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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]

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]

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]

In the present paper, an Ir(III) complex of Ir(PD)(PBT) 2 was synthesized, where PD and PBT stand for pentane-2,4-dione and 2-phenylbenzo[d]thiazole, respectively. The molecular identity of Ir(PD)(PBT) 2 was confirmed by its single crystal. It was found that Ir(PD)(PBT) 2 belonged to monoclinic system with two molecules in each unit cell. Theoretical calculation on Ir(PD)(PBT) 2 suggested that the onset electronic transitions owned a mixed character of metal-to-ligand-charge-transfer and ligand-to-ligand-charge-transfer. By doping this complex into a polymer matrix of poly(vinylpyrrolidone) (PVP), the photophysical features of the resulting composite fibers were discussed and compared with those of Ir(PD)(PBT) 2 solution. It was found that the immobilization in PVP host could improve the photoluminescence performance by restraining the excited state geometric relaxation, showing higher emission energy, longer excited state lifetime and better photostability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Al 2 O 3 /ZrO 2 /La 2 O 3 nanofibrous membranes were fabricated via sol–gel electrospinning and calcination. • The small grain size of fibers improved the elastic and compressible properties. • Al 2 O 3 /ZrO 2 /La 2 O 3 nanofibrous membranes had an excellent elastic performance at 1400 °C and compressible performance at 1500 °C. Developing ceramic nanofibrous membranes for the thermal insulation layer of firefighting protective clothing is vital. However, previous ceramic nanofibrous membranes were brittle and easy to break during service in high-temperature environments. The lack of elastic and compressible properties has limited the high-end applications of ceramic nanofibrous membranes. In this work, elastic and compressible Al 2 O 3 /ZrO 2 /La 2 O 3 nanofibrous membranes were fabricated via sol–gel electrospinning and calcination in air at different temperatures. The as-fabricated Al 2 O 3 /ZrO 2 /La 2 O 3 nanofibrous membranes can maintain excellent elasticity and compressibility in the temperature ranging from −196 to 1400 °C. Moreover, they have low thermal conductivity and high working temperatures. These favorable characteristics make the Al 2 O 3 /ZrO 2 /La 2 O 3 nanofibrous membranes a promising candidate for the thermal insulation layer of firefighting protective clothing. [ABSTRACT FROM AUTHOR]

Abstract: Lotus fiber is a natural cellulose fiber isolated from lotus petiole. Botanically, the fiber is the thickened secondary wall in xylem tracheary elements. In order to obtain essential information for the preparation and processing of lotus fibers, the fine structure and properties of lotus fibers were investigated by the aid of transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), X-ray diffraction (XRD), and so on. The results show that lotus fibers display a rough surface topography and an internal structure different from common plant fibers. The percent crystallinity and preferred orientation of crystallites in lotus fibers are 48% and 84%, respectively. Considering the average breaking tenacity and Young''s modulus, lotus fibers are similar to cotton. The elongation of lotus fibers is only about 2.6% while their moisture regain is as high as 12.3%. [Copyright &y& Elsevier]

