Chemical Modification Of Cellulose Research Articles

Covalent immobilization of organophosphorus hydrolase enzyme on chemically modified cellulose microfibers: Statistical optimization and characterization

Organophosphorus hydrolase (OPH) from Flavobacterium ATCC 27551 was covalently immobilized on epoxy modified plant cellulose powder. The Taguchi method was applied to optimize the conditions of cellulose activation and binding of the OPH to the carrier surface. The chemical modification of cellulose by covalent coupling with 1, 4-butanediol diglycidyl ether was demonstrated using the FTIR technique. TEM analysis proved good linkage of the OPH over the support surface. At the identified optimum condition of affecting parameters, the activity yield of immobilized OPH on the modified cellulose was found to be 68.32%. The kinetic parameters, Km and Vmax values, were calculated and it was determined that the catalytic efficiency of the immobilized OPH was about 4.85-fold lower than that of free enzyme. The storage, thermal, and pH stabilities of the immobilized OPH were improved compared with free counterpart. The results revealed that after incubation for 24 h at 55 °C, the soluble and immobilized OPH retained 8% and 35% of their initial activities, respectively. Furthermore, the immobilized OPH showed a 59% residual activity when used ten times repeatedly. Therefore, plant cellulose as a low-cost carrier has shown excellent properties for enzyme immobilization to be used as biocatalytic material in large scale applications.

A new thermoset for separation of polystyrene and naphthalene in preparative chromatography

ABSTRACTMany research groups in recent years have demonstrated the importance of obtaining new materials and reducing environmental impact. In this context, the chemical modification of cellulose and its derivatives has received much attention. This study synthesized cellulose acetate gel (CAMDIH) obtained through the modification of cellulose acetate (CA) with a degree of substitution of 2.5, by crosslinking reactions using 4,4′‐diphenylmethane diisocyanate in homogeneous medium. The formation of crosslinks were observed by the presence of Fourier transform infrared spectroscopy absorption bands at 3046 and 864 cm−1, which correspond to the absorption of aromatic groups associated with the incorporation of 4,4′‐diphenylmethane diisocyanate in the CA structure. The potential applications of the gel as a stationary phase were tested using column chromatography in the fractionation and separation of standard solutions of polystyrene and naphthalene. The findings showed the effectiveness of the gel as a stationary state in the separation of mixture compounds. Furthermore, the study found that CAMDHI is an innovative material when considering its simple synthesis and the low costs involved in the process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46063.

Direct Modification of Microcrystalline Cellulose with Ethylenediamine for use as Adsorbent for Removal Amitriptyline Drug from Environment.

Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution. The modification reaction was confirmed by X-ray Diffraction (XRD), elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry/Differential Scanning Calorimeter (TG/DSC), solid state Nuclear Magnetic Resonance of 1H and 13C (1H-NMR and 13C-NMR). Moreover, the effectiveness of reaction was confirmed by computational calculations using Density Functional Theory (DFT) at level B3LYP/6-31G(d). This adsorption process was influenced by pH, time, concentration, temperature and did not show significant changes due to the ionic strength variation. Through these experiments, it was observed that the maximum adsorption capacity of AMI by CN polymer at 298 K, 300 min, and pH 7 was 87.66 ± 0.60 mg·g−1.

Chemical Modification of Cellulose Isolated from Underutilized Hibiscus sabdariffa via Surface Grafting: A Potential Bio-based Resource for Industrial Application

Chemical Modification of Cellulose Isolated from Underutilized Hibiscus sabdariffa via Surface Grafting: A Potential Bio-based Resource for Industrial Application

Fabrication and characterization of zirconium cross-linked carboxymethyl cellulose-chitosan microparticles for bone tissue engineering application

