Cellulose最新文献

High-strength composite hydrogels “cellulose–polyacrylamide” were synthesized by free-radical polymerization of acrylamide conducted inside the previously formed physical network of regenerated plant cellulose. Partial hydrolysis of the amide groups of these hydrogels yielded their ionic forms with a degree of hydrolysis of 0.1 and 0.25. The cylindrical hydrogel samples of three compositions were implanted in the preformed osteochondral defects of the rabbit’s femoral knee joints. No signs of migration or disintegration of the tested implants were revealed in the course of in vivo tests as long as 90 and 120 days after the implantation. The mechanical behavior of hydrogel samples-implants before implantation and after their removal from the joints of laboratory animals was studied in detail. The morphology and chemical composition of the removed implants were studied by SEM combined with the EDX method. The results showed that the mechanical characteristics of hydrogel implants remained practically unchanged after in vivo tests. The removed implants, as well as the initial hydrogels, endured cyclic compression loading at the amplitude up to 50%. Compression stresses up to 3–10 MPa were recorded in these tests, which is close to the data obtained by several authors for natural articular cartilages in the same conditions of loading. The principal differences in the chemical composition and morphology of the implant area adjacent to the subchondral bone for non-ionic and ionic types of implants have been revealed. For non-ionic implants in this area intensive mineralization with formation of calcium phosphates inside the polymeric hydrogel network is observed, while the border area of ionic implants practically does not undergo mineralization.

Use of by-product waste from farm products to prepare clinical dressings is a resource-saving and eco-friendly approach. In this research, a series of pH-sensitive hydrogels constructed with oxidized microcrystalline cellulose from pineapple peel, quaternized chitosan from hericium erinaceus residue and gelatin were prepared based on Schiff-base reaction.The structures of the prepared hydrogels were characterized by FT-IR, XRD and SEM. Absorption peak at around 1656 cm⁻¹ (due to –C = N–) appeared and peak at 1726 cm⁻¹ disappeared of the hydrogel confirmed occurrence of Schiff-base reaction. XRD and SEM results showed the composite hydrogels are compatible and well cross-linked. A series of experiments were performed to investigate the blood clotting activity and physicochemical property. It was found that the composite hydrogels show shrink and expansion behaviors under different pH environments, and exhibited adjustable in swelling ability (up to 4383%), water evaporation rate, gel time and mechanical property as change of gelatin content. Oxidized microcrystalline cellulose/quaternized chitosan/gelatin (OMQCS-G) hydrogel showed well coagulation effect and controlled release of the loaded naringin. Naringin release of OMQCS-G5 reached more than 70% within initial 6 h, suggesting the potential of the prepared hydrogels used as wound dressing.

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The brief preparation processes of OMQCS-G hydrogel and used as wound dressing. The oxidized microcrystalline cellulose (OMCC) and quaternized chitosan (QCS) is obtained from pineapple peel residues and hericium erinaceus residues after extraction and modification, the gelatin is from pig skin. Then the OMCC/QCS-G hydrogel is formed via Schiff-base reaction, applied for drug delivery and blood clotting.

Achieving a fabric with good mechanical performance and breathability is significant for the development of protective clothing. The leno structure is a desirable fabric design for enhancing these properties due to its advantageous characteristics, such as flexibility, lightness, diamond-shaped structure, and increased yarn interlacing. However, there is a lack of studies focused on developing novel leno structures because of the difficulty of weaving and exploring the mechanical behavior and breathability of various leno fabrics with different structural characteristics. In this study, we leveraged advanced weaving techniques with improved needle-shaped heald frames to develop a programmed mesh-like four-warp leno cotton fabric that offers outstanding mechanical performance and breathability. The efficacy of the self-locking effects, achieved by manipulating the yarn interweaving to simultaneously regulate yarn friction and fabric porosity, is experimentally demonstrated. Compared to plain structures of the same density, the four-warp leno (FL) fabric exhibits nearly twice the tensile strength and strain in the warp direction. Additionally, the four-warp leno fabric demonstrates greater displacements to reach the junction rupture force point than plain structure of the same density in the yarn pull out tests, owing to the self-locked interweaving of the warp yarns. The yarn pull-out behavior of the FL was analyzed to illustrate the variation in load and displacement. Moreover, the high porosity of the four-warp leno woven fabric results in excellent air permeability, thermal conductivity, and water vapor transmission. This study provides an effective strategy for designing and fabricating four-warp leno fabric with outstanding mechanical performance and breathability for diverse applications.

