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Colloidal carbon dots (C‐dots) are considered as promising heavy‐metal‐free materials to achieve room‐temperature phosphorescence (RTP) properties for promising applications, such as photoelectronic devices, information encryption, and bio‐imaging. However, most of the current obtained RTP C‐dots have a short lifetime with a relatively low quantum yield (QY). In this work, the C‐dots large‐scale synthesized via a vacuum heating approach have multiple RTP emissions (blue, green, and yellow), a long RTP lifetime of as high as 1.92 s, and a high QY of 34.4% by selecting different types of precursors, which is superior to most of reported RTP C‐dots. The multiple atoms doping and strong bonding between neighbored C‐dots promoted by vacuum heating contributes to the excellent RTP properties. As a proof‐of‐concept, the as‐obtained RTP C‐dots are used as optical ink for flexible security codes, exhibiting a bright shape with a lifetime of 1.37 s. This work offers an efficient approach for producing large‐scale high‐quality RTP C‐dots, which can be applied to anti‐counterfeiting and information encryption systems. [ABSTRACT FROM AUTHOR]

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]

The catalytic conversion of cellulose to lactic acid (LA) has garnered significant attention in recent years due to the potential of cellulose as a renewable and sustainable biomass feedstock. Here, a series of Au/W-ZnO catalysts were synthesized and employed to transform cellulose into LA. Through the optimization of reaction parameters and catalyst compositions, we achieved complete cellulose conversion with a selectivity of 54.6% toward LA over Au/W-ZnO at 245 °C for 4 h. This catalyst system also proved effective at converting cotton and kenaf fibers. Structural and chemical characterizations revealed that the synergistic effect of W, ZnO, and Au facilitated mesoporous architecture generation and the establishment of an adequate acidic environment. The catalytic process proceeded through the hydrolysis of cellulose to glucose, isomerization to fructose, and its subsequent conversion to LA, with glucose isomerization identified as the rate-limiting step. These findings provide valuable insights for developing high-performance catalytic systems to convert cellulose. [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]

Luminescent solar concentrators (LSCs) are large-area sunlight collectors for efficient solar-to-electricity conversion. The key point for highly efficient LSCs is the choice of fluorophores, which need to have broad absorption, high quantum yield and large Stokes shift. Among various fluorophores, carbon quantum dots (C-dots) hold great promise as eco-friendly alternatives to heavy-metal-containing quantum dots (QDs) due to their adjustable absorption and emission spectra, non-toxicity, low cost and eco-friendly synthetic methods. However, due to the limited absorption band and relatively low quantum yield in the red region, it is a challenge to obtain efficient LSCs based on C-dots. Here, we demonstrated highly efficient LSCs based on red-emissive C-dots. The as-synthesized C-dots have a cubic structure, broad absorption covering 300–600 nm, and red emission (peak located at 595 nm), with a high quantum yield of ∼65% and a large Stokes shift of 0.45 eV. Transient absorption experiments of the C-dots revealed the ultrafast formation of the broad emissive state (1 ps). Based on the excellent optical properties of the C-dots, the as-prepared large-area LSC (10 × 10 × 0.52 cm3) exhibited an optimized external optical efficiency of 4.81% and a power conversion efficiency of 2.41% under natural sun irradiation (70 mW cm−2). Furthermore, a tandem LSC using green-emissive C-dots (top layer) and red-emissive C-dots (bottom layer) as fluorophores exhibited an external optical efficiency as high as 6.78%. These findings demonstrate the possibility of using eco-friendly carbon-based nanomaterials for highly efficient large-area LSCs. [ABSTRACT FROM AUTHOR]

