Peculiarities in the physico-chemical behaviour of non-statistically substituted carboxymethylcelluloses

Kötz, Joachim; Bogen, Inger Lise; Heinze, Thomas; Heinze, U.; Kulicke, Werner‐Michael; Lange, S.

doi:10.1016/s0927-7757(01)00518-0

Cited by 19 publications

(12 citation statements)

References 18 publications

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“…In comparison, conventionally prepared samples are water soluble starting from a DS of about 0.4 while CMC's synthesized via dissolved cellulose in DMA/LiCl under induced phase separation dissolve at a DS of 1.3 ... 1.5 17) . The results of investigations on structure property relations of the 2,3-O-CMC's will be published elsewhere 27) .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and structure characterization of 2,3‐ O‐ carboxymethylcellulose

Heinze

Klemm

1999

Macromol. Chem. Phys.

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SUMMARY: 2,3-O-Carboxymethylcellulose (CMC) samples of different degree of substitution (DS) were synthesized via 6-O-(4-monomethoxytriphenylmethyl)cellulose under a variety of conditions and with different carboxymethylating agents. The highest DS of carboxymethyl groups of 1.7 was reached with sodium monochloroacetate in dimethyl sulfoxide containing 1% of water as reaction medium. The CMC's dissolve in water starting from a DS of 0.6. In any case, the carboxymethylation is more effective at O-2 compared to O-3. While samples up to a DS of 1 possess a random distribution of the different repeating units, samples of higher DS show a non-random structure. Consequently, a control of the distribution of carboxymethyl groups within both the repeating units and the polymer chain was possible for the first time.

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Section: Resultsmentioning

confidence: 99%

Synthesis and structure characterization of 2,3‐ O‐ carboxymethylcellulose

Heinze

Klemm

1999

Macromol. Chem. Phys.

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“…For the determination of the acidity constants, 0.01% (w/v) solutions of the CMS samples were titrated (dosage rate < 5 mL/h), after ion exchange, with 0.1 M NaOH in the presence of 1 M aqueous NaCl. For caIcuIating of the pK a the modified HendersonHasselbalch equation was applied (pK a = pH + n log [(1-α)/α]) [12].…”

Section: Measurementsmentioning

confidence: 99%

“…2 shows the 13 C-NMR spectra of two 4-monomethoxytrityl starch samples of different DS TrityI dissolved in DMSO-d 6 . The peak assignment was carried out on the basis of the results of Takahashi et al [18] and Camacho et al [12] for trityl cellulose. In the case of sample 5 (DS TrityI = 0.77) the aromatic C-atoms 9,10 and 11 of the MMtrityl substituent give a group of peaks in the region from 126.3-125.2 ppm.…”

Section: Characterization Of Trityl Starchmentioning

confidence: 99%

Starch Derivatives of High Degree of Functionalization. 4. Homogeneous Tritylation of Starch and Subsequent Carboxymethylation

Heinze

Grote

et al. 2001

Starch/Stärke

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“…[7] The conversion with a reagent like sodium monochloroacetate, e. g., leads to carboxymethyl cellulose (CMC). Polymers obtained by this new synthesis concept exhibit a number of unconventional properties and interesting colloidal behavior, [8] compared with CMC prepared in the industrially applied slurry process. HPLC analysis after complete chain degradation revealed that the polymers synthesised exhibit a non-statistic content of the repeating units.…”

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confidence: 99%

Detailed investigation on the molecular structure of carboxymethyl cellulose with unusual substitution pattern by means of an enzyme-supported analysis

Saake¹,

Horner

Kruse

et al. 2000

Macromol. Chem. Phys.

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Four carboxymethyl cellulose samples derived from the synthesis concept of “reaction in reactive microstructures” were characterised in detail by combination of different analytical techniques. Fractionation of one of the samples according to water‐solubility into four fractions revealed that a non‐statistical distribution of the substituents occurred for all fractions. Endoglucanase fragmentation of three samples was performed followed by analytical and preparative SEC. The multi‐detected analytical SEC proved samples of high degree of substitution up to 1.9 to be intensively degraded, supporting the proposed block‐like substitution pattern. The detailed investigation of soluble fragmentation products by preparative SEC, hydrolysis and anion exchange chromatography with pulsed amperometric detection revealed that all samples contain fragments of much higher DS values than the average DS of the starting material. On the other hand, high quantities of degradation products of low DS or almost no substitution occurred. Therefore, a structure can be proposed with segments of very high DS alternating with areas of limited substitution. The result clearly showed that the high substituted fragments were dominated by 2,3,6‐tri‐O‐CMG.

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Peculiarities in the physico-chemical behaviour of non-statistically substituted carboxymethylcelluloses

Cited by 19 publications

References 18 publications

Synthesis and structure characterization of 2,3‐ O‐ carboxymethylcellulose

Synthesis and structure characterization of 2,3‐ O‐ carboxymethylcellulose

Starch Derivatives of High Degree of Functionalization. 4. Homogeneous Tritylation of Starch and Subsequent Carboxymethylation

Detailed investigation on the molecular structure of carboxymethyl cellulose with unusual substitution pattern by means of an enzyme-supported analysis

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