Search

3D concrete printing (3DCP) has developed rapidly in recent years, with a relatively high amount of mortars emerging apt for 3D printing. Some of these mortars include fibers to improve their strength. Despite mechanical properties having been quite well studied, there still is missing information on cost, printability, and environmental impacts. The objective of this research is to select the best mortars with fibers considering four criteria: printability, mechanical strength, and economic and environmental impact applying a multi-criteria decision-making analysis (MCDMA). Seven types of fibers with different dosages were assessed in the reinforced mortars: zylon, aramid, carbon, glass, cellulose, textile, and polypropylene. AHP method and equal weights were used as ponderation techniques of the criteria while WASPAS and TOPSIS methods were used to calculate the rankings of the MCDMA. Printability was measured through rheological tests using a rotational rheometer, mechanical strength through flexural tests at 28 days based on EN 196–1, and cost just considering the materials and environmental impact through a life cycle assessment (LCA). The results showed that 13-mm-long glass fibers with a content of 0.1% were the best alternative, closely followed by the mortar with 6 mm cellulose fibers with a content of 0.05%. For the best option (G13;0.1), the increments in the printability index, flexural strength, cost, and LCA were − 14.37%, 16.70%, 5.88%, and 2.86%, respectively. It can also be concluded that high elastic modulus fibers (zylon and aramid), although able to increase significantly the flexural strength (up to 30% in the case of zylon), prevent them from being an optimal solution due to their high cost. [ABSTRACT FROM AUTHOR]

The study involves extracting and characterizing fibers from the Typha Domingensis Pers (TDP) plant for the development of bio-composite sheets. The mechanical extraction process yielded 9.3% fibers with a high cellulose content of 70.45 wt%. These fibers also had a thermal stability of 210 °C, making them suitable for withstanding high temperatures during the composite preparation process. Using the hand layup process, three variations of bio-composite sheets were made by mixing sodium alginate and paddy husk powder in different ratios. The sheets were then tested for the basic mechanical, absorbency, and biodegradability properties. The bio-composite sheet blend 2 (BC2), which contained 50% fibers and 50% matrix, showed the greatest tensile and flexural strengths of 242 and 292 MPa, respectively, with lower moisture absorption properties. All three bio-composite sheets exhibited 100% biodegradability. However, bio-composite 1 (BC1) showed significant biodegradability within 60 days. The study revealed that fibers from the invasive Typha domingensis Pers plant can be utilized to create biodegradable composites with desirable properties, making them suitable for use as green planters and other similar agricultural applications. [ABSTRACT FROM AUTHOR]

This paper examines the merits of using fibers derived from cigarette butts to enhance the performance of stone matrix asphalt (SMA). To this end, mechanical and environmental performances of SMA mixtures contained cigarette butt fibers were determined and compared with conventional SMA mixtures contained cellulose fibers. Two methods were applied to use cigarette butt fibers in mixtures included encapsulation with asphalt binder and mixing with hot asphalt binder for periods of three, five, and eight minutes. Performance tests included Marshall stability, asphalt binder drainage, moisture susceptibility, semicircular bending (SCB) at low and intermediate temperatures, wheel tracking tests, and toxicity characteristic leaching procedure (TCLP) were carried out on SMA mixtures contained different fibers. Mechanical test results showed that using encapsulated cigarette butts has detrimental effects on durability, low and intermediate temperature fracture resistance, and rutting performance in comparison with cellulose fibers. Nevertheless, utilization of cigarette butt fibers mixed with hot asphalt binder for 8 min improve water resistance, fracture characteristics, and rutting performance of SMA mixtures. Furthermore, by reducing the mixing duration of fibers with hot asphalt binder, moisture susceptibility and mechanical properties of mixtures were adversely impacted. TCLP test results revealed that utilization of cigarette butt fibers in SMA mixtures does not exhibit any environmental consequences. Finally, it was concluded that cigarette butt fibers mixed with hot asphalt binder for 8 min are good replacement for conventional asphalt binder stabilizers. [ABSTRACT FROM AUTHOR]

As increasing fiber hydrophobicity can significantly improve the paper dewatering process, we found that replacing SBKP and HBKP with 0.5% superhydrophobic CPGMA can significantly improve the dewatering of paper sheets. Therefore, it can be concluded that if CPGMA has little effect on paper properties, it will have potential industrial value in the papermaking industry. Consequently, it is necessary to further study the effect of the CPGMAs@CPAM/SiO2/APAM system on paper properties. To evaluate the application potential of the system in the papermaking industry, we investigated the effects of CPGMAs, which replaced the fibers in the stocks, on the paper properties in the CPAM/SiO2/APAM system. The findings demonstrate that as the CPGMA replacement increased, the paper's tensile strength, bursting strength, tear resistance, and folding endurance all declined. The trend can be segmented into two phases: a rapid decrease for substitution amounts below 0.5% and a gradual decline for substitution amounts exceeding 0.5%. When replaced with a small amount of CPGMAs, there was a negligible effect on these properties. Second, the paper air permeability increased with the CPGMA substitution amount in the stock. Furthermore, the trend of paper air permeability can be divided into two stages—a rapid stage with a substitution amount of <0.5% and a slow stage with a substitution amount of >0.5%. A small amount of CPGMAs could distinctly improve the paper's air permeability. Third, CPGMAs, which replaced fibers in the stock, minutely affected the paper formation. A small amount of CPGMAs substantially boosted the efficacy of the process of paper manufacture and certain characteristics of the paper, and it had a negligible impact on the strength of paper. The CPGMAs@CPAM/SiO2/APAM technology has the potential to improve the retention and filtration performance of CPAM/SiO2/APAM. [ABSTRACT FROM AUTHOR]

Haemorrhage control during surgery and following traumatic injury remains a critical, life-saving challenge. Cellulose products are already employed in commercially available haemostatic dressings. This work explores sourcing cellulose from sugarcane trash pulp to produce micro- and nanosized fibres with hydroxyl, carboxylic acid, and trimethylamine functional groups, resulting in either positive or negative surface charges. This paper assesses the influence of these fibres on multiple blood clotting parameters in both dispersed solutions and dry gauze applications. In vitro blood clotting studies demonstrated the significant haemostatic potential of cellulose fibres derived from sugarcane waste to initiate clotting. Plasma absorbance assays showed that the 0.25 mg/mL cellulose microfibre dispersion had the highest clotting performance. It was observed that no single property of surface charge, functionality, or fibre morphology exclusively controlled the clotting initiation measured. Instead, a combination of these factors affected clot formation, with negatively charged cellulose microfibres comprising hydroxyl surface groups providing the most promising result, accelerating the coagulation cascade mechanism by 67% compared to the endogenous activity. This difference in clot initiation shows the potential for the non-wood agricultural waste source of cellulose in haemostatic wound healing applications, contributing to the broader understanding of cellulose-based materials' versatility and their applications in biomedicine. [ABSTRACT FROM AUTHOR]