Kombucha-derived bacterial cellulose (KBC) is a unique natural polysaccharide that has gained increasing interest in biomedical and other applications. However, the relatively low bioactivity of the product has limited its practical applications. In this work, KBC and silk nonwoven fabric (SNF) were integrated to produce a sandwich membrane through in situ growth of KBC in the presence of SNF. Scanning electron microscopy (SEM) showed that KBC grew not only on the surface of SNF but also within the fiber network of SNF. The strength and modulus of SNF were significantly increased after the integration of KBC. The KBC/SNF sandwich membrane was further impregnated with silk sericin (SS) through simple solution absorption to impart strong UV shielding property to the material, which was demonstrated by the near zero UV transmittance of the new KBC/SNF-SS membrane. SEM, Fourier transform infrared spectrometry, and X-ray diffraction results indicated the interactions between the three components. DPPH (2,2-Diphenyl-1-picrylhydrazl) radical scavenging test and cytotoxicity test showed strong antioxidant activity and biocompatibility of the new membrane due to the presence of SNF and SS. These properties make this new biocomposite membrane a promising material for healthcare and skincare applications, such as wound dressing and beauty products. [ABSTRACT FROM AUTHOR]

Water pollution, which is caused by leakage of oily substances, has been recognized as one of the most serious global environmental pollutions endangering the ecosystem. High-quality porous materials with superwettability, which are typically constructed in the form of aerogels, hold huge potential in the field of adsorption and removal of oily substances form water. Herein, we developed a facile strategy to fabricate a novel biomass absorbent with a layered tubular/sheet structure for efficient oil/water separation. The aerogels were fabricated by assembling hollow poplar catkin fiber into chitosan sheets using a directional freeze-drying method. The obtained aerogels were further wrapped with -CH3-ended siloxane structures using CH3SiCl3. This superhydrophobic aerogel (CA ≈ 154 ± 0.4°) could rapidly trap and remove oils from water with a large sorption range of 33.06–73.22 g/g. The aerogel facilitated stable oil recovery (90.07–92.34%) by squeezing after 10 sorption-desorption cycles because of its mechanical robustness (91.76% strain remaining after 50 compress-release cycles). The novel design, low cost, and sustainability of the aerogel provide an efficient and environmentally friendly solution for handling oil spills. [ABSTRACT FROM AUTHOR]

Natural indigo is a traditional dye for textiles. However, a large number of impurities on the surface of dyed fibers have been reported, which leads to poor friction and electrical performance, and exerts a negative impact on the spinning of the fibers. In this paper, a centrifugation pretreatment of the leuco indigo dye liquid was reported to remove the impurities, and the centrifuged dye was then applied to cotton fiber. The results revealed that centrifugation could effectively remove 88.2% of solid impurities, and the fiber after being dyed showed a clean and smooth surface. There was almost no chromatic aberration compared with the original fibers that were dyed with the noncentrifuged dye solution, and the optimized value of the color difference was less than 0.5. The friction and electrical properties of the fibers were improved. There was significantly reduced dust observed during the spinning process of the dyed fibers, and the spinnability of the fibers was improved. The coefficient of variation of single yarn decreased from 28.35% to 21.19%. [ABSTRACT FROM AUTHOR]

Cotton fiber is mainly composed of cellulose, which is rarely separated into different kinds. However, the classification and identification of waste cotton from different countries are essential for the customs service of the country. In this study, the near-infrared classification method was introduced to classify and identify cotton fibers. Waste cotton samples from six different countries were collected, and one-fifth of them were used for validation. The near-infrared calibration and prediction models were constructed using both soft independent modeling of class analogy and partial least squares methods. It was found that the optimized model has a high recognition rate, and the prediction accuracy of the model was 99% for six countries. It was demonstrated that the near-infrared model established in this study can be used for fast and accurate identification of waste cotton from different countries. [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.)

