Callister - An introduction - 8th edition

Chapter 14 Polymer Structures
(a)
(c)
(b)
(a) Schematic representation of the arrangement of molecular chains for a
crystalline region of polyethylene. Black and gray balls represent, respectively,
carbon and hydrogen atoms.
(b) Schematic diagram of a polymer chain-folded crystallite—a plate-shaped
crystalline region in which the molecular chains (red lines/curves) fold back and
forth on themselves; these folds occur at the crystallite faces.
(c) Structure of a spherulite found in some semicrystalline
polymers (schematic). Chain-folded crystallites radiate outward
from a common center. Separating and connecting these
crystallites are regions of amorphous material, wherein the
molecular chains (red curves) assume misaligned and disordered
configurations.
(d) Transmission electron micrograph showing the spherulite
structure. Chain-folded lamellar crystallites (white lines) approximately
10 nm thick extend in radial directions from the center. 12,000 : .
(e) A polyethylene produce bag containing some fruit. [Photograph of Figure
(d) supplied by P. J. Phillips. First published in R. Bartnikas and R. M. Eichhorn,
Engineering Dielectrics, Vol. IIA, Electrical Properties of Solid Insulating
Materials: Molecular Structure and Electrical
Behavior, 1983. Copyright ASTM, 1916 Race Street,
Philadelphia, PA 19103. Reprinted with permission.
Figure (e) from Glow Images.]
(d)
(e)
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