Carboxymethyl Cellulose Matrix Research Articles

A development of a gelatin and sodium carboxymethyl cellulose hydrogel system for dual-release transdermal delivery of lidocaine hydrochloride

This study introduces a dual-release transdermal drug delivery system using a hydrogel matrix of cross-linked gelatin and sodium carboxymethyl cellulose (NaCMC). Designed for immediate drug release from microneedles (MNs) and sustained release from microcapsules (MCs), this system utilizes lidocaine hydrochloride as the model drug. The fabrication process involved casting the hydrogel into MN molds, with MCs embedded in the backing layer, establishing a dual-release mechanism. MCs of gelatin and NaCMC were prepared by emulsion-crosslinking method and using glutaraldehyde as a crosslinker. MCs ranged in size from 50 to 264 μm and exhibited the highest drug release in acidic environments, showcasing a pH-responsive nature. Drug loading efficiency reached 9.8 %, while encapsulation efficiency was 75.8 %. The MNs, which had a conical shape and strong mechanical properties, demonstrated excellent penetration capabilities. The in vitro release profile indicated an initial burst within 10 min, followed by sustained release over 240 min, in line with the Korsmeyer-Peppas model. Additionally, the system displayed significant antimicrobial properties and good biocompatibility, with cell viability exceeding 86 %. This confirms its potential as a safe and effective platform for transdermal drug delivery.

Facile fabrication and characterization of carboxymethyl cellulose hydrogel loaded with TiO2NPs as a promising disinfectant for eliminating the dissemination of waterborne pathogens through wastewater decontamination

The purpose of this work was to develop and characterize an intriguing hydrogel called TiO₂NPs@CMC hydrogel, which is composed of carboxymethyl cellulose (CMC) loaded with titanium oxide nanoparticles (TiO₂NPs) for effective waterborne pathogen disinfection in wastewater. The TiO₂NPs were synthesized through hydrolysis and peptization. Then, incorporated into CMC matrix, and subsequently cross-linked with calcium chloride (CaCl₂). In this study, TiO2NPs was prepared and affirmed the particle distribution with a small size using TEM. The TiO₂NPs@CMC hydrogel exhibited significant antimicrobial and antibiofilm properties against various pathogens, such as Salmonella typhi, E. coli O157, Shigella dysenteriae, Enterococcus faecalis, Bacillus cereus, and Candida albicans, with highest inhibition zone diameters 29 mm for S. typhi. The inhibitory effect demonstrated that the hydrogel significantly decreased bacterial populations at 100 μg/mL concentrations. The hydrogel demonstrated a 2.7-log reduction in microbial counts in sewage within 120 min, achieving complete inactivation of pathogens at a concentration of 2xMIC within 180 min. The biofilm inhibition rate reached 87.6 % against B. cereus. Toxicity assessments demonstrated significant biocompatibility, with no adverse effects noted in environmental applications. The findings indicate that TiO₂NPs@CMC hydrogel is a viable option for sustainable wastewater treatment, providing an efficient, safe, and environmentally friendly method for removing waterborne pathogens and preventing biofilm formation.

Carboxymethyl cellulose based edible nanocomposite coating with tunable functionalities and the application on the preservation of postharvest Satsuma mandarin fruit

This study introduces an innovative carboxymethyl cellulose (CMC)-based edible nanocomposite coating, with two-dimensional layered double hydroxide nanosheets (2D LDH-NSs) and shellac, engineered to address challenges in fruit preservation. The synergistic integration of shellac and LDH-NS into the CMC matrix is strategically designed with tunable functionalities, encompassing wettability, gas barrier, and tensile properties. Our findings reveal that incorporating shellac and LDH-NS significantly improves the coating's wettability on the mandarin fruit surface, thus bolstering its adherence and uniformity, alongside enhancing its water vapor barrier efficacy and influencing the oxygen permeability. The application of this novel edible nanocomposite coating on Satsuma mandarin (Citrus unshiu Marc.) fruits has yielded promising outcomes in prolonging postharvest shelf life while preserving essential quality attributes, including peel surface morphology, weight loss, hardness, color retention, and nutritional values. Our work signifies a significant leap forward for the edible coating technology and bolsters the postharvest preservation of perishable fruits.