Carbon quantum dots (C-dots) have attracted increasing attention because of their nontoxic composition and excellent optical properties, which have seen them widely used as building blocks for various types of optoelectronic devices. However, the large-scale synthesis of C-dots with a high quantum yield is a big challenge. Herein, C-dots were synthesized via a vacuum heating approach, which could provide over 100 g per batch. The purified C-dots had an ultrahigh quantum yield of ∼79%, absorption peaks at 330 and 405 nm, and a narrow fluorescence spectrum with a main peak centered at 520 nm. As a proof of concept, an as-prepared C-dots/polymer aqueous solution was used as a security ink for textile anti-counterfeiting. After printing the ink into the cotton fabrics, the C-dots still had a quantum yield of 42%. By mixing with other colored C-dots, a multiple colored anti-counterfeiting security code was obtained, which could greatly enhance the anti-counterfeiting level. This study provides a reliable approach to provide high-quality C-dots in a large scale and may open possibilities to use C-dots for potential flexible anti-counterfeiting and optoelectronic applications. [ABSTRACT FROM AUTHOR]

Large scale solar‐driven hydrogen production is a crucial step toward decarbonizing society. However, the solar‐to‐hydrogen (STH) conversion efficiency, long‐term stability, and cost‐effectiveness in hydrogen evolution reaction (HER) still need to be improved. Herein, an efficient approach is demonstrated to produce low‐dimensional Pt/graphene‐carbon nanofibers (CNFs)‐based heterostructures for bias‐free, highly efficient, and durable HER. Carbon dots are used as efficient building blocks for the in situ formation of graphene along the CNFs surface. The presence of graphene enhances the electronic conductivity of CNFs to ≈3013.5 S m−1 and simultaneously supports the uniform Pt clusters growth and efficient electron transport during HER. The electrode with a low Pt loading amount (3.4 µg cm−2) exhibits a remarkable mass activity of HER in both acidic and alkaline media, which is significantly better than that of commercial Pt/C (31 µg cm−2 of Pt loading). In addition, using a luminescent solar concentrator‐coupled solar cell to provide voltage, the bias‐free water splitting system exhibits an STH efficiency of 0.22% upon one‐sun illumination. These results are promising toward using low‐dimensional heterostructured catalysts for future energy storage and conversion applications. [ABSTRACT FROM AUTHOR]

Developing ceramic materials for thermal insulation is vital for various applications. However, ceramics have been considered intrinsically rigid and brittle due to the limited crystallographic slips and structural collapse during service. Their lack of flexibility has hampered many high-end applications of ceramic materials. We developed flexible Al2O3/ZrO2 nanofibrous membranes via sol–gel electrospinning and calcination. Al2O3/ZrO2 nanofibrous membranes had flexibility from −196 °C to 1300 °C and low thermal conductivity (∼0.03166 W m−1 K−1 at room temperature). They also supported 1350-times their weight without suffering structual damage. Hence, Al2O3/ZrO2 nanofibrous membranes could be used for thermal insulation in aerospace and industrial fields, and even in harsh environments. [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.)

Silk fibroin (SF) has been intensively studied as a biobased renewable material for biomedical and other applications. However, its relatively low mechanical properties have limited its use in the applications where an improved strength and structural integrity are desired. In this work, a bio-nanocomposite material consisting of SF/polyvinyl alcohol (PVA) as the matrix, TEMPO-oxidized bacterial cellulose nanofiber (TBC) as the reinforcement, and silver nanoparticles (AgNPs) as an antibacterial agent, was facilely synthesized. SF also functioned as a reducing agent and TBC as an immobilization template during the in-situ synthesis of AgNPs. It was found that TBC and AgNPs were homogeneously dispersed in the nanocomposites after the synthesis, which led to outstanding mechanical properties of the materials. The mechanical properties, hydrophobicity, and water vapor barrier property of the materials could be tailored by adjusting the content of TBC. Moreover, the bio-nanocomposite films exhibited strong UV shielding property, antibacterial activities and low silver leakage. These properties make the SF/PVA/AgNPs/TBC bio-nanocomposites promising materials for active food packaging and seed storage/packaging applications. [ABSTRACT FROM AUTHOR]

