Effect of lignocellulosic fiber composition on the aquatic biodegradation of wood pulps and the isolated cellulose, hemicellulose and lignin components: kinetic modelling of the biodegradation process

Cellulose ◽  
2021 ◽  
Author(s):  
Soojin Kwon ◽  
Marielis C. Zambrano ◽  
Joel J. Pawlak ◽  
Richard A. Venditti
TAPPI Journal ◽  
2018 ◽  
Vol 17 (11) ◽  
pp. 611-617
Author(s):  
Sabrina Burkhardt

The traditional kappa number method was developed in 1960 as a way to more quickly determine the level of lignin remaining in a completed or in-progress pulp. A significantly faster approach than the Klason lignin procedure, the kappa number method is based on the reaction of a strong oxidizing agent (KMnO4) with lignin and small amounts of other organic functional groups present in the pulp, such as hexenuronic acid. While the usefulness of the kappa number for providing information about bleaching requirements and pulp properties has arguably transformed the pulp and paper industry, it has been mostly developed for kraft, sulfite, and soda wood pulps. Nonwood species have a different chemical makeup than hardwood or softwood sources. These chemical differ-ences can influence kappa and Klason measurements on the pulp and lead to wide ranges of error. Both original data from Sustainable Fiber Technologies’ sulfur and chlorine-free pulping process and kappa and Klason data from various nonwood pulp literature sources will be presented to challenge the assumption that the kappa number accurately represents lignin content in nonwood pulps.


Author(s):  
E. Sekman ◽  
G. Varank ◽  
A. Demir ◽  
S. Top ◽  
M. S. Bilgili

2009 ◽  
Vol 46 (2) ◽  
pp. 85-91
Author(s):  
K. A. Selim ◽  
F. H. Abd El-Rahiem ◽  
A. A. El-Midany
Keyword(s):  

1993 ◽  
Vol 58 (10) ◽  
pp. 2349-2361 ◽  
Author(s):  
Jaromír Jakeš

Kinetic modelling of the molecular weight distribution (MWD) of polymer obtained by an anionic polymerization with two types of growth centres in a dynamic equilibrium, having different growth rates and lifetimes comparable to the polymerization time, was made for low monomer conversions. On the basis of distribution of the growth centres according to the total time spent in the fast growth state, it was shown that MWD of the resulting polymer are mostly bimodal at the beginning of the polymerization and change to unimodal MWD at sufficiently high polymerization degrees depending on the equilibrization rate. When all centres are in the fast state in the beginning, MWD are essentially unimodal throughout. A hint of trimodality is observed in some cases, in an extent hardly detectable in real chromatograms. Hence, a polymodal MWD can be explained only when more than two growth centres with different growth rates are assumed.


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