Influence of graphene nanoplatelet on carboxymethyl cellulose for enhanced electrochemical performance

Renewable and bio-based polymers are favored over conventional synthetic polymers because of their low-cost, abundance and sustainability, but due to their average electrochemical performance, sometimes their application is limited as battery material. This study investigates the electrochemical properties of nanocomposites composed of carboxymethyl cellulose (CMC) and graphene nanoplatelets (GNP) at varying GNP ratios. Four samples with GNP weight ratios ranging from 0 to 0.33 wt.% were subjected to analysis using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The sample containing 0.33% GNP exhibited the most favorable electrochemical behavior, demonstrating an ionic conductivity of approximately 2.54 × 10−5 S/cm at 25 °C. Cyclic Voltammogram and Nyquist plots indicated an electrochemical process governed by diffusion processes, particularly evident with 0.33% GNP. This sample displayed the highest specific capacitance at 4.290 F/g, representing an 83.07% improvement over the Pure CMC sample, along with a favorable electrochemical window at 375 mV. Bode plot analysis underscored the influence of diffusion and charge transfer on resistance and conductivity, highlighting enhanced ion mobility in this sample. SEM micrographs revealed improved GNP dispersion in the CMC matrix at higher GNP concentrations, enhancing contact. FTIR analysis confirmed effective CMC–GNP interaction, characterized by a specific peak at 1589 cm−1. These findings provide valuable insights into the electrochemical potential of CMC–GNP composites, offering prospects for their application in diverse electrochemical devices.

Regulating Tissue Growth Factors for Healing With Etherified Carboxymethylcellulose Matrix.

Etherified Carboxymethylcellulose Matrix (eCMC) is a revolutionary application of carboxymethylcellulose (CMC) in wound care, known for its potential in hemostasis and tissue regeneration. This study aims to investigate the mechanism of eCMC in tissue healing by establishing a rat burn model and administering eCMC as a treatment. The objective is to analyze cytokines and inflammatory mediators using a Cytokine Array and histochemical staining to understand the effects of eCMC on tissue regeneration. A rat burn model was created, and eCMC was applied as a treatment. Tissue samples were collected at multiple time points to assess the expression of cytokines and inflammatory mediators using a Cytokine Array. In addition, histochemical staining was performed to evaluate tissue regeneration factors. eCMC induced the expression of endogenous cytokines, particularly vascular epithelial growth factor and platelet-derived growth factor, while inhibiting inflammatory cytokines such as CINC-1, CINC-2, and MMP-8. This dual action facilitated wound healing and mitigated the risk of infection. eCMC demonstrates promising potential for enhancing skin regeneration. Further research is warranted to delve into the precise mechanism of eCMC's cytokine regulation. In vitro and in vivo studies should be conducted to comprehensively investigate the therapeutic capabilities of eCMC in wound healing.

Edible film preparation by anthocyanin extract addition into acetylated cassava starch/sodium carboxymethyl cellulose matrix for oxidation inhibition of pumpkin seeds

In this study, an edible film was fabricated by incorporating anthocyanin extract from black rice (AEBR) into acetylated cassava starch (ACS)/carboxymethyl-cellulose (CMC) to enhance the shelf life of pumpkin seeds. The effects of AEBR on the rheological properties of film-forming solutions, as well as the structural characterization and physicochemical properties of the film, were evaluated. Rheological properties of solutions revealed that AEBR was evenly dispersed into polymer matrix and bound by hydrogen bonds, as confirmed by Fourier transform infrared spectroscopy analysis. The appropriate AEBR addition could be compatible with polymer matrix and formed a compact film structure, improving the mechanical properties, barrier properties, and opacity. However, with further addition of AEBR, the tensile strength and water vapor permeability decreased and the tight structure was destroyed. After being stored separately under thermal and UV light accelerated conditions for 20 days, the peroxide value and acid value of roasted pumpkin seeds coated with the AEBR film showed a significant reduction. Moreover, the storage stability of AEBR was improved through the embedding of ACS/CMC biopolymers. These results indicated that AEBR film could effectively delay pumpkin seeds oxidation and prolong their shelf life as an antioxidant material.

