Thermal studies on C-6 substituted cellulose and its subsequent phosphorylated products in air

Jain, Rajesh Kumar; Lal, Krishan; Bhatnagar, Hari L.

doi:10.1016/0040-6031(86)87012-5

Cited by 14 publications

(7 citation statements)

References 12 publications

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“…This indicates that the intermediate char of sample (ii) which contains phosphorus is different from that of Compared with sample (ii), samples (iii, iv) contain nitrogen and a little larger amount of phosphorus. The small endotherm in the temperature range 170-230 C in each DTA curve is due to dephosphorylation and acid-catalyzed dehydration of samples [9]. This proposal is further supported by the accompanying large weight loss ($ 12%) compared with pure fiber ($ 4%) for temperature up to 230 C shown in the TG curves.…”

Section: Resultsmentioning

confidence: 61%

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Study on the Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

Gao

Guo

et al. 2002

Journal of Fire Sciences

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The thermal degradation in air of hemp fabric treated with various compounds containing nitrogen, phosphorus, halogens, and boron, in combinations of two compounds, has been studied by differential thermal analysis and thermogravimetry from ambient temperature to 600 C. The kinetic parameters were obtained using the equation of Broido. The values of activation energies for the oxidative decomposition of samples were found to be in the range 52-102 KJmol 1. Hemp fabric treated with flame retardants showed a high limiting oxygen index and char yield which indicated that the flame retardance of treated hemp was improved. Effect of the different elements on degradation behaviors has been proposed.

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Section: Resultsmentioning

confidence: 61%

“…This is supported by a large weight loss of about 39% as shown by the TG curve. The next exotherm, with a peak at 525 C, is due to the oxidation of the char [9,10]. This exotherm is much smaller than that of sample (i), and there is no other large mass loss in TG curve or any maxima in DTG curve in the range 410-550 C as in Figure 1.…”

Section: Resultsmentioning

confidence: 80%

Study on the Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

Gao

Guo

et al. 2002

Journal of Fire Sciences

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“…In contrast, cellulose tosylate exhibited an exothermic maximum at 175°C (22). The unique behaviour of the C-6 cellulose tosylate was ascribed to a simultaneous endothermic scission of thep-toluenesulfonyl group, as the acid, and induced decomposition of the cellulose chain.…”

Section: Differential Scanning Calorimetly (Dsc)mentioning

confidence: 94%

“…Furthermore, in a recent study of the thermal behaviour of the C-6 substituted cellulose ethers, namely cellulose p-toluenesulfonate, tritylate, and phosphate, Jain et al found an initial small endotherm for the tritylate and phosphate (157 and 160"C, respectively), which they attributed to cleavage of the ethers (22). In contrast, cellulose tosylate exhibited an exothermic maximum at 175°C (22).…”

Section: Differential Scanning Calorimetly (Dsc)mentioning

confidence: 99%

“…The differential thermal analysis results have been previously found to be dependent on the temperature range studied, the period of heating, and the heating rate, as well as on the physical and chemical properties of the cellulose (19)(20)(21)(22). For these reasons, a control DSC curve of the thermal behaviour of the microcrystalline cellulose that was the precursor of both PC-6 and PC-12 was determined (curve A, Fig.…”

Section: Differential Scanning Calorimetly (Dsc)mentioning

confidence: 99%

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Synthesis and characterization of picryl cellulose

Strauss¹,

Torres²,

Phelan³

et al. 1987

Can. J. Chem.