Cellulose nanofiber (CNF) is an advanced bio‐nanomaterial. However, the hydroxyl groups on the surface of CNFs are highly polar, leading to its weak interfacial compatibility with natural rubber (NR). Therefore, it is necessary to organically modify CNFs by silanization to improve the interfacial compatibility between CNFs and NR, which can then be used to prepare high‐performance CNF/NR composites. In this study, the effect of plasma‐activated pre‐silanization of CNFs on the vulcanization characteristics, mechanical properties, Payne effect, and dynamic mechanical properties of CNF/NR composites is investigated. The high‐energy impact of the plasma weakens the agglomeration of CNFs and increased the fiber surface roughness, providing a larger contact reaction area for the silanization reaction between the silane coupling agent and CNFs. The results show that the prepared CNF/NR composites have excellent physical and mechanical properties and processing safety. Compared with the unmodified CNF, its DIN wear increases by 4%, tensile strength increases by 23%, reinforcement factor increases by 7%, rolling resistance decreases by 6.3%, and Mooney viscosity decreases by 17.6%. Overall, this study presents a novel approach for the high‐value utilization of CNFs and the preparation of NR composites with exceptional properties, thereby establishing a solid foundation for the application of all‐steel treads. [ABSTRACT FROM AUTHOR]

Natural fibers are becoming a valid alternative to most commercially used synthetic fibers in sound absorbing materials. In recent years, natural fibers have been considered as valid raw materials for producing ecofriendly sound absorbing materials at low cost. This paper presents a new study on enset nanofiber sound absorbing material which was prepared by enzyme treatment and mechanical hammering of the surface of enset woven fabric. Enset nano fiber (ENF) was fabricated by defibrillation of underutilized abundant byproduct fibers from the surface of enset woven fabrics into micro and nano-scale fibers by alpha-amylase enzyme treatment and then mechanical hammering. The purpose of this approach is that the product will be economic and environmentally friendly and also consumption of eco-friendly products is a serious concern of researchers and policymakers. The study was conducted by using impedance tube method and the sound absorption properties of enset micro and nanofibers in a frequency range of 1000 to 6000 Hz were studied by changing the diameter, thickness and percentage of enzyme concentration during fiber treatments. Parameters for enset nanofibers were: number of board layers (single, double, triple and fourth-layer having sample thickness of 10–13 mm), fine fiber size (micro and nano meter), and fine fiber treatments content (10, 15 and 20% w/v), pressing time (10 min), board density (0.95 g/cm3), press pressure (40 kg/m2) and press temperature (180 °C) were held constant. The experimental results revealed that at the same frequency (4500 Hz), the sound absorption coefficient value was improved by 176 and 213% when neat enset fabric was treated and hammered with 10 and 20 w/v % concentration of amylase enzymatic respectively. The maximum sound absorption of neat enset fabric and enset nanofibers was recorded as 0.47 and 0.99 around 5351 Hz respectively. These results indicate that the acoustic property of enset fiber was improved by 47% when neat enset fiber was converted into green enset nanofiber forms by enzyme treatment and mechanical hammering. The experimental results shown that green synthesis of fine fibers from the surface of woven fabric improved the maximum acoustic peak values by 43% (microscale) and 59% (nanofiber) compared with macroscale enset fibers. These simple and cost effective green cellulosic enset nanofiber formations would have a promising result for small scale acoustic enterprises. [ABSTRACT FROM AUTHOR]

Black textile filaments having good mechanical strength and low water absorbency were spun from carboxymethylated cellulose cross-linked with amine functionalized carboxylated carbon nanotubes (afc-CNT). Incorporating 1 wt.% afc-CNT by crosslinking resulted in filaments with increased mechanical strength (tenacity ~ 1.2 cN/dtex) and a lower water absorbency (water absorbency ~ 0.62 g water/g fiber). The fabricated cellulosic textile filaments also demonstrated antibacterial activity and UV protection capability due to incorporation of afc-CNT. Excellent level of color fastness was achieved for the composite textile filaments because of a chemical bond formation between carboxymethylated cellulose and afc-CNT. [ABSTRACT FROM AUTHOR]

Paper cultural relics, as the carriers of human civilization, inevitably deteriorate during the long-term storage. The restoration of those damaged or aged paper cultural relics is an important part of cultural relics protection. How to obtain the fiber with high permanence property is the key to the repair paper used to cultural relic restoration. Herein, in order to obtain high permanence lignocellulosic fiber, nano-CaCO3 was introduced inside the Wikstroemia bast fiber by in-situ mineralization. Under accelerated aging condition, the microstructure, chemical structure, crystallinity, degree of polymerization, variation of pH, alkali reserve and mechanical strength of the fiber before and after mineralization were studied. The results showed that nano-CaCO3 had no obvious effect on the properties of paper prepared from those mineralized fibers, but it can effectively neutralize the acid generated inside the fiber, slow down the degradation rate of cellulose and improve the permanence of the paper during the aging process. It provides a new insight for the manufacture of repair paper for cultural relics restoration. [ABSTRACT FROM AUTHOR]

Controlling the liquid transport within cellulose-based materials is crucial for numerous applications, including printing, bio-assays, packaging, and cleaning. To control liquid transport and quality, post-processes such as calendering, a way of compressing and smoothen the paper using hard pressure rollers, and hydrophobisation, are commonly employed. To understand how these processes influence liquid uptake, this study uses an Ultra-Fast Imaging (UFI) NMR method to analyse moisture profiles during liquid uptake in various cellulose-based paper sheets with diverse levels of hydrophobisation and calendering. It is demonstrated that calendering decreases penetration speed and increases swelling. The reduction in penetration speed could be linked to a decrease in permeability upon calendering, as measured by the Gurley air permeance. Additionally, it is observed that hydrophobisation delayed and slowed down liquid uptake in the paper samples, and, in extreme cases, completely altered the liquid uptake phenomena. With substantial hydrophobisation, liquid penetration no longer proceeded with a well-defined liquid front but exhibited huge levels of fingering. Furthermore, is was observed that within highly hydrophobised paper, fibres were first prewetted, initiating a first swelling, before the pores between fibres could be filled. Subsequently, water could enter the pores between, allowing fibre bonds to be broken, leading to a second swelling of the paper sheet. The improved understanding will contribute to better control of the flow within cellulose-based materials, benefiting applications such as printing, packaging and microfluidics. [ABSTRACT FROM AUTHOR]

