Chemical Fiber Research Articles

Harnessing microbes for self-healing concrete – A review

This review explores the burgeoning field of microbially enhanced construction materials, with a special focus on self-healing concrete, through the lens of microbial biotechnology. Central to this discourse is the innovative use of bacteria, particularly Bacillus species, to address the pervasive issue of microcracks in concrete, a fundamental material in the construction industry. Traditional remedies, such as chemical admixtures and fiber reinforcements, offer partial solutions; however, self-healing concrete represents a paradigm shift, harnessing the natural calcite-precipitating ability of bacteria to autonomously repair cracks, thereby augmenting structural durability and longevity. Delving into the mechanics, the bacteria, embedded within the concrete matrix, remain dormant until crack formation triggers their metabolic pathways, leading to calcite production that effectively seals the fissures. This bio-mediated repair mechanism not only enhances the structural integrity of concrete but also aligns with sustainable construction practices by minimizing maintenance requirements and material wastage. The review extends beyond self-healing phenomena, encompassing broader applications of microbial technology in construction, including bio-concrete, bio-cement, and soil stabilization methods. These applications underscore the versatility of microbes in enhancing material properties such as compressive strength, tensile resilience, and water impermeability. Empirical evidence underscores the necessity of optimizing bacterial dosages and curing conditions to maximize the self-healing efficiency. Future research trajectories should aim to elucidate the complex interactions between microbial agents and concrete matrices, assess long-term performance, and evaluate the environmental and economic sustainability of microbial interventions in construction. The integration of microbial technology in construction materials heralds a new epoch of innovation, offering robust, sustainable, and resilient solutions to enduring challenges in the industry.

TOʻQUV DASTGOHLARINING ASSORTIMENTLIK IMKONIYATLARI ASOSIDA KOʻNDALANG YOʻL-YOʻL NAQSHLI GAZLAMALARNING YANGI TURLARINI YARATISH MANUFACTURE OF NEW TYPES OF FABRICS

This article provides information on the reforms ongoing in the textile industry of the Republic of Uzbekistan to expand manufacturing from raw materials to finished products. Scientific research based on the broad use of the assortment capacities of existing weaving looms at weaving enterprises and the manufacture of fabrics with geometric patterns is being reviewed, too. Weaves for making striped fabrics were designed on Itema R9500 weaving looms, available at Suntex LLC. Test samples were produced using weft yarns of different linear densities and different fiber compositions based on the technological capacities of the modern weaving loom, shedding unit, multi-color unit, and electronic take-up motion. The operational properties of cross-striped test samples were studied and met the requirements specified in the international standard GOST 29223- 91 for chemical fiber shirts, shirts-suits, and suit cloths.

Evaluation of Chemical and Morphological Properties of Spruce Wood Stored in the Natural Environment.

This paper focuses on the changes in chemical structure and fiber morphological properties of spruce wood during 15 months of its storage in an open forest woodshed. From the chemical composition, the extractives, cellulose, holocellulose, and lignin content were determined. The pH value was measured on the wood surface using a contact electrode. Acetic and formic acid, saccharides (glucose, xylose, galactose, arabinose and mannose), and polymerization degree (PD) of cellulose were analyzed using the HPLC method. Fiber length and width were determined using a fiber tester analyzer. After 15 months of storage the content of both cellulose (determined by the Seifert method) and lignin did not change; the quantity of hemicelluloses decreased by 13.2%, due to its easier degradation and less stability compared to cellulose; and the pH value dropped by one degree. HPLC analyses showed a total decrease in the cellulose DP of 9.2% and in saccharides of 40.2%, while the largest decreases were recorded in the quantity of arabinose, by 72%, in the quantity of galactose, by 61%, and in the quantity of xylose, by 43%. Organic acids were not detected due to their high volatility during wood storage. The total decrease in average fiber length was 38.2% and in width was 4.8%. An increase in the proportion of shorter fibers, and a decrease in the proportion of longer fibers, was recorded. It can be concluded that fundamental changes occurred in the wood, which could affect the quality of further products (e.g., chips, pulp, paper, particleboards).