Event Abstract Back to Event Fabrication and characterization of zirconium cross-linked carboxymethyl cellulose-chitosan microparticles for bone tissue engineering application Bipin Gaihre1 and A Champa Jayasuriya1, 2 1 The University of Toledo, Department of Bioengineering, United States 2 The University of Toledo Medical Center, Department of Orthopaedic Surgery, United States Introduction: Carboxymethyl cellulose (CMC) and chitosan (CS) are natural biodegradable and biocompatible polymers. CMC is an anionic polymer obtained through chemical modification of cellulose and CS is a cationic polymer derived from chitin and hence being oppositely charged these two polymers can undergo ionotropic gelation[1]. Zirconium (Zr) is a tetravalent cationic metal extensively used in orthopedic implants to promote osseointegration in the form of zirconia and has recently been found to stimulate proliferation and differentiation of human osteoblasts by stimulating different signaling pathways[2]. This study was aimed at developing injectable, non-toxic polyelectrolyte polymer complex microparticles based on Zr as a novel cross-linker. We hypothesize the use of Zr as cross-linker will not induce any cytotoxicity and promote adhesion of osteoblasts into microparticle. Methods: Aqueous solution of CMC (3% w/v) was prepared and added dropwise into the homogenous mixture of zirconium tetrachloride solution (5% w/v) and CS solution (1% w/v) and kept under stirring for 1 h. The volume ratio of CMC to CS was optimized at 1:2 for improved complexation between two polymers. The particles thus obtained were then dried at room temperature for 48 h before further analysis. The surface morphology of microparticles was characterized by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) was done for elemental analysis. Fourier transform-infrared (FTIR) spectrometer in ATR mode was used to characterize the intramolecular interaction between the components in microparticle. In vitro cytotoxicity was assessed using live/dead cell assay kit after culturing the murine pre-osteoblasts (OB-6) in the presence of microparticles up to 10 days. In order to specifically determine the viability of cells attached to microparticle, the microparticles were transferred into separate well of 24 well-plate and then live/dead cell assay was performed on day 5 and 10 and imaged under fluorescence microscope. The percent area of microparticle covered with cells was determined using ImageJ taking visible portion of microparticle. Results and Discussion: The microparticles were spherical in shape with an average diameter of 787±0.045 µm. The surface of the microparticles contained uniform grooves and ridges creating rougher surface as seen on SEM image (Fig. 1B). Few intact cracks were also observed on the surface of microparticles which might be due to the excessive evaporation of solvent and hence high shrinkage during drying process. EDS data obtained showed the presence of Zr along the surface of microparticles. The comparison of FTIR spectrum of CMC, CS and microparticle showed the presence of all characteristic peaks of both CMC and CS on microparticle. Moreover, absorbance band at 1580 cm-1 corresponding to the characteristic band of NH3+ and COO- suggested strong electrostatic interaction and hence complexation between two polymers (Fig. 2). The use of Zr as a cross-linker did not induce any cytotoxicity as most of the cells were viable up to 10 days of culture with microparticles. Fluorescence images of cells seeded microparticle showed adhesion of cells to the surface of microparticle (Fig. 3). The area percent of cells covering microparticle was significantly higher at day 10 (42%) compared to that at day 5 (15%) suggesting the proliferation of cells on microparticle. Conclusion: In this study, an injectable CMC-CS polyelectrolyte complex microparticles with Zr as a novel crosslinker was developed. Based on the results obtained, it can be concluded that polyelectrolyte complexation occurs between CS and CMC which can be developed into injectable microparticles by crosslinking with Zr. Zr used in this study was not cytotoxic and provided a suitable surface for cell adhesion and proliferation by enhancing the surface roughness of microparticle. National Institute of Health (NIH) (grant number R01DE023356)

Methylcellulose, a Cellulose Derivative with Original Physical Properties and Extended Applications

This review covers the preparation, characterization, properties, and applications of methylcelluloses (MC). In particular, the influence of different chemical modifications of cellulose (under both heterogeneous and homogeneous conditions) is discussed in relation to the physical properties (solubility, gelation) of the methylcelluloses. The molecular weight (MW) obtained from the viscosity is presented together with the nuclear magnetic resonance (NMR) analysis required for the determination of the degree of methylation. The influence of the molecular weight on the main physical properties of methylcellulose in aqueous solution is analyzed. The interfacial properties are examined together with thermogelation. The surface tension and adsorption at interfaces are described: surface tension in aqueous solution is independent of molecular weight but the adsorption at the solid interface depends on the MW, the higher the MW the thicker the polymeric layer adsorbed. The two-step mechanism of gelation is confirmed and it is shown that the elastic moduli of high temperature gels are not dependent on the molecular weight but only on polymer concentration. Finally, the main applications of MC are listed showing the broad range of applications of these water soluble cellulose derivatives.

