Chapter 2. Chain Structure and Configuration. Polymer chains have three basic properties:. The molecular weight and molecular distribution. The conformation of the chains in space. The configuration of the chain. Coil chain conformation. 2.1 Examples of configurations and conformations.
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Coil chain conformation
2.1.1 Head-to-head and head-to-tail configurations
Thermodynamically and spatially preferred structure is usually the head-to-tail configuration.
The H-to-H and H-to-T configurations cannot be interchanged without breaking primary chemical bonds.
The trans-gauche conformations of polymer chain can be interchanged by simple rotation about the single bond linking the moieties.
2.1.2 Chemical methods of determining microstructure
2.3.1 Chiral centers
Chemically identical but they rotated plane-polarized light in opposite directions.
Polymerization of monosubstituted ethylene
2.4.1 Optical isomerism
The cis-trans isomerism arises because rotation about double bond is impossible without disrupting the structure.
Synthesis of diene type polymers
C-H bending 823 cm-1
C-O stretching 1164 & 1231 cm-1
C=O stretching 1506 cm-1
Skeletal ring vibration 1776 cm-1
cN > (cN)ODT
with (cN)ODT = f(f)
Swollen micelles and
0.20 ~ 0.35
3-D TEM micrographs for PS280-PLLA307 (fPLLA= 0.37) solution-cast samples sectioned along different planes. As shown, the xy plane is the basal plane normal to helical axes and the yz and zx planes are planes parallel to helical axes
Far from the neck region
In the neck region
A + hu = A*
A* + B = A + B*
2.10.2 Excimmer formation
A* + A = (AA)*
(AA)* = 2A + huE
220.127.116.11 Microstructure of polystyrene