Determination of the substitution pattern in the polymer chain of cellulose acetates

Heinrich, Jürgen; Mischnick, Petra

doi:10.1002/(sici)1099-0518(19990801)37:15<3011::aid-pola34>3.0.co;2-m

Cited by 23 publications

(27 citation statements)

References 23 publications

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“…For commercial cellulose acetates (DS 2.5) that were prepared by ester hydrolysis of the "triacetate" preferred 2,3-acetylation was found, while direct acetylation to a DS of 2.66 under alkaline conditions [59] resulted in predominant esterification of positions 2 and 6. There are also significant differences with respect to the pattern in the polymer backbone, as will be reported later on.…”

Section: Nmr Spectroscopymentioning

confidence: 96%

“…At lower DS migration and chain degradation could not be excluded. [59] In principle acyl residues are stable under reductive cleavage conditions. [60] However, complete cleavage of the polysaccharide is best accomplished with a high excess of Lewis acid/triethylsilane under complete reduction of the acyl residues to the corresponding alkyl ethers as has been demonstrated by Lee and Gray.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

“…[61] By this approach even mixed esters can be analyzed. [62] As an alternative, direct hydrolysis under acyl cleavage and formation of partially methylated glucitol acetates [59] or acetyl-alkyl exchange under alkaline conditions with subsequent reductive cleavage [58] can be applied.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

“…2). Application to cellulose acetates [59] with a DS around 2.5 showed slight heterogeneity for commercial samples produced with acetic anhydride/sulfuric acid and subsequent partial ester hydrolysis of the "triacetate". In contrast, a sample that was directly acetylated to a DS of 2.66 after alkaline swelling was randomly substituted along the cellulose backbone.…”

Section: Statistical Approachmentioning

confidence: 99%

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Structure analysis of 1,4-glucan derivatives

Mischnick

Heinrich

Gohdes

et al. 2000

Macromol. Chem. Phys.

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Cellulose, starch and cyclodextrin ethers and esters are produced for many fields of application as for example oil recovery, building and ceramic materials, textile and paper industry, food, cosmetics, and pharmaceuticals. For further development of new types of derivatives and also for a better understanding of their properties a detailed analysis of the usually complex mixtures is required. By complete degradation, separation and quantification of appropriate monomer derivatives the regioselectivity in the glucose unit can be determined. For the determination of the substitution pattern in the polymer chain partial random degradation, oligomer analysis by mass spectrometry, and subsequent statistical evaluation can be applied. The composition of products obtained by enzymatic degradation also reflects the pattern in the polymer chain. In addition a possible heterogeneity of the material must be taken into consideration, since any degradation averages the structural information.

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Section: Nmr Spectroscopymentioning

confidence: 96%

Section: Nmr Spectroscopymentioning

confidence: 99%

Section: Nmr Spectroscopymentioning

confidence: 99%

Section: Statistical Approachmentioning

confidence: 99%

See 2 more Smart Citations

Structure analysis of 1,4-glucan derivatives

Mischnick

Heinrich

Gohdes

et al. 2000

Macromol. Chem. Phys.

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“…Techniques currently employed to deal with some of these wastes, which is largely by burning, further contributes to environmental problems due to the effects of the combustion products such as SOx, NOx, COx, etc (Cunningham and Saigo, 1999). The cellulosic wastes (which are biodegradable) could however be exploited and modified to provide value-added products which could replace conventional synthetic polymers (most of which are nonbiodegradable) and other materials in several fields including oil recovery (Heinrich and Mischnick, 1999), waste water treatment (Yang et al, 1988), cosmetics and food additives or pharmaceutical applications (Wellisch, 1976).…”

Section: Introductionmentioning

confidence: 99%

Studying the Characteristics of Polystyrene- Modified Cocoa (<i>Theobroma cacao</i>) Wood Cellulose Acetate Membrane

Okolo¹,

Adimula²,

Osuoji³

et al. 2014

Bayero J. Pure App. Sci.

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In this work, cellulose was obtained from cocoa wood (Theobroma cacao) by the chlorite pulping process. The harnessed cellulose was acetylated by the process of step-wise acetylation to a degree of acetylation (DA) of 2.06. Ten percent (10%) solution of the acetylated cellulose material in acetone was used to cast membrane. Polystyrene was used to modify the cellulose acetate and was also used to cast membranes. The modified and unmodified membranes were characterized in terms of their salt rejection capacity, extent of dissolved solid (DS) removal, fold endurance, water permeability, swellability in organic liquids and organic liquid separation potentials. The modification of the cellulose acetate with polystyrene increased its potential for salt rejection by 91.10%, dissolved solid (DS) removal by 98.06, fold endurance by 100%, but decreased its permeability to water by 10%. The result of the permeation test for organic solvents showed a variation in the permeation rate of the organic liquids ranging from 6.08x10 -4 molcm -2 sec -1 for hexane, to 9.67x10 -4 molcm -2 sec -1 for ethanol. Overall, the modification of the cocoa wood cellulose acetate membrane with polystyrene has led to improvement of properties.

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Cellulose: faszinierendes Biopolymer und nachhaltiger Rohstoff

et al. 2005

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Als wichtigster Gerüstbildner der Pflanzenwelt ist das Polysaccharid Cellulose ein nahezu unerschöpflicher polymerer Rohstoff mit einem faszinierenden Struktur‐ und Eigenschaftspotenzial. Durch reguläre Verknüpfung von D‐Glucose‐Bausteinen gebildet, zeichnet sich das hochfunktionalisierte lineare und kettensteife Homopolymer Cellulose durch Hydrophilie, Chiralität, Bioabbaubarkeit, breite chemische Modifizierbarkeit und den Aufbau vielfältiger teilkristalliner Fasermorphologien aus. Mit Blick auf die weltweit stark expandierende interdisziplinäre Celluloseforschung und Produktentwicklung der letzten Dekade verknüpft dieser Aufsatz den aktuellen Wissensstand zu Struktur und Chemie der Cellulose mit der Entwicklung innovativer Celluloseester und ‐ether für Beschichtungen, Filme, Membranen, Baustoffe, Bohrtechnologien, Pharmaka und Nahrungsmittel. Mit umweltfreundlichen Cellulosefaser‐Technologien, Bakteriencellulose‐Biomaterialien und In‐vitro‐Synthesen der Cellulose sind Wege ins Neuland einbezogen, ebenso Aussagen zu den weiteren Zielen, Strategien und Perspektiven der Celluloseforschung und ‐applikation.

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Determination of the substitution pattern in the polymer chain of cellulose acetates

Cited by 23 publications

References 23 publications

Structure analysis of 1,4-glucan derivatives

Structure analysis of 1,4-glucan derivatives

Studying the Characteristics of Polystyrene- Modified Cocoa (<i>Theobroma cacao</i>) Wood Cellulose Acetate Membrane

Cellulose: faszinierendes Biopolymer und nachhaltiger Rohstoff

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