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During the drafting process, the fiber acceleration motion contributes significantly to the sliver irregularity. In this study, the drafting simulation based on the improved model of fiber arrangement in the sliver was developed to analyze the sliver irregularity caused by the acceleration motion during the drafting process. The results indicated that the drafting simulation could provide an effective reference for the parameter optimization of the drafting process under the condition of saving raw material cost and time cost. The simulations and calculations denoted that a shorter gauge length and larger input sliver linear density by more concentrated accelerated motion could be conducive to more even slivers during the drafting process. In addition, in order to generate higher sliver evenness, in the double-zone drafting process, the draft ratio of the back drafting zone should be selected to be slightly greater than 1 so that the draft ratio of the front drafting zone would be relatively large when the total draft ratio is constant due to the trend of the additional irregularity caused by the acceleration motion increasing to a peak value firstly and then decreasing as the draft ratio grows. [ABSTRACT FROM AUTHOR]

Air pollution has become a serious threat to human health; hence, it is highly desirable to develop high-efficiency air filters. In this paper, porous cellulose nanofibril (CNF)-implanted air filters with hierarchical structures consisting of LC/PET/CNF composites were prepared using pressurized filtration. The frame of the composite was made of fibrillated lyocell fibres (LC), while polyethylene terephthalate (PET) fibres acted as spacers between the fibrillated LC fibres. CNFs serving as functional fillers were implanted in the LC/PET composite to decrease pressure drop. The results showed that the overall filtration efficiency of the LC/PET composite (50%:50%) with a basis weight of 30 g/m2 for particulate matter (PM) was only 52.69%, while the pressure drop was 56.50 Pa. However, after implantation of CNFs in the LC/PET composite with a weight concentration of only 0.5 g/m2, the overall filtration efficiency significantly improved to 98.22% with an acceptable pressure drop of 145.50 Pa (P50W30t3N0.5). The study provides a new way to achieve high-efficiency fabrication of air filters with high performance for PM removal. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Yarn strength is composed of the total contributions made by all breaking and slipping fibers which are determined by critical slipping length lc. Though the definition of lc has been the focus of many research projects, it still remains unsolved. In this study, idealized assumptions were made on yarn structure, and lc was then estimated. At the same time, the actual contributions that breaking fibers and slipping fibers make to yarn strength were recalculated based on an idealized yarn structure, which was analyzed with the conditional probability method according to fiber length distribution. Then, yarn strength was computed by simulating random fiber arrangement in the yarn. It could be seen from calculated results that the critical slipping length declines as yarn twist multiplier increases. Meanwhile, as the twist multiplier increases, the calculated yarn strength rises to the highest point and then declines, which is in agreement with traditional spinning theory. Thus, the calculation of yarn strength based on critical slipping length could reflect the yarn breaking mechanism with a change in the yarn twist multiplier, and could be applied for further prediction of yarn strength. [ABSTRACT FROM AUTHOR]

To enhance the degumming effect of steam explosion on kenaf fiber, different chemical reagents including hydrogen peroxide (H2O2), sulfuric acid (H2SO4), and sodium hydroxide (NaOH) presoak combined with steam explosion were used and compared in this article. Distilled water coupled with steam explosion treatment and kenaf raw samples were used as control. The fiber morphology, chemical composition, crystalline structure, degree of fineness, and breaking tenacity of kenaf fibers after treatment were studied. The results showed that hydrogen peroxide (H2O2) performs better on removing lignin. It not only splits fibers, but also keeps the fiber's tenacity during steam explosion treatment. Dilute sulfuric acid (H2SO4) performs better on hemicellulose removal, but it damages the fiber cellulose during steam explosion treatment and cause the fiber strength decrease a lot. Sodium hydroxide (NaOH) performs the best on removing hemicellulose and lignin, and splits fiber well. However, the breaking tenacity of the fiber is lower than the fiber pretreated by H2O2. Besides, NaOH is a pollutant to the environment. In conclusion, H2O2 could be considered as the most promising reagent to be used in combined presoak-steam explosion system. [ABSTRACT FROM AUTHOR]

Abstract: Rapid and accurate determination of chemical compositions of ramie is crucial to its application. In this paper, calibration models were established using near-infrared (NIR) spectroscopy to predict the main chemical compositions of ramie. A wet chemical analysis method which was improved on the basis of Chinese national standard for getting calibration data was used in this paper. NIR data of 59 ramie samples were collected using Fourier transform near-infrared spectrometer. The calibration models of chemical compositions of ramie were derived by partial least square (PLS) regression. Prediction of chemical composition of independent ramie samples showed that these models were rapid and accurate in the chemical composition analysis, giving residual predictive deviation (RPD) value higher than 2.5. Such NIR calibration models can be utilized by ramie fiber manufacturers and breeding workers, in order to better manage the degumming process and evaluate the quality of ramie varieties. [Copyright &y& Elsevier]

