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This paper evaluates the modification of fiber morphology and the strength property development of paper from Enset fiber as a function of soda pulping conditions and refining energy. Soda pulping was conducted at pulping temperatures between 160 and 180 °C. The NaOH charge was 16, 20, and 24% based on the initial raw material. The beating of pulp was conducted using a Jokro mill. The refining of pulp was conducted in a laboratory refiner at different refining intensities. The mild Jokro mill beating was not effective on Enset fiber pulp. On the other hand, the laboratory refiner effectively refined the pulp. The fiber morphology was altered in the way of improving the paper formation and strength. The beating degree of the pulp was increased to about 49 °SR. The tensile index was enhanced to around 80 Nm/g using a refining energy input of 250 kwh/t. From the results, it can be concluded that Enset fiber pulp is suitable for packaging papers due to its high strength level. On the other hand, Enset fiber can be a potential raw material for specialty papers like filter paper and tea bags because of its high porosity. [ABSTRACT FROM AUTHOR]

In the design optimization of fiber-reinforced composites, spatial material discontinuity is considered intractable within the manufacturing reality imposed by advanced technologies. This paper presents a topological optimization framework based on truss-like material to design composite structures with continuous fiber. Specifically, the fiber morphology at the scattered design points, which controls the orientation and volume fraction, is taken as design variables. Using the Shepard interpolant scheme, the fiber morphology at any given computational point is interpolated by scattered design variables within a certain circular influence domain. The employed interpolation inherently ensures the spatial continuity and range-restricted of the physical field in an element-independent manner. Since separating the design variable field and analysis mesh on two independent sets of points, this method is well suited for using a sparse design variable field. The computational savings are compelling due to the reduced number of design variables without significantly restricting the design freedom. Numerical instability such as checkerboard and mesh dependencies vanished as no intermediate densities are suppressed in optimization. The continuous fiber-reinforced composites (CFRCs) in the form of truss-like continua are ready to be manufactured with the aid of a simple post-processing. Several numerical examples are investigated to demonstrate the feasibility and effectiveness of the proposed formulation and numerical techniques. [ABSTRACT FROM AUTHOR]

Abstract The fiber index including fiber length, width, wall thickness and lumen diameter of Ferrocalamus strictus culms (1, 2, and ≥ 3 years) from Jinping, Mojiang and Lvchun counties of Yunnan Province was determined and the elemental content of the soil was also determined to analyze the fiber characteristics. The average relative fiber index measured for F. strictus culms were fiber length (1.30 mm), width (21.57 μm), slenderness ratio (60.79 μm), wall thickness (4.21 μm), lumen diameter (7.22 μm), and runkel ratio (1.22 μm), which belonged to the range of middle and long fibers. The fiber length increased with the culm age. The proportion of long fiber increased while short fibers decreased along with culm maturing. The fiber morphology did not show a specific trend with the culm height. Fiber length reached the maximum in the bottom portions of the culms. There is a correlation between fiber morphology and soil elements, the content of organic matter, total potassium, total sulfur, total aluminum, total zinc, total iron, total boron, alkali-hydrolyzed nitrogen and available silicon in the soil affects fiber morphology. The content of organic matter, total boron and alkali-hydrolyzed nitrogen in the soil from Mojiang County was largest. Comparatively, the culm fiber in Mojiang County had the best fiber index performance for utilization, since the greatest proportion of medium and long fibers and the optimal distribution of fiber length frequency was obtained from the culms in Mojiang County. This study can provide a theoretical basis for large-scale bamboo forest cultivation and the development and utilization of bamboo culm fiber.

Deseeded sunflower is a heterogeneous lignocellulosic biomass that has not been well utilized due to the incomplete understanding of its biological structure. In this study, deseeded sunflower was fractioned into the stalk rind, stalk pith, receptacle, bract, bractlet, leaf blade, and petiole, and their anatomy, cell morphology, and fiber dimension were studied using light microscope, environmental scanning electron microscope, and fiber quality analyzer. The results showed that the major fractions were the stalk rind and receptacle (49.4 wt% and 28.1 wt%, respectively) and each of the other fractions was less than 10 wt% of the total biomass. The pith was only composed of parenchyma tissue, and the other fractions were composed of epidermal, parenchyma, and vascular tissues. The arrangement and number of vascular tissues were different among fractions. The fiber length in the stalk rind was 0.823 mm, the width was 21.3 μm, and the aspect ratio was 38.6. The content of fiber fines in other fractions was higher than 50%, and these fractions should be developed for other uses. Fractionation was judged to be an effective way to achieve high value utilization of deseeded sunflower.