Purpose: This work introduces an integrated artificial intelligence schemes to enhance accurately predicting the mechanical properties of cellulosic fibers towards boosting their reliability for more sustainable industries. Design/methodology/approach: Fuzzy clustering and stacked method approach were utilized to predict the mechanical performance of the fibers. A reference dataset contains comprehensive information regarding mechanical behavior of the lignocellulosic fibers was compiled from previous experimental investigations on mechanical properties for eight different fiber materials. Data encompass three key factors: Density of 0.9–1.6 g/cm3, Diameter of 5.9–1,000 µm, and Microfibrillar angle of 2–49 deg were utilized. Initially, fuzzy clustering technique was utilized for the data. For validating proposed model, ultimate tensile strength and elongation at break were predicted and then examined against unseen new data that had not been used during model development. Findings: The output results demonstrated remarkably accurate and highly acceptable predictions results. The error analysis for the proposed method was discussed by using statistical criteria. The stacked model proved to be effective in significantly reducing level of uncertainty in predicting the mechanical properties, thereby enhancing model's reliability and precision. The study demonstrates the robustness and efficacy of the stacked method in accurately estimating mechanical properties of lignocellulosic fibers, making it a valuable tool for material scientists and engineers in various applications. Originality/value: Cellulosic fibers are essential for biomaterials to enhance developing green sustainable bio-products. However, such fibers have diverse characteristics according to their types, chemical composition and structure causing inconsistent mechanical performance. This work introduces an integrated artificial intelligence schemes to enhance accurately predicting the mechanical properties of cellulosic fibers towards boosting their reliability for more sustainable industries. Fuzzy clustering and stacked method approach were utilized to predict the mechanical performance of the fibers. [ABSTRACT FROM AUTHOR]

Controlled development of novel materials fosters innovation in the electrical sector. The hybrid materials based on magnetic nanocellulose are intriguing since they have many uses in electronics, catalysis, medicine, and ecology. The study investigated the structure and morphology of hybrid nanomaterials made from nanocellulose and cobalt ferrite. The nanocellulose was prepared by TEMPO-oxidation and the cobalt ferrite was prepared by sol-gel auto-combustion method. Using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques, it was determined how nanocellulose loading affected the crystal structure of the synthesized composite. To ascertain the variation in the component concentrations, scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDAX) are used. Composite with a higher concentration of nanocellulose fibers (NCF) show lesser particle size, and this may account for the smaller size of nanocellulose fibers, and attachment of nanocellulose nanofibers over the surface of porous cobalt ferrite (CF) found in SEM images. [ABSTRACT FROM AUTHOR]

The transient dimensional changes during hygro-expansion and hydro-expansion of freely and restrained dried, softwood and hardwood sheets and fibers is monitored, to unravel the governing micro-mechanisms occurring during gradual water saturation. The response of individual fibers is measured using a full-field global digital height correlation method, which has been extended to monitor the transient hydro-expansion of fibers from dry to fully saturated. The hygro- and hydro-expansion is larger for freely versus restrained dried and softwood versus hardwood handsheets. The transient sheet-scale hydro-expansion reveals a sudden strain and moisture content step. It is postulated that the driving mechanism is the moisture-induced softening of the so-called "dislocated regions" in the fiber's cellulose micro-fibrils, unlocking further fiber swelling. The strain step is negligible for restrained dried handsheets, which is attributed to the "dislocated cellulose regions" being locked in their stretched configuration during restrained drying, which is supported by the single fiber hydro-expansion measurements. Finally, an inter-fiber bond model is exploited and adapted to predict the sheet-scale hygro-expansion from the fiber level characteristics. The model correctly predicts the qualitative differences between freely versus restrained dried and softwood versus hardwood handsheets, yet, its simplified geometry does not allow for more quantitative predictions of the sheet-scale hydro-expansion. [ABSTRACT FROM AUTHOR]

Nicotiana rustica L. (NRL) is a type of tobacco plant, and its stalk waste is a potential lignocellulosic source for obtaining cellulose fibers freely available in nature. However, they are left in fields after harvesting, and this study provides a green and sustainable method to reuse tobacco waste. Fiber was obtained by retting the plant stalks in water and decomposing them naturally in three weeks. NRL fiber was characterized by comparing it with known bast fibers, and tests were applied to examine its physical, chemical, mechanical, morphological, and thermal properties. With its high cellulose content (56.6 wt%), NRL fiber had a high tensile strength (113.4 MPa) and a good crystallinity index (70%) that helped it to bond with other fibers in the composite matrix. Furthermore, the fiber is an environmentally friendly alternative to synthetic fibers with a diameter of 36.88 μm and low density (1.5 g/cm3). The NRL fiber was found to have a semi-crystalline structure and large crystalline size, which makes it hydrophobic. The thermal gravimetric analysis showed that it can be durable (353.9 °C) in higher temperatures than the polymerization temperature. As a result, it can be concluded that NRL fiber has the potential to be used as a reinforcement in polymer composites, technical textiles, and agricultural applications. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office 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 alkali/urea system is an economical and environmentally friendly solvent system for dissolving cellulose. However, the mechanical performance of cellulose derived materials (such as fibres or films) treated with alkali/urea must be improved. The capacity of this system for cellulose dissolution is limited and the mechanical properties of the regenerated cellulose fibres are still unsatisfactory. Here, cotton linter pretreated with peracetic acid (PAA) was dissolved in a LiOH/urea aqueous suspension in which Zn–Al layered double hydroxide (Zn–Al LDH) nanosheets (NS thickness = 3 nm) were exfoliated in situ. After wet spinning, the strength and toughness of the regenerated cellulose fibres reached 290 ± 7.66 MPa and 23.5 ± 4.40 MJ/m3 respectively, which were 66.7% and 150% higher than those without the LDH NS treatment. It is interesting to note that the synergistic effect of Zn2+ and Al3+ distributed on the surface of the LDH host layer significantly improved the solubility of cellulose at low temperature and the interaction between the cellulose and LDH NSs also improved the mechanical performance. This work provides a strategy for improving both the solubility of cellulose in the alkali/urea system and the mechanical properties of regenerated cellulose fibres. [ABSTRACT FROM AUTHOR]

In this study, sulfated cellulose pulps (SCPs), synthesized via environmentally friendly methods by supporting sulfamic acid and urea on wood-derived cellulose pulps (CPs), were used to prepare completely dispersed cellulose nanofibers (CNs). CP is a sustainable natural polymer that is biodegradable, nontoxic, and relatively inexpensive. Additionally, cellulose nanofibers prepared from CPs have attracted attention as promising natural nanofibers with various useful properties. Therefore, sulfation of CP with sulfamic acid and urea was investigated as a method for preparing completely dispersed CNs. The SCPs were synthesized in high yields through the sulfamic acid ≥ urea (molar ratio) reaction system at 393 K for 30 min. The SCPs contained sulfate groups with 0.79–1.33 mmol g−1 at hydroxy groups of C6, and C2 and/or C3 positions of cellulose, maintained long fibers and exhibited a 429–880 degree of polymerization (DP), retaining 60% more DP than the original CP. Some SCPs attained a maximum water retention value of approximately 3000%, suggesting a swollen fiber structure. Completely dispersed sulfated CNs with a fiber diameter of approximately 3–4 nm could be prepared by defibrating these SCPs. The swollen fiber structure observed in the SCPs reduced the defibrated energy and time required to achieve complete dispersion. [ABSTRACT FROM AUTHOR]