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. Can. J. Chem. 65, 1891Chem. 65, (1987. 2,4,6-Trinitrophenyl cellulose (picryl cellulose) was synthesized by SNAr displacement of chloride from picryl chloride by sodium cellulosate. The cellulosate was prepared in situ from microcrystalline cellulose and sodium methoxide. Depending upon the procedure used, two products with different degrees of picrylation resulted; one contained one picryl ring per ca. 6.5 glucosyl units (PC-6), while the other had ca. one picryl ring per 12 (PC-12). These picryl ethers were characterized by several independent methods: 400-MHz 'H nuclear magnetic resonance spectroscopy of the DMSO-soluble material, temperaturedependent mass spectrometry (ion pyrograms), and differential scanning calorimetry (DSC). ' The nuclear magnetic resonance spectrumdisplays peaks in the low field region (8-9.5 ppm) assigned to the picryl rings; these resonances are well separated from those for possible alternative compounds such as unreacted picryl chloride, picric acid, or 2,4,6-trinitroanisole. It is suggested that the various picryl resonances arise primarily from different microenvironments and (or) conformational preferences of the polymer chain rather than from different substitution sites. Substitution at a primary C-6 position of the glucosyl moiety is favoured. DSC shows that while cellulose undergoes an endothermic decomposition between 320 and 350°C, picryl cellulose exhibits an exothermic decomposition at ca. 230°C. This exotherm is accompanied by the liberation of picric acid, as confirmed by nuclear magnetic resonance; mass spectral results indicate concurrent chain cleavage to yield smaller polysaccharides. A mechanism for initiation of pyrolytic decomposition is proposed, in which loss of picric acid is accompanied by rupture of a glycosidic bond with concomitant formation of glucosan and enolic end groups on the remaining fragments. On a rCalisC la synthese de la trinitro-2,4,6 phCnyl cellulose (picryle de cellulose) en prockdant a une substitution SNAr du chlorure de picryle par le cellulosate de sodium. On a prCparC le cellulosate en faisant rCagir in siru de la cellulose microcristalline avec du methylate de sodium. Suivant la mCthode utiliske, il se forme deux produits comportant des degrks differents de picrylation: un produit qui contient un groupement picryle par 6,5 unitCs glucosyles (PC-6) et un autre qui contient un groupement picryle par 12 unites glucosyles (PC-12). On a caractCrisC ces Cthers picryles par plusieurs mkthodes indtpendantes dont la spectroscopie de rksonance magnCtique nuclkaire du 'H a 400 MHz du produit soluble dans le DMSO, la spectromktrie de masse tempCrature variable (pyrogrammes ioniques) et la calorimktrie a balayage diffkrentiel (CBD). Les spectres rmn prCsentent des bandes dans la rCgion des bas champs (8-9,5 ppm) qui ont CtC attribuCs aux picryles; ces raies sont bien sCparCesde celles qui pourraient provenir d'autres composCs comme le chlorure de picryle qui n'aurait pas rCagi, de l'acide picrique ou du trinitro-2,4,6 anisole. On suggkre que le...

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p‐Toluenesulfonyl esters in cellulose modifications: acylation of remaining hydroxyl groups

Heinze

Rahn

Jaspers

et al. 1996

Macro Chemistry & Physics

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New soluble cellulosics with interesting molecular structures and properties were obtained by the acylation of remaining hydroxyl groups of pure, homogeneously synthesized p-toluenesulfonylcelluloses of different degree of p-toluenesulfonyl (tosyl) substitution (DSTosyJ ranging from 0.5 to 2.0 in pyridine and sodium acetate as a catalyst with various aliphatic, aromatic and unsaturated carbonic acid anhydrides as well as isocyanates. The reactions proceed homogeneously and yield products of a high degree of acyl substitution (DSAcyl). In the case of acetic and propionic acid anhydrides a complete functionalization of all free hydroxyl groups was achieved. Even with fatty acid anhydrides like stearic anhydride 94% of the remaining OH groups were acylated. The new polymers are readily soluble in common organic solvents such as acetone, dimethyl sulfoxide, N, Ndimethylacetamide, N,N-dimethylformamide, and tetrahydrofuran. They are solution processible film-and membrane-forming materials. Tosylcellulose phthalates and trimellitates of appropriate DSTosyl and DSAcyl values are even soluble in aqueous NaOH. Compared to the original tosylcelluloses, the thermal degradation of tosylcellulose acylates was initiated at nearly the same temperature independent of type and degree of esterification providing an equal DSTosyl. The stability found is sufficiently high for processing.

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Thermal studies on C-6 substituted cellulose and its subsequent phosphorylated products in air

Cited by 14 publications

References 12 publications

Study on the Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

Study on the Thermal Degradation of Cellulosic Fibers Treated with Flame Retardants

Synthesis and characterization of picryl cellulose

p‐Toluenesulfonyl esters in cellulose modifications: acylation of remaining hydroxyl groups

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