Carboxymethylation Reaction Research Articles

Carboxymethylation of viscose and cotton fibers: comparisons of water retention and moisture sorption

The aim of the work was to compare the water retention and moisture sorption of viscose (CV) and cotton (Co) fibers carboxymethylated from aqueous media, in presence of NaOH, with sodium monochloroacetate. It was shown previously that under the same treatment conditions, the degree of carboxymethylation was higher in CV and so was the depth within fiber structures to which the carboxymethylation reactions occurred. It was also shown previously, that in terms of their capacity for sorption of a cationic dye (methylene blue), the Co performed better than CV. In this work, the same fibers were tested for their water retention and moisture sorption propensities. The two were sensitive both to the degree of carboxymethylation and the inherent properties of fibers (accessibility, degree of swelling, hornification). But the moisture sorption levels were less sensitive to the degree of carboxymethylation and more to inherent fiber properties whereas the reverse was observed for water retention. In contrast to the prior observations with dye sorption, CV performed better than Co in both moisture sorption and water retention. The poor performance of CV in dye sorption was attributed to the greater depth of carboxymethylation within the fibers that hindered dye permeation, but the same feature was observed to result in better performance (water retention) or not to hinder performance (moisture sorption). These observations highlight the contrasting effects that may arise, of a given set of treatment parameters (fiber type, alkali level in treatment), on efficacy of the product performance.

Action of AA9 lytic polysaccharide monooxygenase enzymes on different cellulose allomorphs

Lytic polysaccharide monooxygenase (LPMO)-catalyzed oxidative processes play a major role in natural biomass conversion. Despite their oxidative cleavage at the surface of polysaccharides, understanding of their mode of action, and the impact of structural patterns of the cellulose fiber on LPMO activity is still not fully understood. In this work, we investigated the action of two different LPMOs from Podospora anserina on celluloses showing different structural patterns. For this purpose, we prepared cellulose II and cellulose III allomorphs from cellulose I cotton linters, as well as amorphous cellulose. LPMO action was monitored in terms of surface morphology, molar mass changes and monosaccharide profile. Both PaLPMO9E and PaLPMO9H were active on the different cellulose allomorphs (I, II and III), and on amorphous cellulose (PASC) whereas they displayed a different behavior, with a higher molar mass decrease observed for cellulose I. Overall, the pretreatment with LPMO enzymes clearly increased the accessibility of all types of cellulose, which was quantified by the higher carboxylate content after carboxymethylation reaction on LPMO-pretreated celluloses. This work gives more insight into the action of LPMOs as a tool for deconstructing lignocellulosic biomass to obtain new bio-based building blocks.

A novel polysaccharide of Undaria pinnatifida: Structural characterization, carboxymethylation and hypoglycemic activity in vivo

A new polysaccharide (UPP) was isolated and purified from Undaria pinnatifida with a low molecular weight of 8.34 kDa. The UPP was modified to obtain carboxymethylated polysaccharide (CM-UPP). UPP and CM-UPP were characterized by FT-IR, Ion chromatography, Congo red, DSC, SEM and NMR, and their hypoglycemic activity in vivo was investigated using the STZ-induced diabetes mice model. UPP mainly contained Ara, Gal, Glc and Man at a molar ratio of 0.18: 0.13: 2.06: 1, and CM-UPP added two alduronic acids including GalA and GlcA. CM-UPP had been prepared successfully and the carboxymethylation reaction might occur partially at the C-2 and C-4 position. There were no triple helix structures in both UPP and CM-UPP. In vivo hypoglycemic activity studies showed that both UPP and CM-UPP could alleviate symptoms of high blood glucose, improve blood lipid level, oxidative stress state and liver glycolytic enzyme activity in diabetic mice. Under the same dose, CM-UPP showed a more significant effect than UPP. These results indicated that carboxymethylation was an effective way to enhance the hypoglycemic activitiy of polysaccharide. UPP and CM-UPP could be potential therapeutic agents of T2DM.

Extraction and Characterization of Cellulose from Broccoli Stems as a New Biopolymer Source for Producing Carboxymethyl Cellulose Films.

