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5.1.5. Side
reactions
in
strong acids
197
5.1.6. Alkaline hydrolysis
198
5.1.7. Alkaline
β
-‐elimination
198
5.1.8. Enzymatic degradation
198
5.1.9. Degradation by
free
radical mechanism
(oxidative-‐reductive depolymerization –
ORD)
200
5.1.10. The Fenton
chemistry
201
5.2. Polysaccharide degradation: Activation energy and
role of pH
202
5.2.1.
Introduction
202
5.2.2. Role of
temperature: Activation
energies and Arrhenius plots
202
5.2.3. Role of pH.
206
5.3. Random depolymerisation of
linear
(unbranched) polymers: Changes
in M
w
and M
n
208
5.3.1. Basic
equations
for a pseudo
first order
reaction
208
5.3.2. Example: Analysis of a polysaccharide degradation
experiment:
210
5.3.3. Towards
the oligomer
range: Higher
α
values
210
5.3.4. Random depolymerisation of
linear
(unbranched) polymers: The
chain
length
distribution
(W
n
)
212
6.1. Solution viscosity and
intrinsic viscosity
216
6.1.1. Viscosity
(symbol
η
) of dilute
solutions
216
6.1.2.
Intrinsic
viscosity: Definition and determination
219
6.1.3.
Intrinsic
viscosity of
solid
spheres
220
6.1.4.
Intrinsic
viscosity of
rigid
rods
221
6.1.5.
Intrinsic
viscosity of
randomly
coiled polymers
222
6.1.6. The Mark-‐Houwink-‐Sakurada
(MHS)
equation
223
6.1.7. Using
the MHS
equation
to
find molecular weights
225
6.1.8. Using
the
intrinsic
viscosity
to determine
the
shape of biopolymers
in
solution
227
6.2. Light
scattering
229
6.2.1. General
229
6.2.2. Scattering
from a
single particle
231
6.2.3. Scattering
from a
large number of
independent particles
231
6.2.4. Rayleigh-‐Gans
scattering
from
large particles
(R
G
<
λ
/2).
234
6.2.5. Light
scattering provides M
w
and R
G,z
in
case of polydispersity
236
6.2.6. Calculations of M
w
, A
2
and R
G
from
light
scattering measurements.
237
6.2.7. The Zimm diagram.
240
6.2.8. A note on polyelectrolytes
in
relation
to
light
scattering
241
6.2.9. Some other practical aspects
241
6.2.10. Light
scattering
in practise.
242
6.3. Size-‐exclusion
chromatography
(SEC) of biopolymers
244
6.3.1. General
244
6.3.2. SEC
separation mechanism
244
6.3.3. SEC
calibration
246
6.3.4. SEC
‘universal’
calibration
248
6.4. Size-‐exclusion
chromatography combined with on-‐line
light
scattering
(SEC-‐
MALLS)
249
6.4.1. General
249
6.4.2. R
G
-‐M analysis
from SEC-‐MALLS
255
6.5. SMV: SEC-‐MALLS with an additional viscosity detector
257
6.5.1. General
257
6.5.2. Further analysis
259