New PP/PLA/cellulose composites: effect of cellulose functionalization on accelerated weathering behavior (accelerated weathering behavior of new PP/PLA/cellulose composites)

Polylactic acid (PLA) was used as partial replacement for conventional thermoplastic matrix, new composites comprising cellulose, polypropylene (PP), and PLA being realized. In order to obtain a compatible interface between cellulosic pulp and polymeric matrix, two chemical modifications of cellulose with stearoyl chloride and toluene di-isocyanate (TDI) were performed, structural changes being evidenced by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The composite materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic scanning calorimetry, impact, tensile and melt rheological tests, surface tension, and dynamic vapor sorption. Because promising results for impact strength and Young modulus were recorded when replacing 15% of PP with PLA in blends of PP with the same cellulosic pulp load, the aim of our study was to assess the behavior to accelerate weathering of composites comprising PP, cellulosic pulp, and PLA. Although the slight decrease in the mechanical properties was recorded after accelerated weathering, the use of functionalized cellulose successfully prevented the deterioration of surface materials, especially for composite comprising stearoyl chloride treated cellulose pulp. Copyright © 2015 John Wiley & Sons, Ltd.

Molecular weight parameters of cellulose nitrates modified with alcohols

We have studied molecular weight parameters of the products prepared via chemical modification of cellulose nitrates with aliphatic alcohols. Proceeding from the quantum-chemical simulation data the most probable pathways of degradation of cellulose nitrate macromolecules have been elucidated.

Preparation and cytocompatibility evaluation for hydrosoluble phosphorous acid-derivatized cellulose as tissue engineering scaffold material

Chemical modification of cellulose by phosphorylation enhances its bioactivity and provides new derivatives and materials with specific end uses. In the present study, cellulose derivatized with phosphorous acid was obtained using the reaction of microcrystalline cellulose with phosphorous acid-urea mixture, in molten state, in comparison with others methods that used different solvents and catalysts. Completely water soluble films with a substitution degree close to one were obtained and characterized by analytical and spectral analysis (FT-IR, (31)P NMR), contact angle, metallographic microscopy and atomic force microscopy (AFM). 31P NMR spectra of derivatized cellulose showed a signal at 2.58 ppm (assigned to P-O-C6) while the doublets at 4.99-5.29 and at 7.38 ppm were assigned to P-O-C2 and P-O-C3, respectively; thus, the formation of monosubstituted phosphorous acid esters of cellulose is advocated. Contact angle measurements showed that the work of adhesion is more important in water than in ethylene glycol, for the phosphorous acid derivatized cellulose. The cytocompatibility of this hydrosoluble derivatized cellulose was tested by direct contact and also by indirect assays on normal human dermal fibroblasts and on osteoblast-like cells (human osteosarcoma). Cell growth on phosphorylated cellulose pellicle and the results from viability assays had shown a good cytocompatibility and lack of toxicity. Phosphorous acid derivatized cellulose would offer a promising biomaterial, useful as scaffolds for new biopolymer composites, and subject for further development as an ionic crosslinker.

Design and synthesis of peptide-cellulose conjugate molecules —Aspects from energy/steric profiles—

A multipurpose chemical modification of cellulose to yield soluble cellulose derivatives was investigated on the basis of (i) O-acylation of the parent cellulose using N-Boc-protected Gly, αAla, and βAla, and subsequent Boc-removal, (ii) N-acylation of amino acid-modified cellulose in homogenous solution reaction system using Boc-oligopeptides with multiple types of the side-chain functionalities, and (iii) N-acylation of βAla-Cellulose using 10 kinds of simple Boc-oligopeptides. As for the (i), Thermochemical computation to estimate ΔG transition was well coincided with the observed yields in Oacylations. In the case of (ii), beside the similar ΔG-schemes, a strain energy profile, which is coupled with the preferred conformer transition of the amino acid-modified cellulose, was involved to rule out the N-acylation. The symmetric anhydrate in the N-acylating agents in the (iii) are tend to be in torsions due to the β-strand-like steric stabilizations in the peptides, resulting in the highest N-acylation yields as much as 98 %.

