ABSTRACT
JORGE HELLER / SRI In ternat ional , Menlo Pa rk , California
I . In t roduct ion 140
I I . Polymer Classification and Polymerization Mechanisms 141
A. Chain Polymerizations 143 B . S tep-Growth Polymerizations 151
II I . Polymerization Methods 152
A. Polymerization Methods for Chain Polymerizations 152 B . Polymerization Methods for S tep-Growth
Polymerization 156 IV. Polymer Fabricat ion 156
A. Molding 156 B . Extrusion 159 C. Preparat ion of Films 159 D. Use of Addit ives 163
V. Polymer Proper t ies 164
A. Molecular Weight and Molecular Weight Distr ibut ion 164
B . Polymer Hydrophobici ty 166
C. Glass Transi t ion Tempera ture 167 D. Crystal l ini ty 168
VI. Polymer Character izat ion 169
A. Molecular Weight 169 B . Thermal Analysis 172 C. Mechanical Proper t ies 174
I. INTRODUCTION
Polymers , also known as macromolecules, a re ve ry large molecules consis t ing of many repea t ing uni ts and are formed by a p rocess called polymerization, which links toge the r small molecules known as monomers . The monomers can be l inked toge the r in various ways to give r ise to linear polymers (Fig. l a ) , b r anched polymers (Fig . l b ) , or crossl inked polymers (Fig. l c ) . In these represen ta t ions A is a
A * ^ X - 2 A" x r degree of polymerization DP
A» and A" = terminal groups [a)
A (A)n Y —
(c) Fig . 1 Various polymer t y p e s : (a) l inear polymer, (b) b ranched polymer, and (c) c ross l inked polymer.