Chemical properties, crystallinity, and fiber biometry of Jabon (Anthocephalus cadamba) wood for pulp raw material: the effect of age and position

Abstract Jabon (Anthocephalus cadamba) is a promising plant species with straight, visually pleasing trunks that can be harvested at a young age as a resource for pulp and paper production due to the rapid growth rate possessed. Therefore, this study aims to investigate the chemical composition and fiber biometry of 3, 6, and 9-year-old Jabon wood, determining their suitability as a pulp and paper raw material. Samples were collected from both stem and branch sections and analyzed according to the Tappi standard. Fiber cell maceration was conducted to enable the precise measurement of fiber dimensions and derivatives. The results showed high cellulose, holocellulose, and lignin content in Jabon wood, with low to moderate levels of extractives and ash. Additionally, the crystallinity index (CrI) increased with age, particularly from 3 to 9 years old. The branch of the plant, with Grade II fiber derivative quality, had lower CrI compared to the stem, while the inner stem showed a lesser value than the outer part. In conclusion, 3-year-old Jabon wood is a potential raw material for pulp and paper production.

Investigation of Plant-Level Volatile Organic Compound Emissions from Chemical Industry Highlights the Importance of Differentiated Control in China.

The chemical industry is a significant source of nonmethane volatile organic compounds (NMVOCs), pivotal precursors to ambient ozone (O3), and secondary organic aerosol (SOA). Despite their importance, precise estimation of these emissions remains challenging, impeding the implementation of NMVOC controls. Here, we present the first comprehensive plant-level assessment of NMVOC emissions from the chemical industry in China, encompassing 3461 plants, 127 products, and 50 NMVOC compounds from 2010 to 2019. Our findings revealed that the chemical industry in China emitted a total of 3105 (interquartile range: 1179-8113) Gg of NMVOCs in 2019, with a few specific products accounting for the majority of the emissions. Generally, plants engaged in chemical fibers production or situated in eastern China pose a greater risk to public health due to their higher formation potentials of O3 and SOA or their proximity to residential areas or both. We demonstrated that targeting these high-risk plants for emission reduction could enhance health benefits by 7-37% per unit of emission reduction on average compared to the current situation. Consequently, this study provides essential insights for developing effective plant-specific NMVOC control strategies within China's chemical industry.

Occupational health risk for workers in the production of synthetic polyacrylonitrile fibers

The high proportion of workers in the chemical industry working in hazardous working conditions and the justification of measures to preserve their health are an urgent task in the field of protecting the health of the working population, however, aspects of the formation of occupational risks in the production of chemical fibers remain insufficiently studied. The article presents the results of prospective cohort comprehensive studies of working conditions and health status of 137 workers in the production of polyacrylonitrile fibers. The factors of the working environment (chemical, microclimate, noise), the severity and intensity of the labor process, the first identified and chronic non-infectious morbidity for 2017–2021 were studied. It has been established that workers work under the influence of a complex of factors harmful to their health, including chemicals of hazard classes 1–4 (acrylonitrile, methyl acryate, hydrocyanide, sulfuric acid, caustic alkalis, ethylene glycol, isopropyl alcohol), industrial noise, physical and neuro-emotional overloads, the levels of which, to varying degrees, exceed the hygienic standards, forming harmful working conditions (classes 3.1–3.4). In the structure of the accumulated chronic morbidity of workers, the leading ranking places belonged to diseases of the musculoskeletal system and connective tissue (24.3 %), the circulatory system (16.04 %), and the genitourinary system (15.0 %). As a result of the assessment of cause-and-effect relationships of health disorders with work, the production conditionality of diseases of the musculoskeletal system and connective tissue, represented by dorsalgia of various levels, of an average degree (RR = 1.893; EF = 47.183 %; CI = 1.192–3.007) was established. Quantitative assessment of group occupational risk corresponded to the category of «high risk» (4.780 × 10–2), indicating the need to reduce it to an acceptable level. The limitation of the study was the study of occupational risk factors for health disorders among employees of one enterprise. The results obtained were used to develop measures to reduce occupational health risks for workers in the production of synthetic polyacrylonitrile fibers.

