibacterial biocompatible polycaprolactone/keratin nanofibrous mats by electrospinning

AbstractKeratin‐based materials are widely used in biomedical applications due to excellent biocompatibility and biodegradability. In this study, keratin was extracted from waste wool fibers and blended with polycaprolactone (PCL) to produce PCL/keratin nanofibrous mats by electrospinning. The electrospun PCL/keratin nanofibrous mats were chlorinated in diluted sodium hypochlorite solution to endow antibacterial properties. The prepared nanofibrous mats were characterized by scanning electron microscopy, X‐ray photoelectron, and Fourier infrared spectroscopy. The effect of the chlorination time on the active chlorine loading of the mats was investigated. The chlorinated PCL/keratin nanofibrous mats with 0.78 ± 0.009 wt% active chlorine displayed potent antibacterial activity against Gram‐positive Staphylococcus aureus (ATCC 6538) and Gram‐negative Escherichia coli O157:H7 (ATCC 43895) with 6.88 and 6.81 log reductions, respectively. It was found that the mats were compatible with mouse fibroblast cells (L929). The chlorinated PCL/keratin nanofibrous mats might find promising applications in the biomedical field.

Study on dissolution and recovery of waste wool by sodium sulfide system

In this research, keratin was extracted from the waste wool fiber using sodium sulfite as dissolving agent. The reaction results showed that the optimum conditions were as follows: the dosage of sodium sulfite 30 g/L, the sodium hydroxide 6 g/L, the sodium dodecyl sulfate (SDS) 10 g/L and in 90 °C for 3 h. Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and SDS-polyacrylamide gel electrophoresis were used to characterize the properties of regeneration keratin. Compared with the wool fiber, the regenerated keratin retains its chemical structure and thermal stability.

Sound absorption, thermal, and flame retardant properties of nonwoven wall cloth with waste fibers

In order to solve the recycling problem of waste fibers, the nonwoven wall cloth was prepared with waste wool fibers and low-melting-point polyamide fibers as raw materials by combing into a net and hot-pressing method. The effect of fiber length, hot pressing temperature, mass fraction of the waste wool fibers, volume density, thickness of materials, and thickness of the rear air layer on the sound absorption properties were studied by single factor experiments. Under the optimized technological conditions, the sound absorption coefficient was above 0.91 and the noise reduction coefficient was 0.56. Then, the sound absorption mechanism was analyzed. In order to meet the fire resistance requirements of materials in the construction industry, by the orthogonal experiments, range analysis, and variance analysis, the optimal process conditions were as follows: potassium fluotitanate concentration of 8%, treatment time of 40 min, and treatment temperature of 80°C. The limit oxygen index of the nonwoven wall cloth was 32.5%. The nonwoven wall cloth had good sound absorption and flame retardant properties.

A Study on Extraction and Characterization of Keratin Films and Nanofibers from Waste Wool Fiber

ABSTRACTFabrication and characterization of keratin films extracted from waste Merino wool fiber using two different methods and three different pH concentrations is the main focus of this study. Also, wool keratin (WK) loaded polymer surfaces were fabricated. The chemical, structural and morphological characteristics of keratin extracted from aqueous solutions were analyzed and compared for both methods. It is concluded that optimized results in this study could contribute in future research studies to select the parameters and methods to extract keratin films from recyclable wool fibers. Also, WK loaded nanofibrous films could be potential in filtration, air purification and tissue engineering.

Modification of waste wool fiber as low cost adsorbent for the removal of methylene blue from aqueous solution

Removal of methylene blue (MB) from water using adsorbent developed from waste wool fiber has been investigated by batch adsorption experiments in the present work. Wool fiber waste (WF) was collected from a local Spinning and Weaving Company, cleaned and further treated with citric acid to increase its adsorption capacity toward basic dyes. Raw and treated WF were ball milled to produce wool powder (WP) and modified wool powder (MWP), respectively. The carboxyl content was increased steadily as the citric acid solution concentration increased. The introduction of the carboxyl groups also has been proved by streaming potential measurements. The effect of contact time, wool dose and dye solution pH on the adsorption process were studied too. The adsorption isotherm was examined using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. The adsorption equilibrium was attained within 20 minutes with a maximum removal percentage of 70 and 78 for WP and MWP, respectively. The wool dose affects the adsorption process significantly, especially for MWP which removes a higher percentage of MB (86 %) compared to WP (75 %). Both Freundlich and D-R were well fitting the adsorption equilibrium data with R2 > 0.9. The values of Freundlich exponent factor (n) and D-R adsorption energy (E) reveal the chemisorption nature of the MB adsorption on both WP and MWP. This work demonstrated that, chemical and physical modifications of the waste wool fiber with citric acid has enhanced the adsorption of MB.

