Relation of Intrinsic Viscosity to Cellulose Chain Length. Degree of Polymerization Range below 400

1957 ◽  
Vol 49 (8) ◽  
pp. 1303-1306 ◽  
Author(s):  
W. J. Alexander ◽  
Otto. Goldschmid ◽  
R. L. Mitchell
Keyword(s):  
Chain Length ◽  
Intrinsic Viscosity ◽  
Degree Of Polymerization ◽  
Cellulose Chain

Evaluation of post-consumer cellulosic textile waste for chemical recycling based on cellulose degree of polymerization and molar mass distribution

2019 ◽  
Vol 89 (23-24) ◽  
pp. 5067-5075 ◽  
Author(s):  
Helena Wedin ◽  
Marta Lopes ◽  
Herbert Sixta ◽  
Michael Hummel
Keyword(s):  
End Of Life ◽  
Intrinsic Viscosity ◽  
Mass Distribution ◽  
Service Sector ◽  
Molar Mass ◽  
Degree Of Polymerization ◽  
Molar Mass Distribution ◽  
Chemical Recycling ◽  
Cellulose Content ◽  
Cellulosic Textiles

The aim of this study is to improve the understanding of which end-of-life cellulosic textiles can be used for chemical recycling according to their composition, wear life and laundering—domestic versus service sector. For that purpose, end-of-life textiles were generated through laboratorial laundering of virgin fabrics under domestic and industrial conditions, and the cellulose content and its intrinsic viscosity and molar mass distribution were measured in all samples after two, 10, 20, and 50 laundering cycles. Results presented herein also address the knowledge gap concerning polymer properties of end-of-life man-made cellulosic fabrics—viscose and Lyocell. The results show that post-consumer textiles from the home consumer sector, using domestic laundering, can be assumed to have a similar, or only slightly lower, degree of polymerization than the virgin textiles (−15%). Post-consumer textiles from the service sector, using industrial laundering, can be assumed to have a substantially lower degree of polymerization. An approximate decrease of up to 80% of the original degree of polymerization can be expected when they are worn out. A higher relative decrease for cotton than man-made cellulosic textiles is expected. Furthermore, in these laboratorial laundering trials, no evidence evolved that the cellulose content in blended polyester fabrics would be significantly affected by domestic or industrial laundering. With respect to molar mass distribution, domestic post-consumer cotton waste seems to be the most suitable feedstock for chemical textile recycling using Lyocell-type processes, although a pre-treatment step might be required to remove contaminants and lower the intrinsic viscosity to 400–500 ml/g.

scholarly journals H.p.l.c. of oligo(sialic acids). Application to the determination of the minimal chain length serving as exogenous acceptor in the enzymic synthesis of colominic acid

1991 ◽  
Vol 280 (3) ◽  
pp. 575-579 ◽  
Author(s):  
M A Ferrero ◽  
J M Luengo ◽  
A Reglero
Keyword(s):  
Chain Length ◽  
Complete Separation ◽  
Sialic Acids ◽  
Degree Of Polymerization ◽  
Direct Transfer ◽  
Maximal Rate ◽  
Colominic Acid ◽  
Membrane Bound

A rapid, sensitive and easy h.p.l.c. method was developed for the quantitative analysis of oligosialic acids. This procedure which permits the complete separation (in 23 min) of several sialyloligomers with a degree of polymerization of between 1 and 16, has been employed to establish the minimal chain length of oligomer accepted, as an exogenous acceptor, by Escherichia coli K-235 sialytransferase complex (ST) leading to the synthesis in vitro of colominic acid. We showed that this membrane-bound enzyme catalyses the direct transfer of Neu5Ac residues (one by one) from CMP-Neu5Ac to an exogenous acceptor molecule which contains at least three Neu5Ac residues. Free Neu5Ac or (Neu5Ac)2 were not recognized as substrates, whereas the maximal rate of polymer elongation was achieved when (Neu5Ac)5 was used as substrate.

scholarly journals Effects of Chain Length of Chitosan Oligosaccharides on Solution Properties and Complexation with siRNA

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1236 ◽  
Author(s):  
Delas ◽  
Mock-Joubert ◽  
Faivre ◽  
Hofmaier ◽  
Sandre ◽  
...  
Keyword(s):  
Gene Delivery ◽  
Chain Length ◽  
Biological Properties ◽  
Degree Of Polymerization ◽  
Point Of View ◽  
Solution Properties ◽  
Chitosan Oligosaccharides ◽  
Colloidal Properties ◽  
Small Complex ◽  
Binding Enthalpy

In the context of gene delivery, chitosan has been widely used as a safe and effective polycation to complex DNA, RNA and more recently, siRNA. However, much less attention has been paid to chitosan oligosaccharides (COS) despite their biological properties. This study proposed to carry out a physicochemical study of COS varying in degree of polymerization (DP) from 5 to 50, both from the point of view of the solution properties and the complexing behavior with siRNA. The main parameters studied as a function of DP were the apparent pKa, the solubility versus pH, the binding affinity with siRNA and the colloidal properties of complexes. Some parameters, like the pKa or the binding enthalpy with siRNA, showed a marked transition from DP 5 to DP 13, suggesting that electrostatic properties of COS vary considerably in this range of DP. The colloidal properties of siRNA/COS complexes were affected in a different way by the COS chain length. In particular, COS of relatively high DP (≥50) were required to form small complex particles with good stability.

Relation between Intrinsic Viscosity and Degree of Polymerization

Nature ◽  
1952 ◽  
Vol 170 (4329) ◽  
pp. 667-667 ◽  
Author(s):  
W. G. HARLAND
Keyword(s):  
Intrinsic Viscosity ◽  
Degree Of Polymerization
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