Crosslinking Of Carboxymethylcellulose Research Articles

Fabrication of a novel bio-polymer adsorbent with high adsorptive capacity towards organic dyes

A novel adsorbent, CMC-T-CH, was fabricated by crosslinking of carboxymethyl cellulose (CMC) and chitosan (CH) with triethylenetetramine. The adsorbent's efficacy in removing the hazardous dyes, Direct blue (DB) and Congo red (CR), was investigated. Different physical, chemical, and biological methods have been employed to eliminate CR and DB dyes from aqueous solution, and adsorption has shown potential in eradicating these dyes effectively. Various characterization methods were employed to investigate the physicochemical characteristics of CMC-T-CH. The removal process was performed at optimized conditions of pH 6 for CR and pH 5 for DB at the temperature of 35 °C, resulting in maximum removal efficiencies of 99 % and 98.33 % for CR and DB, respectively. Langmuir isotherm and pseudo-second-order kinetic mathematical models were utilised to analysed the interaction of adsorbate and adsorbent during the removal process. The maximum theoretical adsorptive capacities of 519.53 and 534.25 mg/g were achieved for CR and DB removal, respectively. The regeneration study revealed that the dye-loaded CMC-T-CH could be reused several times. The phytotoxicity assay showed that the germination of Vigna mungo seeds improved after the removal treatment, thus confirming the potential of CMC-T-CH in the elimination of CR and DB.

Development of carboxymethyl cellulose/gelatin hybrid hydrogels via radiation-induced cross-linking as novel anti-adhesion barriers

Adhesion after abdominal and pelvic surgery results in severe clinical outcomes and a negative impact on the quality of life of a patient. Implanting barrier materials is a common strategy for preventing postoperative adhesion, and non-adhesive carboxymethylcellulose (CMC) is a widely used material for such purpose. Herein, we present CMC/gelatin (CMC/G) hybrid hydrogels as novel barrier materials that aim to reduce the foreign body response (FBR) by combining the biocompatibility and biodegradability of gelatin and the non-adhesiveness of CMC and by realizing mechanical matching with the host tissue. The hydrogels were prepared by the simple reagent-free γ-ray irradiation-induced cross-linking of CMC and gelatin. The hydrogel composition was controlled by varying the initial mixing ratio. The gelatin fraction provided enzyme-mediated degradability at a content ≥ 40%, and the degradation rate was controlled by the radiation dose. The compressive moduli of the hydrogels were tuned to be identical to that of target abdominal organs (several tens of kPa) via 10–30 kGy radiation. The hydrogels sufficiently prevented adhesion of 3T3-Swiss fibroblast cells owing to the non-adhesive capability of CMC which surpassed the high cell adhesiveness of gelatin in the hydrogels. On the other hand, the added gelatin significantly improved the viability of the few cells that adhered to the hydrogels. We found that hydrogels composed of 60% CMC and 40% gelatin exhibited significantly higher cell viabilities while maintaining the non-adhesiveness which is desirable as barrier materials. The in vitro assessments demonstrated the potential of the hydrogel as a novel barrier material with excellent biocompatibility, wound healing promoting effect, and FBR reducing effect by realizing mechanical matching with the host abdominal organs, especially when it was composed of 60% CMC and 40% gelatin and cross-linked at 10–30 kGy to impart compressive modulus of 20–100 kPa.

Facile In Situ Cross-Linked Robust Three-Dimensional Binder for High-Performance SiOx Anodes in Lithium-Ion Batteries.

Silicon oxide (SiOx, 0 < x < 2) is considered one of the most promising anode materials for next-generation lithium-ion batteries due to its high theoretical capacity. However, its commercial application is limited by the non-negligible volume change during cycling. Herein, a three-dimensional (3D) structure of carboxymethyl cellulose (CMC) cross-linked with iminodiacetic (c-CMC-IDA150) was facilely formed through in situ thermal cross-linking of CMC and iminodiacetic acid (IDA) in the fabrication process of the electrode, which could construct a robust network to restrain the volume change of the SiOx anode and maintain the integrity of the electrode. In addition, the 3D cross-linked c-CMC-IDA150 provides sufficient contact sites to improve the adhesive strength. Thus, SiOx@c-CMC-IDA150 shows a prolonged cycle life, achieving a capacity of 1020 mAh g-1 after 100 cycles at a current density of 0.2 A g-1. With the increase in the current density to 1.0 A g-1, SiOx@c-CMC-IDA150 exhibits a reversible capacity of 899 mAh g-1 after 200 cycles with a capacity retention of 70.2%. This work provides a potential perspective to fabricate high-performance SiOx anodes and promote the stability of high-capacity Si-based anodes.