The use of food and agricultural waste-derived carboxymethyl cellulose (CMC) has become of interest due to their biodegradability and cost-effectiveness. In the current research, cellulose was extracted from broccoli stems to produce carboxymethyl cellulose using a carboxymethylation reaction via chloroacetic acid (CAA) and sodium hydroxide (5-10 M). The effects of different synthesis conditions on the degree of substitution (DS) and viscosity of the synthesized CMC powder were investigated. The mechanical properties, water vapor permeability (WVP), and colour of CMC films were also evaluated. The results showed that CMC with the highest DS value (0.60) and the highest viscosity of 0.5 Pa·s could be synthesized from broccoli stems at a concentration of 7.5 M NaOH and a cellulose-to-chloroacetic acid ratio of 1 : 1.2. At CMC concentration of 4 g/100 mL with 0.8 g/100 mL of glycerol, the films had the highest tensile strength (31.91 MPa), whereas with 1.2 g/100 mL glycerol, more flexible films with elongation at break of 27.56% were produced. CMC films with the highest WVP (7.87 × 103 gm2·mmHg-1/day) were made with 6 g/100 mL of CMC and 1.8 g/100 mL of glycerol. This research proposes a new source of cellulose to produce biodegradable packaging materials to initiate a practical basis for food waste reuse.

Electron beam pre-irradiation enhances substitution degree, and physicochemical and functional properties of carboxymethyl peanut shell nanocellulose

Nanocellulose (NC) has attracted close attention in research and industry fields because of its excellent properties and plentiful hydroxyl group accessible for surface modification. In this study, the cellulose isolated from peanut shells was used to prepare carboxymethylated nanocellulose (CMNC) under different reaction conditions, and Electron beam irradiation (EBI) pretreatment with different doses (40, 80 and 120 KGy) was previously used before modification to improve the reaction accessibility of nanocellulose. The substitution degree (DS), structural, physicochemical and functional properties of carboxymethyl CMNC with EBI pretreatment were investigated. The results showed that the peanut shell nano cellulose was a typical rod-like structure with a diameter of 5–40 nm and a length of 50–300 nm, the aspect ratio distribution was about 6.37, and EBI pretreatment significantly improved the modification effect of CMNC. The DS of the unirradiated sample was 0.38 and 0.48, and the DS increased to 0.66 and 0.69 at the irradiation dose of 120 kGy, which increased by 74% and 44%, respectively. The carboxymethyl modification changed the morphology of nanocellulose from the original short rod-like to spherical particles, and the effect was more evident with the increase of irradiation dose. FTIR showed that the nanocellulose successfully introduced carboxyl groups, the crystalline structure of nanocellulose was changed by carboxymethyl reaction. The Zeta potential result showed that the dispersion stability of CMNC suspension was improved. These results provide a helpful basis for further investigations on the modification in nanocellulose induced by EBI, verifying the effectiveness and feasibility of using EBI to modify nanofibers. They are expected to guide the transformation of nanocellulose and its most possible applications in the future to improve its performance in different applications.

Removal of Pb (II), Zn (II), Cu (II), and As (III) ions from water using kraft pulp-based carboxymethylated cellulose in a fixed-bed column adsorption process

Carboxymethylated cellulose containing 1.2 mmol -COOH/g was synthesized from kraft pulp (KP) through a carboxymethylation reaction. This carboxymethylated KP was employed as a sustainable adsorbent for the removal of heavy metal ions, including Pb (II), Zn (II), Cu (II), and As (III), from water. The adsorption process was conducted in both single and multi-component systems using a fixed-bed column. The results showed that the adsorbent effectively removed approximately 99 % of each metal ion from water under the following conditions: feed pH of 5.5, feed flow rate of 15 mL/min, and feed concentrations of 10 mg/L (for the single component system) and 2.5 mg/L for each metal ion (for the multi-component system). The metal ion retention capacities of the adsorbent were determined as 101.0 mg/g for Pb (II), 33.7 mg/g for Zn (II), 31.7 mg/g for Cu (II), and 20.0 mg/g for As (II) in the single component system, and 20.3 mg/g for Pb (II), 8.4 mg/g for Zn (II), 7.8 mg/g for Cu (II), and 4.5 mg/g for As (III) in the multi-component system. Moreover, a simple acid treatment using a 0.01 M HCl solution was found to be highly effective in regenerating the adsorbent. Even after the fifth regeneration/reuse cycle, the adsorbent was completely regenerated, demonstrating its potential for repeated use.

