Page 42 - Academic Press Encyclopedia of Physical Science and Technology 3rd Polymer

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Encyclopedia of Physical Science and Technology EN008C-602 July 25, 2001 20:31

Macromolecules, Structure

Peter A. Mirau Frank A. Bovey
Bell Laboratories Lucent Technologies Bell Laboratories Lucent Technologies (retired)

Lynn W. Jelinski
Lousiana State University

I. The Nature of Macromolecules
II. Molecular Weight and Size
III. Microstructure of Macromolecules
IV. Chain Conformations of Macromolecules
V. Solid-State Morphology

GLOSSARY small molecules such as water. Also called step
polymerization.
Addition polymerization Polymerization reaction in Configuration Stereochemical sequence, composed of
which monomer units join by double bond or ring open- isotactic (“meso,” symbolized by m) and syndio-
ing without splitting out small molecules. Also called tactic (“racemic,” symbolized by r) monomer dyad
chain polymerization. sequences.
Amorphous Polymers in which the chain packing is Conformation Spatial arrangement of a polymer mol-
highly disordered or random. ecule along its contour.
Atactic Arrangement of successive units of a polymer Copolymer Polymers that have chains of two or more
chain so that the side-chain substituents are distributed comonomer units, generally classed into categories of
randomly on both sides of the zigzag plane. random, block, and graft copolymers.
Block copolymers Polymers that contain relatively long Crystalline State of solid polymers in which the individ-
sequences of one monomer covalently bonded to a sim- ual chains are packed in a highly regular and repeating
ilar sequence of another monomer. Block copolymers manner.
can be of the a–b, a–b–a, or random type. Defects Deviations from strictly ideal polymer structure
Chain polymerization See addition polymerization. caused by the reaction chemistry during or following
Characteristic ratio C ∞ , ratio between the unperturbed synthesis. Defects can be branches (either short- or
and the random walk dimensions of a polymer long-chain) or head-to-head:tail-to-tail structures.
chain. End-to-end distance Root mean square end-to-end dis-
2 1/2
Condensation polymerization Polymerization reaction tance ¯ r of a polymer chain.
in which monomer units join with splitting out of Excimer Association complex between an excited

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