Artemisia vulgaris is an economic plant that is spreading widely in central China. Its unused bast generates a large amount of biomass waste annually. Utilizing the fibers in Artemisia vulgaris bast may provide a new solution to this problem. This research attempts to strengthen the understanding of Artemisia vulgaris by analyzing its fiber compositions and preparing micro- and nano-cellulose fibers, which can be used as raw materials for composites. In this work, Artemisia vulgaris bast powder (AP) and microcellulose and nanocellulose fibers (AMFs and ANFs) were produced and characterized by optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TG), and bacteriostatic test. The results indicated that cellulose, hemicellulose, and lignin were the main components in the Artemisia vulgaris bast. The cellulose content reached 40.9%. The Artemisia vulgaris single fibers were microcellulose fibers with an average length of 850.6 μm and a diameter of 14.4 μm. Moreover, the AMF had considerable antibacterial ability with an antibacterial ratio of 36.6%. The ANF showed a length range of 250–300 nm and a diameter of 10–20 nm, and it had a higher crystallinity (76%) and a lower thermal stability (initial degradation temperature of 183 °C) compared with raw ANF (233 °C). This study provides fundamental information on Artemisia vulgaris bast cellulose for its subsequent utilization. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile (PAN) composite microfibers with different contents of graphene oxide (GO) were fabricated via wet‐spinning route in this work. Based on nonsolvent‐induced phase separation theory, N,N‐dimethyl formamide/water mixture system was employed as coagulation bath, nonsolvent (water) diffused into PAN spinning solution and led to a quick PAN fiber solidification. Nematic liquid crystal state of GO dispersions and GO/PAN spinning solutions were determined via polarized optical microscopy images, and the morphology and structure of the composite fibers were characterized via scanning electron microscope, Transmission electron microscopy, Fourier transform infrared spectra, and X‐ray diffraction. 1 wt % GO/PAN composite fibers exhibited outstanding mechanical properties, 40% enhancement in tensile strength and 34% enhancement in Young's modulus compared with pure PAN fiber. The results of dynamic mechanical analysis indicated that the composite fiber with 1 wt % GO performed the best thermal mechanical property with 5.5 GPa and 0.139 in storage modulus and loss tangent, respectively. In addition, thermogravimetric analysis showed that thermal stability of the composite fibers enhanced with the increasing GO contents. GO/PAN composite fibers can be as the candidate of carbon fiber precursor, high performance fibers, and textiles applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46950. [ABSTRACT FROM AUTHOR]

Conventional methods faced challenges in pretreating natural cellulose fibres due to their high energy consumption and large wastewater drainage. This research devised an efficient solid-state pretreatment method for pretreating hemp fibres using ethanolamine (ETA) assisted by microwave (MW) heating. This method produced a notable removal rate of lignin (85.4 %) with the highest cellulose content (83.0 %) at a high solid content (30 %) and low temperature (70 °C). Both FT-IR and XRD analyses indicated that the pretreatment did not alter the structure of cellulose within the hemp fibres but increased crystallinity as the CrI increased from 84 % in raw hemp fibre to 89 % in pretreated fibre. As a result, it produced hemp fibres with impressive fineness (4.6 dtex) and breaking strength (3.81 cN/dtex), meeting the requirement of textile fibre. In addition, an improvement in glucose concentration (15.6 %) was observed in enzymatic hydrolysis of the MW pretreated hemp fibres compared to the fibres pretreated without MW. Furthermore, the FT-IR and NMR data confirmed that the amination of lignin occurred even at low temperature, which contributed to the high lignin removal rate. Thus, this study presents a potentially effective energy-saving, and environmentally sustainable solid-state method for pretreating hemp fibres. [Display omitted] [ABSTRACT FROM AUTHOR]

Efficient degumming is crucial for valorisation of bast fibres. However, severer conditions and high energy consumption hinder their practical application. This work developed a photocatalytic degumming method assisted by both ZnIn 2 S 4 catalysis and lignin autocatalysis at mild conditions. The method achieved high lignin removal rate (71.6%) and cellulose yield (94.8%) in degumming of hemp fibres, decreasing the major content of β-O-4 bond and β-β bond in lignin from 32.0% to 10.7% and 6.8% to 3.4%, respectively. The pretreated fibres possessed excellent breaking strength (4.46 cN/dtex) and fineness (6.83 dtex). Moreover, the pretreated fibres were readily hydrolysed by cellulase, improving the glucose concentration by 58.3% compared to the alkaline degumming. Furthermore, the synergistic action of ZnIn 2 S 4 and lignin on generation of free radicals was observed. Thus, this work explored the potential of photocatalysis degumming of bast fibres, and discovered the synergistic action of ZnIn 2 S 4 and lignin autocatalysis. [Display omitted] • A mild photocatalytic degumming for fractionation of bast fibres. • High lignin removal (71.6%) at low temperature (30 °C). • The degummed fibers possessed excellent physical and mechanical properties. • Increasing the glucose concentration by 58.3% in enzymatic hydrolysis. • The mechanism of the synergistic action of ZnIn 2 S 4 and lignin was proposed. [ABSTRACT FROM AUTHOR]