A Study of the Properties of Mineral, Chemical, and Vegetable Fibers

A Study of the Properties of Mineral, Chemical, and Vegetable Fibers

Circular utilization of discarded oyster farming bamboo scaffolding in pulp and papermaking

Oyster Farming is one of important fisheries and aquaculture industries in Taiwan. Each year, approximately 4000–5000 tons of discarded bamboo scaffolding (BS) used in oyster farming, are generated, so the treatment and utilization of BS should be taken seriously. This study evaluates the suitability of BS for pulp and papermaking by assessing the chemical compositions, microstructural, and fiber morphology. The pulping properties is investigated by soda pulping. The chemical composition of BS shows the potential for application in pulping. The BS microstructure shows that can enhance pulping reactions, while the fiber morphology indicates the possibility of producing high-strength paper. Through the pulping experiment, it demonstrated that BS is suitable for pulping with lower NaOH dosage and longer digestion time. The condition at 170 °C with 14% NaOH dosage for 90 min digestion has the highest yield. After refining the highest pulping yield BS pulp, it can improve the handsheet strength and bulk of the OCC-BS mixed pulp, which can achieve the strength property required for industrial paper. In summary, BS exhibits the potential for pulping application and produces a better paper strength than OCC pulp, exhibiting the feasibility of enhancing the circular utilization value of BS in Taiwan.

Non-contact online inspection method for the appearance diameter uniformity of chemical fiber filaments

As chemical fiber filaments diameter variation directly affects spinning quality, spinning condition monitoring becomes more and more important in an intelligent manufacturing environment. Firstly, based on the single-slit Fraunhofer diffraction model and the Babinet principle, the non-contact filaments diffraction model is developed to generate diffraction fringe patterns by irradiating chemical fiber filaments with He–Ne laser. Secondly, for the characteristics of diffraction fringe patterns, a segmentation mask window-based diffraction fringe center of gravity extraction method is proposed, and a zero-phase Butterworth low-pass filter is designed and applied to the diffraction light intensity curves to accurately extract the extreme points positions of the adjacent dark fringe and calculate the diameter information. Finally, the non-contact chemical fiber filaments appearance diameter online inspection experiment platform is built to carry out static and dynamic experiments of filaments. The experimental results show that the maximum absolute value of absolute error is less than 1.1 μm for static measurement and less than 10 μm for dynamic measurement.

Drop-weight Impact Responses of Kenaf Fibre-Reinforced Composite-Metal Laminates: Effect of Chemical Treatment and Fibre Composition

Recently, fiber-metal laminates have gained high attention from material scientists and engineers, particularly when it comes to impact-critical applications. When compared to metallic alloys and composite materials, fiber-metal laminates offer several distinguishing advantages. This work intends to evaluate the low-velocity response of kenaf fiber-reinforced polypropylene metal-composite laminates with various fiber compositions, in line with the current trend of using natural fiber as possible reinforcement in composite materials. In addition, a comparison was made between the low-velocity impact response of non-treated and chemical-treated kenaf fiber-reinforced composite-metal laminates. A hot molding compression technique was employed to fabricate the laminates. Low-velocity impact tests were performed based on ASTM D7136 to determine the peak force, maximum displacement, and energy absorption of the materials. The results confirmed that NaOH treatment and increased fiber content resulted in a higher peak force of NaOH-treated kenaf-based metal laminates. For NaOH-treated laminates, the peak force of laminates with 70 wt% was found to be 11.20% higher than laminates with 50 wt% at the impact energy of 60 J. At fiber content of 70 wt%, the peak force of NaOH-treated laminates is 2.14% greater than that of untreated laminates when subjected to low-velocity impact with an energy level of 60 J. However, laminates with low fiber content and without NaOH treatment manifested higher maximum displacement and energy absorption due to the ductile behavior of such materials.