Chemically deuterated cellulose fiber was expected to provide novel applications due to its spectral, biological, and kinetic isotope effect. In this research, the performance of the chemically deuterated cotton fibers, including their mechanical property, enzymatic degradation performance, effect on bacterial treatment, and fast identification (near-infrared modeling) was investigated. The breaking tenacity of the deuterated cotton fibers was slightly lower, which might be attributed to the structural damage during the chemical deuteration. The glucose yield by enzymatic hydrolysis was less than that of the protonic cotton fibers, implying the deuterated fibers are less sensitive to enzymatic degradation. Furthermore, the deuterated fibers could promote the growth of bacteria such as Escherichia. coli , which was associated with the released low-level deuterium content. At last, the near-infrared technique combined with partial least squares regression successfully achieved a fast identification of the protiated and deuterated cotton fibers, which significantly promoted the potential application of deuterated cellulose as anticounterfeiting materials (e.g., special paper). [ABSTRACT FROM AUTHOR]

Preparation of deuterium incorporated cellulose is a vital tool to investigate cellulose internal structure and to expand the application fields of cellulose materials. In this study, cellulosic cotton fibers with anti-rehydration (exchange-resistant) deuterium incorporated in cellulose were prepared by chemical hydrogen–deuterium exchange treatment. The chemical hydrogen–deuterium exchange process, along with exchange time, were characterized by nuclear magnetic resonance hydrogen spectroscopy (1H-NMR). The anti-rehydration deuterium incorporation was determined by Fourier Transform infrared spectroscopy (FTIR) and Stable Isotope Ratio Mass Spectrometer (IRSM). The effect of the deuterium hydroxyl substitution on cotton fiber's spectral data, microstructure, crystalline information, degree of polymerization, as well as it's thermogravimetric analysis (charcoalization and combustion) are explored. Analysis of the chemical exchange process indicated that the hydrogen–deuterium exchange occurred preferentially in the amorphous cellulose component over the first several minutes. Deuterium exchange in the anti-rehydration crystalline phase took several hours. Increasing the treatment time, enhanced exchange-resistant deuterium incorporation to as high as about 60% of the cotton fibers' cellulose hydroxyl groups was achieved. The characterization of FTIR, Fourier transform Raman (FT-Raman), and near-infrared spectra (NIR) all exhibited the deuterium spectral isotope effect on cellulose hydroxl groups. While, apart from the effect of reaction temperature, deuterium incorporation isotope effect did not affect the cellulose microstructure, crystalline index and the degree of polymerization properties. Furthermore, the thermogravimetric analysis of deuterated cotton fibers under N2 and air atmosphere were both altered due to the thermodynamic isotope effect. These observations revealed the hydrogen–deuterium exchange treatment process and impacts on cellulose fiber properties, which helped us to better understand the cellulose internal structure and may facilitate the potential utilization of deuterated cellulosic materials. [ABSTRACT FROM AUTHOR]

Luminescent solar concentrators (LSCs) are large-area sunlight collectors, consisting of a waveguide embedded with fluorophores. LSCs could reduce the use of expensive silicon solar cells, thus decreasing the cost of electricity. Although great efforts have been made for fabricating high efficiency large-area LSCs, there is still a lack of knowledge of the temperature effect on the performance of the LSCs based on colloidal quantum dots (QDs) because the LSCs need to be operated in outdoor conditions. In this work, we investigated the thermal effect on the performance of the LSCs based on colloidal QDs upon sunlight irradiation under different temperatures (10–40 °C). The optical properties (e.g. quantum yield and optical efficiency) of the LSCs are strongly dependent on the operating temperature. With increasing operating temperature, the quantum yield and optical efficiency decrease significantly. Among three types of configuration, the LSC based on thin-film QDs coated on glass has the lowest temperature increase under operation, due to the higher thermal conductivity of the glass compared to the polymer matrix. Considering the real operating conditions of the LSCs, the glass-based LSCs have promising potential for future high-efficiency LSC-PV systems. [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.)