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The artificial cultivation and management were extensively carried out in Dendrocalamus brandisii stands. However, the influences of artificial management on the anatomical and chemical characteristics of the bamboo culms were unknown. In this study, the fiber morphology, chemical composition and sugar accumulation of the D. brandisii culms with management and without management were compared in order to determine the influences of artificial management on bamboo culms. The results indicated that artificial management had a significant influence on the fiber morphology, resulting in shorter fiber length, larger L/T ratio, and smaller W/Lu value. However, the management not only increased the contents of moisture, ash, SiO2, and extractive, but also increased the holocellulose contents and decreased the lignin contents, as compared to those without management. Moreover, the management significantly increased the endogenous carbohydrates storage in the culms so as to improve the shoot production. The bamboos under management conditions could still be utilized as a raw material for papermaking. This provided a theoretical basis for the artificial management of D. brandisii stands. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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 China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

Given the crucial role of periosteum in bone repair, the use of artificial periosteum to induce spontaneous bone healing instead of using bone substitutes has become a potential strategy. Also, the proper transition from pro-inflammatory signals to anti-inflammatory signals is pivotal for achieving optimal repair outcomes. Hence, we designed an artificial periosteum loaded with a filamentous bacteriophage clone named P11, featuring an aligned fiber morphology. P11 endowed the artificial periosteum with the capacity to recruit bone marrow mesenchymal stem cells (BMSCs). The artificial periosteum also regulated the immune microenvironment at the bone injury site through the synergistic effects of biochemical factors and topography. Specifically, the inclusion of P11 preserved inflammatory signaling in macrophages and additionally facilitated the migration of BMSCs. Subsequently, aligned fibers stimulated macrophages, inducing alterations in cytoskeletal and metabolic activities, resulting in the polarization into the M2 phenotype. This progression encouraged the osteogenic differentiation of BMSCs and promoted vascularization. In vivo experiments showed that the new bone generated in the AP group exhibited the most efficient healing pattern. Overall, the integration of biochemical factors with topographical considerations for sequential immunomodulation during bone repair indicates a promising approach for artificial periosteum development. The appropriate transition of macrophages from a pro-inflammatory to an anti-inflammatory phenotype is pivotal for achieving optimal bone repair outcomes. Hence, we designed an artificial periosteum featuring an aligned fiber morphology and loaded with specific phage clones. The artificial periosteum not only fostered the recruitment of BMSCs but also achieved sequential regulation of the immune microenvironment through the synergistic effects of biochemical factors and topography, and improved the effect of bone repair. This study indicates that the integration of biochemical factors with topographical considerations for sequential immunomodulation during bone repair is a promising approach for artificial periosteum development. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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 Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences 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.)

Poly(vinyl alcohol) is one of the most attractive polymers with a wide range of uses because of its water solubility, biocompatibility, low toxicity, good mechanical properties, and relatively low cost. This review article focuses on recent advances in poly(vinyl alcohol) electrospinning and summarizes parameters of the process (voltage, distance, flow rate, and collector), solution (molecular weight and concentration), and ambient (humidity and temperature) in order to comprehend the influence on the structural, mechanical, and chemical properties of poly(vinyl alcohol)-based electrospun matrices. The importance of poly(vinyl alcohol) electrospinning in biomedical applications is emphasized by exploring a literature review on biomedical applications including wound dressings, drug delivery, tissue engineering, and biosensors. The study also highlights a new promising area of particles formation through the electrospraying of poly(vinyl alcohol). The limitations and advantages of working with different poly(vinyl alcohol) matrices are reviewed, and some recommendations for the future are made to advance this field of study. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

The increasing use of wood in the forest industry and reduction of forest resources have prompted the paper industry to look for new materials. To this end, this study examined the biometric coefficients of the seven woody stems grown in different regions and investigated suitability for papermaking as an alternative to the use of wood. Wood samples of each species were collected from two different regions in Türkiye: the Kozan region, which has a Mediterranean climate, and the Yuvacık region, which has a mostly oceanic climate. The species included in the study were Phillyrea latifolia (mock privet), Arbutus andrachne (greek strawberry tree), Erica arborea (tree heath), Spartium junceum (spanish broom), Laurus nobilis (bay tree), Pistacia turpentine (cyprus turpentine tree), and Rhus coriaria (elm-leaved sumac). All fibers were classified as short. The longest fiber was observed for Spartium junceum (spanish broom) in Kozan. The fiber diameter was highest for Arbutus andrachne (greek strawberry tree) from Kozan, followed by Rhus coriaria (elm-leaved sumac) from Yuvacık and Laurus nobilis (bay tree) from Kozan. The fiber dimensions and the relationship between them were statistically analyzed. These included the slenderness ratio, flexibility coefficient, Runkel ratio, rigidity coefficient, Luce’s shape factor, F-factor, and Muhlsteph ratio. Although differences in fiber properties were detected between the two regions, it was determined that these were not enough to affect the desired properties for paper production. It was concluded that the fibers could be used in pulp, paperboard, and corrugated board production when mixed with long fibers.