Possibilities of Sale Forecasting Textile Products with a Short Life Cycle

Almost 115 million tons of fibers comprising almost 90 million tons of chemical fibers were produced in the world in 2021, which are mainly used for the production of clothing and footwear. A total of 30% of textile and apparel products are never sold, which means extreme waste production. This article points out possibilities of forecasting the sales of clothing in the case of one relatively large online store. Inadequate stocks of textile products in the company lead to losses and overstock leads to the need to sell products at a discount, which is undesirable and not sustainable for the company. Therefore, the aim of this research is to design a forecasting system based on classical methods (with emphasis on seasonality) and its verification in practice. The results were verified directly with the real sale or with results from a model based on a neural network. The problem with textile products is that they have a short life cycle, i.e., the length of the life cycle is approximately half a year, and a high seasonality is also presented. Therefore, the seasonal indices and Holt–Winters methods (multiplication and additional approaches) were used for forecasting products. Ultimately, this model could contribute to reducing the loss of unsold goods and thus reduce the waste of resources and increase the use of goods in other similar companies.

Creating Nature-Inspired Surface Roughness and Modifying Surface Chemistry of PVDF Electrospun Fibers Using Low-Pressure Plasma towards Omniphobic Membrane for Long-term Distillation

Today, water scarcity as one of the world's most pressing challenges, has caused many concerns. Seawater desalination based on membrane distillation (MD) has been introduced as an effective solution to deal with this problem. The surface of membranes used in MD is required to be modified to guarantee long-term performance via creating resistance against membrane wetting by low surface tension feeds. In this regard, beetle skin-inspired roughness was created on the surface of poly(vinylidene fluoride) (PVDF) electrospun fibers using low-pressure plasma technique. Synergistically, 1H, 1H, 2H, 2H-perfluorooctyl acrylate (PFOA) was polymerized on the fiber surface to modify its chemistry. In other words, using the plasma polymerization technique, the membrane surface energy was reduced thanks to (1) the increase in membrane surface roughness and (2) the change in the membrane surface chemistry, as confirmed by field-emission scanning electron microscope (FESEM) imaging, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. These changes led to an omniphobic membrane repelling water, engine oil and isopropanol with contact angles of 150°, 135°, and 119°, respectively. The long-term performance of the developed omniphobic membrane was demonstrated by conducting air gap membrane distillation (AGMD) for a duration as long as 600 min using a feed solution containing 3.5 wt% NaCl and 0.6 mM sodium dodecyl sulfate (SDS), which is ten times better than the performance of pristine membrane (60 min). Overall, the surface modification technique considered in this work yields an omniphobic membrane with stable long-term performance without compromising the membrane flux and salt rejection.

Scalable fabrication of textile-based planar-structured supercapacitors with excellent capacitive performance

The researchers have been engaged in the development of textile-based high-performance flexible energy storage devices. The conventional fabrics are transformed into electrode composites by uniformly depositing polypyrrole (PPy) coating onto them using a simple interfacial solution polymerization method. The traditional textiles encompass cellulose fabrics such as cotton and ramie, protein fabrics like silk and wool, as well as chemical fiber fabric including polyester, polyamide, and acrylon. The PPy can be effectively coated onto the surface of cellulose fibers and penetrate into their interior, resulting in significantly higher loading capacity on cotton and ramie fabrics compared to other types of fibers. The two fabric electrodes (cotton@PPy and ramie@PPy) have better capacitive properties, especially the areal capacitance of ramie@PPy reaches 2836 mF cm−2. The PPy-coated fabric is precisely divided into standardized interdigital electrodes of consistent dimensions through the utilization of laser cutting techniques. The fabrication of a planar supercapacitor can be achieved through the straightforward assembly of two interdigital electrodes. The planar supercapacitor based on ramie@PPy shows a maximum energy density of 8.21 μWh cm−2 at power density of 0.20 mW cm−2. After undergoing 5000 cycles, the device demonstrates a remarkable ability to retain 90 % of its initial capacitance. The assembled supercapacitors exhibit exceptional flexibility and practicality, enabling power supply to electronic devices when connected in series. The fabric-based flexible supercapacitor can be easily mass-produced, making it a promising candidate for flexible energy storage devices.

