Probing the dependence of the properties of cellulose acetates and their films on the degree of biopolymer substitution: use of solvatochromic indicators and thermal analysis

Fidale, Ludmila C.; Ißbrücker, Constance; Silva, Priscilla L.; Lucheti, Camila M.; Heinze, Thomas; Seoud, Omar A. El

doi:10.1007/s10570-010-9438-2

Cited by 20 publications

(17 citation statements)

References 68 publications

(84 reference statements)

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“…This use is appropriate because recent measurements (using solvatochromic indicators) have indicated that the polarity at the surface of cellulose is akin to that of aliphatic alcohols. 19 Single-ion enthalpies of transfer indicate that Li + is more efficiently solvated by DMAc than by alcohols (hence by cellulose). That is, the equilibrium shown in Equation 2 is endothermic:…”

Section: 15mentioning

confidence: 99%

A physical organic chemistry approach to dissolution of cellulose: effects of cellulose mercerization on its properties and on the kinetics of its decrystallization

Ramos¹,

Morgado²,

Gessner³

et al. 2011

Arkivoc

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The effects of alkali treatment on the structural characteristics of cotton linters and sisal cellulose samples have been studied. Mercerization results in a decrease in the indices of crystallinity and the degrees of polymerization, and an increase in the α-cellulose contents of the samples. The relevance of the structural properties of cellulose to its dissolution is probed by studying the kinetics of cellulose decrystallization, prior to its solubilization in LiCl/N,N-dimethylacetamide (DMAc). Our data show that the decrystallization rate constants and activation parameters are only slightly dependent on the physico-chemical properties of the starting celluloses. This multistep reaction is accompanied by a small enthalpy and large, negative, entropy of activation. These results are analyzed in terms of the interactions within the biopolymer chains during decrystallization, as well as those between the two ions of the electrolyte and both DMAc and cellulose.

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Section: 15mentioning

confidence: 99%

A physical organic chemistry approach to dissolution of cellulose: effects of cellulose mercerization on its properties and on the kinetics of its decrystallization

Ramos¹,

Morgado²,

Gessner³

et al. 2011

Arkivoc

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“…Examples are the dependence on DS of the following properties of cellulose carboxylic acid esters: solubility in organic solvents, e.g., chloroform and acetone (Carollo 2004;Rustemeyer 2004); optical properties (Necula et al 2010); glass-transition-, melting-, and decomposition temperature (Fidale et al 2010). Another classic example is carboxymethyl cellulose, CMC, which is employed in diverse applications ranging from the food and pharmaceutical industries to the muds employed in petroleum drilling.…”

Section: Introductionmentioning

confidence: 99%

“…Probes have been employed in order to study the properties of inorganic solid surfaces, e.g., silica, alumina, and titanium dioxide Fidale et al 2010;Khristenko et al 2006;Spange et al 2000Spange et al , 2005Zimmermann et al 2002). They have also been employed in order to probe the surface properties of: Untreated and treated celluloses and other carbohydrates (microcrystalline cellulose; bacterial cellulose; cotton linters; regenerated cellulose; sulfite kraft pulp; starch; chitin, chitosane) (Fidale et al 2010;Fischer and Spange 2000;Fischer et al 2002;Spange et al 2003 Fig.…”

Section: Introductionmentioning

confidence: 99%

“…They have also been employed in order to probe the surface properties of: Untreated and treated celluloses and other carbohydrates (microcrystalline cellulose; bacterial cellulose; cotton linters; regenerated cellulose; sulfite kraft pulp; starch; chitin, chitosane) (Fidale et al 2010;Fischer and Spange 2000;Fischer et al 2002;Spange et al 2003 Fig. 1 Molecular structures of the probes of interest in the present work.…”

Section: Introductionmentioning

confidence: 99%

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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

et al. 2011

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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.

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“…Tables 1-3 Tables 1-3. Inverse to Sp, the solvatochromic parameters do not show a linear correlation with the volume fraction of constituents in the mixture, so they must be measured. All these parameters have been derived from previous studies [17][18][19] that are listed in Tables 1-3.…”

Section: Methodsmentioning

confidence: 99%

Solvents Design on the Basis of Molecular-Microscopic Properties of Binary Mixtures for Lycopene Extraction

Salari¹,

Rohani²,

Elahifard³

et al. 2012

CHEMISTRY

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Lycopene is a natural compound with high-value of nutritional and medical properties. Nowadays, the extraction of Lycopene with mixtures of solvents to obtain more efficiency and less toxicity is interested. In this study, the Lycopene extraction in three binary mixtures of solvents (Ethyl-acetate/Ethanol, Hexane/Isopropanol and Benzene/Isopropanol) was measured and then the effects of solvatochromic parameters (π*, dipolarity/polarizability; β, hydrogen-bond acceptor basicity; α, hydrogen-bond donor acidity) and solvophobicity (Sp) parameters on the extraction from tomato tissues have been considered. Among the all parameters, Sp shows the biggest contribution in the extraction that is well justified, knowing that Lycopenes are lypophobic. Our calculation results show that in addition to Sp, another parameter is needed to get the reasonable correlation between the parameters and the extraction. For Ethanol/Ethyle-acetate mixture, β, for Isopropanol/Benzene mixture, π* and for Isopropanol/Hexane mixture, α, participated in the correlation equation in addition to Sp.

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Probing the dependence of the properties of cellulose acetates and their films on the degree of biopolymer substitution: use of solvatochromic indicators and thermal analysis

Cited by 20 publications

References 68 publications

A physical organic chemistry approach to dissolution of cellulose: effects of cellulose mercerization on its properties and on the kinetics of its decrystallization

A physical organic chemistry approach to dissolution of cellulose: effects of cellulose mercerization on its properties and on the kinetics of its decrystallization

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

Solvents Design on the Basis of Molecular-Microscopic Properties of Binary Mixtures for Lycopene Extraction

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