Hydrogen Bonds in Blends of Poly(N-isopropylacrylamide), Poly(N-ethylacrylamide) Homopolymers, and Carboxymethyl Cellulose

Recently, it was reported that the physical crosslinking exhibited by some biopolymers could provide multiple benefits to biomedical applications. In particular, grafting thermoresponsive polymers onto biopolymers may enhance the degradability or offer other features, as thermothickening behavior. Thus, different interactions will affect the different hydrogen bonds and interactions from the physical crosslinking of carboxymethyl cellulose, the lower critical solution temperatures (LCSTs), and the presence of the ions. This work focuses on the study of blends composed of poly(N-isopropylacrylamide), poly(N-ethylacrylamide), and carboxymethyl cellulose in water and water/methanol. The molecular features, thermoresponsive behavior, and gelation phenomena are deeply studied. The ratio defined by both homopolymers will alter the final properties and the gelation of the final structures, showing that the presence of the hydrophilic groups modifies the number and contributions of the diverse hydrogen bonds.

Dual crosslinked carboxymethyl cellulose/polyacrylamide interpenetrating hydrogels with highly enhanced mechanical strength and superabsorbent properties

Carboxymethyl cellulose (CMC)-based hydrogels possess superabsorbent properties and are biocompatible; however, their use is limited because of their low mechanical strength. In the present study, we used a sequential dual crosslinking strategy to produce new CMC-based interpenetrating polymer network (IPN) hydrogels with high mechanical strength and superabsorbent properties. The newly synthesized CMC-based IPN hydrogels were first crosslinked with CMC using ethylene glycol diglycidyl ether (EGDE) under basic conditions and were then subjected to secondary radical polymerization by adding acrylamide, N,N′-methylene bis-acrylamide (MBA), and ammonium peroxodisulfate. The structure and morphologies of the CMC with polyacrylamide (PAM) IPN hydrogels were characterized by Fourier transform infrared spectroscopy in the attenuated total reflectance mode (FTIR-ATR), solid-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), rheology analysis, tensile test, and compressive test. The synthesized CMC/PAM IPN hydrogels exhibited highly enhanced mechanical strength with high density internal structure due to the double crosslinking of CMC and PAM. The tensile length and compressive strengths of CMC/PAM-1 IPN hydrogels were up to 2.6 and 4.5 times higher than that of the CMC gel, respectively. Moreover, CMC/PAM-1 IPN hydrogels presented higher superabsorbent properties than any other CMC-based IPN hydrogels reported so far. The present study proposes a novel method for the synthesis of CMC-based hydrogels that can simultaneously have very high mechanical strength as well as superabsorbency. These hydrogels do not show biotoxicity against in vitro animal cell and has the potential to be used as a biomaterial.

Furazolidone Immobilized in a Hydrogel Based on Crosslinked Carboxymethyl Cellulose

The paper deals with the obtainment of a polymer-drug system with controlled release of the biological active principle, based on furazolidone included in a hydrogel obtained by crosslinking of carboxymethylcellulose with epichlorohydrine. The influence of temperature and duration of crosslinking reaction on the&lt;br /&gt;crosslinking degree of carboxymethylcellulose (indirectly appreciated by its swelling capacity in polar liquids as water and dimethylformamide/water mixtures) is studied. Kinetic data concerning the inclusion of furazolidone from solution, in the hydrogel of crosslinked carboxymethylcellulose, as well as the release of the drug from the obtained polymer-drug system, are performed. The obtained results evidence that the inclusion&lt;br /&gt;rate as well as the amount of furazolidone diffused into the support depend on the dymethylformamide/water ratio utilized as solvent, and on the drug concentration in solution. The product obtained through the insertion of furazolidone from a DMF/water mixture = 5/1 (with a content of 8.9 mg drug/hydrogel) was studied as to the kinetics of the active principle’s release, in vitro, by using as an eluent a buffer solution, which simulates the gastric fluid (pH = 2.4). The experimental results prove the obtention of a polymerdrug system with controlled release of the biologically active principle, conform to a zero order kinetic, in the time interval ranging between 3–12 hours.