Hemp represents a valuable resource of natural fibers on account of its environment favorable characteristics and excellent fiber quality. To fabricate hemp fibers, the traditional alkaline boiling degumming is used in the industry, which consumes a lot of water and generates a substantial amount of wastewater. In the present study, a novel eco–friendly solid–state degumming method was developed by using ethanolamine (ETA). The ETA degumming exhibited a high lignin removal rate (87.5%) at a high solid loading (30%), decreasing water consumption by 33.3%. Moreover, the ETA solution was readily reused up to five times without purification. The degummed hemp fibers possessed commendable fitness (4.2 dtex) and breaking strength (3.75 cN/dtex) without change of the crystalline cellulose structure. Besides, the lignin in wastewater was confirmed to be aminated, which is beneficial to the potential valorization of the by–product. Thus, the solid–state ETA degumming method holds significant potential for the fabrication of hemp fibers. [Display omitted] • A novel eco-friendly solid–state degumming method by using ethanolamine. • A high lignin removal rate (87.5%) at a high solid loading (30%). • Ethanolamine solution was reused up to five times without purification. [ABSTRACT FROM AUTHOR]

Hemp fiber is a promising textile resource. Because hemp fibers contain high gum content, an efficient degumming method needs to be developed. This study proposed a novel cascade degumming process coupling organosolv pretreatment and alkali boiling. Glycolic acid was optimally selected as a pretreatment reagent. The cascade process achieved a high lignin removal rate (69.81%) and hemicellulose removal rate (84.83%). The degummed hemp fibers showed excellent properties (4.18 ± 0.99 cN/dtex and 8.34 ± 0.01 dtex). Moreover, the glycolic acid solution could be reused three times without purification. The glycolic acid pretreatment led to decreased consumption of alkali reagents by 96.15%. Furthermore, the effect of glycolic acid pretreatment on lignin removal was analyzed by chemical composition analysis, FTIR, XRD, TGA, GPC, and HSQC NMR analysis. These results indicate that the novel cascade degumming process is an efficient and eco-friendly degumming method. [Display omitted] • A novel cascade process for hemp fiber degumming. • Organosolv pretreatment promoted efficient removal of lignin and hemicellulose. • Glycolic acid can be reused without purification. • The mechanism of lignin removal in cascade degumming process was studied. [ABSTRACT FROM AUTHOR]

Traditional degumming methods of bast fibers are largely limited due to long procedures, high energy consumption, serious environmental pollution, or low efficiency. In this study, deep eutectic solvents (DESs) synthesized with hydrogen bond acceptor (HBA) and three representative hydrogen bond donors (HBDs) were applied to kenaf bast degumming. The morphologies, chemical compositions, crystallinities, polymerization degrees and physical properties of the kenaf fibers were determined. The effects and mechanisms of different DESs on dispersing kenaf bast were discussed. The results showed that alkalinity amide DES (ChCl-urea, CU) showed the best degumming effect. The optimal processing temperature is 160 °C and the processing time is 2 h. Due to competition from chloride ions, DES first weakens the hydrogen bond interaction in kenaf fibers. Then, the alkalinity amide DES removed lignin by deprotonation of phenolic hydroxyl groups and breakage of β-O-4 bonds for different lignin units. Finally, the solvent can be reused at least 3 times. The results showed that CU degumming treatment could effectively remove the gummy components in kenaf bast and had the potential to prepare refined dry kenaf fibers. This study provided a simple and green degumming method for kenaf bast. [Display omitted] • A facile and greener DES degumming method for preparation of kenaf fibers. • Recycable and reusable DES degumming waste. • The mechanisms of kenaf bast degumming by three kind of DESs. [ABSTRACT FROM AUTHOR]

• With the microwave-assisted ultrasonic treatment, the degumming process was more eco-friendly and efficient. • All properties were better than those of the fibers from traditionally degumming process. • The new method helped improve the technology for rapid and clean preparation of new biomass fibers. Apocynum venetum (AV) is a promising textile resource but lacks efficient degumming method. This study proposed a novel degumming process which coupled microwave pretreatment with ultrasonic degumming on AV bast. The traditional chemical degumming was also carried out for comparison. The raw AV bast and produced fibers were characterized with wet chemistry analyses, SEM, FTIR and GPC. Compared with traditionally degummed product, the AV fibers prepared by microwave-assisted ultrasonic degumming showed a better breaking tenacity (7.67 cN/dtex, comparing to 6.90 cN/dtex with the traditional method) and superior average length (32.5 mm, comparing to 23.0 mm). Moreover, compared with the traditional degumming method, the processing time of the new method was reduced to 31.2 %, and the chemical usage was reduced to 44.8 %. The new degumming method could efficiently produce higher quality AV fibers with less pollution. [ABSTRACT FROM AUTHOR]