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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 black (CB) is usually used to reinforce rubbers such as styrene-butadiene rubber (SBR). CB has sustainability and human health issues owing to its energy-intensive production process. Focusing on developing sustainable alternatives, bi-modal distributed cellulose fibers (CF) were used to partially replace CB. Cellulose fibers were pre-dispersed and surface modified and mixed with SBR matrices using internal and open rubber mill mixers. The properties of the prepared samples were measured and compared with CB/SBR counterparts. This study highlights the combined effects of CF bi-modality, surface modification, and pre-dispersion on dispersion quality, viscoelastic, curing, and mechanical properties. Our results showed that surface modification of bi-modal CFs and their pre-dispersion promoted dispersion by 15% and 12%, respectively. In comparison with CB as a common additive in SBR composites, the SBR samples filled with pre-dispersed modified bi-modal CF resulted in better dispersion, up to a 24% increase in tensile strength, a 50% improvement of modulus, and a 27% rise in tear strength. Given the sustainability feature of CFs, our results confirmed that the combined effects of pre-dispersed modified bi-modal CFs could be an industrially viable, cost-effective alternative to partially replace CB in SBR composites where the gains in strength are obtained by NFCs, and micro-fibrillated fibers are used to replace the additional NFCs for unrequired excessive strength. [ABSTRACT FROM AUTHOR]

The growing worldwide demand in the pulp market has fostered research that evaluates alternative fiber sources with specific characteristics that attend the needs of the consumer market, with a view to add value to the final product and reduce production costs. Acacia mearnsii De Wild wood is a by-product of the extraction of tannin from the trunk bark, used for firewood, charcoal and pellets. However, its wood is still poorly studied, especially its anatomical characteristics, which can provide important information about its industrial potential. This study evaluated the anatomical characteristics of Acacia mearnsii wood for the production of pulp and paper. Ten trees at approximately seven years old were cut down, five from the seed production area (SPA) and five from the clonal population area (CPA). From each tree, one trunk disc was sectioned at the diameter at breast height (DBH), resulting in 10 (ten) wood samples. From each disc, a sapwood specimen was made oriented in the tangential longitudinal, radial longitudinal and transversal planes, for later obtaining the anatomical cuts and the macerates. The anatomical description of the wood followed the recommendations of the International Association of Wood Anatomists-IAWA. From the dimensions of the fibers, their quality evaluation ratios for the production of pulp and paper were calculated. Results obtained from the anatomical characterization allowed to conclude that the Acacia mearnsii woods from SPA and CPA are indicated as a source of raw material for the pulp and paper production. [ABSTRACT FROM AUTHOR]

Quality attributes of tissue products establish important differentials in the current scenario of fierce competition. Although the formation of the tissue paper is not monitored in industrial processes, it is imperative to recognize its importance for developing quality properties. A theoretical analysis of influences of the fiber morphology and furnish composition on the prediction of mass distribution uniformity in the paper forming process is presented. The theory utilizes the Poisson distribution for the grammage probability of points on the sheet, taken as a random fibrous network. The simulations revealed that lower grammage coefficients of variation could be achieved with total or predominant addition of eucalyptus fibers in mixtures with Pinusfibers. The results provide meaningful insights into the understanding of how the selection of fiber type and pulp blend could help in achieving suitable structural uniformity of the sheet, in the forming process, in view of the expected paper quality. [ABSTRACT FROM AUTHOR]

The development of bamboo pulp has provided a solution for the pulp and paper industry to alleviate the shortage of forest resources. Bamboo pulp exhibits different properties from softwood pulp during the beating process, necessitating a deeper understanding of the morphological behavior of bamboo fibers to comprehend its beating characteristics. In this work, the fiber morphology and ultrastructure of kraft bamboo pulp were observed to investigate the special structure of bamboo fiber formation in the beating process. Bamboo fibers formed balloon-like structures at the collars of non-beaten fiber during the beating process, which resulted in the rapid shortening of the fiber in the early stage of beating due to strong shear force and transverse expansion. The formation of balloon-like structure was related to the multilayered structure of bamboo fiber, wherein each layer exhibited varying microfibril angles (MFA). The broad layer with a small MFA swelling results in an interlayer gap, which weakens the bonding force between the layers of bamboo fibers during beating and leads to flake peeling of the outer cell wall. Therefore, studying the formation mechanism and evolution of balloon-like structure is of great significance to the optimization of the beating process of bamboo pulps. [ABSTRACT FROM AUTHOR]

This study presents preparing and characterization of polyacrylonitrile (PAN) fibers containing various content of tetraethoxysilane (TEOS) incorporated via mutual spinning solution or emulsion using wet and mechanotropic spinning methods. It was shown that the presence of TEOS in dopes does not affect their rheological properties. The coagulation kinetics of complex PAN solution was investigated by optical methods on the solution drop. It was shown that during the interdiffusion process phase separation occurs and TEOS droplets form and move in the middle of the dope's drop. Mechanotropic spinning induces the TEOS droplets to move to the fiber periphery. The morphology and structure of the fibers obtained were investigated by scanning and transmission electron microscopy, as well as X-ray diffraction methods. It was shown that during fiber spinning stages the transformation of the TEOS drops into solid silica particles takes place as a result of hydrolytic polycondensation. This process can be characterized as the sol-gel synthesis. The formation of nano-sized (3–30 nm) silica particles proceeds without particles aggregation, but in a mode of the distribution gradient along the fiber cross-section leading to the accumulation of the silica particles either in the fiber center (wet spinning) or in the fiber periphery (mechanotropic spinning). The prepared composite fibers were carbonized and according to XRD analysis of carbon fibers, the clear peaks corresponding to SiC were observed. These findings indicate the useful role of TEOS as a precursor agent for both, silica in PAN fibers and silicon carbide in carbon fibers that has potential applications in some advanced materials with high thermal properties. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