Flexible intelligent response devices are fabricated using several matrix materials. Among these, bacterial cellulose (BC) exhibits higher crystalline characteristics along with a higher degree of polymerization, elastic modulus, tensile strength, and water absorption. In this study, to further increase the response of fiber-based materials and expand their wearable applications, BC-based Janus fibers are prepared via wet spinning and used as fibrous intelligent response materials driven under photothermal stimulation. The BC-based Janus fibers exhibited excellent photothermal response with hydrophilic graphene oxide (GO)/BC as the actuation layer and hydrophobic graphene/BC as the supporting layer. When an infrared light was used to stimulate the GO side, the resulting dehydration and contraction of the GO side drove deformation. When the infrared stimulus was removed, the BC and GO quickly absorbed water and expanded owing to their favorable water-absorption properties. The material recovered its original straight shape, achieving reversible deformation. The experiment showed that the fibers prepared with 35 wt% GO and 100 wt% graphene exhibited a superior photothermal actuation performance compared to the BC fibers, GO/BC fibers, and graphene/BC fibers. When the actuation layer was exposed to infrared light for 27 s, the fibers started to bend upward along the illuminated section. After 55 s of exposure, the bending angle reached 135°. After the infrared light was turned off, the bent fibers returned to their original straight shape. [ABSTRACT FROM AUTHOR]

Cellulose derivatives are obtained from renewable sources, making them an environmentally friendly option in many industrial applications. Manufacturing fine cellulose fibers is confronted with multifaceted challenges due to cellulose's intricate nature, such as its highly organized structure and hydrogen bonding chain. In this study, for the first time, fibers in the nanometer to micrometer scale diameter from cellulose derivatives were successfully produced without the assistance of polymer precursors using the pressurized gyration (PG) technique. The cellulose derivatives investigated in this work were ethyl cellulose (EC) and cellulose acetate (CA), representing the ether and ester cellulose derivatives, respectively. Electrospinning (ES) technique was also used to compare the fibers produced by this technique with those produced by PG. Both PG and nozzle-PG succeeded in producing EC-based fibers with diameters ranging from 488 to 825 nm, with a higher production rate than ES. In contrast, ES succeeded in producing bead-free fibers from EC and CA with a wide range of solvent systems and concentrations. Scanning electron microscopy was used to analyze the fiber morphology, diameter distribution, and alignment. Additionally, Fourier transform infrared spectroscopy, x-ray diffraction, and differential scanning calorimetry were used to compare the physicochemical nature of the fibers produced by PG and ES. These tests revealed that the fibers produced from the two spinning methods had identical physicochemical structures and properties. With further research and development efforts, PG has the potential to be a promising technique for producing cellulose derivative-based fibers with a high production rate, which could be employed for applications in drug delivery, tissue engineering, and wound dressing. [ABSTRACT FROM AUTHOR]

The paper presents the new eco-friendly method of bleaching process of the cellulose fibre materials. Cellulose materials were bleached using hydrogen peroxide (both in aqueous solution, vapours, ozone and by the combined action of gaseous hydrogen peroxide and ozone. The method using hydrogen peroxide in aqueous solution presents the standard procedure and was used as the comparison technique. The bleaching processes using gaseous oxidants were carried out in a prototype device for dry, low-temperature treatment of fibrous materials with the use of oxidising agents in the gas phase. The influence of the innovative gas-phase bleaching method on the cotton samples' properties was analysed by Scanning Electron Microscopy (SEM), evaluation of the colour and whiteness, assessment of the polymerisation degree (DP), analysis of the mechanical properties and sorption capacity as well as microbiological assessment against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The comparison of the obtained results led to the conclusion that the bleaching processes using gas-phase agents—vaporised hydrogen peroxide, ozone or their combination—are non-invasive. The applied bleaching processes resulted in a slightly lower whiteness parameters than standard bath bleaching. After the bleaching processes with ozone and vaporised hydrogen peroxide separately, the decrease in the DP and tensile strength was similar to that observed after the bleaching with aqueous H2O2. When both processes were used together, a higher reduction in DP and tensile strength was noticed. Both oxidising agents showed a strong biocidal effect against bacteria. Gas-phase bleaching procedures, due to the lower temperature (35 °C vs. 98 °C) and minimal water consumption, have economic and environmental advantages, which allows their use in semi-industrial applications. It has been shown that the treatment of cotton fabrics using ozone and hydrogen peroxide in the gas phase allows to simultaneously obtain the bleaching and disinfection effect. [ABSTRACT FROM AUTHOR]

Nowadays, a high percentage (> 50%) of the paper produced in Europe uses recovered paper (secondary fibers) as raw material. In order to improve the mechanical properties of the paper produced, different kinds of additives are usually incorporated into the paper. Emerging renewable materials based on agricultural or forest residues, such as cellulose nanomaterials, have recently proved good capacities as reinforcing agents for different applications. In this work, pulp from wheat straw with a content of cellulose nanomaterial has been produced and tested as a mechanical reinforcing agent for paper production. A soda semi-chemical process was applied for the delignification of straw, to produce pulp with high cellulose content. Posteriorly, pulps with cellulose nanofibers were obtained in a high-pressure homogenizer, applying three different pretreatments to the cellulose pulp (acid hydrolysis, enzymatic hydrolysis and thermal treatment with glycerol) in order to facilitate the obtention of cellulose nanomaterial. Handsheets of paper were prepared from two sources of secondary fiber (fluting paper and old corrugated containers), adding different percentages of wheat straw derivatives (0, 3.5, 5 and 7%). The fibers' morphology and the papers' mechanical properties were investigated. Noticeable improvement rates (up to 25%) were observed for some mechanical properties of paper containing nanocellulose produced after the enzymatic and acid pretreatments. The quality of the secondary fibers source also affected the improvement rates achieved, with higher percentage changes for the lower-quality recycled paper. [ABSTRACT FROM AUTHOR]

A number of natural fibers are being proposed for use in composite materials, especially those extracted from local plants, especially those able to grow spontaneously as they are cost-efficient and have unexplored potential. Sansevieria cylindrica, within the Asparagaceae (previously Agavacae) family, has recently been considered for application in polymer and rubber matrix composites. However, its characterization and even the sorting out of technical fiber from the stem remains scarce, with little available data, as is often the case when the fabrication of textiles is not involved. In this study, Sansevieria cylindrica fibers were separated down to the dimensions of a filament at an 8-15 micron diameter from the stem of the plant, then characterized physically and chemically, using Fourier transform infrared spectroscopy (FTIR), morphologically by scanning electron microscopy (SEM), as well as their thermal degradation, by thermogravimetric analysis (TGA). Their crystallinity surface roughness was measured by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The results indicate over 70% cellulose fibers content with a very high crystallinity (92%) and small crystallite size (1.45 nm), which suggests a low water absorption, with thermal degradation peaking at 294°C. Despite this, due to the significant porosity of the cellular structure, the density of 1.06 g cm-3 is quite low for a mainly cellulose fiber. Roughness measurements indicate that the porosities and foamy structure result in a highly negative skewness (-3.953), in the presence of deep valleys, which may contribute to an effective relation with a covering resin. [ABSTRACT FROM AUTHOR]

