Chemical Structure Of Cellulose Research Articles

Sustainable Production of Carboxymethyl Cellulose: A Biopolymer Alternative from Sugarcane (Saccharum officinarum L.) Leaves

This study explores the potential of sugarcane (Saccharum officinarum L.) leaves (SCLs), a significant agricultural waste, for the sustainable production of carboxymethyl cellulose (CMC) utilizing an innovative approach of carboxymethylation with monochloroacetic acid and varying sodium hydroxide (NaOH) concentrations (ranging from 20 to 60 g/100 mL). The optimal carboxymethylation condition was identified as 40 g/100 mL NaOH, which yielded the highest degree of substitution (DS = 0.86). Furthermore, a higher ash content in the obtained CMC indicated significant carboxymethyl substitution within the structure. The chemical structure of cellulose and the resulting polymers were characterized using Fourier transform infrared spectroscopy (FTIR). The FTIR spectrum exhibited characteristic peaks of carboxymethyl groups and their salts at wavenumbers of 1588–1591 cm−1 and 1413–1415 cm−1, respectively. The analyses from X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) revealed detailed insights into the crystallinity and morphology of carboxymethyl cellulose (CMC). The levels of heavy metals, including arsenic, lead, cadmium, and mercury, in the purified CMC were assessed using inductively coupled plasma mass spectrometry (ICP-MS) and were found to be within the recommended WHO/FAO limits, except for lead, which exceeded permissible levels. The prepared CMC demonstrated high purity at 99.34%, surpassing the 98.00% purity requirement for commercial-grade CMC. This product exhibits strong potential for diverse industrial applications, including paper coating, textile sizing and printing, ceramic glazing, and various uses in the oil industry.

Cellulose-Based Nanomaterials Advance Biomedicine: A Review.

There are various biomaterials, but none fulfills all requirements. Cellulose biopolymers have advanced biomedicine to satisfy high market demand and circumvent many ecological concerns. This review aims to present an overview of cellulose knowledge and technical biomedical applications such as antibacterial agents, antifouling, wound healing, drug delivery, tissue engineering, and bone regeneration. It includes an extensive bibliography of recent research findings from fundamental and applied investigations. Cellulose-based materials are tailorable to obtain suitable chemical, mechanical, and physical properties required for biomedical applications. The chemical structure of cellulose allows modifications and simple conjugation with several materials, including nanoparticles, without tedious efforts. They render the applications cheap, biocompatible, biodegradable, and easy to shape and process.

Conversion of Carbohydrates in Lignocellulosic Biomass after Chemical Pretreatment

The aim of the study was to determine the quantitative and qualitative changes taking place in biomass components actively participating in methane fermentation, i.e., in carbohydrates, as a result of chemical pretreatment. Analyses were conducted on agricultural waste (corn stover, also called corn straw, and corncobs) as materials most commonly used in methane fermentation, as well as poplar wood, a material relatively rarely used in biogas production. Pretreatment with the aim of increasing efficiency of methane fermentation was carried out with the use of acid and alkaline solutions of different concentrations. The effect of pretreatment on carbohydrates was analyzed based on the quantitative and qualitative changes in this component. Due to the structural heterogeneity of carbohydrates, their varied reactivity and fermentability were determined in terms of holocellulose, cellulose, and pentosans. The chemical structure of cellulose was also analyzed. It is shown in this study that chemical pretreatment causes transformations of carbohydrate components, which differ quantitatively and qualitatively in the compared raw materials. It was found that the alkaline treatment caused smaller changes in the percentage shares of the carbohydrate biomass components as compared to the acid treatment. Moreover, it was observed that the compared materials differ in terms of quantitative changes in their chemical composition depending on the composition of the raw material prior to pretreatment. In the case of corn waste subjected to the action of 1 and 3% NaOH, the share of pentosans in the biomass increased. It was established that this is a change with a positive effect on fermentation efficiency. The action of acids and alkalis on the biomass led to similar structural changes in cellulose, which are adverse for the fermentation process.