Recent investigations proposed alternatives for utilization of Açaí (Euterpe oleracea Mart.) fruit wastes, seeds, and lignocellulosic fibers. However, Açaí leaves may also be obtained without harvesting the palms and could be used in higher value-added products. Alkali reaction (1% and 5% of NaOH), different temperatures (70°C, 80°C, and 100°C), and bleaching were combined to produce fibres from the Açaí leaves. Scanning electron microscopy, X-ray diffraction, and thermogravimetry were used to evaluate the effect of treatments on fibers, whereas X-ray diffraction and calorimetry were employed to characterize Portland cement pastes containing fibers. Results indicated that Açaí leaves could be transformed into short-length fibers with improved degrading temperature. Alkali treatment at 5% sodium hydroxide (90°C) and bleaching increased fibers’ crystallinity and showed efficiency in removing non-cellulosic components. Cement paste evaluation also indicated that fibers treated at 5% NaOH solution caused fewer changes in calorimetric profile and therefore present a greater potential for cement-based composites.

The properties of the fibers determine the quality of the pulp and, thus, the quality of the paper made from it. Recognition of properties, which fiber and paper pulp should be characterized by, in order to achieve required paper properties, is, therefore, a subject of research and interest of many papermaking research experts and scientists. Fibers are subject to deformation and possible weakening under the influence of chemical and mechanical factors, and therefore the quality of the fibers decreases each time they are used in production when it comes to recycled pulps. Then again, the key factor determining the quality of the primary fiber is the degree of pulp delignification. In the article, an attempt was made to define the impact of delignification of virgin pulp on morphological properties of fibers, and compare them with the properties of recycled paper pulp, in order to find correlations. The current economic and raw material situations in the wood market force one to seek new solutions to limit the use of virgin fibers, which is extremely important for the economy of the paper mill, environmental protection and raw material management. [ABSTRACT FROM AUTHOR]

Composite nanofibers with excellent physical and chemical properties are widely used in new energy, biomedical, environmental, electronic, and other fields. Their preparation methods have been investigated extensively by many experts. High-speed centrifugal spinning is a novel method used to fabricate composite nanofibers. The slip mechanism of polymer solution flows is an important factor affecting the morphology and quality of composite nanofibers prepared by high-speed centrifugal spinning. As the polymer solution flows, the liquid wall slip occurs inside the nozzle, followed by liquid–liquid interface slip and gas–liquid interface slip. The factors affecting polymer slip were investigated by developing a mathematical model in the nozzle. This suggests that the magnitude of the velocity is an important factor that affects polymer slip and determines fiber quality and morphology. Under the same rotational speed, the smaller the nozzle diameter, the greater the concentration of velocity distribution and the smaller the diameter of the produced composite nanofibers. Finally, PEO/PVA composite nanofibers were prepared using high-speed centrifugal spinning equipment at 900–5000 rpm and nozzle diameters of 0.2 mm, 0.4 mm, 0.6 mm, and 0.8 mm. The morphology and quality of the collected PEO/PVA composite nanofibers were analyzed using scanning electron microscopy (SEM) and TG experiments. Then, the optimal parameters for the preparation of PEO/PVA composite nanofibers by high-speed centrifugal spinning were obtained by combining the external environmental factors in the preparation process. Theoretical evaluation and experimental data were provided for the centrifugal composite spinning slip mechanism and for the preparation of composite nanofibers. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

Biobased and biodegradable polyhydroxyalkanoates (PHAs) are currently gaining momentum. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) polymer has a useful processing window for extrusion and injection molding of packaging, agricultural and fishery applications with required flexibility. Processing PHBHHx into fibers using electrospinning or centrifugal fiber spinning (CFS) can further broaden the application area, although CFS remains rather unexplored. In this study, PHBHHx fibers are centrifugally spun from 4–12 wt.% polymer/chloroform solutions. Beads and beads-on-a-string (BOAS) fibrous structures with an average diameter (ϕav) between 0.5 and 1.6 µm form at 4–8 wt.% polymer concentrations, while more continuous fibers (ϕav = 3.6–4.6 µm) with few beads form at 10–12 wt.% polymer concentrations. This change is correlated with increased solution viscosity and enhanced mechanical properties of the fiber mats (strength, stiffness and elongation values range between 1.2–9.4 MPa, 11–93 MPa, and 102–188%, respectively), though the crystallinity degree of the fibers remains constant (33.0–34.3%). In addition, PHBHHx fibers are shown to anneal at 160 °C in a hot press into 10–20 µm compact top-layers on PHBHHx film substrates. We conclude that CFS is a promising novel processing technique for the production of PHBHHx fibers with tunable morphology and properties. Subsequent thermal post-processing as a barrier or active substrate top-layer offers new application potential. [ABSTRACT FROM AUTHOR]