Liquid handling properties of carboxymethyl modified chitosan nonwovens for medical dressings

Chitosan (CS) is known to have excellent antibacterial, anti-inflammatory and hemostatic properties, while its liquid handling performances are dissatisfactory, making it hard to maintain a moist environment as wound dressings. In this study, the carboxymethyl chitosan (CMCS) needle-punched nonwovens were prepared by chloroacetic acid method. The structure and properties of CS and CMCS nonwovens were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), mass per unit area and thickness. Moreover, the liquid handling properties, including liquid absorption, retention, diffusion and contact angle were further investigated. The optimal parameters for carboxymethyl modification were explored via orthogonal experiments. Results demonstrated that CMCS nonwovens were successfully prepared, and the optimal conditions for carboxymethyl reaction were NaOH concentration of 30%, NaOH to chloroacetic acid molar ratio of 5:1, and etherification time of 4 h. The liquid absorption, retention, diffusion and hydrophilic properties of CMCS nonwovens were evidently enhanced compared with pristine CS nonwovens. Owing to the outstanding liquid handling properties, the proposed CMCS nonwovens might have potential application as medical dressings.

Evaluation of the Physical Properties of Carboxymethylated Cellulose Nanofiber Derived from Red Algae Pulp

This study investigated the utility of red algae bleached pulp (RaBP) as a raw material for producing carboxymethylated cellulose nanofiber (CM-CNF). Hardwood bleached kraft pulp (HwBKP) was used as control. Two types of carboxymethyl celluloses (CMCs) made from RaBP and HwBKP, respectively, were prepared according to the degree of carboxymethylation (CM), while considering the sodium hydroxide and chloroacetic acid dosage: low and high CM. Furthermore, the fiber morphology and charge density of the CMCs were evaluated to verify the carboxymethylation reaction. The final CM-CNFs produced from CMCs were ground for five passes using a microgrinder, and their fiber width, low-shear viscosity, and zeta-potential were analyzed.BRMorphology of CMCs revealed that the fibers were swollen and dissolved in water to produce transparent fibers. The charge density of the CMCs increased with increasing chemical dosage. When comparing CMCs according to species, the fiber size and charge density of CMC made from RaBP showed lower values than HwBKP. As the chemical dosage increased, fiber width and zeta-potential of CM-CNFs decreased, and their low-shear viscosity increased. The CM-CNFs made from RaBP had a lower fiber length and zeta-potential than those made from HwBKP. Therefore, RaBP can be potentially used to manufacture small and anionic CM-CNF by combining a carboxymethylation pretreatment and micro grinding.

A novel approach in increasing carboxymethylation reaction of cellulose

Carboxymethyl cellulose (CMC) with a high degree of substitution (DS) was prepared from hardwood bleached pulp by a novel method. In this method, pulp was refined in PFI mill and/or enzymatically treated prior to carboxymethylation. The DS value of CMC increased from 0.5 to 2.4. The yield and molecular weight of CMC increased with increasing DS value. The correlation coefficient between DS and molecular weight was 0.9992. Spectroscopic, thermogravimetric, x-ray diffraction and scanning electron microscopic (SEM) and titrimetric analyses were performed to confirm the degree of substitution and surface modification of the cellulose. Micrograph and SEM image confirm surface modification of cellulose in prior treatment. A comparison of the FTIR spectra of the prepared CMC and standard CMC shows the presence of bands corresponding to ˗O˗, CH2˗ and ˗COO in the CMC, while these bands do not appear for cellulose. The crystallinity of untreated pulp was slightly decreased, while the crystallinity of the prepared CMCs was diminished.

Effects of Reaction Time on Degree of Substitution, Yield and Morphology of Carboxymethyl Cellulose from Banana Peel

Carboxymethyl cellulose(CMC) was extracted from cultivated banana peel (BP) agricultural waste. Cellulose was first extracted from BP through delignification, bleaching and hydrolysis processes. Then, CMC was prepared by the carboxymethylation reaction using monochloroacetic acid as a modifying agent. A mixture of 30% sodium hydroxide solution and isopropanol was used as the solvent medium for etherification with reaction time of 1-5 hours. The effects of reaction time on physical appearance, chemical structure, degree of substitution (DS), percent yield (%yield) and morphology of CMC were studied. Results indicated that banana peel cellulose (BPC) powder could be extracted from BP with yield of 14.81%±7.20. CMC was successfully prepared from BPC powder and confirmed by FT-IR technique. DS and %yield of CMC increased when reaction time increased from 1 to 4 hours but decreased when reaction time reached 5 hours. Reaction time of 4 hours gave optimal DS and %yield at 0.61±0.05 and 152.65±17.93, respectively. BPC presented bulk particle shape with a dense and smooth surface. After etherification, morphology of BPC was changed to a mixture of small particles with fibrous shape and a porous rough surface.