Chemical modification of cellulose by in situ reactive extrusion in ionic liquid

In order to prepare the spinning solution of cellulose with high concentration in environmentally friendly solvent, cellulose was chemically modified by in situ reactive extrusion with several chemicals, such as urea, phthalic anhydride (PA), maleic anhydride (MA) and butyl glycidyl ether (BGE) and with ionic liquid namely 1-N-butyl-3-methylimidazolium chloride (BMIMCl) as reaction medium. These four modifiers all in situ grafted onto cellulose and the modification effectiveness was found to decrease in the sequence, MA>PA>BGE>urea. The formation of side chain on cellulose backbone destroyed the regularity of cellulose chains and the hydrogen bond network efficiently. The concentration of modified cellulose in spinning solution can be up to 14–25%, comparing with 9% for unmodified cellulose in BMIMCl. The high solid content results in high efficiency and less energy consumption of fiber production and solvent recycle.

Modification of cellulose as a promising direction in the design of new materials

The published data on the chemical and physical modifications of cellulose aimed at creation of a wide variety of new innovative materials for hi-tech and priority directions in the development of science and engineering are summarized. Investigations into the chemical modification of cellulose via nucleophilic substitution, regioselective insertion of functional groups, graft copolymerization, oxidation, and esterification are covered. The importance of studies dealing with the search for new solvents of cellulose aimed at extension of the potential inherent in its modification and processing and in the design of nanocellulose-based materials is emphasized. On the basis of analysis of the literature data, the potential for creation of new functional materials for biomedical investigations, medicine, and electronics is shown.

Cationic derivative of electrospun non-woven cellulose-chitosan composite fabrics for immobilization of aminoacylase-I

The chemical modification of cellulose (Cs)-chitosan (Ch)-electrospun non-woven (ESNW) composite fabrics is described. Since the as-spun Cs/Ch-composite ESNW (Cs : Ch = 4 : 6) deforms in water, an insolublilization procedure using an alkaline-ethanol solution was developed to extend the applications in an aqueous environment. The fine fiber surface was modified with bifunctional isocyanate in order to introduce the -NCO groups on the ESNW surfaces. The -NCO groups were condensed with N, N-(diethyl)ethylene diamine to generate a cationic diethylaminoethyl (DEAE)-ESNW. An enzyme, aminoacylase-I, was immobilized onto the cationic matrix under mild conditions. The immobilized enzyme was subjected to the stereo-specific recognition of Nα-acetyl-methionines. The results suggest that the chemically modified Cs/Ch-ESNW is a useful support matrix for biological catalysts.

Study on the Chemical Modification of Cellulose in Ionic Liquid with Maleic Anhydride

Dissolution and regeneration of cotton cellulose using ionic liquids as solvent was investigated. In this paper, modification of celluloses with maleic anhydride (MA) was carried out in ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).The maleylation celluloses with degrees of substitution (DS) between 0.85and 1.46 were accessible in IL. The effects of reaction time, temperature and mass ratio of the MA in cellulose were investigated. These maleylation celluloses were characterized by infrared spectroscopy, thermogravimetric analysis (TGA). Experiments showed that the optimal conditions for grafting were: mass ratio of maleic anhydride and cotton cellulose 0.8; reaction time of 90 min; temperature of 80 °C.

Ionic liquids--promising but challenging solvents for homogeneous derivatization of cellulose.

In the past decade, ionic liquids (ILs) have received enormous interest as solvents for cellulose. They have been studied intensively for fractionation and biorefining of lignocellulosic biomass, for dissolution of the polysaccharide, for preparation of cellulosic fibers, and in particular as reaction media for the homogeneous preparation of highly engineered polysaccharide derivatives. ILs show great potential for application on a commercial scale regarding recyclability, high dissolution power, and their broad structural diversity. However, a critical analysis reveals that these promising features are combined with serious drawbacks that need to be addressed in order to utilize ILs for the efficient synthesis of cellulose derivatives. This review presents a comprehensive overview about chemical modification of cellulose in ILs. Difficulties encountered thereby are discussed critically and current as well as future developments in this field of polysaccharide research are outlined.