Chemotherapy is an important method for treating breast cancer. However, multidrug resistance is one of the major challenges in breast cancer chemotherapy. There is an urgent need to develop novel, effective antitumor strategies that will perfect existing therapeutic regimens. In this study, the double-targeted nanocarrier, Quercetin-3'3-dithiodipropionic acid-Astragalus polysaccharides-Folic acid (QDAF), was successfully synthesized and self-assembled into a neoteric nano-targeted delivery strategy, named nano-pomegranates, and which were utilized to effectively inhibit multidrug resistance in estrogen receptor α (ERα)-positive breast tumor. The outstanding abilities of nano-pomegranates to release the drug in a reducing environment was determined by in vitro release assay. The cellular studies in MCF-7 cells were examined that nano-pomegranates have remarkable efficiencies of enhancing cellular uptake, inhibition and necrosis and apoptosis. In vivo antitumor experiments showed that nano-pomegranates have better anti-tumor effects and lower systemic toxicity than free Cur. In conclusion, nano-pomegranates have great potential in anti-breast cancer treatment. [ABSTRACT FROM AUTHOR]

Plant dye is a promising dyestuff to be used in textiles due to its unique environmental compatibility. However, currently there is no effective method for the identification of plant-dyed and chemical-dyed textiles. In this study, near-infrared (NIR) spectroscopy combined with three kinds of pattern recognition methods, namely soft independent modeling of class analogy (SIMCA), partial least squares (PLS) regression and principal component regression (PCR), were applied to identify cotton fabrics dyed with plant and chemical dyes. A total of 336 plant dye and chemical dye dyed cotton fabrics were prepared and the NIR spectra were collected; 267 samples were used as the calibration set, while the remaining 69 samples were used as the validation set. After pretreatment with the Savitzky–Golay first derivative, the calibration model was constructed. In the SIMCA model, the correct recognition rate values of the calibration and prediction sets were 100% and 98.55%, respectively. The PLS model showed that the number of principal components (PCs) and the correlation coefficient (R 2) were 8 and 0.9978, respectively, and the results of PCR were PC = 10, R 2 = 0.9937. Both methods were satisfactory for the predicted results. The overall results indicated that NIR spectroscopy could be used for rapid and nondestructive identification of plant-dyed cotton fabrics and chemical-dyed cotton fabrics. [ABSTRACT FROM AUTHOR]

Production of deuterated cellulose is important from both theoretical and practical perspectives. In this study, cellulose fibers of cotton and Tencel fibers with exchange-resistant deuterium incorporation were prepared by hydrogen–deuterium exchange treatment. The effect of the micro-structure of cellulose crystallinity index as well as the reaction conditions including catalyst, reaction time, and temperature on the exchange-resistant deuterium incorporation process are reported. The ability of deuterated cellulose fibers to resist protium-exchange during H2O washing was also explored. The results found that higher crystallinity index is beneficial to stabilize the deuteration of cellulose fibers. Furthermore, alkaline catalysts such as sodium hydroxide or potassium carbonate and higher exchange temperature as well as longer reaction time contribute significantly to the stabilization of deuterium incorporation in the deuterated cellulose fibers. These observations revealed that the hydrogen–deuterium exchange treatment is effective to obtain exchange-resistant deuterium incorporated cellulose fibers. In addition, cotton fibers with several deuteration levels were produced and could be considered for the study of deuterium effect on cellulose properties. [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.)

Biodegradable polymer stents are attracting more attention with their advantages of biocompatibility and biodegradable and dispensing with surgical removal. However, the lower radial force is the main bottle neck of their application. In the present research, poly-L-lactic monofilaments with three different diameters were adopted to produce multi-ply strands and then fabricated into Z-structure stents. The effects of strand parameters on stent radial force were studied. The monofilament, strand and stents were subsequently degraded in vitro for 48 weeks. The thermal properties, morphology change, mass retention and strength retention of samples were recorded to forecast the long-term application effects of the stents. The results of this research provided theory to optimize the processing technique of stents with a textile structure to acquire higher radial force. [ABSTRACT FROM AUTHOR]