In this paper, using Styphnolobium japonicum, Cryptomeria fortunei and Pinus yunnanensis as raw materials, cellulose (CE) was first extracted by chemical method (CM1) and biological enzymatic method 2 (BM2), and then further prepared into nanocellulose fiber (CNF) by biological enzymatic method 1(CPM (CPM stands for cellulase and pectinase)). The CE and CNF were characterized by FTIR, XRD, SEM, DSC and TG. The results showed that the CNF prepared by CM1-CPM was cellulose type II, CNF prepared by BM2-CPM was cellulose type I. The best crystallinity of the CNF prepared by CM1-CPM reached 74.1% (C. fortunei CNF), the best yield was 24.0% (S. japonicum CNF) and the minimum average diameter was 62.6 nm (C. fortunei CNF). However, the best crystallinity of CNF prepared by BM2-CPM reached 80.1% (C. fortunei CNF), the best yield was 27.4% (C. fortunei CNF), and the minimum average diameter was 31.6 nm (C. fortunei CNF). And also, the thermal degradation analysis of the CNF prepared from the three raw materials revealed that the CNF prepared by BM2-CPM had better thermal degradability. Finally, the thermal stability analysis of the C. fortunei CNF was carried out, and it was found that the residual mass of CNF prepared by BM2-CPM was 48%, while the residual mass of C. fortunei CNF prepared by BM1-CPM was 22%, which showed the C. fortunei CNF prepared by BM2-CPM had better thermal stability. Therefore, the properties of nanocellulose prepared by BM2-CPM are optimal. [ABSTRACT FROM AUTHOR]

In this study, Kozo fibres were fibrillated using the stone wet milling method and the wet atomisation method both deriving from nanocellulose production processes. Kozo fibres with a high degree of external fibrillation were obtained by using the stone mill wet grinding method. Although fibres exhibited the same structure as untreated Kozo fibres, their bonding properties improved. Applying the wet atomisation method, fibrillated Kozo fibres with different degrees of fibrillation were obtained depending on the number of treatments. Fibrillated Kozo fibres can be used in conservation as an adhesive for lining and other stabilisation treatments and may in certain cases replace starch paste, which is susceptible to microbiological damage. Only Kozo fibres and water were used in both mechanical fibrillation methods; therefore, the resulting material can be considered a safe alternative to more traditional adhesives. [ABSTRACT FROM AUTHOR]

Natural fibers extracted from plants are preferred as an alternative to synthetic products. The main reasons for this preference are their affordable cost, light weight and good mechanical properties. However, finding new natural raw materials is challenging due to growth limitations in different geographical areas. Platanus orientalis L. (Eastern plane tree) is a tree with abundant fruits that can grow in many regions of the world. The aim of this study was to determine the mechanical (tensile strength, tensile modulus, elongation), physical (density, fiber diameter) and chemical (cellulose, hemicellulose and lignin) properties of Platanus orientalis L. fruit's stem by fiber extraction from the stems of the tree. It was determined that the extracted fiber had good mechanical properties and cellulose content of 42.03%. As a result of thermogravimetric analysis, it was determined that the plane tree fruit's stem fiber had thermal resistance of up to 299 °C. The tensile strength value was 157.76 MPa, the tensile modulus value was 1.39 GPa and the elongation value was 22.01%. It was determined that it is suitable for use in fiber reinforcement in thermoplastic-based composites at temperatures below 299 °C. According to the results obtained by the mechanical, chemical and physical analysis of Platanus orientalis L. fruit's stem fiber (PoLfs), it could be recommended as a suitable alternative as a reinforcing fiber in thermoplastic and thermoset composites. [ABSTRACT FROM AUTHOR]

Recycled paper has become increasingly used as a raw material in the paper industry. However, hornification limits its application. Herein, the effect of recycling on the mechanical properties and microstructure of khasi pine pulp was systematically studied. The mechanical properties deteriorated and water retention value decreased after recycling. X-ray diffraction and Fourier-transform infrared spectroscopy revealed that cellulose crystallinity increased and partial cocrystallization occurred on cellulose microfibrils. Through the analysis of the morphology of secondary fibers by FQA, the loss of fine fibers caused by each reuse was found. Using the filtration method to prepare the recycled paper reduced the loss of fine fibers and improved the mechanical properties, with the tensile strength of a sample prepared using a sand core filter unit for five cycles (8.37 MPa) being like that of a sample prepared using a paper machine after one cycle. The investigation of the internal structure of the paper showed that the retained fine fibers were bonded between the long fibers, promoting the bonding between the fibers. Fine fibers improve the curling and twisting of fibers to some extent, especially in the first three recycling cycles. The hornification phenomenon of recycled paper was studied from the viewpoint of the fiber components, which is important to promote the development and application prospect of recycled paper. [ABSTRACT FROM AUTHOR]

Holocellulose fibers provide great potential to make paper with high performance. However, inappropriate reaction conditions may limit its improvement in paper performance due to the lack of sufficient research data. In this work, paper is prepared from the birch holocellulose fibers based on peracetic acid treatment and the papermaking process. The features of resulting holocellulose fibers are evaluated for different peracetic acid treatment conditions such as temperature and time. It reveals that high temperature and long treatment time lead to the degradation of hemicellulose/cellulose and the destruction of fibers, which further results in the poor mechanical performance of paper. By optimization for the treatment condition of holocellulose fibers, the corresponding paper exhibits the highest tensile strength (93 MPa), good bursting strength (601 kPa), and tearing strength (647 mN). The determination of optimum conditions will provide guidelines for the industrial production of holocellulose fibers and paper. [ABSTRACT FROM AUTHOR]

In view of the problem that the heat setting technology of Lyocell filament was not clear, Lyocell washed filaments were prepared by dry-jet wet spinning technology and the effects of heat setting tension, temperature and time on the mechanical properties and dimensional stability were investigated. The crystal, orientation and micropore structure of Lyocell filaments were analyzed by means of wide angle X-ray diffraction, small angle X-ray scattering and birefringence, and the relationship between structure and properties under heat setting was clarified. The results show that the moisture in the filaments can be removed when the washed filaments are heat-set at 100-130 °C for 3 min. During the heat setting process, the crystal structure of the filament changes little while the decrease of micropore size and the shrinkage of chain segments improve the densification and decrease the orientation degree. The mechanical properties cannot be weakened at the tension of 0.5-2.3 cN/dtex and the thermal shrinkage is lower than 0.7%. The heat setting with tension inhibits the disorientation of the cellulose segments effectively and keeps high crystallinity and high orientation of Lyocell filament, which guarantee both mechanical properties and dimensional stability of Lyocell filament. [ABSTRACT FROM AUTHOR]