Nanocellulose Extraction of Pineapple Leaves for Chitosan-starch Nanocomposites

ABSTRACT Cellulose fibers obtained from waste pineapple leaves were chemically treated with acid hydrolysis for reduction to nanoscale size. Once the cellulose nanofibers were obtained, they were used as a reinforcing material (0.3%–1.0%) of a chitosan-starch matrix. Transmission and scanning electron microscopy was used to check the morphology and reduction of the fiber, with which it was demonstrated that the chemical structure of cellulose was not damaged. Once the composites were obtained, thermal tests were carried out through a thermogravimetric analysis and differential scanning calorimetry, in which it was observed that the thermal stability was not affected by the use of the reinforcement. Fourier transform infrared (FTIR) analysis confirmed interactions between hydroxyl groups and amino groups of polysaccharides. Finally, a dynamic mechanical analysis was performed, in which the increase in the storage module of up to 90% was observed with only 0.7% of the nanofiber reinforcement. Through the results obtained in this research, the use of pineapple leaves as raw material for obtaining cellulose nanofibers is verified, which can be an alternative as a use of matrix reinforcement, suggesting an alternative for the replacement of synthetic reinforcements.

Preparation and characterization of gentamycin sulfate-impregnated gelatin microspheres/collagen–cellulose/nanocrystal scaffolds

In this study, a kind of antibacterial collagen (Coll)/cellulose nanocrystals (CNCs) scaffolds was prepared and characterized, which can be applied in skin trauma as a promising dressing. In order to achieve the goal of antibacterial function for a period of long time, the Gentamycin sulfate (GS) was absorbed in the prepared gelatin microsphere (GMs) then doped in the porous Coll–CNCs freeze-drying scaffold. The CNCs had a width of 20–40 nm and length of 150–350 nm from electron microscopy (TEM), retained the basic chemical structure of cellulose observed from Fourier transform infrared, and increased the machinery properties of Coll scaffold from thermal property analysis. From the SEM, the mean pore size of the compound scaffolds was about 120 μm with or without GMs. The in vitro release profile of GS showed a sustained release of this GS/GMs/Coll–CNCs composite scaffold. The biological compatibility experiments showed the composite scaffold low cellular cytotoxicity of NIH-3T3 cells. The significant inhibition zones indicated the antibacterial efficacy of the composite scaffold against Escherichia coli and Staphylococcus aureus.

Value added of mulberry paper waste by carboxymethylation for preparation a packaging film

Cellulose from mulberry paper waste was converted to carboxymethyl cellulose (CMCm) by etherification using chloroacetic acid and various sodium hydroxide (NaOH) concentrations (30-60 g/100 mL). The degree of substitution of the various CMCm materials produced ranged between 0.33-0.45. The chemical structure of cellulose and the synthesized CMCm materials was characterized using Fourier transform infrared spectroscopy. CMCm films were cast and tested. The tensile strength (TS) and percent elongation at break (EB) of the films were investigated. The highest TS (32.58 MPa) and EB (2.39%) were found using the 50g /100 mL NaOH-synthesized CMCm film. The effect of glycerol as a plasticizer on TS and EB of this CMCm film was also evaluated. Increasing the glycerol content decreased TS and increased EB of the CMCm films.

Pretreatment of Bamboo Powder for Cellulose Nanocrystalline by Sulfuric Acid Hydrolysis

The pretreatment of bamboo fiber by the sulfuric acid was investigated by means of experiments. Effect of the sulfuric acid concentration, reaction temperature, hydrolysis time, and solid-liquid ratio on the yield of Cellulose Nanocrystalline (CNC) was studied by orthogonal experiments and single factor experiments. Pretreatment with 60% sulfuric acid and 1:8 solid-liquid ratio for 90 min at 45°Cwas found to be the most optimal condition for pretreatment of bamboo powder for CNC. After pretreatment at the optimal condition, 30.2% of theoretical yield was obtained. Meanwhile, the study of rheological properties showed that CNC had a shear thinning phenomenon, the viscosity of CNC varied in different temperature and different concentrations. We can draw the conclusion through Transmission electron microscopy (TEM) that CNC was mainly existed in two forms of rod and porous network, and had a basic chemical structure of cellulose, while the molecular internal hydrogen bonds were destroyed.

High-flux and anti-fouling cellulose nanofiltration membranes prepared via phase inversion with ionic liquid as solvent

It is well-known that cellulose is difficult to dissolve in common organic solvent and be directly processed into porous membrane. In this work, using ionic liquid, 1-allyl-3-methylimidazolium chloride (AMIMCl) as solvent, high flux and anti-fouling cellulose nanofiltration (NF) membranes were fabricated by phase inversion method from 8.0 wt.% of cellulose/AMIMCl solutions. Pure water was employed as the non-solvent in phase inversion process. From the result of polarized light microscopy, we found that cellulose was completely dissolved in the AMIMCl at 90 °C. The characterizations of Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopies showed that no obvious changes occurred in the chemical structure of cellulose after membrane formation, but the crystallinity had a remarkable decreased. Membrane morphologies of the fabricated cellulose membranes including the cross-section and the surface were analyzed by scanning electron microscopy (SEM). It was found that the AMIMCl had a distinctive effect on phase inversion process and the cellulose selective layer displayed a macrovoid-free and relatively dense layered structure. Based on the filtration experimental results, the pure water permeation flux of the membranes reached 128.5 L/m 2h under 0.4 MPa, and the molecular weight cut-off was less than 700 Da. The membranes exhibited a good stability and anti-fouling ability in water-phase separation process, and were suitable as NF membranes to separate the organic compounds with a medium molecular weight.