Base triggered release of insecticide from bentonite reinforced citric acid crosslinked carboxymethyl cellulose hydrogel composites

Biopolymeric clay hydrogels composites, synthesized from crosslinking of carboxymethyl cellulose with citric acid in the presence of bentonite, were used to develop base triggered release formulations (TRFs) of thiamethoxam (3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro)amine) through an ex-situ encapsulation technique. Hydrogels, hydrogel-bentonite composites and their formulations were characterized by 1H NMR, IR spectroscopy, XRD, and SEM-EDS. Triggered release of thiamethoxam from the developed formulations was studied in water (pH 7–11) with the help of HPLC and subjected to kinetics analysis using different models. The kinetics study showed the release from developed TRFs followed Gallagher–Corrigan equation with an immediate burst release phenomena and higher release rate of thiamethoxam was observed at alkaline pH than neutral condition (pH 7.0). These TRFs of thiamethoxam may be useful for the efficient control of insects which are having alkaline pH in their gut.

Preparation and characterization of a novel composite containing carboxymethyl cellulose used for bone repair

The composite biomaterial made from nano-hydroxyapatite(n-HA) and chitosan(CS) cross-linked with carboxymethyl cellulose(CMC) by a co-solution method has been studied. Fourier transform infrared absorption spectra (IR), X-ray diffraction (XRD), burn-out test, chemical analysis, transmission electron microscope(TEM) and universal material testing machine were used to test the properties of the composite. The experiment of SBF soaking for 8 weeks was used to investigate their degradation and bioactivity in vitro. The results show that the formation of composite is mainly contributed to the ionic cross-linking of CMC with CS, and n-HA particles in the form of nanometer grade short crystals are uniformly distributed in the organic network structure of polyelectrolyte complexes, which endows the composite with high compressive strength and good bioactivity. The compressive strength and degradation rate are concerned with the content of n-HA. It can be stated that the n-HA/CS/CMC composite whose weight ratio is 40/30/30 may be a potential candidate as one of novel bone repair materials because of its high compressive strength and acceptable degradation rate as well as good bioactivity, displaying a promising prospect of the clinical application of CMC-contained composite in the field of bone repair.

Effect of activated carbon on the properties of carboxymethylcellulose/activated carbon hybrid hydrogels synthesized by γ-radiation technique

Activated carbon (AC) was incorporated into carboxymethylcellulose (CMC) to form CMC/AC hybrid hydrogels with excellent elasticity and flexibility by radiation crosslinking. The effect of AC on the formation, properties and structure of CMC/AC hybrid hydrogels was discussed in terms of gel fraction, gel strength, gel swelling, TGA, FTIR spectra and SEM image. Compared with pure CMC hydrogel, the gel fraction, gel strength and thermal stability were improved obviously after incorporating AC into CMC hydrogels, and similar swelling ability were maintained up to the hybrid of 5%AC. FTIR and TGA spectra of the prepared gels after extracting sol revealed two findings: (1) radiation crosslinking reaction of CMC occurs in side chain of CMC molecules due to the presence of –OH and –CH 2 groups; (2) AC enhanced the radiation crosslinking of CMC because AC was binding to CMC through physical adsorption and hydrogen bond as well as other interactions. From SEM images, it was found that AC particles were embedded in the network of CMC gels to form a uniform structure.