Facile Post-Carboxymethylation of Cellulose Nanofiber Surfaces for Enhanced Water Dispersibility.

To improve the water dispersibility of cellulose nanofibers without deteriorating the physical properties, it is necessary to develop methods that can selectively modify fiber surfaces. Herein, the reaction conditions for carboxymethylation of the surface of nanofibrillated bacterial cellulose were optimized using chloroacetic acid as an etherification agent. Carboxymethylation in a high-concentration alkaline solution (>5 wt %) in the presence of isopropanol caused the mercerization and carboxymethylation of not only the nanofiber surface but also the cellulose crystals within the nanofiber, resulting in nanofiber swelling and an increase in fiber width. In contrast, with a dilute alkaline aqueous solution (3 wt %), the nanofiber surface was successfully carboxymethylated without changing the inner structure. Furthermore, the morphology was not affected by the carboxymethylation reaction, and no fiber swelling occurred under these reaction conditions. When the substitution reaction proceeded only on the nanofiber surface, the maximum degree of substitution (i.e., the average number of carboxymethyl groups substituted per anhydroglucose residue in cellulose) was 0.091. After surface modification, the nanofibers became more negatively charged, which improved the dispersibility in water through electrostatic repulsion, resulting in a drastic increase in the transparency of the nanofiber dispersion. This method provides a general approach for the surface modification of cellulose nanofibers to increase water dispersibility.

Synthesis and Characterization of Carboxymethyl Cellulose from Eichhornia crassipes and Pennisetum purpureum as Potential Source of Sustainable Drilling Mud Additives

Cellulose extracted from Eichhornia crassipe (Water hyacinth) and Pennisetum purpureum (elephant grass) yielded 21.88% and 31.39% respectively. Cellulose extracted was used to synthesize carboxymethyl cellulose (CMC) under heterogeneous condition with ethanol as the supporting medium. Effect of concentration of sodium hydroxide (NaOH) on the modification of cellulose to yield CMC was investigated. It was observed that percentage CMC yield increased with increase in NaOH concentration. Comparative studies of the two biomass samples through physico-chemical analyses in terms of degree of substitution (DS), water absorption capacity, water loss, pH, conductivity and analytical characterization using SEM-EDX, FT-IR and EDXRF spectroscopy of the extracted cellulose and synthesized CMC were done. The DS of CMC obtained by alkalization reaction of cellulose from E. crassipe and P. purpureum with monochloroacetic acid was in the range of 0.54-0.75 which showed that it is highly soluble. Fourier Transform-Infrared (FT-IR) spectrophotometer showed changes of functional group from cellulose to CMC. The absorption at 3283 cm-1 and 3320 cm-1 as observed in E. crassipe and P. purpureum spectra showed OH vibration of polymeric compounds. The presence of bands at 1592 cm-1 and 1417 cm-1 in E. crassipe spectrum and bands at 1566 cm-1 and 1410 cm-1 observed in P. purpureum spectrum showed the presence of –COO group as a result of carboxymethylation reaction on cellulose during modification process. EDXRF was applied for quality control and product development due to the unavailability of the elemental composition of elephant grass and water hyacinth in the literature. The morphology and elemental compositions on the surface of the biomass were analyzed by SEM-EDX and among the chemical elements detected were C, O, Na, Mg, Al, S, Cl, K, Ca, Fe Si and Zr which confirms the elements identified with EDXRF spectroscopy. XRF spectra show high peaks at Fe, K and Sn for untreated P. purpureum samples and high peaks at Ca, Fe and Sr for untreated E. crassipe fiber. Both samples are rich in Iron (Fe). Samples were free from some toxic elements such as Pb, As, Hg, V and Ni which makes them safe for use as novel raw materials for industrial applications. Also very low concentration of Sulphur in the samples, make them safe to be considered as additives in drilling mud formulation.