A bio-antifelting agent based on waterborne polyurethane and keratin polypeptides extracted by protease from waste wool

A bio-composite made from keratin polypeptides and waterborne polyurethane was firstly employed as a bioantifelting agent for wool fabric. The keratin polypeptides, extracted from the waste wool fibers with the protease Esperase8.0L, possessed 5271 weight-average molecular weight. The bio-composites containing different contents of keratin polypeptides were applied for wool anti-felting treatment by a pad-dry-cure process. The results indicated that with increasing content of keratin polypeptides from 0 to 6 wt.%, the area-shrinking rate of the treated wool fabrics was decreased from 4.55 % to 0.47 %, respectively. The warp and weft tensile strength at break of the fabric was increased by 8 % and 12 %, respectively and reduced by about 55 % consumption of waterborne polyurethane. The film of bio-composites had more excellent thermal stability, higher mechanical property in elasticity, and better cytocompatibility compared with the pure waterborne polyurethane film.

A novel heterogeneous Fenton photocatalyst prepared using waste wool fiber combined with Fe3+ ions for dye degradation

Wool fiber Fe complex (Fe-Wool) was prepared with waste wool fiber and Fe3+ ions by a simple exhaust method, and characterized using SEM, FTIR, XRD, XPS, and diffuse reflectance UV-vis spectroscopy. The activity of Fe-Wool was tested as a novel heterogeneous Fenton catalyst for dye degradation in a wide pH range. Effect of Fe content, incorporation of Cu2+ ions, and light irradiation on its catalytic activity was also examined. The results indicated that amino and carboxylic groups or disulfide crosslinks from wool fiber as the ligand sites could react with Fe3+ ions to form Fe-Wool, and the Fe content in Fe-Wool was highly dependent on Fe3+ initial concentration and temperature. Fe-Wool showed a better catalytic activity on the dye degradation under light irradiation than in the dark because it was activated in the UV and visible regions. Incorporation of Cu2+ ions could significantly increase catalytic activity of Fe-Wool for the dye degradation, especially in neutral and alkaline pH range.

Thermal and sound insulation materials from waste wool and recycled polyester fibers and their biodegradation studies

This paper reports a study on thermal and sound insulation samples developed from waste wool and recycled polyester fibers (RPET) for building industry applications. Waste wool fiber is a potential source of raw material for thermal and sound insulation applications, but its quantities are limited. In order to overcome the above problems, waste wool fibers were mixed with RPET fibers in 50/50 proportions in the form of a two layer mat. Another set of three samples from 100% waste wool and 100% RPET fibers were also prepared. All samples were tested for thermal insulation, acoustic, moisture absorption and fire properties. Also, behavior of the samples under high humidity conditions was evaluated. An extensive biodegradability study was conducted to analyze the conversion of organic carbon into carbon dioxide by composting method for 50 days. Two layer 50% waste wool and 50% RPET mat provided the best insulation, acoustic, moisture absorption and fire properties. The RPET/waste wool mats were absorbing more than 70% incident noise in the frequency range of 50–5700Hz. The RPET/waste wool mats have adequate moisture resistance at high humidity conditions without affecting the insulation and acoustic properties. 65–70% biodegradation was achieved for wool/RPET mats for 50 days composting period.

Wool micro powder as a metal ion exchanger for the removal of copper and zinc

Waste wool fibers (WF) were oxidized and ball milled to enhance the exchanging ability toward some metal ions, namely copper and zinc. Wool fibers were oxidized with hydrogen peroxide and tetra acetyl ethylene diamine, followed by grinding process. Optimization of the exchanging medium with regard to the metal ion concentration, pH, and exchanging time was performed. It was observed that the ability of the wool powder (WP) and oxidized wool powder (OWP) to exchange greater amount of metal ions than the ordinary waste wool fibers. Mostly, current results verify a significant ability of the OWP to exchange copper and zinc ions from their aqueous medium. Nevertheless, the ability of all wool substrates used to exchange copper is more than their ability to exchange zinc, and as the pH of the exchanging medium increases, the uptake % of both copper and zinc ions by WF or WP increases to reach its maximum at pH 6. The efficiency of WF, WP, or OWP to adsorb copper and zinc ions after a number of adsorption/desorption tests was also studied.

The Bio-inspired Study of Homogeneous Composite Materials

Wool is the most popular natural material. In the textile industries, the release of a lot of waste wool fibers and their products lead to the idea of regeneration of wool keratin materials. However, the most significant limitation may be the poor fracture resistance of neat keratin films. Greater failure resistance can be achieved by fiber-reinforced matrix when compared to the matrix materials alone. In this article, the fibrils of wool were used as the reinforcements in composite films, which can meet the requirement of biocompatibility. The fibrils morphology was investigated, that is, plain fibrils and fractal-tree structure fibrils. Finite element analysis and tensile tests were used to conduct a direct study on the mechanical properties of composites. It was found that the branched fibrils lead to both higher strength and fracture toughness for the composites than the plain fibrils.

Effect of Reduction and Succinylation on Water Absorbance of Wool Fibers

Succinylation and reduction of wool fibers increase their water absorbability and enhance the re-use of waste wool fibers for functional materials. Water absorbability of these fibers improves with simple reduction and corresponds fairly well with the SH content of the reduced wool. When wool fibers are reduced and succinylated, water absorbability rises remarkably with increased add-on of succinic anhydride. In its most absorbent state, the reduced and succinylated wool holds 39 g · water/g · wool. The carboxyl groups introduced by succinylation into the fibers significantly contribute to the increased water absorbance of reduced and succinylated wool.