Development of eco-friendly biofilms by utilizing microcrystalline cellulose extract from banana pseudo-stem

Banana pseudo-stem, often considered as an underutilized plant part was explored as a potential reinforced material to develop an eco-friendly biofilm for food packaging applications. In this study, Microcrystalline cellulose (MCC) was extracted from banana pseudo-stem by alkali and acid hydrolysis treatment. The extracted MCC was used as a reinforced material in different concentrated polyvinyl alcohol (PVA) matrix alone as well as both PVA and Carboxymethyl Cellulose (CMC) matrix to develop biofilm by solvent casting method. The synthesized MCC powder was characterized by scanning electron microscope to ensure its microcrystalline structure and to observe surface morphology. The biofilms composed of MCC, PVA, and CMC were assessed through Fourier-transform infrared spectroscopy (FTIR), mechanical properties, water content, solubility, swelling degree, moisture barrier property (Water Vapor Permeability - WVP), and light barrier property (Light Transmission and Transparency). The FTIR analysis showed the rich bonding between the materials of the biofilms. The film incorporating a combination of PVA, CMC, and MCC (S6) exhibited the highest tensile strength at 26.67 ± 0.152 MPa, making it particularly noteworthy for applications in food packaging. MCC incorporation increased the tensile strength. The WVP content of the films was observed low among the MCC-induced films which is parallel to other findings. The lowest WVP content was showed by 1% concentrated PVA with MCC (S4) (0.223 ± 0.020 10−9 g/Pahm). The WVP content of S6 film was also considerably low. MCC-incorporated films also acted as a good UV barrier. Transmittance of the MCC induced films at UV range were observed on average 38% (S2), 36% (S4) and 6% (S6) which were almost 6% lower than the control films. The S6 film demonstrated the lowest swelling capacity (1.42%) and water content, indicating a significantly low solubility of the film. The film formulated with mixing of PVA, CMC and MCC (S6) was ahead in terms of food packaging characteristics than other films. Also, the outcomes of this study point out that MCC can be a great natural resource for packaging applications and in that regard, banana pseudo-stem proves to be an excellent source for waste utilization.

Carboxymethyl cellulose-based multifunctional film integrated with polyphenol-rich extract and carbon dots from coffee husk waste for active food packaging applications

Sustainable carboxymethyl cellulose (CMC)-based active composite films were developed through the addition of polyphenol-rich extract from coffee husk (CHE) and carbon dots (CDs) prepared using the biowaste residue of CHE extraction. The influences of various CDs contents on the physicochemical and functional characteristics of composite films have been researched. The 6% (w/w) CHE and 3% (w/w) CDs were uniformly dispersed within the CMC matrix to produce a homogenous film with enhanced mechanical properties. The CMC/CHE/CDs3% film exhibited outstanding UV-light blocking, improved water and gas barriers, potent antioxidant activity with above 95% DPPH and ABTS scavenging rates, and effective antibacterial capabilities against L. monocytogenes and E. coli. The food packaging experiment demonstrated that this active composite film slowed the rotting of fresh-cut apples and extended their shelf-life to 7 days at 4 °C storage. Therefore, the obtained multifunctional film showed promise as an environmentally friendly food packaging material.

Preparation and characterization of chitosan/dialdehyde carboxymethyl cellulose composite film loaded with cinnamaldehyde@zein nanoparticles for active food packaging

In this study, zein-loaded cinnamaldehyde (Cin@ZN) nanoparticles were incorporated into Chitosan (CS)/dialdehyde carboxymethyl cellulose (DCMC) matrix to fabricate the active food packaging materials possessing outstanding antioxidant and antibacterial properties. The research investigated how varying levels of Cin@ZN nanoparticles affected the morphology, microstructure, physicochemical properties of CS/DCMC composite films. The inclusion of Cin@ZN could significantly improve the mechanical strength, reduce the water vapor and oxygen permeability of CS/DCMC composite films and endow films with UV-light blocking properties. It's worth noting that the antibacterial and antioxidant capacities of CS/DCMC films had an astonishing enhancement with Cin@ZN blending, in which ABTS scavenging ratio of the composite films (100 mg) with different Cin@ZN contents reached >90 %. Furthermore, CS/DCMC/Cin@ZN 35 % composite film has the ability to efficiently protect strawberries from microbial damage and decelerate the spoilage rate of strawberries under ambient condition. Consequently, the CS/DCMC/Cin@ZN composite film can be applied as packaging material to extend the lifespan of fruits.