Despite the many existing fibrillation processes for the production of cellulose nanofibrils (CNFs), their exact destructuration effects on fibers remain poorly understood. This work reports the use of disk refining, twin-screw extrusion (TSE), ultra-fine grinding and homogenization for CNF production, alone or in combinations. The same raw material (birch fibers) and pretreatment (enzymatic hydrolysis) were used for comparable process conditions, with a systematic measurement of the energy consumption and a calculation of the process theoretical shear rates. The modifications of cellulose fiber and nanofibril properties were assessed by morphological analysis, optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), tensile tests and multi-scale quality index analysis. The water retention value (WRV) and degree of polymerization (DP) were also measured. All processes resulted in 8–14 nm-wide CNFs as well as larger CNF bundles. Residual fiber fragments were observed after refining and TSE. The latter resulted in the most significant decrease of crystallinity index (CI), DP and mechanical properties, while CNFs produced by ultra-fine grinding and homogenization displayed the best mechanical and optical properties. These processes were then combined with a preliminary disk refining step, to assess the influence of the morphology of the initial fibers on their fibrillation efficiency. Such combinations had a negative effect for TSE and homogenization. Lower properties were obtained for these samples, compared to CNFs produced by the processes used individually. In contrast, the combination of disk refining and ultra-fine grinding was found to greatly enhance the resulting CNF properties, with a significant increase in optical transmittance. These results provide an insight on the destructuration effects of each process, and pave the way to further research on the physical phenomena at work. The cellulose fibers destructuration effects of four mechanical fibrillation processes were evaluated in detail. The relevance or irrelevance of their combinations was assessed, the best results being obtained with processes with similar geometries. [ABSTRACT FROM AUTHOR]

This research investigates the formation progression of fibers with beaded and grooved structures, as well as the effect of electric field on jet motion and fiber morphology for three circumstances: no auxiliary electrode, 12 kV auxiliary electrode, and 18 kV auxiliary electrode. The observations discover that adding auxiliary electrode and modifying the voltage of the auxiliary electrode can influence the electric field in the jet area, affecting the fiber morphology. The auxiliary electrode with 12 kV voltage provides a uniformly distributed strong electric field in the jet area which can balance the jet's surface tension, generating bead-free fibers with a grooved structure on the surface. An increase of auxiliary voltage to 18 kV induces the linear section of the jet to enlarge, the whipping zone to narrow, and the instability of the jet, resulting in the reappear of the beaded structure as in the case without the addition of an auxiliary electrode. This research indicates that optimizing the electric field produces more delicate fibers and enhance fiber collection at a high production rate. Furthermore, the inhomogeneous and unstable electric field during the spinning process causes the fibers to develop a hierarchical structure. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) is one of the most attractive polymers with a wide range of uses because of its water solubility, biocompatibility, low toxicity, good mechanical properties, and relatively low cost. This review article focuses on recent advances in poly(vinyl alcohol) electrospinning and summarizes parameters of the process (voltage, distance, flow rate, and collector), solution (molecular weight and concentration), and ambient (humidity and temperature) in order to comprehend the influence on the structural, mechanical, and chemical properties of poly(vinyl alcohol)-based electrospun matrices. The importance of poly(vinyl alcohol) electrospinning in biomedical applications is emphasized by exploring a literature review on biomedical applications including wound dressings, drug delivery, tissue engineering, and biosensors. The study also highlights a new promising area of particles formation through the electrospraying of poly(vinyl alcohol). The limitations and advantages of working with different poly(vinyl alcohol) matrices are reviewed, and some recommendations for the future are made to advance this field of study.

The objective of this work is to systematically evaluate the performance of the hydrolysis-based kraft pulping process and associated pulp and black liquor characteristics. Acacia wood chips were auto-hydrolyzed under various severities, then the hydrolyzed wood chips were kraft pulping. The results indicated that the yield of pulp significantly dropped with intensifying the auto-hydrolysis severity. Meanwhile, the removal rate of pentosan reached 98.6% in the screened pulp at the P-factor of 1 000. The fiber length, fines and fiber crimp of the screened pulp were not affected by the auto-hydrolysis treatment. Auto-hydrolyzed pulps deteriorated fibrillation and beating response of the pulp in a refining process. However, fiber length and fines changed obviously after beating treatment. After auto-hydrolysis, the tensile index of the paper matrices decreased, some particle substances were found on the surface of the pulp fiber, and the solid and organic content of the black liquor were improved.

The main objective of this work was to explore the prospects of producing pulp and paper from leftover lignocellulosic fibers. In this study discarded Cocos nucifera fibers were collected from an abandoned site and were washed thoroughly. FTIR analysis, chemical composition and fiber morphology studies were conducted. FTIR showed the presence of holocellulose and lignin in the fibers. Chemical analysis showed the holocellulose content as 37.8 wt%. Fiber length, fiber diameter, lumen diameter and cell wall thickness were observed using microscope and derived fiber indices that determine the possibility of producing paper were evaluated. The derived indices such as Runkel index, slenderness ratio, co-efficient of rigidity, flexibility co-efficient, Luce’s shape factor and Solids factor of the fibers were evaluated as 67.9%, 44.11, 58.83%, 0.199, 0.49 and 278.53x103 respectively. All these indices are in good agreement with fibers recommended and used for pulp and paper production. High lignin content present in the fibers is a limitation and it can be removed through appropriate delignification techniques. Thus the study showed that discarded fibers can be used for producing pulp, paper and allied products.

