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Tailoring the Degree of Polymerization of Low Molecular Weight Cellulose

โœ Scribed by Marcel Meiland; Tim Liebert; Thomas Heinze


Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
495 KB
Volume
296
Category
Article
ISSN
1438-7492

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โœฆ Synopsis


Abstract

The degradation of cellulose to lmw samples with $\overline {DP} _{{\rm w}} $ varying from 15 to 130 is investigated. Cellulose samples prepared from the hydrolysis of regenerated cellulose fibers in dilute HCl possess $\overline {DP} _{{\rm w}} $โ€‰=โ€‰50. Applying homogenous degradation of microcrystalline cellulose in H~3~PO~4~ at RT for 3 weeks, samples with $\overline {DP} _{{\rm w}} $โ€‰=โ€‰35 and a PDI of 1.58 are obtained. Decreasing the hydrolysis temperature to 8โ€‰ยฐC results in lmw cellulose with $\overline {DP} _{{\rm w}} $โ€‰>โ€‰70. Fractionation in DMA/LiCl provides samples with $\overline {DP} _{{\rm w}} $โ€‰=โ€‰12 to 130, together with a narrow molecular weight distribution. Detailed structural analysis by 2D NMR spectroscopy reveals that the prepared lmw celluloses are suitable as mimics for cellulose. magnified image


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โœ J. Matuszewska-Czerwik; S. Polowiล„ski ๐Ÿ“‚ Article ๐Ÿ“… 1985 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 292 KB ๐Ÿ‘ 2 views

Polymerization of styrene to high degrees of conversion (up to 99.8%) was carried out. The obtained polystyrene was fractionated by distribution between two liquid phases and also by fractionating precipitation. Molecular weights of the fractions were determined and the molecular weight distribution