The influence of fine structure on the pyrolysis of cellulose. II. Pyrolysis in air

Basch, A.; Lewin, Menachem

doi:10.1002/pol.1973.170111205

Cited by 48 publications

(16 citation statements)

References 6 publications

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“…The percentage residue (i.e., the weight remaining after thermal decomposition), and the percentage char (i.e. the weight remaining at 500 ~ were calculated from the TG curves and based on the dry weight of cellulose [4].…”

Section: Thermogravimetrymentioning

confidence: 99%

“…Golova et al [3] reported that the packing density of cellulose altered the amount of levoglucosan formed during vacuum pyrolysis. Basch and Lewin [4] showed that there was a correlation between the crystallinity degree of polymerization and the pyrolysis of cellulose. For a complete understanding of this fact, more analysis needs to be carried out on different cellulose crystal forms.…”

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confidence: 98%

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Effects of structural changes on thermal properties and pyrolysis of modified cotton fibres

Saafan

1989

Journal of Thermal Analysis

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The changes resulting in the supramolecular structure Of cotton fibres after mercerization at different temperatures were investigated by means of X-ray diffraction, sorption measurements and determination of the degree of polymerization. For comparison, corresponding measurements were also carried out after liquid ammonia treatment. Pyrolysis of the mercerized cotton samples showed that the levoglucosan yield of NaOH-treated samples is less than that of untreated or NH3-treated samples. Comparisons were made of the thermal stability of the modified cotton samples, as indicated by DTA and TG. A decrease in the percentage crystallinity was found to lower the onset and peak temperatures of the major decomposition reactions. An NH3-treated sample (acetone) was less thermally stable than untreated or mercerized samples.There are several reasons for studying the pyrolysis of cellulose. For example, such studies are important for the development of flame retardants for cotton fibres [1]. Thermal analysis is a useful technique for assessing the flammability of cellulosic materials. Thermoanalytical techniques can provide an insight into how a cellulosic material might react on exposure to fire, e.g. the nature and temperature of its decomposition, the amount of volatiles versus char residue, etc. The thermal degradation of cellulosic materials proceeds through a series of complex chemical reactions. The reactions are highly influenced by the nature and period of heating, the surrounding atmosphere and impurities. The postulated pyrolysis paths can be depicted as shown in Scheme 1. Heating at lower temperatures favours dehydration and subsequent char formation. Heating at higher temperatures favours the formation of gaseous combustible products. Theories about the pyrolysis mechanisms for cellulose have been based on the origin of two main pyrolysis products: tar and char. Several investigations have established that levoglucosan (1,6-anhydro-fl-D-glycopyranose) is the major tar component. A large number of other materials have been identified as cellulose pyrolysis products. However, Glassner and Pierce [2] demonstrated that the chromatograms obtained forJohn Wiley & Sons, Limited, Chichester AkadAmiai Kiadr, Budapest

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Section: Thermogravimetrymentioning

confidence: 99%

mentioning

confidence: 98%

Effects of structural changes on thermal properties and pyrolysis of modified cotton fibres

Saafan

1989

Journal of Thermal Analysis

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“…Cellulose with lower crystallinity forms more char and less volatile products including levoglucosan [6][7][8]. Golova et al [7] studied the levoglucosan formation from various kinds of cellulose samples compared with glucose and they reported that levoglucosan yield increases with the increasing crystallinity of cellulose.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneity in cellulose pyrolysis indicated from the pyrolysis in sulfolane

Kawamoto

Saka

2006

Journal of Analytical and Applied Pyrolysis

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In sulfolane (tetramethylene sulfone), which is a good solvent for the primary product, levoglucosan, cellulose is pyrolyzed completely into soluble products without forming any char. Residues during pyrolysis in sulfolane at 200, 240 and 330 8C were obtained always as colorless noncarbonized substances. From the change in the crystallinity and crystallite size as compared with the ordinary pyrolysis, a heterogeneous mechanism is indicated for cellulose pyrolysis, starting from a molecule which is less stabilized due to lack of some intermolecular interactions. #

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“…However, grafting reactions were carried out in heterogeneous3–6 and homogeneous reaction conditions and all the reported homogeneous reactions were investigated in solvent systems like dimethyl sulfoxide and paraformaldehyde (DMSO/PF) 7, 8, 11, 12. It was reported that crystallinity, crystal size, and degree of polymerization of cellulose greatly affect the pyrrolysis kinetics of high α‐cellulose,9, 10, 13 attributed to the synthetic polymer chains hindering the crystallization of cellulose chain. The thermal behavior of homogeneously grafted high α‐cellulose products in the DMSO/PF solvent system were studied, although the thermal degradation behavior of homogeneously grafted high α‐cellulose products in the DMAc/LiCl solvent system has not been reported so far.…”

Section: Introductionmentioning

confidence: 99%

Thermal behavior of some homogeneously polymethyl methacrylate (PMMA)‐grafted high α‐cellulose products

Das

Saikia

Dass

2004

J of Applied Polymer Sci

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ABSTRACT:The graft copolymerization of methyl methacrylate (MMA) onto high ␣-cellulose was carried out homogeneously in an N,N-dimethyl acetamide/lithium chloride solvent system by using benzoyl peroxide as radical initiator. The rate of grafting was evaluated as a function of concentrations of initiator and monomer, reaction time, and temperature. The grafted products were characterized with the help of infrared spectroscopy, whereas the thermal decomposition of optimum PMMA-grafted high ␣-cellulose was studied using TGA, DTG, and DTA techniques at two heating rates, 10 and 20°C/min, in nitrogen atmosphere in the range of room temperature to 650°C. Three major decomposition steps were identified and the relative thermal stabilities of the PMMA-grafted high ␣-cellulose products were assessed. The kinetic parameters for the three decomposition steps were estimated with the help of two wellknown methods. The thermal stability of the grafted products decreased with the increase of graft yield (GY). Crystallinity or peak intensity of wide-angle X-ray diffraction patterns decreased with the increase of GY.

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The influence of fine structure on the pyrolysis of cellulose. II. Pyrolysis in air

Cited by 48 publications

References 6 publications

Effects of structural changes on thermal properties and pyrolysis of modified cotton fibres

Effects of structural changes on thermal properties and pyrolysis of modified cotton fibres

Heterogeneity in cellulose pyrolysis indicated from the pyrolysis in sulfolane

Thermal behavior of some homogeneously polymethyl methacrylate (PMMA)‐grafted high α‐cellulose products

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