The microstructural, morphological, chemical, pulp, and paper properties of four fast growing Thai bamboo species, Bambusa vulgaris, Bambusa longispiculata, Dendrocalamus membranaceus, and ×Thyrsocalamus liang, were characterized to evaluate their potential as alternative fibrous raw materials in pulping and papermaking. It was found that the chemical composition of the four bamboo species was not significantly different. The alpha cellulose, lignin, and ash contents were between 46% and 50%, 27% and 29%, and 2% and 3%, respectively. The average fiber length ranged between 1.74 and 2.16 mm and had long fibers similar to softwood fibers. The bamboo fibers were thick-walled, narrow, had a small lumen, and were rigid. The pulp yield of all the bamboo species, prepared by kraft pulping, was high between 45% and 50% and had a low rejection of 0.12–0.33%. The handsheets were prepared from the bamboo pulp using various beating time to develop strength properties. It was observed that the handsheet quality improved with increasing beating time. We conclude that these properties indicate a great potential for these bamboo species for pulp and paper production.

From the perspective of full-component utilization of woody fiber biomass resources, areca nut husk is an excellent woody fiber biomass feedstock because of its fast regeneration, significant regeneration ability, sustainability, low cost, and easy availability. In this study, fiber cell morphologies, chemical compositions, lignin structures, and carbohydrate contents of areca nut husks were analyzed and compared with those of rice straw, and the application potentials of these two materials as biomass resources were compared. We found that areca nut husk fibers were shorter and wider than those of rice straw; areca nut husk contained more lignin and less ash, as well as less holocellulose than rice straw; areca nut husk and rice straw lignin were obtained by ball milling and phase separation, and areca nut husk lignin was found to be a typical GHS-type lignin. Herein, the yield of lignocresol was higher than that of milled wood lignin for both raw materials, and the molecular size was more homogeneous. Tricin structural monomers were discovered in the lignin of areca nut husk, similar to those present in other types of herbaceous plants. Structures of areca nut husk MWL (AHMWL) and AHLC were comprehensively characterized by quantitative NMR techniques (that is, 1H NMR, 31P NMR, and 2D NMR). The molecular structure of AHLC was found to be closer to the linear structure with more functional groups exposed on the molecular surface, and the hydroxyl-rich p-cresol grafting structure was successfully introduced into the lignin structure. In addition, the carbohydrate content in the aqueous layer of the phase separation system was close to the carbohydrate content in the raw material, indicating that the phase separation method can precisely separate lignin from carbohydrates. These experimental results indicate that the phase separation method as a method for lignin utilization and structure study has outstanding advantages in lignin structure regulation and yield, and areca nut husk lignin is suitable for application in the same phase separation systems as short-period herbs, such as rice straw and wheat grass, and has the advantages of low ash content and high lignification degree, which will provide guidance for the high-value utilization of areca nut husk in the future. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

In response to deal with the increasingly serious environmental problems and shortage of fiber raw materials, biological enzyme pretreatment is an effective way to replace a large number of chemical additives to improve the properties of waste paper fibers. Fiber characterization of old corrugated container bleached pulp with laccase and glycine (Lac/Gly) pretreatment was investigated by means of Fourier transform infrared spectroscopy (FTIR), headspace gas chromatography (HSGC), fiber quality measurements (FQA), X-ray diffraction method (XRD), and atomic force microscope (AFM). Results showed that, compared with the control pulp, the whiteness and brightness of the Lac/Gly-treated pulp increased by 16.17% and 7.41%, respectively. And the FTIR showed that Lac/Gly pretreatment promotes the effective removal of lignin by hydrogen peroxide (H2O2) bleaching. The content of carboxyl groups in pulp increased remarkably by 21.92%. The paper physical analysis showed that the paper strength properties have improved remarkably. The fiber quality analyses indicated that the fiber length, coarseness, and curl index changed a little. The XRD analysis showed that the crystallinity decreased by 5.83% due to Lac/Gly treatment. The AFM analysis showed that through Lac/Gly treatment, the lignin and extracts over the fiber surface are decreased significantly. [ABSTRACT FROM AUTHOR]

The main objective of this work was to explore the prospects of producing pulp and paper from leftover lignocellulosic fibers. In this study discarded Cocos nucifera fibers were collected from an abandoned site and were washed thoroughly. FTIR analysis, chemical composition and fiber morphology studies were conducted. FTIR showed the presence of holocellulose and lignin in the fibers. Chemical analysis showed the holocellulose content as 37.8 wt%. Fiber length, fiber diameter, lumen diameter and cell wall thickness were observed using microscope and derived fiber indices that determine the possibility of producing paper were evaluated. The derived indices such as Runkel index, slenderness ratio, co-efficient of rigidity, flexibility coefficient, Luce’s shape factor and Solids factor of the fibers were evaluated as 67.9%, 44.11, 58.83%, 0.199, 0.49 and 278.53x10³ respectively. All these indices are in good agreement with fibers recommended and used for pulp and paper production. High lignin content present in the fibers is a limitation and it can be removed through appropriate delignification techniques. Thus the study showed that discarded fibers can be used for producing pulp, paper and allied products. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher 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.)