Enhancing PANox fiber properties through controlled oxidation and tensioning: A study on shrinkage inhibition and structural analysis

PANOX fiber is a unique organic material used in high-performance applications such as automotive and aeronautics. It is a non-flammable, infusible, and non-drip fiber, obtained from the controlled oxidation of PAN. During this process, fibers tend to shrink. The resulting chemical composition and mechanical properties of the fiber are dependent on the time and temperature of the process, as well as on the tension applied to the fiber during oxidation. In this work, it was questioned whether fiber shrinkage could be prevented by applying tension to the bundle of fibers during the stabilization process and whether the effect of fiber length variation on the chemical structure and mechanical properties of PAN fibers could be studied. Chemical reactions were investigated by differential scanning calorimetry coupled with thermogravimetric analysis, Fourier-transform infrared spectroscopy, solid-state nuclear magnetic resonance spectroscopy, while strength and Young's modulus were determined by tensile tests. Results unravel a tension-applied, stabilization-process trade-off: enhanced stress reduces the yield of cyclization and dehydrogenation reactions. Fiber elongation inhibits these processes but boosts tensile strength and elastic modulus, particularly improving Young's modulus, however, it had a marginal influence on elongation at break. When the shrinkage of fibers was about 30 % (no stress applied) the tensile strength and Young's modulus were found to be the lowest values, 130 MPa and 4 GPa, respectively. The best compromise was found when the shrinkage was kept to about 5 %, resulting in improved strength of approximately 175 MPa and a modulus of 5 GPa. Therefore, effective tension management allows precise adjustment of PANOX fiber chemistry and mechanical properties, enabling tailored product design for diverse applications.

A machine-learning assisted multi-cluster assessment for decarbonization in the chemical fiber industry toward net-zero: A case study in a Chinese province

China has pledged to achieve carbon neutrality by 2060, requiring deep decarbonization in its manufacturing sector, aligning with sustainable development goals such as climate action and responsible production. Notably, China's chemical fiber industry contributes over 70% of global production, facing challenges in net-zero transition due to differences in enterprise scale and energy efficiency. This study proposed an assessment framework for the decarbonization pathway for this type of manufacturing industries, use the chemical fiber industry as a case study. A hybrid model based on machine learning was introduced to predict the industry's energy consumption, while multiple-cluster standards were established to assess energy efficiency improvement potential. Monte Carlo simulation was employed to analyze the carbon trading impact on industry decarbonization. Using a Chinese province's chemical fiber industry as a case, results suggest its carbon emissions could reach 1.58 × 107 tCO2 by 2030, and energy efficiency enhancements could reduce emissions by approximately 22.6%. Achieving carbon neutrality would cause the industry to reduce profits by approximately 10%∼15% on higher-priced emissions trading system (ETS), unless additional carbon reduction techniques are adopted. This assessment framework can be applied to study decarbonization transitions in other manufacturing industries.

