Thermal degradation of cellulose and cellulose esters

Huang, Mei‐Rong; Li, Xin‐Gui

doi:10.1002/(sici)1097-4628(19980411)68:2<293::aid-app11>3.0.co;2-z

Cited by 146 publications

(92 citation statements)

References 5 publications

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“…The apparent kinetic parameters calculated from this study have been used to arrive at the lifetime of the formulations. The estimated lifetime of a polymer to failure has been defined as the time when the mass loss reaches 5 wt%, i.e α = 0.05 [21][22][23]. From the integration of Equation (2), the lifetime can be estimated by Equation (5): (5) or Equation (6):…”

Section: Lifetime Predictionsmentioning

confidence: 96%

“…The reaction order value (n) can be obtained directly from the symmetrical index of a derivative thermogravimetry (DTG) peak based on the second Kissinger technique [23], Equation (7): (7) where, the indices L and R correspond to the left and right peak (d 2 α/dt 2 ) values on the second derivative thermogravimetry (DDTG) curve for the decomposition process.…”

Section: Lifetime Predictionsmentioning

confidence: 99%

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Thermal degradation studies of LDPE containing cobalt stearate as pro-oxidant

Roy¹,

Parthasarathy²,

Rajagopal³

et al. 2007

Express Polym. Lett.

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Abstract. The influence of a typical prooxidative additive, cobalt stearate, on the thermal stability, degradation kinetics and lifetime of low-density polyethylene (LDPE) was investigated using non-isothermal thermogravimetric analysis (TGA) in both nitrogen and air atmosphere. The derivative thermogravimetric (DTG) curves indicate single stage and multistage decomposition process in nitrogen and air atmosphere respectively. The kinetic parameters of degradation were evaluated using the Flynn-Wall-Ozawa iso-conversion technique. The apparent activation energies for decomposition have been calculated for degradation under nitrogen atmosphere. The lifetime of LDPE (time for 5% mass loss) was estimated to be 8.2·10 26 min in nitrogen and was found to decrease dramatically with increase in the concentration of cobalt stearate thereby revealing its pro-oxidative ability. Studies indicated that the service/process temperature also has a strong influence on the lifetime of all the formulations investigated. The effect of cobalt stearate on the air oven aging behavior of LDPE at two different temperatures (70°C and 100°C) was also investigated to demonstrate the pro-oxidative nature of cobalt stearate.

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Section: Lifetime Predictionsmentioning

confidence: 96%

Section: Lifetime Predictionsmentioning

confidence: 99%

Thermal degradation studies of LDPE containing cobalt stearate as pro-oxidant

Roy¹,

Parthasarathy²,

Rajagopal³

et al. 2007

Express Polym. Lett.

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show abstract

“…room temperature to 110 °C, is related to the evaporation of residual absorbed water. The second step ends near 450 °C, and can be described by an abrupt mass loss stage that is related to the main thermal decomposition process [40,41] .…”

Section: Characterization Of Cellulose Acetatesmentioning

confidence: 99%

Thermal decomposition of mercerized linter cellulose and its acetates obtained from a homogeneous reaction

