Biomedical Engineering Reference
In-Depth Information
2,4
2,2
2,0
1
10
Stability Ratio, W
Figure7.8
Fractaldimensionsasafunctionofstabilityratio.Thestraightlineinthefigureis
derivedfroma linear regressionof thedatapointsand follows: d
f
=
0
.
324 log
10
(W).
ReprintedwithpermissionfromNorgrenetal. (2002).Copyright (2002),AmericanChemical
Society.
2
.
04
+
KL self-associates
MeO
OH
CH
2
OMe
OMe
HC
HOH
2
C
O
OH
H
H
CH
2
CH
OH
O
OMe
MeO
O
OH
C=O
CH
2
OH
HC
CH
2
OMe
HOOC
OH
CH
OH
HC
MeO
O
CH
OH
OH
OH
MeO
OH
CHOH
CH
HO
OMe
HC
CH
CH
COOH
CH
2
OH
S
CH
2
OH
macromolecular KL
colloidal KL particles
fractal KL cluster
Figure 7.9
A schematic representationof themodes of aggregation in kraft lignin systems
starting from macromolecular kraft lignin and finally reaching fractal kraft lignin clusters.
ReprintedwithpermissionfromNorgrenetal. (2002).Copyright (2002),AmericanChemical
Society.
7.5
Surface Chemistry of Solid State Lignin
Lignin, as stated previously, is difficult to describe in terms of a single macromolecular
chemical structure with a defined repeat monomer unit connected in a uniform way.
Thus, no two lignin polymer chains will be alike. Furthermore, as solid state lignin
is amorphous due to the irregular branching and molecular weight of the biomacro-
molecules, structural heterogeneity also persists. This poses a significant problem in the
study of the fundamental physicochemical properties of lignin which has part way been
overcome by the preparation of model lignin surfaces. The goal of any model surface
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