Thermal and calorimetric analysis of cellulose, its derivatives and their mixtures with plasticizers

Uryash, V.P.; Rabinovich, I.B.; Mochalov, A.N.; Khlyustova, T.B.

doi:10.1016/0040-6031(85)85103-0

Cited by 19 publications

(3 citation statements)

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“…Our measurements did not confirm the heat capacity anomalies between (300 and 350) K reported in refs and and the concave heat capacity curves between 140 and 300 K observed in refs and . The heat capacity of microcrystalline cellulose from this work and refs , , and are compared in Figure .…”

Section: Resultscontrasting

confidence: 72%

Thermodynamic Properties of Plant Biomass Components. Heat Capacity, Combustion Energy, and Gasification Equilibria of Cellulose

et al. 2011

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Heat capacities and enthalpies of formation were determined for the well-characterized samples of cellulose of different origins. The obtained experimental results allowed us to obtain the accurate values of thermodynamic properties for this material. It was demonstrated that the heat capacity and entropy of cellulose samples can be linearly related with their crystallinity index. The equilibria of the processes of cellulose gasification were considered. The adiabatic temperatures of the gasification and energetic characteristics of the products of cellulose thermolysis were evaluated. ' INTRODUCTIONThe use of plant biomass as fuel and raw material for chemical processing is being increased. 1 The effective operation of energy and processing plants using plant biomass is possible if their working conditions are thermodynamically justified. However, very limited information about thermodynamic properties of cellulose and lignin, the major components of the stem part of biomass, is available. In refs 2 to 3 the heat capacity of cellulose fibers was measured in a drop calorimeter. The heat capacity changes near T = 400 K corresponding to the glass transition were observed. Hatakeyama et al. 4 measured heat capacity of cellulose in the temperature range of (330 to 450) K by differential scanning calorimetry (DSC) and found no anomalies below T = 440 K. In refs 5 to 8 the heat capacity of cellulose was determined in adiabatic calorimeters. Karachevtsev and Kozlov 6 measured the heat capacity in a range of temperatures of (80 to 300) K for two samples dried by different methods and found that the results depend on the method of drying. Uryash et al. 8 determined the heat capacity for cotton microcrystalline cellulose in the temperature range (80 to 330) K. In ref 8 the anomalies at 291 K, 343 K, and 403.5 K were observed in the differential thermal analysis (DTA) curve, and the first anomaly was also found in the heat capacity curve. The energies of combustion for various samples of cellulose were also reported in ref 8 though the samples were not characterized by the ash content.In this work the heat capacities in the temperature range of (5 to 370) K and the enthalpies of formation were determined for the samples of cellulose of different origins and degrees of crystallinity. The obtained experimental results allowed us to obtain the reliable values of thermodynamic properties of cellulose required for the calculation of equilibria of the reactions with the participation of this compound, the adiabatic temperatures of the processes of its gasification, and energetic characteristics of the products of cellulose thermolysis.

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Section: Resultscontrasting

confidence: 72%

Thermodynamic Properties of Plant Biomass Components. Heat Capacity, Combustion Energy, and Gasification Equilibria of Cellulose

et al. 2011

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“…3c above 235 K, where the experimental c p is increasingly larger than calculated results as temperature increases. This is in line with observations made by Hatakeyama et al [2] and Uryash et al [20]. Furthermore, experimental data for amorphous cellulose in the 80-200 K temperature range is best fitted with skeletal vibrations described by only a uniform frequency distribution, i.e.…”

Section: Resultssupporting

confidence: 91%

“…It is clear that skeletal vibrations mainly contribute in the 5-200 K range, whereas the change in heat capacity with temperature above 250 K is due to group vibrations. This change in behaviour from one dominated by skeletal to group vibrations is typical [5,19], since the previous The equilibrium melting (glass transition) temperature, T m is taken from [20,[36][37][38][39][40] a Despite its amorphous nature, molecular modelling and experimental results [41] indicate that the glass transition temperature is similar to that of crystalline cellulose have vibrational frequencies in the lower frequency range. Therefore, these vibrations are excited before the group vibrations.…”

Section: Resultsmentioning

confidence: 99%

Explaining the heat capacity of wood constituents by molecular vibrations

Thybring

2013

J Mater Sci

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The heat capacity of wood and its constituents is important for the correct evaluation of many of their thermodynamic properties, including heat exchange involved in sorption of water. In this study, the dry state heat capacity of cellulose, hemicelluloses and lignin are mathematically described by fundamental physical theories relating heat capacity with molecular vibrations. Based on knowledge about chemical structure and molecular vibrations derived from infrared and Raman spectroscopy, heat capacities are calculated and compared with experimental data from literature for a range of bio-and wood polymers in the temperature range 5-370 K. A very close correspondence between experimental and calculated results is observed, illustrating the possibility of linking macroscopic thermodynamic properties with their physical nano-scale origin.

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Microwave‐assisted derivatization of cellulose in an ionic liquid: An efficient, expedient synthesis of simple and mixed carboxylic esters

Possidonio

Fidale

Seoud

2009

J. Polym. Sci. A Polym. Chem.

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Microwave (MW)‐assisted cellulose dissolution in ionic liquids (ILs) has routinely led either to incomplete biopolymer solubilization, or its degradation. We show that these problems can be avoided by use of low‐energy MW heating, coupled with efficient stirring. Dissolution of microcrystalline cellulose in the IL 1‐allyl‐3‐methylimidazolium chloride has been achieved without changing its degree of polymerization; regenerated cellulose showed pronounced changes in its index of crystallinity, surface area, and morphology. MW‐assisted functionalization of MCC by ethanoic, propanoic, butanoic, pentanoic, and hexanoic anhydrides has been studied. Compared with conventional heating, MW irradiation has resulted in considerable decrease in dissolution and reaction times. The value of the degree of substitution (DS) was found to be DSethanoate > DSpropanoate > DSbutanoate. The values of DSpentanoate and DShexanoate were found to be slightly higher than DSethanoate. This surprising dependence on the chain length of the acylating agent has been reported before, but not rationalized. On the basis of the rate constants and activation parameters of the hydrolysis of ethanoic, butanoic, and hexanoic anhydrides in aqueous acetonitrile (a model acyl transfer reaction), we suggest that this result may be attributed to the balance between two opposing effects, namely, steric crowding and (cooperative) hydrophobic interactions between the anhydride and the cellulosic surface, whose lipophilicity has increased, due to its partial acylation. Four ethanoate‐based mixed esters were synthesized by the reaction with a mixture of the two anhydrides; the ethanoate moiety predominated in all products. The DS is reproducible and the IL is easily recycled. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 48: 134–143, 2010

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Thermal and calorimetric analysis of cellulose, its derivatives and their mixtures with plasticizers

Cited by 19 publications

References 1 publication

Thermodynamic Properties of Plant Biomass Components. Heat Capacity, Combustion Energy, and Gasification Equilibria of Cellulose

Thermodynamic Properties of Plant Biomass Components. Heat Capacity, Combustion Energy, and Gasification Equilibria of Cellulose

Explaining the heat capacity of wood constituents by molecular vibrations

Microwave‐assisted derivatization of cellulose in an ionic liquid: An efficient, expedient synthesis of simple and mixed carboxylic esters

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