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In this study, a wet spinning method was applied to fabricate regenerated cellulose fibers filled with low graphene loading which was systematically characterized by SEM, TEM, FTIR and XRD techniques. Subsequently, the mechanical and thermal properties of the resulting fibers were investigated. With only 0.2 wt% loading of graphene, a ∼ 50% improvement of tensile strength and 25% enhancement of Young's modulus were obtained and the modified Halpin-Tsai model was built to predict the mechanical properties of composite fibers. Thermal analysis of the composite fibers showed remarkably enhanced thermal stability and dynamic heat transfer performance of graphene-filled cellulose composite fiber, also, the presence of graphene oxide can significantly enhance the thermal conductivity of the composite fiber. This work provided a facile way to improve mechanical and thermal properties of regenerated cellulose fibers. The resultant composite fibers have potential application in thermal insulation and reinforced fibrous materials., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

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]

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]

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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]

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]

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]

Abstract: Nelumbo nucifera (Nn.) fiber is the isolated secondary wall of the Nn. leafstalk Tracheary elements which has a unique shape. As the shape of the fiber may strongly affect the industrial uses especially for textile usage, the morphology and structure of Nn. fiber at different growth stages were investigated by several techniques in the present work. The Nn. fiber has spriral morphology with cellulose I structure. The diameter of mature fiber is about 4μm and the cross-section shows elliptical or slightly oval shape without lumen. These findings aim to deeply understand the structure of Nn. fiber which is expected to be helpful to bring Nn. fiber into industrial use. [Copyright &y& Elsevier]

The pyrolytic behavior of several biomass components including cellulose, hemicellulose, lignin, and tannin, from two sources of waste biomass (i.e., pine bark and pine residues) were examined. Compared to the two aromatic-based components in the biomass, carbohydrates produced much less char but more gas. Surprisingly, tannin produced a significant amount of water-soluble products; further analysis indicated that tannin could produce a large amount of catechols. The first reported NMR chemical shift databases for tannin and hemicellulose pyrolysis oils were created to facilitate the HSQC analysis. Various C–H functional groups (>30 different C–H bonds) in the pyrolysis oils could be analyzed by employing HSQC-NMR. The results indicated that most of the aromatic C–H and aliphatic C–H bonds in the pyrolysis oils produced from pine bark and pine residues resulted from the lignin and tannin components. A preliminary study for a quantitative application of HSQC-NMR on the characterization of pyrolysis oil was also done in this study. Nevertheless, the concepts established in this work open up new methods to fully characterize the whole portion of pyrolysis oils produced from various biomass components, which can provide valuable information on the thermochemical mechanisms. [ABSTRACT FROM AUTHOR]