• Co@CHNFs were fabricated through coaxial electrospinning technique followed by a subsequent carbonization process. • Pt ACs were doped on MoS 2 nanosheets by thermodynamically induced spontaneous interfacial redox between MoS 2 and H₂PtCl₆. • The content of Pt ACs in the catalyst was 0.46 wt%, 43 times lower than commercial Pt/C (20 wt%). • The binder-free Pt-MoS 2 -Co@CHNF electrode achieves an ultra-high current density of 500 mA cm−2 in 1 M KOH seawater electrolyte. The application of layered molybdenum disulfide (MoS 2) in catalytic hydrogen production has attracted great interest, while their catalytic properties are limited by poor electron conductivity and a few catalytically active sites. In this work, we demonstrated a highly active electrocatalyst for large-scale hydrogen production, consisting of two-dimensional (2D) Pt-MoS 2 nanosheets along one-dimensional (1D) cobalt nanoparticle integrated carbon hollow nanofibers (Co@CHNF). The as-prepared Pt-MoS 2 -Co@CHNF had a large specific surface area (44.5 m2 g−1). X-ray photoelectron spectrometer (XPS) and spherical aberration corrected transmission electron microscope (AC-STEM) demonstrated that Pt atomic clusters (Pt ACs) were doped on MoS 2 nanosheets by thermodynamically induced spontaneous interfacial redox between MoS 2 and H₂PtCl₆. The Pt-MoS 2 -Co@CHNF based catalysts exhibited an overpotential as low as 91 mV for 10 mA cm−2 and 258 mV for 200 mA cm−2 in 1 M KOH electrolyte, and there is no significant floating for catalytic active with 14 h continuous operation, which demonstrates its excellent long-term operation durability, significantly superior to the previously reported state-of-the-art Co-based or Mo-based catalysts. In particular, the self-supporting binder-free Pt-MoS 2 -Co@CHNF catalyst-based electrode showed an ultra-high current density of 500 mA cm−2 at a low overpotential of 301 mV, without any decrease after 24 h operation at 500 mA cm−2 in 1 M KOH seawater electrolyte, representing a great potential for large-scale seawater hydrogen production. [ABSTRACT FROM AUTHOR]

Solar-driven hydrogen production is one of the most promising strategies for solar-to-hydrogen energy conversion. Compared to inorganic quantum dots (QDs), carbon quantum dots (C-dots) have attracted a lot of attention for optoelectronic devices due to their structure-dependent optical properties and green composition. However, the solar-to-hydrogen conversion efficiency of most of the photoelectrochemical (PEC) devices based on colloidal QDs is still low. Here we demonstrated a highly efficient and stable ecofriendly PEC device using C-dots sensitized TiO 2 photoanode, Pt loaded on carbon nanofibers as counter electrode, and glucose aqueous solution as electrolyte. The red-color C-dots were prepared using a solvothermal reaction, with an absorption spectrum ranging from 300 to 600 nm and a quantum yield (QY) of 50%. The C-dots have excitation independent photoluminescence peak positions and highly crystalline structure. The hydroxyl group on the C-dots can strongly interact with the TiO 2 , forming a very stable complex. Benefiting from these features, the PEC devices based on C-dots exhibit a saturated photocurrent density as high as ~4 mA/cm2 at 0.6 V vs. RHE and the device is very stable (keeping 95% of its initial value after 10-hour illumination upon 100 mW/cm2). This work indicates the promising properties of the C-dots/TiO 2 system, which holds huge potential for applications in the fields of optoelectronic and catalytic devices. [Display omitted] • The red C-dots have an excitation independent emission peak and highly crystalline structure with dominant energy levels. • A PEC device consists of C-dots/TiO 2 as photoanode, Pt/CNFs as CE, and glucose aqueous solution as electrolyte. • The PEC device exhibits saturated photocurrent density as high as ~ 4 mA/cm2 at 0.6 V vs. RHE and the device is very stable. [ABSTRACT FROM AUTHOR]

As a large-area solar radiation collector, luminescent solar concentrators (LSCs) can be used as power generation units in semitransparent solar windows, modernized agricultural greenhouses and building facades. However, the external optical efficiency and long-term stability of the LSCs limit their practical applications due to the sensitivity of the emitters to the light and environmental conditions. Here, we used the concept of "laminated glass" to prepare LSCs, which consist of two waveguide layers and the quantum dots (QDs)/polymer interlayer, and we tune the refractive index of the different parts of the system to improve the external optical efficiency and stability of the LSCs, simultaneously. The waveguide layer can be glass, quartz, polymethyl methacrylate (PMMA) and other transparent materials. The CdSe/CdS core/shell QDs were used as fluorophores to prepare the interlayer of the LSCs. The external optical efficiency of the laminated LSCs is associated with the refractive index of the three layers: the closer the refractive index, the higher the η opt. The highest external optical efficiency of 3.4% has been achieved for the laminated PMMA/QDs-polymer/PMMA LSCs, which improved ~92% compared to the single-layered CdSe/CdS based LSCs. To the best of our knowledge, this is the highest efficiency for the LSCs based on CdSe/CdS QDs. These results pave the way to realize high efficiency laminated windows as power generation units by suitably tuning the structure of the LSC, and provide the theoretical guidance for the LSCs utilized in building integrated photovoltaics. External optical efficiency of the laminated LSCs with different refractive index configuration. Inset is the photograph of the laminated LSCs based on CdSe/CdS QDs. Image 1 • We report refractive index-engineered laminated LSCs based on CdSe/CdS QDs. • The optical efficiency strongly depends on the refractive index configuration. • The laminated LSCs exhibits an optimal external optical efficiency of ~3.44%. [ABSTRACT FROM AUTHOR]