Heterogeneous Preparation of Polyaniline-Cellulose Conductive Composites with Cellulose Pretreated by Ultrasonic and its Electrical Properties

A series of conductive composites polyaniline(PANI)-cellulose were heterogeneously synthesized by chemical oxidative polymerization of aniline with native cellulose pretreated by ultrasonic. The morphology and chemical structure of the composites were examined by SEM and FTIR. TGA was used to study their thermal properties. The electrical conductivity was measured at room temperature by the standard four-probe method. For the sake of illuminating the influence of ultrasonic pretreatment on the structure and properties of PANI-cellulose composites, the SEM microphotographs, FTIR spectrum and TG curve of the PANI-cellulose composites prepared with native cellulose without any treatment were also shown in this paper to serve as reference. The PANI content and electrical conductivity of these two composites were also compared. It was found that cellulose surface was severely eroded by ultrasonic wave, and PANI homogeneously dispersed on this eroded cellulose surface in the form of particles. In reverse, the PANI particles loaded on the surface of untreated cellulose with evident aggregation. The homogeneous dispersion of PANI particles would be favor for the improvement of the electrical conductivity of the composites. From the FTIR spectra, it was verified that there was no difference between these two composites. It indicated that ultrasonic force did not lead to the variation of the chemical structure of cellulose. TG curves revealed that the thermal stability of PANI-cellulose composites was obviously enhanced than pure cellulose due to the protection of PANI particles deposited on its surface. Nevertheless, ultrasonic has a negative effect on the thermal stability of the composites, which resulted in the long cellulose molecular chains change into shorter ones, so the decomposition of composite occurred at lower temperature. It was because that ultrasonic pretreatment contributed to the homogeneous dispersion of PANI and more PANI particle depositing on the cellulose surface. Therefore, the PANI-cellulose composites with ultrasonic pretreated cellulose have more PANI content and higher electrical conductivity than the composites with untreated cellulose. Moreover, the difference of these two factors between the two composites became more and more marked with increasing of the amount of aniline. When aniline used was up to 0.5 g, the PANI content in the former was 48.2% more than the latter. This work provided a facile method for the synthesis of PANI-cellulose conductive composites with excellent conductivity.

Graft copolymerization of vinyl monomers on modified cottons. VI. Vinyl graft copolymerization initiated by manganese (IV)

The ability of potassium permanganate in the presence of different acids to induce grafting of methyl methacrylate and acrylonitrile onto sodium hydroxide-treated cotton, partially carboxymethylated cotton, partially cyanoethylated cotton, and partially acetylated cotton was investigated. The copolymerization reaction was carried out under a variety of conditions. The graft yields are greatly enhanced by increasing concentration of monomer, reaction time, and temperature. The opposite holds true for initiator at higher concentrations. The effectiveness of the acids was: nitric acid > sulfuric acid > perchloric acid > hydrochloric acid. The change in the physical and/or chemical structure of cellulose by its modification via etherification reaction or esterification reaction had a significant effect on the susceptibility of cellulose toward grafting. While partial carboxymethylation or partial cyanoethylation of cellulose prior to grafting increased the graft yield, partial acetylation caused a decrease.

Chemical structure of cellulose modified with diglycidyl ether

Chemical structure of cellulose modified with diglycidyl ether

Studies in chemically modified celluloses. II. Some aspects of physical properties of chemically modified celluloses

AbstractThe changes in physical properties such as moisture regain, tensile strength, elongation at break, bursting strength, and resistance to abrasion of cellulose modified with different oxidizing agents such as dichromate–sulfuric acid, sodium hypochlorite in presence of leuco vat dyes, and potassium metaperiodate and of the corresponding products obtained as a result of reduction with sodium borohydride and those by oxidation with chlorous acid have been studied. Results are critically discussed in the light of existing knowledge on the changes that occur in the fine structure as well as in the chemical structure of cellulose during the mentioned modifications. It is pointed out that complex changes in physical properties of cotton cellulose brought about by chemical modification could hardly be evaluated and interpreted in terms of one or two physical or chemical parameters.