14-07-2012, 11:47 AM
Basic Structures of Polymers
[attachment=27625]
Polymer Chains
Different arrangements of atoms and
substituents of the polymer chain brought about by rotations about single bond
The configuration/“microstructure” of the chain.
The term “configuration” refers to the organization of the atoms along the chain.
EXAMPLES OF CONFIGURATIONS
Head-to-Tail Configuration
Head-to-tail placement of the monomeric
units, or mers, during polymerization
Configuration of Pseudoasymmetric Carbon
The first few atoms of the two chain segments attached to C* are responsible for the optical activity, not those farther away. These near atoms are seen to be the same, and hence the polymer is optically inactive.
Effect of Trans-Gauche Conformations
Two other distinct consequences arise from the multiplicity of the rotational states and the rapid interchanges
Chain size on average is much smaller than the chain length
Molecular Size
At any instant, the various parts of a flexible chain molecule distributed around its centre of mass.
[attachment=27625]
Polymer Chains
Different arrangements of atoms and
substituents of the polymer chain brought about by rotations about single bond
The configuration/“microstructure” of the chain.
The term “configuration” refers to the organization of the atoms along the chain.
EXAMPLES OF CONFIGURATIONS
Head-to-Tail Configuration
Head-to-tail placement of the monomeric
units, or mers, during polymerization
Configuration of Pseudoasymmetric Carbon
The first few atoms of the two chain segments attached to C* are responsible for the optical activity, not those farther away. These near atoms are seen to be the same, and hence the polymer is optically inactive.
Effect of Trans-Gauche Conformations
Two other distinct consequences arise from the multiplicity of the rotational states and the rapid interchanges
Chain size on average is much smaller than the chain length
Molecular Size
At any instant, the various parts of a flexible chain molecule distributed around its centre of mass.