Tailoring microstructure of superabsorbent film for active food packaging using carboxy methyl cellulose and biogenic vaterite CaCO3–Ag hybrid microspheres

Eliminating microbial growth and preventing food degradation from excess moisture is an important technological advance in packaging. This article describes the development of a novel antimicrobial superabsorbent pad for food packaging, which uses carboxy methyl cellulose (CMC) as a polymer matrix and biogenic vaterite calcium carbonate microspheres loaded with AgNPs (CaCO3–Ag). The spherical vaterite CaCO3–Ag hybrid was obtained by precipitating CaCO3 from discarded eggshells in silver colloid. The vaterite CaCO3–Ag microspheres were incorporated into the CMC matrix, which underwent physical cross-linking initially and was further chemically cross-linked during film surface treatment. The resulting three-layer film exhibits improved hardness and modulus of 0.09 and 3.30 GPa, respectively. The crystallinity was enhanced, and water absorption capacity attained was 13.87 times of film weight. The antimicrobial activity with inhibition zones of 6 and 14 mm against Escherichia coli and minced pork bacteria, makes it suitable for use as an antimicrobial superabsorbent pad in meat packaging applications.

Novel amino-ethyl carboxymethyl cellulose crosslinked ampholyte hydrogel development for Methyl Orange Removal from Waste water: Kinetics, isotherms, and thermodynamics studies

In this study, a novel ampholyte hydrogel known as amino-ethyl carboxymethyl cellulose crosslinked hydrogel (AECMC) was synthesized and utilized to remove Methyl orange (MO), an azo-dye commonly found in dyes contaminated wastewater. This marks the first instance of such a hydrogel being generated for this specific application. The presence of induced amine groups in the modified carboxymethyl cellulose matrix facilitated the creation of adsorption positive charge centers, which effectively attracted MO azo-dye anions. The level of amination exhibits a clear correlation with both the percentage of MO adsorption and the capabilities of adsorbents. An initial rapid adsorption phenomenon was seen within the first 15 min, followed by a gradual decrease in the rate of adsorption until reaching a plateau. The adsorption capacity is notably influenced by the temperature of adsorption, particularly in the case of employing low aminated carboxymethyl cellulose (CMC) derivative. The aforementioned effect exhibits a decrease in magnitude when increasing levels of aminated carboxymethyl cellulose (CMC) derivatives are employed. The kinetics of the adsorption process was assessed by the use of three models: Pseudo-first-order, Pseudo-second-order, and Elovich. Moreover, the mechanism of the adsorption process was monitored using two models, namely Dumwald–Wagner and intraparticle models, which described the liquid film diffusion or intraparticle diffusion, while the external mass transfer was examined by the Boyd model. The Boyd diffusion model determines that the process rate is limited by film diffusion. Additionally, the adsorption isotherm was examined using established models such as Langmuir, Freundlich, and Temkin isotherms. The thermodynamic characteristics of the MO adsorption process have been investigated at various adsorption temperatures using the Van't Hoff model. The results obtained from the study indicate that the process of MO adsorption adhered to the Pseudo-second-order kinetic model. Additionally, the Langmuir isotherm model was found to be applicable, with a maximum adsorption capacity of 2.033 mg/g for the Langmuir monolayer. Furthermore, it was observed that the adsorption process was spontaneous and exhibited an endothermic character.

Preparation and characterization of active films based on oregano essential oil microcapsules/soybean protein isolate/sodium carboxymethyl cellulose

This study aimed to prepare oregano essential oil microcapsules (EOMs) by the active coalescence method using gelatin and sodium alginate as wall materials and oregano essential oil (OEO) as the core material. EOMs were added to the soybean protein isolate (SPI)/sodium carboxymethyl cellulose (CMC) matrix to prepare SPI-CMC-EOM active films, and the physical and chemical features of the active films and EOMs were characterized. The results showed that the microencapsulated OEO could protect its active ingredients. Scanning electron microscopy results showed that EOMs were highly compatible with the film matrix. The solubility of active films decreased upon adding EOMs, and their ultraviolet resistance and thermal stability also improved. When the added amount of EOMs was 5 %, the active films had the best mechanical properties and the lowest water vapor permeability. The active films prepared under this condition had excellent comprehensive performance. Also, adding EOMs considerably enhanced the antioxidant of the active films and endowed them with antibacterial properties. The application of the SPI-CMC-EOM films to A. bisporus effectively delayed senescence and maintained the freshness of the postharvest A. bisporus. This study provided a theoretical foundation for the incorporation of EOMs into active films based on biological materials.

