Employing perichromism for probing the properties of carboxymethyl cellulose films: an expedient, accurate method for the determination of the degree of substitution of the biopolymer derivative

Abstract

The properties of films of carboxymethyl cellulose, CMC, of different degree of substitution, DS, have been examined by the use of perichromic indicators (probes). The film properties that have been determined are: empirical polarity, E T (33); ''acidity'', a; ''basicity'', b; and dipolarity/polarizability, p*. This has been achieved by employing the following perichromic probes: 4-nitroaniline, 4-nitroanisole, 4-nitro-N,N-dimethylaniline, and 2,6-dichloro-4-(2,4, 6-triphenyl-pyridinium-1-yl)phenolate, WB. The correlations between both E T (33)-or p* and DS were found to be linear; that between b and DS is a second order polynomial; no obvious correlation was found between a and DS. The polarities of CMC films are in the range of those of butyl alcohols. As models for CMC, we have employed cellulose plus CMC of high DS; oxidized cellulose with degree of oxidation = 0.5; sodium glucuronate. The former model behaved akin to CMC, but the plots of the perichromic properties versus DS showed different slopes/intercepts. FTIR data and molecular dynamics simulations on the solvation of WB have shown that this difference can be traced to more efficient hydrogen bonding between the film of the model and the probe. This affects the intra-molecular charge-transfer energy of the latter, leading to different responses to the variation of DS. Based on the excellent linear correlation between E T (33) and DS, for CMC from different origins, we suggest that perichromism is a simple, accurate, and expedient alternative for the determination of DS of the biopolymer derivative.

Cellulose carboxylate/tosylate mixed esters: Synthesis, properties and shaping into microspheres

“…Moreover, the carbonyl frequencies of Cel-Ac/Tsmix (Table SM-4) are higher than that observed to Cel-Ac/Ts. These results indicate that in cellulose ester obtained by physical mixing the hydrogen bonding efficiency is lower than in cellulose ester where both groups are covalently linked to the biopolymer backbone, in agreement with previous results on carboxymethyl cellulose and cellulose acetates (Fidale et al 2012;Fidale et al 2010).…”

PyridiniumN-Phenolate Betaine Dyes

“…Pyridinium N -phenolate betaines have been used in the investigation of the polarity of various heterogeneous materials, such as bare silicas, − chemically functionalized silicas, ,,, alumina, , titanium dioxide, organic polymers, ,,− such as polystyrene, ion-exchange resins, starch, glycogen, amylopectine, amylose, cellobiose, chitin, chitosan, cellulose, and modified celluloses, and inorganic/organic hybrid materials . For instance, betaine 1 was incorporated into ORMOSIL networks by means of a sol/gel process, or chemically bonded to the silica surface .…”

Natural Polymers for Dye‐Sensitized Solar Cells: Electrolytes and Electrodes

“…Each unit contains carboxyl and hydroxyl groups, which enable hydrogen bonding. The average number of carboxymethyl groups per anhydroglucose unit is theoretically three, but in commercially available samples it usually varies from 0.5 to 1.5 (15). Owing to its low cost, biocompatibility and edibility (used in food additives, toothpastes, diet pills) (16), CMC has recently been introduced in the field of energy harvesting and conversion as biomass in enzymatic biofuel cells (17) and as binding agents for nanocrystalline anodes in lithium-ion batteries (18).…”