Deep eutectic solvent (DES) pretreatment coupled with alkaline degumming on Apocynum venetum bast was studied for developing an eco-friendly and effective degumming method. A 1:2 mixture of choline chloride and urea was used in a microwave-assisted DES pretreatment optimized to 60 min and 110 °C. The impact of the deep eutectic solvent pretreatment on the properties of produced semi-degummed and refined dry fibers were assessed by examining the fiber chemical composition, surface microstructure, cellulose crystallinity, degree of polymerization, and fiber thermal properties. The combined DES and alkaline degumming treatment effectively removed the gummy matter including hemicellulose and lignin from the A. venetum bast, providing a smooth and clean fiber surface. This combined DES and alkaline degumming treatment also shows the ability to extract amorphous cellulose, leading to an increase of fiber crystallinity and a decrease of the average cellulose molecular weight. The thermal stability of the fibers was improved significantly after the degumming treatment. The refined dry fibers produced by this combined DES-alkaline treatment exhibited comparable chemical and physical properties (e.g. residual gum content, fiber length, fiber fineness, breaking tenacity) compared with traditionally alkali degumming method. These results revealed that DES is a practical and feasible pretreatment protocol for A. venetum bast degumming. [ABSTRACT FROM AUTHOR]

Alginate scaffold with high porosity has great potential in the field of tissue engineering due to its biocompatibility and degradability. However, the poor mechanical performance of pure alginate scaffold has limited its use in many applications. Cellulose nanofibers (CNFs) have attracted attention as reinforcing agents to fabricate composite scaffolds with alginate. In this paper, CNF obtained from raw ramie fibers was incorporated with sodium alginate to make a composite scaffold by the freeze-drying method. CNF contents of 0.025, 0.05, 0.1, 0.2, 0.4, 0.8, and 1.6% were selected to study the effect of CNF on scaffold characterization. The composite scaffold exhibited fewer pores but more compact structure than the pure alginate scaffold. Fourier transform infrared spectroscopy was used to study the changes in the functional groups between the ramie fiber and its CNF, pure alginate scaffold, and the composite scaffold. X-ray diffraction indicated that the crystallinity of scaffold increased with addition of CNF. The mechanical performance of scaffold was successfully improved by adding CNF, but the porosity and swelling ratio were decreased. Hence, by combining CNF with alginate, the porous structure, mechanical properties, and swelling behaviors could be tailored, which could expand its use in the field of tissue engineering. [ABSTRACT FROM AUTHOR]

A comparison of bending flexibility between bare biodegradable polydioxanone biliary stents (BBPBSs) and fully covered biodegradable polydioxanone biliary stents (FCBPBSs) developed for humans is presented in this study. Firstly, a series of BBPBSs and FCBPBSs were prepared by braiding method in order to investigate the relationship between the bending load and structure parameters (monofilament diameter and braid-pin number) through a three-point bending method. In addition, a series of three-point bending models based on actual stent specimens above was established and the bending flexibility of BBPBSs and FCBPBSs in three-point bending models was evaluated by the finite element method (FEM). Results showed that the simulation was in good agreement with the experiment, indicating that the simulation results could be used as the reference to access the mechanical behaviors of BBPBSs and FCBPBSs. Furthermore, the distinction in bending flexibility between BBPBSs and FCBPBSs was compared in this simulation and demonstrated that the existence of a nanomembrane component (NMP) in FCBPBS causes remarkable performance variation including bending load (all FCBPBSs increased by at least 0.65%), stress, plastic strain and energy conversion of the stent (the plastic dissipation energy of all FCBPBSs increased by at least 2.33J) in the bending process. [ABSTRACT FROM AUTHOR]

The high content of lignin is the major disadvantage for kenaf fiber separation. In order to remove lignin effectively as well as to improve the dispersion of kenaf fibers, a novel degumming process with steam explosion followed by Fenton treatment was applied in the present study. Fibers prepared by traditional chemical degumming process and raw kenaf samples were employed as control. The fiber microstructure, chemical composition, and physical and mechanical properties were characterized and analyzed in this paper. The results revealed that steam explosion coupled with Fenton treatment could effectively remove the gum materials from kenaf bast, which performed noticeably effectively in lignin removal. The refined dry fibers showed a clean and smooth surface. The average fineness of the refined dry fibers degummed by the novel process was measured to be higher than 70 dtex, which is much better than fibers prepared by the traditional chemical degumming process. It can be concluded that the novel degumming process of combined steam explosion and Fenton treatment is feasible and effective for kenaf degumming. [ABSTRACT FROM AUTHOR]