The Effect of Chemical Treatment of Cellulose with Epoxidized Soybean Oil (ESO) on the Properties PVC/Cellulose Composites

The adhesion between vegetable fibres and the polymeric matrix remains one of the technological bolts of the development of composites. Indeed cellulose, the principal constituent of vegetable fibres, is not generally compatible with thermoplastic matrices. Many studies thus focus on the improvement of these properties, in particular by the means of physical or chemical treatments of fibres. The objective of this work was the chemical modification of cellulose by epoxidized soybean oil to improve compatibility between the cellulose and the matrix. The effect on the physico-mechanical properties of the PVC/cellulose composites containing 10 to 30% treated cellulose was studied. The resultant composites were characterized various tests (mechanical, thermal and morphological).

Progress on homogeneously chemical modification of cellulose

Cellulose,as an environmentally friendly renewable resource,has received more and more attention.It has been investigated extensively by both academic and industrial researchers Because of the depletion of oil resources,the increasing pollution of the environment and the urgent need for sustainable development.Based on the unique structure and reactivity of cellulose,chemical modifications play dominant roles in improving the overall utilization of this bioresource.Cellulose derivatives have been found in numerous applications in a variety of fields,including the paper and textile,food,cosmetics,chemical,and pharmaceutical industries.Moreover,homogeneous modification of cellulose has been one focus of cellulose research for a long time.In this review,research development of chemical modification of cellulose in the homogeneously systems in the recent 10 years was summarized and 155 references were cited.Esterification,etherification and graft copolymerization of cellulose in LiCl/N,N-dimethylacetamide,dimethyl sufoxide/tertrabutylammonium fluoride,ionic liquids,and NaOH/urea aqueous solutions have been described in detail.

Chemical modification of cellulose by acylation: Application to adsorption of methylene blue

Cellulose was modified under mild conditions in order to increase its capability to trap pollutants. Nicotinoyl chloride hydrochloride (NCHC), with its pyridine ring able to adsorb cations, was grafted on the substrate. This grafting has been monitored by infrared spectroscopy and elemental analysis. We have studied the adsorption of Methylene Blue (MB) onto grafted and unmodified cellulose. It was observed that grafting increases three times the retention capacity of cellulose and the kinetics of adsorption is perfectly represented by a pseudo second order model. The adsorption is well described by a Langmuir-type isotherm showing a homogeneous adsorption phenomenon through the formation of a monolayer. Besides the reaction is spontaneous and exothermic, suggesting the possibility of recycling the substrate by desorbing the dye at elevated temperature.

Experimental evaluation of eco-friendly flocculants prepared from date palm rachis

Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in many industrial sectors including food, textiles, papers, adhesives, paints, pharmaceuticals, cosmetics and mineral processing. CMCNa was produced by chemical modification of cellulose, and represents many advantages: natural, renewable, non-toxic and biodegradable. In this study, different kinds of CMCNa, prepared from an agricultural waste date palm rachis, were tested as eco-friendly flocculants for drinking water treatment and their performances as flocculants in turbidity removal enhancement were assessed. The prepared materials were characterized by the degree of substitution (DS) and polymerisation (DP). The study of the effect of some experimental parameters on the coagulation-flocculation performance, using the prepared materials combined with aluminium sulphate (as coagulant), showed that the best conditions for turbidity treatment were given for pH 8, coagulant dose 20 mg/L, flocculant concentration of 100 mg/L and stirring velocity (during the flocculation step) of 30 r/min. Under the optimum conditions, the turbidity removal using CMCNa, prepared from raw material, was about 95%. A comparison study between the flocculation performance of a commercial anionic flocculant ( A 100PWG: polyacrylamide) and that of the prepared CMCNa showed that the performance of the waste-based flocculant with a DS of 1.17 and a DP of 480 was 10% better than that achieved by the commercial one.

Regeneration of Bagasse Cellulose by Ionic Liquid

Bagasse is an abundant agricultural byproduct. The use of bagasse has generated much interest due to its low cost, possibility of environmental protection and use of locally available renewable resources. In this paper, cellulose was dissolved in the ionic liquid （1-butyl-3-methylimidazolium chloride） and regenerated in water. FT-IR and SEM were used to characterize the structure of the original and regenerated cellulose. It was found that the treatment of the original cellulose in the ionic liquid significantly degraded the cellulose and completely destroyed the cellulose crystals. Despite many studies of the chemical modification of cellulose published around the world in this area, only a few have been investigated about the regeneration of sugarcane bagasse. Theoretical basis was established for further research on the application of the regenerated cellulose in material science.