Solution plasma mediated synthesis of antibacterial nanobiocomposites using carboxymethyl cellulose and silver as electrodes

In this study, carboxymethyl cellulose (CMC)/Silver nanoparticles (AgNPs) biocomposites were synthesized using a solution plasma process (SPP). The utilization of AgNO3 as a precursor, along with tungsten electrodes, introduces significant impurities into the biocomposites. Therefore, to ensure purity, we employed silver electrodes in the production of biocomposites. The SPP involved discharging plasma at 800 V, 30 kHz for 7 min in CMC solutions with concentrations of 0.3, 0.5, and 1.0%. The UV–Vis spectroscopy results revealed a peak near 400 nm, and the intensity of the peak increased as the CMC concentration decreased. The biocomposites had no change in the chemical structure during SPP. Porous matrix with fringed edges and spherical AgNP was observed by SEM/EDS and TEM analysis. The average particle size and the zeta potential of CMC/AgNPs determined by DLS analysis were 3.1 ± 0.1 nm and −41.8 ± 0.9 mV, respectively. The CMC/AgNP (0.3%, 7 min) exhibited growth inhibition zones ranging from 9.8 to 17.2 mm. The minimal inhibitory concentrations for Gram-positive bacteria, Gram-positive bacteria, and yeast were found to be in the ranges of 33.9–50.9, 102 and 338 μg mL−1, respectively. These results demonstrate that biocomposites of CMC/AgNPs, synthesized using silver electrodes within a CMC matrix, exhibit efficient antimicrobial properties, indicating their potential for sustainable utilization as polymer-based materials for wound healing.

Carboxymethyl cellulose based films enriched with polysaccharides from mulberry leaves (Morus alba L.) as new biodegradable packaging material

The objective of this study was to determine the properties of a new active packaging film developed by the addition of mulberry leaves polysaccharides (MLP) into carboxymethyl cellulose (CMC). Biodegradable CMC-MLP films were fabricated by casting method with various concentrations of MLP (1, 5 and 10 % w/w). The addition of MLP into the CMC matrix resulted increased thickness (0.126 to 0.163 mm) and roughness of the films. Also, the decline in moisture content from 27.91 to 14.12 %, water vapor permeability from 8.95 to 5.21 × 10−10 g−1 s−1 Pa−1, and a swelling degree from 59.11 to 37.45 % were observed. With the increasing concentration of MLP, the mechanical properties of the films were improved and higher dispersion of UV light were noted. Fourier transform - infrared spectroscopy (FT-IR) and X-ray diffraction revealed good inter-molecular interaction between CMC matrix and MLP. The prepared films showed excellent thermal stability, antioxidant and antibacterial properties as well as susceptibility to biodegradation in the soil environment. Moreover, it was proved that the films have ability to retard oil oxidation. Overall, it was concluded that CMC-MLP films constitute a promising biomaterial that may be applied as active food packaging.

Preparation and Application of Edible Film Based on Sodium Carboxymethylcellulose-Sodium Alginate Composite Soybean Oil Body

In the study, edible films were successfully prepared by incorporating soybean oil body (SOB) into sodium alginate-sodium carboxymethyl cellulose (SA-CMC) matrix. The effects of different concentrations (0–4% w/w) of SOB on the physicochemical and antioxidant activities of films were systematically evaluated based on mechanical strength, barrier properties, thermal stability, and preservation effect. Findings revealed that the oxidation resistance, water vapor barrier, and thermal stability enhanced after the addition of SOB, while the water content, water solubility, and swelling rate decreased. When 3% SOB was added, the edible film performed the best in terms of mechanical properties and thermal stability; water vapor permeability was reduced by 21.89% compared to the control group, and the fresh life of pigeon meat was extended by 5–7 days. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses showed that the addition of SOB results in a more stable molecular structure network, which improved its physical properties. Overall, the findings indicated that SOB improved the quality of edible films as an environmentally friendly food packaging material and increased the feasibility of edible film application in the food industry.