Local defects in cellulose fibres, commonly referred to as microcompressions, increase the apparent strain to fracture in paper, an increasingly important parameter for products demanding stretch. This study presents an investigation into the origin of microcompressions by examining the behaviour of aspen wood under uniaxial compression applied along the grain, a process mimicking the action of a screw press and refiners during mechanical pulping. Using X-ray micro-computed tomography, a series of 10 tomograms with 30 µm of compressive deformation between images were acquired at 1.2 µm voxel size. For each tomogram, image analysis routines were developed to segment and label individual tracheids, vessel and ray elements, and track their motion between sequential frames. We classified the evolution of the axial trajectory of each element as either non-buckled or buckled, with a prominent presence of microcompression with axial deformations of less than 3%. We argue that microcompression precedes buckling. Significantly, we advance that localized deformation events (microcompressions, buckling, telescopic shortening) nucleate near vessel elements, and spread with increasing levels of compression; no particular structure appears to be immune to collapse. Finally, we liberated fibres in the compressed sample through chemical pulping and found that the damage occurring from compression was permanent. [ABSTRACT FROM AUTHOR]

Catechol formaldehyde resin microspheres with surface-distributed silver nanoparticles (Ag@CFR microspheres) were synthesized and then used as functional additives to fabricate antimicrobial viscose fibers (Ag@CFR/viscose fibers) through the wet spinning method. Ag@CFR microspheres showed high broad-spectrum antibacterial properties and presented low cytotoxicity on mammalian cells. With 0.1, 0.3, and 0.5 wt% additions of Ag@CFR microspheres in the viscose solution, all the viscose spinning solutions exhibited a little change in the viscosity and showed long-term stability without any sedimentation of the particles. With only 0.5 wt% additions of Ag@CFR microspheres, Ag@CFR/viscose fibers achieved high antimicrobial activities and severally presented a bacteriostasis and fungistatic rate of 99.6%, 99.4%, and 92.7% against E. coli, S. aureus, and C. albicans. Ag@CFR microspheres had very little influence on the mechanical and moisture absorption performance of the fiber. This work can provide an approach for the large-scale production of antibacterial viscose fibers and widen the application of Ag NPs in high-quality functional regenerated cellulose fibers. [ABSTRACT FROM AUTHOR]

Inverted nozzle-pressurized gyration was used as a processing methodology for regenerating cellulose extracted from Laminaria hyperborea for the first time. The viscoelasticity of cellulose/1-ethyl-3-methylimidazolium acetate (EMIM OAc) solutions exhibited high concentration dependence, leading to the production of cellulose products with diverse structures. The regenerated cellulose transitioned from thin films to fibers (≈ 5 μm diameter) as the concentration was increased. The impact of collection distance and working pressure on the morphology and yield of fibers was investigated. This work provides a new sustainable route for processing biopolymers, offering significant potential for applications in biomedicine and healthcare. [ABSTRACT FROM AUTHOR]

At a time of growing epidemic hazards caused by a very rapid evolution of dangerous pathogens, there is a pressing demand for bioactive textiles. Therefore, the development of high-quality knitted structures that could be used as bioactive protective materials has become a priority. This publication describes the fabrication of functional knitted structures from previously prepared antibacterial cellulose fibers containing nanosilica with immobilized silver nanoparticles. The structural and physical parameters of knitted fabrics made from them were studied with a view to their potential application in bioactive protective gloves. Tests of the basic structural and physical parameters of the knitted fabrics did not show that the nanomodifier applied in fibers significantly impacts the physical properties of the resulting fabrics. Moreover, water vapor permeability, cut resistance, and pH test results relevant to the functional and protective properties of interest and to user comfort showed that the obtained fabrics can be used in the production of bioactive protective gloves. [ABSTRACT FROM AUTHOR]

Cellulose, the most abundant biopolymer in nature, is derived from various sources. The production of pharmaceutical textiles based on cellulose represents a growing sector. In medicated textiles, textile and pharmaceutical sciences are integrated to develop new healthcare approaches aiming to improve patient compliance. Through the possibility of cellulose functionalization, pharmaceutical textiles can broaden the applications of cellulose in the biomedical field. This narrative review aims to illustrate both the methods of extraction and preparation of cellulose fibers, with a particular focus on nanocellulose, and diverse pharmaceutical applications like tissue restoration and antimicrobial, antiviral, and wound healing applications. Additionally, the merging between fabricated cellulosic textiles with drugs, metal nanoparticles, and plant-derived and synthetic materials are also illustrated. Moreover, new emerging technologies and the use of smart medicated textiles (3D and 4D cellulosic textiles) are not far from those within the review scope. In each section, the review outlines some of the limitations in the use of cellulose textiles, indicating scientific research that provides significant contributions to overcome them. This review also points out the faced challenges and possible solutions in a trial to present an overview on all issues related to the use of cellulose for the production of pharmaceutical textiles. [ABSTRACT FROM AUTHOR]

Alkali treatment followed by alkalinized hydrogen peroxide delignification yielded 73.90% cellulose from Ensete ventricosum pseudo stem fibre, with parameters optimized using response surface methodology. The optimal reaction parameters were 157 min, 73 °C, and 3.8% NaOH concentration. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transfer infrared (FTIR), and scanning electron microscopy were used to examine the thermal properties, crystal structure, chemical structure, and morphological structure of isolated cellulose (SEM). Based on the findings, cellulose has a rod-like shape. The XRD results revealed that the crystallinity index of cellulose increased from 65 to 75% when compared with raw E. ventricosum pseudo stem fibre (Ensete fibre). The resultant cellulose demonstrated relatively higher thermal stability than the unprocessed ensete fibre, according to the thermogravimetric examination. When compared to raw ensete fibre, FTIR analysis revealed that cellulose had a modified chemical functional structure, which suggested that alkali and alkalized hydrogen peroxide treatments had altered the chemical structure of cellulose. As a result of the isolated cellulose's high yield, high crystallinity index, good thermal stability, and morphological structure, cellulose nanocrystals can be extracted. Two step pretreatments were employed to extract cellulose from ensete fibre. Isolated cellulose characterized for it morphological, thermal, functional changes. Cellulose from ensete fibre exhibited good thermal, physical, chemical properties. X-ray diffractometer result depicted that cellulose from ensete fibre has good crystallinity. Cellulose extraction condition was optimized to obtain optimum yield of cellulose. [ABSTRACT FROM AUTHOR]