Recent investigations proposed alternatives for utilization of Açaí (Euterpe oleracea Mart.) fruit wastes, seeds, and lignocellulosic fibers. However, Açaí leaves may also be obtained without harvesting the palms and could be used in higher value-added products. Alkali reaction (1% and 5% of NaOH), different temperatures (70°C, 80°C, and 100°C), and bleaching were combined to produce fibres from the Açaí leaves. Scanning electron microscopy, X-ray diffraction, and thermogravimetry were used to evaluate the effect of treatments on fibers, whereas X-ray diffraction and calorimetry were employed to characterize Portland cement pastes containing fibers. Results indicated that Açaí leaves could be transformed into short-length fibers with improved degrading temperature. Alkali treatment at 5% sodium hydroxide (90°C) and bleaching increased fibers' crystallinity and showed efficiency in removing non-cellulosic components. Cement paste evaluation also indicated that fibers treated at 5% NaOH solution caused fewer changes in calorimetric profile and therefore present a greater potential for cement-based composites. [ABSTRACT FROM AUTHOR]

In this paper, two extraction methods for kenaf fiber, The chemical process and the enzymatic one, were performed. These processes were used to extract fibers from the kenaf stem and the chemical, mechanical and morphologic properties of the extracted fibers were investigated. We notice that the fiber diameter decrease when increasing the concentration of the enzyme and the time treatment (101,35 µm for Enz1 and 91,37 µm for Enz4) the same result is obtained for the chemical extraction when increasing the duration, temperature or NaOH concentration. Also the fiber crystallinity index is improved due to the elimination of the noncellulosic materials from the fiber. The results obtained show that we have an increase in this index for all treated fiber however it is more important for the chemical extraction (crude fiber 57.39%, chemical-treated fiber 71.93% and 66.70% for the enzyme-treated fiber). This increase explains also the increase of fiber tenacity and the decrease of strain and we found through the tensile test that kenaf fiber has a pure elastic behavior for all treated fiber. So, the properties of extracted fibers compared to the crude fibers prove that the enzymatic extraction preserves more the fiber structure than the chemical extraction.

ABSTRACT: The growing worldwide demand in the pulp market has fostered research that evaluates alternative fiber sources with specific characteristics that attend the needs of the consumer market, with a view to add value to the final product and reduce production costs. Acacia mearnsii De Wild wood is a by-product of the extraction of tannin from the trunk bark, used for firewood, charcoal and pellets. However, its wood is still poorly studied, especially its anatomical characteristics, which can provide important information about its industrial potential. This study evaluated the anatomical characteristics of Acacia mearnsii wood for the production of pulp and paper. Ten trees at approximately seven years old were cut down, five from the seed production area (SPA) and five from the clonal population area (CPA). From each tree, one trunk disc was sectioned at the diameter at breast height (DBH), resulting in 10 (ten) wood samples. From each disc, a sapwood specimen was made oriented in the tangential longitudinal, radial longitudinal and transversal planes, for later obtaining the anatomical cuts and the macerates. The anatomical description of the wood followed the recommendations of the International Association of Wood Anatomists-IAWA. From the dimensions of the fibers, their quality evaluation ratios for the production of pulp and paper were calculated. Results obtained from the anatomical characterization allowed to conclude that the Acacia mearnsii woods from SPA and CPA are indicated as a source of raw material for the pulp and paper production.

A hardwood dissolving pulp and bleached softwood Kraft pulp were subjected to continuous ultrasonic cavitation assisted TEMPO-mediated oxidation. The effects of such processing on the yield of carboxylic groups, morphological changes of the fibers as well as the effects on the final nanocellulose dispersion were studied. Ultrasonic cavitation in the TEMPO-mediated oxidation phase enhanced the yield of carboxylic groups on both pulps while having a negligible effect on materials losses due to fiber fines formation. The effect of ultrasonic cavitation was purely mechanical and acted as an additional high-shear mixer in the pre-treatment phase. As a result, the morphological changes on the fibers were enhanced, with additional swelling and fiber straightening being observed. Furthermore, the ultrasonic cavitation also influenced the properties of the nanocellulose dispersion obtained from subsequent microfluidization. The sonicated samples exhibited higher optical clarity, higher elasticity in gels while also having somewhat lower viscosities. On nanoscale, ultrasonic cavitation helped the subsequent microfluidization in releasing better individualized nanofibrils as they had smaller diameters than in non-sonicated samples. Sonication also had no effect on the crystallinity properties of the nanocellulose, the observed slight reduction was a result of intense microfluidization that was used to produce the nanocellulose dispersion. Ultrasonic cavitation in the TEMPO-oxidized pre-treatment phase was shown to be a method that can increase the throughput in lab-scale by mechanical activation of pulps and enabling shorter processing times for TEMPO-mediated oxidation. [ABSTRACT FROM AUTHOR]

