Carboxymethyl cellulose, function

X. Wei, L. Qi, J. Tan, R. Liu, F. Wang, A colorimetric sensor for determination of cysteine by carboxymethyl cellulose-functionalized gold nanoparticles, Analytica Chimica Acta 671 (2010) 80-84. 

Utilization of a microfabricated rf coil and gradient set for viscosity measurements has recently been demonstrated [49]. Shown in Figure 4.7.9 is the apparent viscosity of aqueous CMC (carboxymethyl cellulose, sodium salt) solutions with different concentrations and polymer molecular weights as a function of shear rate. These viscosity measurements were made using a microfabricated rf coil and a tube with id = 1.02 mm. The shear stress gradient, established with the flow rate of 1.99 0.03 pL s-1 was sufficient to observe shear thinning behavior of the fluids. 

Carboxylic functional polyester curing agents, 10 401-406 Carboxyl ion system, 19 193 Carboxyl-terminated butadiene nitrile, rubbers and, 10 376-375 Carboxymethyl cellulose (CMC),... 

Whey protein concentrates (WPC), which are relatively new forms of milk protein products available for emulsification uses, have also been studied (4,28,29). WPC products prepared by gel filtration, ultrafiltration, metaphosphate precipitation and carboxymethyl cellulose precipitation all exhibited inferior emulsification properties compared to caseinate, both in model systems and in a simulated whipped topping formulation (2. However, additional work is proceeding on this topic and it is expected that WPC will be found to be capable of providing reasonable functionality in the emulsification area, especially if proper processing conditions are followed to minimize protein denaturation during their production. Such adverse effects on the functionality of WPC are undoubtedly due to their Irreversible interaction during heating processes which impair their ability to dissociate and unfold at the emulsion interface in order to function as an emulsifier (22). 

Figure 3 is the result of pulse radiolysis experiment about the reaction of hydrated electron with polymer chains(0 or 30 mM carboxymethyl chitosan solution with 0.3 M terf-butanol under Ar saturation), and shows the decay of the absorbance as a function of time. This absorbance was measured at wavelength 720 nm, which is the absorption peak of hydrated electron. As seen in Figure 3, the absorbance increases immediately after the irradiation, and attenuates afterwards. This means that hydrated electron is generated immediately after irradiation and diminishes gradually by some reactions of hydrated electron. Compared the absorbance decay of polymer solution with the decay of solution without polymer, the decay of polymer solution is faster than without polymer, so it is obvious that hydrated electron reacts with polymer chains. The decay curve can be fitted by pseudo first-order decay. The pseudo first-order decay is shown by equation (8). From estimating the slope of the pseudo first-order decay rate of the absorbance at 720 nm against polymer concentration, the rate constant of the reaction of hydrated electron with polymer chains can be calculated Figure 4). The rate constants of the reaction of hydrated electron with CM-chitin and CM-chitosan was determined as l.lxlO7 and MxlO M V1]. These values are almost the same with the value of carboxymethyl cellulose(2< ).

One of the first polysaccharide derivatives used for insolubilization was the acid azide (or hydrazide) of 0-(carboxymethyl)cellulose. Treatment of the methyl ester of O-(carboxymethyl) cellulose with hydrazine gives the hydrazide 31 which, with nitrous acid, yields the azide (32). The azido group evidently reacts with the free functional groups of lysyl, tyrosyl, cysteinyl, and seryl residues (see Ref. 436), and evidence for formation of a covalent bond, as in 33, comes from the fact that the... 

Sodium carboxymethyl cellulose SCMC is a low-cost, soluble, and polyanionic polysaccharide derivative of cellulose that has been employed in medicine as an emulsifying agent in pharmaceuticals and in cosmetics. The many important functions provided by this polymer make it a preferred thickener, suspending aid, stabilizer, binder, and film-former in a wide variety of nses. In biomedicine, it has been anployed for preventing postsurgical soft tissue and epidural scar adhesions. 

Our published articles focused on using carboxymethyl cellulose and hydroxyethyl cellulose, and cellulose acetate, as ligands for cellulose derivative-metal complexes. These derivatives are examples of water-soluble cellulose ethers and solvent-soluble cellulose esters, respectively. The micro-analyses, electronic and IR-spectra, and magnetic susceptibility measurements were used as tools for studying the nature of the chemical structures of cellulose ethers complexes with some transition metals [10-16], while electrical and thermal analyses were carried out to identify the functional properties of cellulose ether provided from chelation with metal ions [17-20]. 

Infrared spectroscopy is a useful tool to identify functional groups through vibrational frequencies in polymers to evaluate changes in structure This research was focused in graft copolymerization of Hydroxyethyl methacrylate (HEMA) onto chicken feathers fibers (CFF) and carboxymethyl cellulose (CMC), evaluating effect of reaction conditions (time reaction, monomer concentration, initiator concentrations) on grafting yield and probe presence of HEMA in copolymers by means Infrared Spectroscopy (IR). 

Carboxymethyl cellulose (CMC) is the most important cellulose ether commercially. Its DS is 0.4-1.4. DS more than 0.6-0.8 gives a good water solubility. Carboxymethyl cellulose is one of the important modified celluloses that is widely used as an additive in industries. It possesses advantageous properties, especially solubility in water, immiscibility in oil and organic solvency, which makes it act as a multifunction agent. Therefore, it functions as stabilizer, thickener, binder and suspension agent in industries such as food and pharmaceutical. Hence, analysis of the CMC production process has been studied by researchers in order to enhance the efficiency of the process to achieve specific properties of CMC needed. There are many published works about CMC. For example, optimization of carboxymethyl cellulose production from etherification cellulose has been studied by Muei in 2010 [33]. 

Fig. 3.13. Reduced viscosity as a function of the concentration for a carboxymethyl cellulose (DS-07) with a high content of gel particles. The solution was filtered with different types of filters and pore sizes. In addition to the filtration in some solutions the gel particles were separated by centrifugation...

Fig. 4.3. Viscosity q ed a function of the concentration c for carboxymethyl cellulose (CMC) of different molar masses in 0.1 mol/l NaNOj solution with 200 ppm NaNj at 7=25 °C.The degree of substitution with carboxymethyl groups is constant at DS. In addition the relative viscosity range of qr=. 2-2.5 is shown In which the data points for a good viscosimetric measurement should lie...

---