In this paper, the crystalline modification of isotactic polypropylene (PP) with a rare earth β nucleating agent (WBG) with different ultrasound conditions was investigated by scanning electron microscopy (SEM), wide-angle X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The relationship between the ultrasound conditions and the crystalline structure, as well as the mechanism for the behavior, were revealed. SEM showed that the dispersion of the nucleating agent in the PP matrix was better at shorter ultrasound distances. In addition, the higher the water cooling temperature, the better the nucleating agent was dispersed in the PP matrix. The results of XRD and DSC showed that the crystallinity and the relative content of the β-crystal were increased with nearer ultrasound distance, as well as increased in higher water cooling temperatures. In particular, under the same conditions, the crystallinity and the relative content of the β-crystal after ultrasonic treatment were much higher than those without ultrasound. [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]

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]

Highlights • In situ NMR monitoring provides insights into the reaction mechanism. • The bond energy trend of H/D exchange rates are clearly dependent on position on the ring for Ir, Pt, Ru. • The H/D exchange rates for MCP are listed as Ru>> Pd > Ir>>Pt at 110 °C. • Ru is a good ring-opening catalyst and effectively activates C C bonds and C H bonds. • Ru is effective for C C bond cleavage and shows a very fast H/D exchange for cyclohexane at 110 °C. Abstract One of the key challenges in studying the upgrading processes for the conversion of biomass is developing an understanding of the underlying conversion mechanism at the atomic scale. This study proposed an innovative high pressure in situ NMR monitoring approach for an isotopic traced upgrading process, which demonstrated a powerful capability to identify key products and provide insights into the reaction structure. The investigations for ring opening of two basic model compounds – methylcyclopentane (MCP) and cyclohexane (CH) on Ir, Pt, Ru and Pd/γ-Al 2 O 3 at 55 and 110 °C have been accomplished. For the study performed at 110 °C on Ir, Pt and Ru catalysts, the trend of H/D exchange rates were clearly dependent on the position on the ring with the highest exchange rate for the unhindered (or open side) and the lowest rate with the methyl group. However, Pd could perform almost equally efficient H/D exchanges for all sides, which may indicate that the "turnover" reactions could also occur on Pd. For both MCP and CH, Ru performed the most efficient H/D exchanges (C–H bond activation), and ring opened products were only observed with the Ru catalyst at 110 °C suggesting it is the most promising ring opening catalyst. [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]

Rabbit hair is an excellent textile fiber owing to its softness and luster. However, the poor spinnability of rabbit hair restricts its application on textiles. In this article, ionic liquid (IL) solutions were used to treat rabbit hair at five different temperatures. The raw and treated rabbit hair was then characterized by microscope, scanning electron microscope (SEM), mechanical property, XRD, and properties related to spininability (crimp and friction property, moisture regain, and electrical performance). The results showed that the rabbit hair fiber's morphology was obviously curled, and mechanical properties and crystallinity were reduced after ILs treatment. Moreover, the friction performance was increased by 15% and the crimp rate was increased by 7.2 times. These results suggest that with proper temperatures of ILs treatment, the rabbit hair could show better potential for spinning. [ABSTRACT FROM AUTHOR]