Considering the global burden of cigarette consumption, the disposal of cigarette butts has become an inevitable issue. Compared to traditional disposal methods, such as landfilling or incinerating, the recycling of these wastes is clearly an eco-friendlier solution. In this research, waste electronic cigarette butts (E-CBs) were collected and recycled in bituminous mixtures, aiming to increase the use of sustainable road construction materials. The objective of this research is to explore the possibility of using waste E-CBs as an alternative stabilising fibre in asphalt mixtures. To this end, shredded waste E-CBs were incorporated in Stone Mastic Asphalt (SMA) and compared with the conventional cellulose fibres. Furthermore, to investigate the effects of powders (below 0.063 mm) from the waste E-CBs on the rheological properties of bitumen, tests were conducted on base SBS-modified bitumen and its mastics. Results show that the waste powder was unfavourable to the thermal susceptibility of the resulting binder. SMA samples with shredded E-CBs were also characterised through physical and mechanical tests and compared to the reference mixture using cellulose fibres. It was concluded that using waste E-CBs in SMA can be considered a promising alternative for replacing cellulose fibres and avoiding the disposal of cigarette butts. [ABSTRACT FROM AUTHOR]

Hemicellulose-rich pulp raw materials are avoided in the production of man-made cellulosic textile fibres due to hemicellulose reactivity with the currently used industrial solvent systems. Incorporation of hemicelluloses in regenerated fibres could, however, increase the share of used wood biomass and thus improve the environmental footprint of regenerated fibre products. Superbase ionic liquids have shown potential in dissolving and regenerating all the major wood polymers i.e. cellulose, hemicellulose and lignin into regenerated products. In this work, regenerated fibres were spun from hemicellulose-rich softwood and eucalyptus paper-grade pulps and eucalyptus dissolving pulp using a superbase ionic liquid [mTBNH][OAc]. Before dissolution and spinning, intrinsic viscosities of the paper-grade pulps were adjusted either enzymatically or by using a mild acid-treatment to improve dope rheology for dry-jet wet spinning. In fibre spinning, hemicellulose was found to regenerate in high yield and the obtained regenerated fibres had high dry tenacities (5.3 to 15 cN/dtex). The best mechanical properties were measured from fibres with high hemicellulose content (17.3% (w/w)). Pulp pretreatment was found to be critical for achieving good mechanical properties. Acid-pretreatment, which modified both cellulose and hemicellulose, yielded regenerated fibres with better mechanical properties compared to an enzyme-pretreatment which did not alter the hemicellulose structure. Removal of hemicellulose substituents and hydrolysis of hemicellulose backbone in acid-pretreatment may be the key to improved mechanical properties in hemicellulose-containing regenerated fibres. Enzymatic peeling and imaging with a xylan-specific monoclonal antibody (CCRC-M138) suggest that hemicelluloses were enriched to the outermost layers of the regenerated fibres. [ABSTRACT FROM AUTHOR]

One of the critical challenges in the fiber-based packaging industry is to produce low-density paperboards with high functionality and attractive cost structure. In this study, we examine how control of the hierarchical fiber swelling can be used to enhance bonding and generate a low-density fiber network with excellent strength properties. Here, the osmotic pressure inside the cell wall is increased by adding phosphate groups with a deep eutectic solvent (DES) functional drying method. Together with mechanical refining, this process causes the fibril aggregates to split and swell up massively. This effect was measured by a novel thermoporosimetry analysis method. The treated fibers have enhanced external fibrillation, fibrillar fines and bonding potential. When mixed with relatively stiff, unrefined fibers, a well-bonded sheet with lower density than a conventionally refined reference sheet was achieved. The results suggest that pulp fibers can be "nanoengineered" to enhance performance without the complications of producing and adding nanocellulose. [ABSTRACT FROM AUTHOR]

Eco-unfriendliness of viscose process − the main producer of tire cord from wood cellulose − does not meet the growing need for creation of "green" tires. Alongside viscose cord fiber, production of a new cord fiber, Lyocell, from wood cellulose by eco-clean NMMO process is developing. Technical fibers were obtained from high-molecular flax cellulose by the method of its solid-phase dissolution in N-methylmorpholine-N-oxide. Comparative studies of the structure and mechanical and thermal properties of flax fibers and industrial cord fibers showed correspondence of their properties and that the stiffness of the flax fiber is almost 30 % higher than that of the cord fiber. Flax fibers are resistant to cyclic deformative actions and their deformation at high temperature is less than that of commercial samples. Water losses by the samples in the process of thermal studies at temperatures up to 170 °C have a reverse nature, which is confirmed by the stability of the mechanical properties of the samples under equilibrium conditions after thermal action. The obtained data set indicates sufficiently high fatigue strength of flax fibers and makes it possible to use them as cord fiber at par with cord fiber from wood cellulose. [ABSTRACT FROM AUTHOR]

Fiber demand of cellulosic fibers is rapidly increasing; however, these fibers are mainly based on the use of wood pulp (WP), which often have long transport times and, consequently, a high CO2 footprint. So, alternative pulps based on non-wood, annual fast-growing plants are an option to cover the demand for raw materials and resources. Herein, we report on the use of a novel developed hemp pulp (HP) for man-made cellulosic fiber filament spinning. Commercial WP was used as a reference material. While HP could be used and directly spun as received without any further pretreatment, an additional step to adjust the degree of polymerization (DP) was needed to use the wood pulp. Continuous filaments were spun using a novel dry-jet wet spinning (HighPerCell® process) technique, which is based on the use of 1-ethyl-3-methylimidazolium octanoate ([C2C1im][Oc]) as a solvent. Via this approach, several thousand meters (12,000 m–15,000 m) of continuous multifilament filaments were spun. The HP pulps showed excellent spinning performance. The novel approach allows the preparation of cellulosic fibers for either technical—with high tensile strength—or textile—possessing a low fibrillation tendency—applications. Textile hemp-based filaments were used for first weaving trials, resulting in a flawless fabric. [ABSTRACT FROM AUTHOR]

By virtue of remarkable biocompatibility and their promising applications in biomedical fields, biomass‐regenerated fibers, such as wool keratin fiber and cellulose fiber, have attracted extensive attention. However, the insufficient mechanical performance still hinders their yarn manufacturing capability and further large‐scale applications. Herein, an ultra‐strong and ultra‐tough regenerated wool keratin fiber by regulating keratin conformation with high‐quality small‐size graphene (HQSGr) and mechanical training treatment (M‐HQSGr‐RWKF) is fabricated. With the assistance of mechanical training, a small addition of HQSGr (0.1 wt.%) remarkably augments the secondary structure transition from α‐helix to β‐sheet of the keratin, which delivers a tensile strength of 215.4 ± 5.2 MPa, surpassing all reported natural wool and regenerated wool or even poultry fibers. Benefiting from the excellent mechanical strength, wet‐state toughness (158.9 MJ m−3), and recoverable strain (205.0%), M‐HQSGr‐RWKF has been demonstrated as a biocompatible artificial muscle to drive the biomimetic motion, which manifests ultrahigh actuation strain greater than 100.0% and stress of 16.7 MPa. The derived ultra‐strong and ultra‐tough keratin fiber opens a new avenue for developing smart fiber from biomass resources. [ABSTRACT FROM AUTHOR]