Enhanced the properties of carbon‐paste nanocomposite by carboxylation of multi‐walled carbon nanotubes

AbstractIn the present study, attempts were made to manufacture innovative conducting polymer nanocomposites (CPCs) with high performance, low cost, and appropriate electrical, mechanical, and thermal properties. However, one of the main challenges in creating CPCs is the tendency of nanofillers to agglomerate and accumulate, resulting in a decrease in the electrical properties and performance of CPCs. To address this issue, the study developed an efficient and eco‐friendly CPC using carboxymethyl cellulose (CMC) as a binder and carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) as nanofillers. The study employed a chemical functionalization method to modify CNTs and enhance their compatibility and dispersion properties in the CMC matrix. The prepared CPCs were characterized using various techniques, including Fourier‐transform infrared spectroscopy, x‐ray diffraction, and field emission scanning electron microscopy. The results showed an improvement in homogeneity and surface cohesion between CMC and O‐CNTs through chemical surface modification of CNTs via carboxylic acid functional groups. The study observed good dispersion of nanofillers without any aggregation of the CMC/GNP/O‐CNT compared with the nontreated CMC/GNP/CNT composite. While a decrease in the degree of crystallinity was observed, conductivity increased for the CPC containing oxidized CNTs. The study found that the highest conductivity of ~112 S/m was obtained for D‐CMC/GNP/O‐CNT with 25 wt% of O‐CNT, while the maximum conductivity of D‐CMC/GNP/CNT was ~80 S/m with 35 wt% of CNTs. Additionally, the study observed an improvement in electrochemical properties after treatment of CNTs in the form of higher cathodic current in cyclic voltammetry and lower charge transfer resistance in impedance spectroscopy of D‐CMC/GNP/O‐CNT35 compared to untreated one.Highlights Preparation of new conductive nanocomposite consisting of CMC, CNTs, and GNPs. Carboxylation of CNTs to improve O‐CNT and CMC intermolecular interaction CMC/GNP/O‐CNT is 40% more conductive than unmodified CNT nanocomposite. Higher thermal stability and mechanical properties were observed by using O‐CNT. O‐CNT caused higher current density and lower electron transfer resistance for CPCs.

Probing Microscale Structuring-Induced Phase Separation with Fluorescence Recovery Diffusion Dynamics in Poly(ethylene glycol) Solutions.

Apart from biocompatibility, poly(ethylene glycol) (PEG)-based biomedical constructs require mechanical tunability and optimization of microscale transport for regulation of the release kinetics of biomolecules. This study illustrates the role of inhomogeneities due to aggregates and structuring in the PEG matrix in the microscale diffusion of a fluorescent probe. Comparative analysis of fluorescence recovery after photobleaching (FRAP) profiles with the help of diffusion half-time is used to assess the diffusion coefficient (D). The observations support a nontrivial dependence of diffusion dynamics on polymer concentration (volume fraction, φ) and that of fillers carboxymethyl cellulose (CMC) and nanoclay bentonite (B). D values follow the Rouse scaling D ∼ φ-0.54 in PEG solutions. The diffusion time of the fluorescent probe in the PEG+bentonite matrix reveals the onset of depletion interaction-induced phase separation with an increase in bentonite concentration in the PEG matrix beyond 0.1 wt %. Beyond this concentration, structure factors obtained from prebleach FRAP images show a rapid increase at low Q. The two-phase system (PEG-rich and bentonite-rich) was characterized by the hierarchical structural topology of bentonite aggregates, and aggregate sizes were obtained at different length scales with phase contrast imaging, small-angle neutron scattering, and small-angle X-ray scattering. The microscale transport detection presented captures sensitively the commencement of phase separation in the PEG + bentonite matrix, as opposed to the PEG or PEG + CMC matrix, which are observed to be one-phase systems. This method of diffusion half-time and prebleach image analysis can be used for the fast, high-throughput experimental investigation of microscale mechanical response and its correlation with structuring in the polymer matrix.