Synthesis and Characterization of Carboxymethyl Cellulose Derived from Empty Fruit Bunch

Oil palm empty fruit bunch (EFB), a cellulose rich lignocellulosic biomass has huge potential to be utilised as a raw material for the synthesis of carboxymethyl cellulose (CMC). In this study, CMC was synthesised from EFB extracted cellulose at the optimum carboxymethylation reaction conditions. The extracted cellulose yield obtained by alkaline treatment followed by bleaching with hydrogen peroxide was 45.5 wt.%. The cellulose structure was elucidated using thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) patterns. Meanwhile, the synthesised CMC was characterised with FT-IR, XRD and scanning electron microscopy (SEM). The maximum degree of substitution (DS) obtained was 1.30 with the yield of 177.51 wt.% and purity 89% determined using chemical methods at the optimum conditions of 30 wt.% of NaOH, 18 g of SMCA, 65 °C, 3 h reaction time and less than 75 μm of EFB-cellulose particle size. XRD analysis inferred low crystallinity while FTIR spectra verified the CMC structure and presence of different functional groups. The results for DS and EFB CMC yield obtained from this work were considerably higher than those reported in the literature. The synthesised EFB CMC can be further utilised in various industries such as detergent, mining, flotation, and oil and gas drilling muds applications.

Modification of Branched Polyethyleneimine Using Mesquite Gum for Its Improved Hemocompatibility.

In the present study, the modification of branched polyethyleneimine (b-PEI) was carried out using mesquite gum (MG) to improve its hemocompatibility to be used in biomedical applications. In the copolymer synthesis process (carboxymethylated mesquite gum grafted polyethyleneimine copolymer (CBX-MG-PEI), an MG carboxymethylation reaction was initially carried out (carboxymethylated mesquite gum (CBX-MG). Subsequently, the functionalization between CBX-MG and b-PEI was carried out using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as crosslinking agents. The synthesis products were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Thermogravimetric analysis showed that CBX-MG and CBX-MG-PEI presented a lower decomposition temperature than MG. The CBX-MG-PEI has a high buffer capacity in the pH range of 4 to 7, similar to the b-PEI. In addition, the CBX-MG-PEI showed an improvement in hemocompatibility in comparison with the b-PEI. The results showed a non-hemolytic property at doses lower than 0.1 µg/mL (CBX-MG-PEI). These results allow us to propose that this copolymer be used in transfection, polymeric nanoparticles, and biomaterials due to its physicochemical and hemocompatibility properties.

Chemical treatment of grafted rubber‐based conductive polymer film for homogeneity improvement

AbstractConductive polymer film that possess stable electrical conductivity and good mechanical performance was prepared with the incorporation of polyaniline (PAni) and carboxymethyl cellulose (CMC) in grafted rubber (MG49) matrix was synthesized in this research study. PAni was synthesized through the chemical oxidation process while CMC was produced using the carboxymethylation reaction. Besides, conductive polymer films of MG 49/PAni/CMC were synthesized using ex‐situ polymerization. The optimum reinforcement of CMC in the polymer films was proven through UTM analysis at 8% CMC loading with tensile strength and Young Modulus of 12.1 and 630 MPa, respectively. The chemical interaction, crystallinity, thermal stability, and morphology behaviors of the conductive polymer films before and after chemical modifications were confirmed by FTIR, XRD, TGA, and SEM analyses. Chemical modification by the introduction of silane coupling agent into conductive polymer films significantly enhances the homogeneity of the composites by giving a stable and narrow range of electrical conductivity with the value of 6.931 × 10−7–8.768 × 10−7 S cm−1. As conclusion, the mechanical performance, and electrical conductivity of MG49/PAni/CMC(8%)‐TMMS is more homogenous and fulfils the requirements of conductive polymer film that can be potentially applied in the flexible conductors of stretchable electronics.

Effect of porous corncob on the removal of HCN in cigarette mainstream smoke

In order to reduce the hydrogen cyanide (HCN) release in cigarette mainstream smoke, a new type of porous corncob (PCC) material which was different from traditional corncob-based activated carbon was prepared by a two-step chemical reaction of carboxymethylation and cupric ion complexation. Fourier Transformation Infrared Spectroscopy (FTIR) showed that the carboxymethyl group had been introduced onto the corncob, the carboxymethyl content and the cupric ion loading amount were measured. The x-ray photoelectron spectrometer (XPS) results showed that the Cu content on the surface of PCC was much higher than that of the whole material. The scanning electron microscope (SEM) and nitrogen adsorption-desorption results suggested that PCC had a porous structure. With the increase of the amounts of chloroacetic acid and sodium hydroxide in carboxymethylation reaction and the concentration of cupric ion aqueous solution in complexing reaction, the BET surface areas and pore volumes increased, while the most probable pore sizes of PCCs were close to each other. Compared with the control cigarette, the addition of PCC could effectively remove the HCN release in cigarette mainstream smoke, and the highest reduction rates of HCN per total particulate matter (TPM) was 72.4 %.

