What is the difference between carboxymethyl cellulose and methylcellulose?
The key difference between carboxymethyl cellulose and hydroxypropyl methylcellulose is that carboxymethyl cellulose has a lower water retention rate, whereas hydroxypropyl methylcellulose has a higher water retention rate when compared in same amounts.
Is CMC negatively charged?
So, the CMC chain remains negatively charged when it is immersed in salt-free aqueous medium at pH 6.0; about 63% of the dissociated groups are compensated by the diffuse counterions in the ionic atmosphere.
What is CMC solution?
Carboxymethylcellulose (CMC) is an anionic, water-soluble cellulose derivative. Solubility of CMC depends on the DP as well as the degree of substitution and the uniformity of the substitution distribution.
What is degree of substitution of CMC?
Carboxymethyl cellulose (CMC) is nearly always sold as sodium salt of carboxymethylcellulose and is used in this readily soluble form. The acid form is insoluble. It has an average degree of substitution of 0.75, and a maximum viscosity of 4000 cP for 1% concentration.
What is the difference between CMC and MC?
As used in paper conservation, MC is soluble in cold water but not in hot water (either as the dry powder or as the dry film). Sod. CMC is soluble in either cold or hot water. Both, in an aqueous solution, can be diluted to some degree by organic solvents such as ethanol or acetone.
Which is better CMC or HPMC?
Results: In comparison with HPMC, CMC effected less corneal staining, greater comfort, and better vision after the procedure, Conclusion: CMC proved to be a viable and superior alternative to HPMC as a gonioscopic solution.
Is carboxymethyl positive or negative?
At neutral pH the carboxymethyl group is ionized as -CH2OCH2COO¯ so that CM- cellulose is negatively charged, so it is a weak cation exchanger. DEAE-cellulose contains an diethylaminoethyl group. It is positively charged at neutral pH and so DEAE-cellulose is a weak anion exchanger.
Is carboxymethyl cellulose a cation exchange matrix?
The correct answer is a cation exchange matrix.
How do you dilute CMC?
The solubility of CMC generally depends upon the degree of substitution of CMC itself. The low DS will have lower solubility whereas higher DS will have high DS. However, you can dissolve CMC by heating water at 60 C and stirring at very high speed.
How do you dissolve carboxymethylcellulose?
What is the meaning of degree of substitution?
Abstract. The degree of substitution (DS) of a polymer is the (average) number of substituent groups attached per base unit (in the case of condensation polymers) or per monomeric unit (in the case of addition polymers). The term has been mainly used in cellulose chemistry.