This article analyses high-consistency pulp refining using a disk refiner. During the experiment, the size of the gap between the rotor and stator cutters (0.5 to 1.5 mm), rotor speed (2,000 to 2,500 rpm), pulp consistency (10 to 20%), and freeness value (15 to 60 °SR) of the pulp were varied. The refining results were characterised by changes in 10 output parameters: morphological properties of cellulose fibres (average length, width, fibrillation index, water retention value, average kink angle, and coarseness) and the physical and mechanical characteristics of handsheets (breaking length, bursting strength, tearing resistance, and folding endurance). A total of 56 observations were made on the samples. Factor and cluster analysis methods were used to study the structure of correlations between the output parameters. More than 96% of the total dispersion of all output parameters was due to a change in two latent (hidden) factors: the first one was responsible for 79.6% of the dispersion and is presumably identified as the degree of external fibre fibrillation and the second one (16.6% of the dispersion) as fibre flexibility (including coarseness and average kink angle). [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant and "green" biomass resource on earth and gains tremendous attention. It is expected to become an alternative for traditional chemical and petroleum resources. This review describes the traditional solvents used for industrial processes, the non‐derivative organic solvents, and the aqueous solution systems, along with their dissolution mechanisms and development of fiber‐spinning processes. The problems associated with the industrial production of viscose fibers and cuprammonium fibers are also discussed. This paper focuses on the research status of regenerated cellulose fibers (RCFs) prepared with green and no‐pollution aqueous solutions and provides some effective strategies and methods for improving the mechanical strength of RCFs and promoting the implementation of industrial production. Lastly, the current developments of RCFs are summarized and prospected and it would serve as a guide for the developmental trend and research direction of RCFs in the future. [ABSTRACT FROM AUTHOR]

Brittle fracture initially occurs at the nanometric and/or interatomic scale without prior plastic deformation under elastic loading. Fibres of different dimensional scales in hybrid composites provide dense packaging and act as reinforcements in the corresponding scales and dimensions. This study evaluated the effect of the inclusion of cellulose pulp (CP) (5wt%, 4.5wt%, 4wt% and 3.5wt%) combined with cellulose nanofibrils (CNF) (0.5wt%, 1wt% and 1.5wt%) from recycled cardboard on the water absorption, density, dimensional stability, thermal insulation, flexural strength and durability of earth-based materials. The total cellulose content (CP and CNF) is set at 5wt%. The results show that the partial replacement of CP by CNF contributes to an increase in the moisture content of the composite from 18% to 21%, while there is a reduction in their dry shrinkage from 2.29% to 1.29% and in their thermal conductivity from 0.42 to 0.39 W/m.K. This is attributed to the different dimensional scales of the fibres in hybrid composites, which provide a dense assembly with greater dimensional stability. The 3.5% CP content combined with 1.5% CNF showed the highest flexural strength (2.76 MPa) and modulus of elasticity (1.93 GPa) of the hybrid materials under four-point bending loading, due to the high anchorage between the cellulose fibres and the matrix. CP and CNF as reinforcing agents in an earth-based matrix is a suitable solution for improving the flexural strength, density, dimensional stability and durability of building bricks. However, bricks reinforced only with CP are recommended where flexural strength and toughness are essential requirements. [ABSTRACT FROM AUTHOR]

The aim of this investigation is to evaluate the use of new lignocellulosic fiber extracted from Centaurea hyalolepis plant as a potential reinforcement for light-weight composite applications. In this study, anatomical structure and morphological surface of Centaurea hyalolepis fiber were conducted. The physical-chemical, thermal, crystalline,mechanical, characteristics of extracted fibers were also examined using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and tensile test. ATR-FTIR analysis confirmed the existence of the main components of lignocellulosic fiber (lignin, cellulose, and hemicellulose). XRD revealed the presence of cellulose with a crystallinity index of 57.93%.By densimetry, the density of Centaurea hyalolepis was determined as 1.13 g/cm3. The Centaurea hyalolepis was found to be thermally stable up to 271°C. The kinetic activation energy was determined as 115.943 kJ/mol. Tensile tests revealed that the mean tensile strength and Young's modulus of Centaurea hyalolepis fiber were about 372,5 MPa and 9.036 GPa respectively. Because of the dispersion in the experimental tensile results, the Weibull statistical analysis with two parameters was carried out. Regard these findings, the Centaurea hyalolepis fibers can be a suitable candidate for low density polymeric composites reinforcement. [ABSTRACT FROM AUTHOR]

The use of recycled aggregate concrete (RAC) in construction is one of the most effective ways to solve the environmental problems of concrete waste. The purpose of the present study is to improve the high-temperature resistance of RAC by incorporating hybrid cellulose and basalt fibers. The mechanical properties of the specimens with different volume fractions of cellulose and basalt fibers after high temperature were studied. Additionally, in order to study the degradation behavior of the specimens, the microstructure of interface between fibers and the cement matrix of RAC was examined by scanning electron microscope. Results show that hybrid fiber can reduce the explosive spalling and mass loss of RAC after being subjected to high temperatures. Compared with the brittle failure of RAC, the failure mode of hybrid fiber recycled aggregate concrete (HFRAC) was transformed into ductile failure under compression and splitting test. After high temperature, the compressive strength and splitting tensile strength of HFRAC were higher than those of RAC, and the cellulose–basalt fibers displayed an excellent synergistic effect on the mechanical properties of RAC. Among all the RAC specimens with different volume fractions of cellulose and basalt fibers, specimen hybrid with 0.15% cellulose fiber and 0.15% basalt fiber showed the best mechanical properties. Microstructure analysis research shows that small channels can be left in the matrix after the melting of cellulose fiber after elevated temperature, which improves the permeability of concrete and reduces the spalling damage of RAC. [ABSTRACT FROM AUTHOR]

The conditions for the synthesis of stable hydrosols of metallic silver in the presence of flax fiber extracts were studied by "green chemistry." It was proved that the synthesized sols can be used to impart the antimicrobial activity or biosecurity to cellulose-containing materials. The synthesis of ultrafine silver particles in the presence of accompanying natural impurities of flax fibers, isolated from them during high-temperature alkaline treatment, was studied by spectrophotometry, photon correlation spectroscopy, and visual observation. The effect of the composition of the extract on the dynamics of formation of stable silver nanoparticles was determined. It was proved by IR spectroscopy and potentiometric titration that increased alkalinity of the cooking solution leads not only to an increase in the amount of impurities in solution, but also to their destruction, and the resulting set of reducing substances formed in solution can act as a reducing agent for silver ions even at low extraction temperatures. It was also proved that the antimicrobial activity with respect to the test cultures of the synthesized sols and the cellulose tissue treated with them depends on the synthesis conditions. [ABSTRACT FROM AUTHOR]