Carboxymethyl cellulose synthesis from durian seed flour: The effect of sodium chloroacetate variation

Carboxymethyl Cellulose (CMC) is cellulose derivate that is soluble in water, CMC is synthesized by reacting cellulose with sodium hydroxide and chloroacetate acid or its salt. This study purpose is to see the effect of sodium chloroacetate salt in carboxymethylation reaction to the CMC degree of substitution. To test the quality of the CMC product, the analysis that is conducted in this study are: degree of substitution analysis as written in ASTM D 1439, FTIR, and SEM-EDX. The best result that is got from this study is producing the CMC with degree of substitutions of 0.42 with addition of 3 gr sodium chloroacetate salt.

Synthesis, Characterization, and Application of Carboxymethyl Cellulose from Asparagus Stalk End.

Cellulose from Asparagus officinalis stalk end was extracted and synthesized to carboxymethyl cellulose (CMCas) using monochloroacetic acid (MCA) via carboxymethylation reaction with various sodium hydroxide (NaOH) concentrations starting from 20% to 60%. The cellulose and CMCas were characterized by the physical properties, Fourier Transform Infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, mechanical properties of CMCas films were also investigated. The optimum condition for producing CMCas was found to be 30% of NaOH concentration for the carboxymethylation reaction, which provided the highest percent yield of CMCas at 44.04% with the highest degree of substitution (DS) at 0.98. The melting point of CMCas decreased with increasing NaOH concentrations. Crystallinity of CMCas was significantly deformed (p < 0.05) after synthesis at a high concentration. The L* value of the CMCas was significantly lower at a high NaOH concentration compared to the cellulose. The highest tensile strength (44.59 MPa) was found in CMCas film synthesized with 40% of NaOH concentration and the highest percent elongation at break (24.99%) was obtained in CMCas film treated with 30% of NaOH concentration. The applications of asparagus stalk end are as biomaterials in drug delivery system, tissue engineering, coating, and food packaging.

Preparation and Characterization of Carboxymethyl Chitosan Nonwovens for Wound Dressing

Chitosan has various merits including antimicrobial activity but shows poor liquid handling properties such as fluid absorption and retention, keeping moisture environment, and gel-formation. In order to improve the characteristics of chitosan nonwovens as a wound dressing material, carboxymethyl chitosan nonwovens were prepared by direct carboxymethylation reaction of needle-punched chitosan nonwovens. FT-IR and degree of deacetylation analysis showed O-substitution was dominant, and the amount of sodium chloroacetate and sodium hydroxide had effects on degree of substitution. As the degree of substitution increased, fluid absorption capacities, fluid retention capacities, wet dimensional stability, and tensile strength were increased. Liquid spreading and moisture evaporation were suppressed with the increase of degree of substitution. Overall, O-carboxymethyl chitosan has good potential as a moist wound dressing material.

Investigations on Microwave-Assisted Synthesis of Carboxymethyl Cassia Gum

The objective of this study was to chemically alter Cassia gum by means of carboxymethylation reaction with the aid of microwave radiations, producing highly substituted carboxymethylated Cassia gum. The carboxymethyl substitution of Cassia gum was optimized using response surface methodology. The optimal parameters were found to be microwave power of 50 W and microwave exposure time of 7.36 minute which provided carboxymethylated gum with a degree of substitution of 2.5 (Predicted 2.3). Structural changes after carboxymethylation reaction were confirmed using Fourier-transform infrared and X-ray diffraction. Further, diclofenac sodium-loaded Ca2+- gelled carboxymethylated Cassia gum beads were prepared. The effect of microwave exposure on beads was studied at different powers. However, no significant influence of microwave exposure on the release of diclofenac from beads was observed. The beads were observed to release diclofenac by zero-order kinetics with anamolous release mechanism. In conclusion, the microwave-assisted carboxymethyl modification of Cassia gum can be carried out to prepare modified gum with potential for use as matrix material for pharmaceutical applications.