The fumed silica influence on the morphology, coagulation processes, and rheological properties of suspensions in dimethyl sulfoxide (DMSO) and polyacrylonitrile (PAN)–DMSO solutions has been studied for the production of composite films and fibers. It has been shown that silica–DMSO concentrated suspensions (24 wt%) form a weak gel with a yield point of about 200 Pa. At concentrations of ~5 wt% and above the dispersions, depending on the shear stress, are pseudoplastic or dilatant liquids. It has been found that the silica addition method into a PAN solution has a significant impact on the aggregates dispersibility and the rheological behavior of the obtained systems. A thixotropy appearance and a sharp increase in the relaxation time were observed for PAN solutions at a SiO2 content of more than 3−5 wt%, which indicates the formation of structures with a gel-like rheological behavior. Upon reaching the critical stress their destruction takes place and the system starts to behave like a viscoelastic liquid. Two spinning methods have been used for preparing fibers: standard wet and mechanotropic. By the mechanotropic method it is possible to achieve a higher draw ratio at spinning and to obtain fibers with better mechanical properties. It is possible to spin fibers from PAN solutions containing up to 15 wt% of silica per polymer with a tensile strength up to 600 MPa. [ABSTRACT FROM AUTHOR]

Single-use face masks pose a threat to the environment and are not cost-effective, which prompts the need for developing reusable masks. In this study, pressurized gyration (PG) successfully produced bead-on-string polyvinylidene fluoride (PVDF) fibers with fiber diameters ranging from 2.3 μm to 26.1 μm, and bead diameters ranging from 60.9 μm to 88.5 μm by changing the solution parameters. The effect of the solution parameters on the crystalline phase was studied by Fourier-transform infrared spectroscopy (FT-IR), where the β-phase contents of PG PVDF fibers reached over 75%. The fiber morphology and β-phase contents of PG PVDF fibers indicated the potential mechanical and electrostatic filtration efficiency of PG PVDF fibers, respectively. Additionally, the hydrophobicity was investigated by static water contact angle tests, and the PVDF fibers showed superior hydrophobicity properties (all samples above 125°) over commercial polypropylene (PP) single-use masks (approximately 107°). This study supports the notion that the PG PVDF fiber mats are a promising candidate for future reusable face masks. [ABSTRACT FROM AUTHOR]

The electro-optical properties of the nanofibre/nanoparticle/polymer dispersed liquid crystals (PDLC) composite system were investigated. The nanofiber network was prepared by electrostatic spinning and introduced into the PDLC system as a carrier of nanoparticles. The effects of nanofibers and the doping of CeO2 nanoparticles on the PDLC system were investigated. It was found that the nanofibers had a significant impact on the response time of PDLC, while the nanoparticles could improve the contrast of PDLC very well. The fiber morphology, and the polymer mesh morphology, were characterised by SEM; the distribution of nanoparticles on the fiber was characterized by EDS. The experimental results show that nanofiber/nanoparticle doping can optimise the performance of PDLC and achieve low response time as well as high contrast in display applications. [ABSTRACT FROM AUTHOR]

The fiber morphology and extractive content of Aquilaria cumingiana (Decne.) Ridl. wood collected in Davao Oriental, Philippines were determined to gather pioneering information about the properties of A. cumingiana for better characterization and classification. Wood samples were classified according to color with the aid of a Nix Mini 1 Color Sensor and labeled as A, B, C, and D. The result of the study showed an increasing trend of color lightness percentage from samples A (32.74%) to D (74.96%). Morphologically, both samples C and D (1.03 mm) showed the longest fiber, sample A showed the largest fiber (35.41 µm) and lumen diameter (27.77 µm), and sample C showed the thickest cell wall (4.71 µm). On the other hand, the highest Runkel ratio, slenderness ratio, and flexibility ratio were shown in samples B (0.49), C (33.00), and A (78.13), respectively. The amount of extractives obtained in the study decreases from samples A to D regardless of the solvents used. Statistically, the color lightness, morphological properties, and extractive content were significant across sample classifications. Among solvents used, the extractive content showed a significant result. The color lightness and extractive content showed a negative relationship, which signifies that the color lightness may be used to evaluate the amount and quality of extractives in A. cumingiana wood. Based on the morphological properties, A. cumingiana fibers are found favorable in pulp and paper production. The classification and characterization of A. cumingiana wood properties along the infected portions of a tree and chemical profiling of the extracts would be relevant information to consider. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) capture and storage is a fundamental global environmental issue that has driven researchers to develop ingenious strategies to overcome this issue. Herein, N-enriched nanoporous carbon fibers were prepared from commercially available polyacrylonitrile fiber through a one-pot simultaneous carbonization/activation strategy. The effect of the amount of the activating agent and carbonization temperature on the nanoporous/surface chemical properties of carbons and the consequent CO2 adsorption performance was fully investigated. This direct activating strategy protected the fiber morphology of the resulting nanoporous carbons, while also resulting in a well-developed porous structure. The as-prepared nanoporous carbon fiber shows the maximum Brunauer–Emmett–Teller surface area and total pore volume of 2330 m2 g–1 and 1.25 cm3 g–1, respectively, together with a nitrogen content of up to 14.36 wt %. The optimal nanoporous carbon fiber exhibited CO2 uptakes of 6.16 and 4.03 mmol g–1 at 1 bar and 0 and 25 °C, respectively, with an acceptable CO2/N2 selectivity of 23. Besides, the optimal sample depicts a dynamic CO2 capture capacity of 0.84 mmol g–1 and only a 3% CO2 uptake capacity loss after five adsorption–desorption cycles. Overall, the combined effect of narrow microporosity and nitrogen functionalities determined the CO2 uptake of this series of N-doped nanoporous carbon fibers. [ABSTRACT FROM AUTHOR]