In this study, sustainable and eco-friendly route for production of 3D printable phosphorylated cellulose (PC) gel was developed using low-cost agro-based chemicals followed by in situ growth of MoS₂ via hydrothermal treatment. The rheological studies show PC gel with incorporated salts exhibited shear-thinning behaviour with excellent 3D printability. The produced PC gel contains covalently modified phosphate groups with high surface charge, providing sites for electro-static interaction of salts and growth of MoS₂, as confirmed by FTIR and XPS spectroscopy studies. XRD and Raman spectroscopy studies confirmed the high loading of MoS₂ with mixed 2H/1 T phase and cellulose II structural transformation during hydrothermal treatment. Interestingly, the developed 3D-printed PC-based MoS₂ structures show simultaneous photodegradation and microbial decontamination capabilities with high recyclability (~ five times). The optimized PCMo0.5% exhibited efficient photodegradation (~ 82–99%) of high concentration of methylene blue (MB) dye (50–500 mg/L) with maximum degradation capacity of 202.97 mg/g. The developed PCMo0.5% also showed a band gap of 1.30 eV and ~ 82.6% of DPPH scavenging activity. It also displayed a strong antibacterial response against Gram-positive Escherichia coli and Gram-negative Staphylococcus aureus with a distinct zone of inhibition. Most importantly, easily scalable 3D printable PC-based MoS₂ structures demonstrated continuous mode photodegradation and microbial decontamination, making it promising for the potential remediation of real wastewater at large volumes for practical applications.

Solid mechanochemistry, as an environmentally sustainable technology, is widely applied to prepare functional materials, but suffers from some issues such as limited reaction from short exposure time and low reactivity within the solid phase. Here, we proposed a combined approach of mechanochemistry and surface-confined reaction to facilitate cellulose phosphorylation. Specially, cellulose with 4 wt% H₂O are mixed together to form a hydration layer on the surface followed by a conventional ball milling treatment. The confined-water layers, as a reaction medium, could not only cause location ionization of hydroxy groups in cellulose to reduce the activation barrier, but also immobilize phosphorylating agents on the cellulose surface, facilitating the phosphorylation process. As a result, the phosphorylated cellulose demonstrated a high degree of substitution of approximately 0.087. To this end, the potential of the phosphorylated cellulose as a promising flame-retardant, was demonstrated in wood pulp paper and polyvinyl alcohol film. This study highlights the promoting effect of confined water on the mechanochemical phosphorylation of cellulose, and can also be extended to preparation of functional cellulose.

This study focuses on using agricultural straw—specifically sugarcane bagasse—as the raw material and employs single-factor optimization and response surface modeling strategies to develop a low-temperature NACO pulping process. A mathematical prediction model was constructed to explore the leaching patterns of chemical components in sugarcane bagasse, reveal the reaction mechanism of selective lignin removal through the new oxygen-alkali synergistic approach, and elucidate the green pulping mechanism of the low-temperature NACO method. The research findings indicate that at a temperature as low as 114.3 °C and a Na₂CO₃/ NaOH mass ratio of 1.86, the paper pulp exhibits optimal performance, with a freeness yield of 52.83%, a viscosity of 675.77 ml/g, a whiteness of 40.95% ISO, and a kappa number of 19.85. At this condition, only 43.96% of the silicon element enters the black liquor. Response surface variance analysis shows that the studied variables have statistically significant effects on different response levels, with all correlation coefficients (R²) greater than 0.93, indicating that the model has good predictive capability for the low-temperature NACO pulping process. Finally, the paper produced from the pulp under the optimal conditions exhibits excellent physical properties, with a tear index of 4.9 kPa·m²·g⁻¹, burst index of 3.8 mN·m²·g⁻¹, tensile index of 70.9 N·m·g⁻¹, and ring crush index of 11.6 N·m·g⁻¹, which are 1.9, 1.8, 1.6, and 2.3 times, respectively, compared to the performance of paper made by traditional oxygen-alkali chemical pulping methods.

This study focused on exploring the optimal pretreatment conditions of FeCl₃-catalyzed organosolv pretreatment by response surface methodology (RSM) and adding additives to reduce the adverse impact of lignin, thus boosting the enzymatic hydrolysis of corn stover. Results showed that the optimum glucose yield after 24 h (29.8 g/100 g raw material) was achieved at 175.9 °C, 19 min with 77.7 mmol/L FeCl₃ catalyzed organosolv pretreatment, representing 87.4% of total glucose in native corn stover. This enhancement was attributed to the structure alteration, which removed ~ 100% hemicellulose and 83.5% lignin. Furthermore, the influence of different additives on enzymatic hydrolysis was investigated, and the results suggested that Tween 80, PEG 6000, pepton and calcium lignosulfonate (CL) exhibited superior performance in improving glucose yield under low-solid and high-solid loading enzymatic hydrolysis. With the addition of PEG 6000 under 1/2 reduced enzyme loading, the highest glucose yield at 2% (w/v) and glucose concentration at 30% (w/v) reached 87.9% and 181.4 g/L (involving 8.3 g/L oligomer glucose), respectively. Further prolonging the hydrolysis time, the increased glucose yields with additives were strengthened, especially in enhancing the oligomer glucose during high-solid loading enzymatic hydrolysis.