Hydrogel of biodegradable cellulose derivatives. II. Effect of some factors on radiation‐induced crosslinking of CMC

AbstractThe effects of high‐energy radiation on sodium carboxymethylcellulose (CMC) with a degree of substitution of 2.2 were investigated. Moderate CMC concentrations formed hydrogels by intermolecular crosslinking. Significant influences on the results of irradiation, in addition to the concentration, were the dose and dose rate and the presence of oxygen in the surrounding atmosphere. Up to a 95% gel fraction was obtained from 50 and 60% CMC solutions irradiated by an electron beam. CMC hydrogels swelled by absorbing more than 800 g of water per gram of dry gel at a low applied dose. Swelling tests of CMC hydrogels in salt solutions and in media of various pHs showed that the swelling decreased with the salt concentration and was lower at acidic pH values. Radiation yields of crosslinking and scission were calculated on the basis of gel–sol analysis. Crosslinked CMC, in the form of the hydrogel, was degraded by the action of cellulase enzyme, thereby entering the class of environmentally friendly polymers. © 2001 John Wiley &amp; Sons, Inc. J Appl Polym Sci 81: 3030–3037, 2001

Hydrogel of biodegradable cellulose derivatives. I. Radiation-induced crosslinking of CMC

Radiation crosslinking of carboxymethylcellulose (CMC) with a degree of substitution (DS) from 0.7 to 2.2 was the subject of the current investigation. CMC was irradiated in solid-state and aqueous solutions at various irradiation doses. The DS and the concentration of the aqueous solution had a remarkable affect on the crosslinking of CMC. Irradiation of CMC, even with a high DS, 2.2 in solid state, and a low DS, 0.7 in 10% aqueous solution, resulted in degradation. However, it was found that irradiation of CMC with a relatively high DS, 1.32, led to crosslinking in a 5% aqueous solution, and 20% CMC gave the highest gel fraction. CMC with a DS of 2.2 induced higher crosslinking than that with a DS of 1.32 at lower doses with the same concentration. Hence, it was apparent that a high DS and a high concentration in an aqueous solution were favorable for high crosslinking of CMC. It is assumed that high radiation crosslinking of CMC was induced by the increased mobility of its molecules in water and by the formation of CMC radicals from the abstraction of H atoms from macromolecules in the intermediate products of water radiolysis. A preliminary biodegradation study confirmed that crosslinked CMC hydrogel can be digested by a cellulase enzyme. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 278–283, 2000

Practical description of the process called the Daguerreotype, which consists in the spontaneous reproduction of the images of natural objects, in the Camera Obscura, not with their colours, but with great delicacy in the gradation of the tints

Adhesion after abdominal and pelvic surgery results in severe clinical outcomes and a negative impact on the quality of life of a patient. Implanting barrier materials is a common strategy for preventing postoperative adhesion, and non-adhesive carboxymethylcellulose (CMC) is a widely used material for such purpose. Herein, we present CMC/gelatin (CMC/G) hybrid hydrogels as novel barrier materials that aim to reduce the foreign body response (FBR) by combining the biocompatibility and biodegradability of gelatin and the non-adhesiveness of CMC and by realizing mechanical matching with the host tissue. The hydrogels were prepared by the simple reagent-free γ-ray irradiation-induced cross-linking of CMC and gelatin. The hydrogel composition was controlled by varying the initial mixing ratio. The gelatin fraction provided enzyme-mediated degradability at a content ≥ 40%, and the degradation rate was controlled by the radiation dose. The compressive moduli of the hydrogels were tuned to be identical to that of target abdominal organs (several tens of kPa) via 10–30 kGy radiation. The hydrogels sufficiently prevented adhesion of 3T3-Swiss fibroblast cells owing to the non-adhesive capability of CMC which surpassed the high cell adhesiveness of gelatin in the hydrogels. On the other hand, the added gelatin significantly improved the viability of the few cells that adhered to the hydrogels. We found that hydrogels composed of 60% CMC and 40% gelatin exhibited significantly higher cell viabilities while maintaining the non-adhesiveness which is desirable as barrier materials. The in vitro assessments demonstrated the potential of the hydrogel as a novel barrier material with excellent biocompatibility, wound healing promoting effect, and FBR reducing effect by realizing mechanical matching with the host abdominal organs, especially when it was composed of 60% CMC and 40% gelatin and cross-linked at 10–30 kGy to impart compressive modulus of 20–100 kPa.