Morgado

Frollini

2011

Polímeros

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Abstract:Cellulose acetates with different degrees of substitution (DS, from 0.6 to 1.9) were prepared from previously mercerized linter cellulose, in a homogeneous medium, using N,N-dimethylacetamide/lithium chloride as a solvent system. The influence of different degrees of substitution on the properties of cellulose acetates was investigated using thermogravimetric analyses (TGA). Quantitative methods were applied to the thermogravimetric curves in order to determine the apparent activation energy (Ea) related to the thermal decomposition of untreated and mercerized celluloses and cellulose acetates. Ea values were calculated using Broido's method and considering dynamic conditions. Ea values of 158 and 187 kJ mol -1 were obtained for untreated and mercerized cellulose, respectively. A previous study showed that C6OH is the most reactive site for acetylation, probably due to the steric hindrance of C2 and C3. The C6OH takes part in the first step of cellulose decomposition, leading to the formation of levoglucosan and, when it is changed to C6OCOCH 3 , the results indicate that the mechanism of thermal decomposition changes to one with a lower Ea. A linear correlation between Ea and the DS of the acetates prepared in the present work was identified. Keywords: Linter cellulose, cellulose acetates, thermal decomposition. Decomposição Térmica de Celulose de Linter Mercerizado e seus Acetatos Obtidos a partir de Reação HomogêneaResumo: Acetatos de celulose com graus de substituição, GS, variando entre 0,6 e 1,9, foram preparados previamente a partir de celulose de linter mercerizado, em meio homogêneo, usando N,N-dimetilacetamida/cloreto de lítio como sistema de solvente. A influência de diferentes graus de substituição nas propriedades dos acetatos de celulose foi investigada usando a análise termogravimétrica (TGA). Métodos quantitativos foram aplicados nas curvas termogravimétricas obtidas a fim de determinar a energia de ativação aparente (Ea) relacionado à decomposição térmica de celulose não-tratada e mercerizada e acetatos de celulose. Valores de Ea foram calculados usando o método de Broido e considerando condições dinâmicas. Valores de Ea de 158 e 187 kJ mol -1 foram obtidos para a celulose não-tratada e mercerizada, respectivamente. Em trabalho anterior verificou-se que o C6OH é o sítio mais reativo na acetilação, provavelmente devido ao impedimento estérico de C2 e C3. O C6OH participa da primeira etapa de decomposição da celulose, levando à formação de levoglucosana e, quando se tem a substituição para C6OCOCH 3 , o resultado indica que o mecanismo de decomposição térmica muda para um com Ea menor. Uma correlação linear entre Ea e o GS dos acetatos preparados no presente trabalho foi identificada. Palavras-chave: Celulose de linter, acetatos de celulose, decomposição térmica.

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“…The glass transition temperatures and the melting points of cellulose esters have been investigated extensively [15][16][17]. The thermal stability of cellulose and short-chain cellulose esters have been studied [18]. The thermal degradation kinetic of non-fatty cellulose esters and partially esterified cellulose with long chain fatty acids were discussed by Jandura et al [17] and Sairam et al [19].…”

Section: Introductionmentioning

confidence: 99%

Thermal Properties and Thermal Degradation of Cellulose Tri-Stearate (CTs)

Huang

2012

Polymers

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Cellulose tri-stearate (CTs) was synthesized employing trifluoroacetic anhydride (TFAA), stearic acid (SA), with microcrystal cellulose (MCC) and characterized with FT-IR and 1 H-NMR. The degree of substitution of CTs was determined by the traditional saponification method and 1 H-NMR. The thermal properties of CTs were investigated by the thermogravimetric analysis (TGA) under Ar flow in dynamic heating conditions. Thermal stability, activation energy, as well as the degradation mechanism of the decomposition process were revealed. The results showed that the thermal stability of CTs is superior to that of raw materials-MCC, and that the degradation of CTs in argon is a first-order weight loss; the initial decomposition temperature and the temperature corresponding to maximum degradation rate (T p ) increase with an increase in heating rate. The activation energy values were calculated with the Ozawa method, Coats-Redfern method and Kinssinger method, respectively. Analyses of experimental results suggest that the degradation mechanism 0.10 < α < 0.80 is F2 type, A3 for α < 0.1, and R3 for α > 0.80. The degradation mechanism of CTs in the whole conversion range is a complex mechanism, and is the combination of A3, F2 and R3.

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Thermal degradation of cellulose and cellulose esters

Cited by 146 publications

References 5 publications

Thermal degradation studies of LDPE containing cobalt stearate as pro-oxidant

Thermal degradation studies of LDPE containing cobalt stearate as pro-oxidant

Thermal decomposition of mercerized linter cellulose and its acetates obtained from a homogeneous reaction

Thermal Properties and Thermal Degradation of Cellulose Tri-Stearate (CTs)

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