The use of mineral-based fillers in papermaking is a widely studied area due to their ability to enhance paper properties and reduce steam consumption during the drying stage of paper production. However, a significant challenge with high filler addition rates is the poor retention of these fillers within cellulose fibers. To address this issue, various studies have explored filler surface modifications. In this study, xylan (XS), which is readily available from pulp refining and is also environmentally friendly, renewable, sustainable, biodegradable, and biocompatible and is applied as a chemomechanical pulp-strengthening agent for papermaking was cationized through quaternization, and the surface of precipitated calcium carbonate (PCC) was modified accordingly for use in papermaking. The physical and chemical properties of paper samples containing modified PCC were compared to those with unmodified PCC. Results showed that the filler retention capability of the modified PCC was superior to that of unmodified PCC in cellulose fibers. The mechanical and optical properties of hand-sheet papers were also enhanced when filled with modified PCC, which is attributed to the improved compatibility between the cationic XS on the PCC surface and the cellulosic fibers. Enhanced mechanical and optical properties in the paper samples confirmed these improvements. Additionally, Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetry (TG), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and Field-Emission Scanning Electron Microscopy (FESEM) were employed to characterize the samples, verifying the successful attachment of XS to the PCC surface. This study proposes a novel approach to filler modification that mitigates the negative interactions between cellulosic fibers and fillers, offering a promising alternative for papermaking applications.

Bacterial nanocellulose (BNC) is a versatile biopolymer with diverse applications across various domains. The global market for BNC is currently valued at approximately USD 300 million, and projections suggest that it could grow to USD 750 million by 2032. Given its increasing importance and relevance, there is a pressing need to comprehensively examine the current BNC landscape. This study aimed to conduct an original scientometric analysis of BNC research, utilizing data from the Web of Science Core Collection, focuses on the most recent 20 years to provide a comprehensive view of contemporary trends and developments in the field, covering from 2006 to March 2024. This analysis employed Topic Search term “bacterial nanocellulose”, since this term is increasingly used to distinguish this material from plant-derived cellulose. A total of 1796 documents was selected, which were refined to 959 for further analysis using CiteSpace (6.3. R2) and Excel (2016). English was the predominant language, and articles were the most prevalent document type. Notably, citations and publications exhibited a consistent upward trend from 2013 to 2024, reflecting global research trends. A correlation was observed between publication volume and investments in nanotechnology, with China and the USA emerging as leading contributors. These countries showed different research trends: China led a group focusing on composite membranes, the USA spearheaded researched on BNC scaffolds, India concentrated on biodegradable food packaging, and groups in Iran and Portugal explored bone tissue engineering. Regarding research frequency, the most prominent areas were polymers, applied and multidisciplinary chemistry, and materials sciences. However, biotechnology, biochemistry, and molecular biology were identified as the most influential fields. In conclusion, this scientometric study provides valuable insights into the key factors shaping the current state of BNC research, offering guidance for researchers and professionals.

Cellulose regeneration is a critical step in the production of textiles, cellulose derivates, edible films for packaging or biomedical products because the regeneration process alters the cellulose properties. Cellulose regeneration involves complex intermolecular interactions and kinetics that determine the structure and properties of the regenerated cellulose products. Homogeneous quality is crucial for meeting market demands, but it is challenging due to variations in raw materials, process conditions, and other factors. On-line real-time monitoring of the cellulose regeneration process will allow researchers to optimize the process and producers to assess and control the key parameters involved during the regeneration process, ensuring both optimal product quality and process efficiency. This paper describes for the first time the potential of using focused beam reflectance measurements (FBRM) to monitor the evolution of cellulose regeneration under different conditions. The analysis of the evolution of the cellulose particle growth under different conditions allow us to confirm that the mechanism of cellulose aggregation is initiated by hydrophobic interactions and to understand the contribution of the different processes involved during the regeneration such as nucleation, particle growing, cellulose flocculation and floc break down. The results indicate that hydrolysis of urea in alkaline conditions, accelerated by elevated temperatures, has a major impact on the regeneration process confirming the idea that urea prevents hydrophobic interactions. The effects of temperature, initial cellulose concentration, seeding and aging have been quantified. FBRM analysis offers crucial insights that enhance understanding of the regeneration process, enabling its optimization and facilitates the creation of customized cellulose-based materials tailored for specific applications.

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