In this paper, the crystalline modification of isotactic polypropylene (PP) based on rare earth β‑nucleating agent (WBG) with surface modification were investigated by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). First, the relationship between the different functional additives for WBG surface modification and nucleation-inducing capability of WBG in PP matrix, as well as the possible reason for the change of nucleation-inducing capability of surface-treated WBG with different functional additives in PP matrix were further studied. It revealed that surface treatment can significantly improve the nucleation-inducing capability of WBG, especially silane coupling agent was more beneficial to increase the nucleation-inducing capability of WBG. Compared with titanate coupling agent and stearic acid, the aliphatic chain length of silane coupling agent was suitable to effectively entangle with the surrounding large molecular chain of PP, and not enough to dilute the large molecular chain of PP near it. In addition, the alkoxysilane groups can react with the carbonyl group of PP main chain so that the interaction between WBG and PP matrix was further enhanced and affinity was greatly improved between them. Hence the nucleation-inducing capability was improved. Second, the influence of WBG with surface modification on the crystalline structure and the stratified crystalline structure of PP was also studied. The results showed that silane coupling agent in three functional additives could further improve the β-crystal induction ability of WBG for PP modification. In view of the stratified crystalline structure of PP, the surface-treated WBG with coupling agent, especially with silane and stearic acid, could weaken the effect of cooling environment and was beneficial for further promoting the β-crystal formation in skin layer but also in core layer. [ABSTRACT FROM AUTHOR]

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]

Degumming is the dominant method to isolate cellulosic fibers in the textile industry. High content of lignin is the principle obstacle in bast-fibers degumming. In order to remove lignin efficiently, the treatment using steam explosion coupled with Fenton oxidation was conducted on kenaf bast in this study. The influence and mechanism of the combined treatment of steam explosion and Fenton oxidation were studied. Fiber microstructure, composition proportion and distribution, cellulose Segal crystallinity and polymerization as well as residual lignin structure were analyzed. The results showed that the pretreatment of steam explosion could sufficiently extract most of the hemicellulose from kenaf bast. Also, the Fenton oxidation followed by alkaline boiling could effectively remove the lignin from the fiber, especially from the fiber surface. The refined dry fibers produced only remained 8.82% of hemicellulose and 9.36% of lignin. And the whole treatment process didn’t change the cellulose crystalline structure but could gradually degrade hemicellulose, lignin and other amorphous gummy matter as well as disordered areas in cellulose, leading to the increase of fiber Segal crystallinity from 62.02 to 70.12%. Part of cellulose was damaged with the increase of degumming intensity, resulting in the decrease of the polymerization degree of cellulose. Meanwhile, the structure of residual lignin changed during the degumming stages of steam explosion, Fenton oxidation and alkaline boiling. All the results revealed that the treatment of combined steam explosion and Fenton oxidation is significantly effectual for isolating bast-fibers. [ABSTRACT FROM AUTHOR]

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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]

The study of the main chemical composition degradation, especially cellulose degradation at high temperatures and within high moisture environments, provides important information that can guide biomass processing using steam explosion (STEX) and other similar treatments. In this paper, kenaf bast was treated using STEX at pressures of 0.5, 1.0, and 1.5 MPa. The chemical composition change and the infrared spectra were investigated. The crystalline index and degree of polymerization of kenaf cellulose were also quantified. It was found that pectin and hemicellulose could be easily degraded with the STEX treatment, while lignin only exhibited slight decomposition; cellulose degraded at 1.5 MPa STEX treatment on the kenaf. Research also indicates that cellulose with a low molecular weight can be removed with a low-pressure STEX treatment. By coupling STEX with chemical degumming process, the high-quality kenaf fiber with 7.12% residue gum content and 134.5 Nm fineness can be obtained. [ABSTRACT FROM AUTHOR]