Selective adsorption of heavy metal ions by different composite-modified semi-carbonized fibers

Highly efficient remediation materials can treat wastewater contaminated by heavy metals. In this study, semi-carbonized plant fiber (Spf) and chemical fiber (Spf) were prepared as the research material. Dodecyl dimethyl betaine and chitosan were used to singly modify semi-carbonized fibers (Sfs). Then, the single-modified Sfs were remodified by sodiumalginate to produce composite-modified Sfs. The microscopic morphology of the tested materials was studied by using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG) analysis, energy dispersion spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and specific surface area (SBET) detection. The selective adsorption effect of the tested materials on water polluted by multiple heavy metals was studied, and the effects of temperature, pH, and ionic strength were compared. SEM, FTIR, and TG results proved that single and composite modifiers were modified on the surface and changed the surface properties of Spf and Scf. The metal ion adsorption capacity of modified Spfs was higher than that of modified Scfs. The maximal adsorption capacity of metal ions on test materials presented the trend of Zn(II) > Cd(II) > Pb(II). The optimum adsorption conditions were 30 °C, pH = 6, and ionic strength of 0.1 mol/L, and the adsorption process was a spontaneous, endothermic, and entropy-increasing reaction. Electrostatic adsorption, precipitation, complexation, and ion exchange were the forms of adsorption for heavy metal ions. SBET and cation exchange capacity of the modified Sfs were the key factors that determine the adsorption capacity of heavy metal ions.

Experimental and Theoretical Study of the Interaction of a Low-Energy Ion Flow with Chemical Fibers

Experimental and Theoretical Study of the Interaction of a Low-Energy Ion Flow with Chemical Fibers

Protein fibers with self-recoverable mechanical properties via dynamic imine chemistry

The manipulation of internal interactions at the molecular level within biological fibers is of particular importance but challenging, severely limiting their tunability in macroscopic performances and applications. It thus becomes imperative to explore new approaches to enhance biological fibers’ stability and environmental tolerance and to impart them with diverse functionalities, such as mechanical recoverability and stimulus-triggered responses. Herein, we develop a dynamic imine fiber chemistry (DIFC) approach to engineer molecular interactions to fabricate strong and tough protein fibers with recoverability and actuating behaviors. The resulting DIF fibers exhibit extraordinary mechanical performances, outperforming many recombinant silks and synthetic polymer fibers. Remarkably, impaired DIF fibers caused by fatigue or strong acid treatment are quickly recovered in water directed by the DIFC strategy. Reproducible mechanical performance is thus observed. The DIF fibers also exhibit exotic mechanical stability at extreme temperatures (e.g., −196 °C and 150 °C). When triggered by humidity, the DIFC endows the protein fibers with diverse actuation behaviors, such as self-folding, self-stretching, and self-contracting. Therefore, the established DIFC represents an alternative strategy to strengthen biological fibers and may pave the way for their high-tech applications.

Multifactor Prediction of Ecological Indicators of Production of Chemical Fibers Based on Neural Networks

Multifactor Prediction of Ecological Indicators of Production of Chemical Fibers Based on Neural Networks

A Three-Dimensional Fiber-Network-Reinforced Composite Solid-State Electrolyte from Waste Acrylic Fibers for Flexible All-Solid-State Lithium Metal Batteries.

The large amount of waste chemical fiber textiles that exists has posed pressure on the sustainable development of the natural environment and of society. Therefore, it is of great importance to increase the added value of waste chemical fiber textiles and expand their applications in other fields. Herein, acrylic yarn from waste clothing is used as the raw material to construct a three-dimensional (3D) acrylic-based ceramic composite nanofiber solid electrolyte. The electrochemical properties of batteries based on this solid electrolyte are also investigated. We found that the fabricated composite electrolyte has good performance in lithium ion conduction and electrochemical stability because of its 3D acrylic-based ceramic composite fiber framework. The introduction of this composite electrolyte to a lithium symmetric battery enabled the battery to circulate stably for 2350 h at 50 °C without short-circuiting. In addition, all-solid-state batteries using a LiFePO4 cathode exhibited high reversible capacity. Lastly, a flexible lithium metal pouch battery was able to operate safely and stably under extreme conditions. This work demonstrates a strategy for upcycling waste textiles into ion-conducting polymers for energy storage applications.