Isolation of cellulose nanofibers from rapeseed straw via chlorine-free purification method and its application as reinforcing agent in carboxymethyl cellulose-based films

In this study, cellulose nanofibers (CNFs) were successfully isolated from rapeseed straw (RS) whose valorization has been rarely investigated to date. A combined bleaching method without chlorine was applied for the purification of cellulose fibers, previously unexplored for RS. Chemical composition analysis and Fourier-transform infrared spectroscopy (FTIR) indicated that the purification method eliminated hemicellulose and reduced lignin content from 24.4 % to 1.8 %. The isolation of CNFs was performed using sulfuric acid hydrolysis under different acid concentrations (55 and 60 % v/v) and hydrolysis times (15, 30, and 45 min). The isolated CNFs were characterized by FTIR, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The formation of CNFs was confirmed by a significant increase in crystallinity index from 46.45 % of RS to >79.41 % of CNFs, depending on acid concentration and isolation duration. Carboxymethyl cellulose (CMC) films with different contents of CNFs were prepared by casting method. The mechanical properties and cytotoxicity of the prepared films were investigated. The CNFs obtained from RS via a chlorine-free purification method showed promising results for their usage as reinforcement in CMC matrix and film fabrication for various applications such as transdermal medicine and food packaging.

Solvent-free rapid synthesis of carbon nanodots at atmospheric pressure: Preparation of transparent light conversion films with ultrahigh efficient UV and blue light shielding

In this age of technology, people are inevitably surrounded by electronic devices and light-emitting devices, but the radiation generated by these devices is very harmful to humans. Therefore, it is crucial to develop a stable absorbing material with efficient absorption capacity for UV and high-energy blue light (HEBL). In this paper, we report that carbon nanodots (CDs) with strong absorption peaks in the UV and HEBL can be rapidly synthesized in large scale by simply heating urea and citric acid at high temperature under atmospheric pressure without using any solvents. Interestingly, the large-scale prepared CDs possess green fluorescence emission upon excitation in both the UV and HEBL regions, exhibiting good photoconversion ability. Furthermore, ultrahigh efficient UV and HEBL shielding films can be prepared by embedding the CDs in a carboxymethyl cellulose matrix. By characterizing their transmission and absorption spectra, it can be found that the cellulose films containing 0.2 wt% CDs achieve almost complete shielding of UV-A, UV-B, and HEBL with a guaranteed visible light (550 nm) transmission rate of 80% or above. Finally, this cellulose film was further attached to a light-emitting diode (LED) chip to investigate its practical use in the field of UV and strong blue light shielding.

Superabsorbent Polymer Sponge for Saliva Absorption Pad

Aim: Saliva is a significant hindrance to most dental procedures (e.g., root canal treatment) as the flow of saliva increases in patients undergoing dental treatment due to anxiety. Saliva absorption pads based on superabsorbent polymers can provide a dry oral environment to ease the dental treatment procedure and reduce the swallowing reflexes common during cotton use. This study focused on developing an indigenous saliva absorption pad using biodegradable superabsorbent polymer (BSAP) sponges. Materials and Methods: BSAP sponges were synthesized using carboxymethyl cellulose (CMC) as the base matrix. Different crosslinking mechanisms were implemented to prepare BSAP sponges, such as ionic crosslinking using aluminum ammonium sulfate (AlAS) and chemical crosslinking using methylene bisacrylamide. Three different BSAP sponges (Sap-2, SAP-PAA-1, and SAP-PAA-2) were characterized for their free swell capacity and thermal degradation kinetics along with other characterization techniques to optimize the composition for saliva absorption pad. One-way ANOVA was used for statistical evaluation. Results: SAP-2, synthesized using 10 wt.% AlAS showed the highest free swell capacity in water and saline (83.21 ± 3.8 g/g and 40.7 ± 3.4 g/g, respectively). However, the moisture content of the particular BSAP sponge was higher (~13%) compared to the standard limit (ISO 17190-4:2001(E)). It was observed that as the crosslinking density increases free swell capacity increases to a threshold point and decreases thereafter. As reported earlier, percentage swelling was controlled by multiple factors including crosslinking that opposes swelling and polymer/water interaction and Donnan pressure that promotes swelling. Conclusion: BSAP sponge based on crosslinked CMC matrix is highly advantageous in developing saliva absorption pad. Hydrophobic surface modification is recommended to reduce the moisture content to improve the storage stability of BSAP sponges.