Correction of 'Solvothermal synthesis of MnFe2O4 colloidal nanocrystal assemblies and their magnetic and electrocatalytic properties' by Zhen Li et al., New J. Chem., 2015, 39, 361–368, https://doi.org/10.1039/C4NJ01466A. [ABSTRACT FROM AUTHOR]

To enhance the mechanical performance and ultraviolet shielding property, graphene oxide was incorporated as the functional nanofiller into a sodium alginate matrix to form a composite film via a solvent-casting method. The as-obtained films were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermal gravimetric; their mechanical and ultraviolet blocking properties were also systemically evaluated and compared. The results showed that the maximum tensile strength increased to 84 MPa at 6 wt.% graphene oxide loading, nearly 265% greater than that of pure sodium alginate film. The increased tensile strength may have resulted from the existence of hydrogen bonding and high interfacial adhesion between graphene oxide filler and sodium alginate matrix. Furthermore, the sodium alginate/graphene oxide films also demonstrated robust ultraviolet shielding capacity; the corresponding ultraviolet protection factor reached up to 133.61 at 8 wt.% graphene oxide loading. [ABSTRACT FROM AUTHOR]

In this article, submicron barium sulfate particles, as the radiation-resistant component, were incorporated into regenerated cellulose spinning solution. Then a series of X-ray radiation-resistant fibers were fabricated via a primarily industrialized wet-spinning trail, and the resultant fibers were knitted into fabrics by knitting loom. The morphology and structure of the fibers were studied with the aid of scanning electron micrography, Fourier-transform infrared spectroscopy, and X-ray diffraction. The composite fibers exhibited reasonably good properties, which met the criteria of mechanical requirements of commercial textiles—dry breaking strength and elongation (>1.5 cN/dtex and 26%) and wet breaking strength and elongation (>1.4 cN/dtex and 22%) and permanent laundry-resistant abilities even after being washed 20 times. An effective and feasible X-ray radiation-resistant method, the medical digital X-ray photography system, was proposed to evaluate the radiation resistance of the composite fiber and its fabric. The X-ray attenuation ratio of the sample tended to increase with increasing barium sulfate content and finally reached a dose of a 0.1 mmPb lead equivalent. Therefore, these fibers and fabrics can be utilized as the base materials for X-ray radiation-resistant lightweight apparel and detective surgical yarn. [ABSTRACT FROM AUTHOR]

Ductile appearance, remarkable length-diameter ratio, flexible fabrication properties and featured additional functions of functional composite fibers elicit great interest in applications. In this paper, chitosan/poly(vinyl alcohol) composite fibers with different graphene oxide additive (1-7 wt.%) were spun via continuous wet-spinning route and the resultant fibers revealed improved thermal, UV blocking and dye absorptive properties. In details, the component of fibers was characterized by SEM, TEM, FTIR, XRD and the results indicated that the graphene oxide dispersed well in chitosan/PVA matrix and the hydrogen bond was occurred between these components. As expected, the highest graphene oxide content case (7 wt.% GO) possessed the extraordinary UV blocking property as its UPF value reached to 500 arising from UPF=8.11 of 0 wt.% GO case. However, the composite fiber with 1 wt.% GO, rather than 7 wt.% GO, expressed the remarkable thermal stability and dye absorptive property, and the dye absorptive property of 1 wt.% GO showed the highest absorptive capacity of 407 mg/g among all the resultant fibers. [ABSTRACT FROM AUTHOR]

The main objective of this research was to construct accurate near-infrared reflectance (NIR) models of wood chemistry. Wet chemistry procedures and high-performance liquid chromatography methods were employed to analyze the chemical composition of southern pine. The NIR spectra were collected from 21 wood samples, which were milled down to different particle size classes. NIR calibration and prediction models were established using two modeling methods with different pretreatments. Furthermore, the spectrum range used in the NIR models was refined to achieve higher prediction accuracy. Results showed that NIR model precision could be improved considerably by decreasing the particle size to a very fine powder coupled with a targeted spectrum range. Superior prediction models for lignin and holocellulose content were constructed, while models for extractives and cellulose contents were also strong. [ABSTRACT FROM AUTHOR]