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Unformatted text preview: us section, secondary of
Describing solid, usually isotropic,
both primary and secondary bonds. As mentioned in either the same or a
rtion of matter bounded by a bonds inﬂuence the macroscopic material properties only when there is an absence of
joined crystals orthan the solvent.
different species grains.
primary bonds in certain regions of a material. Many of the polymers described in the next
ically separate from any other
polymer solid solution A bonds. solution of
section display propertiesEngineering material composedin which
interstitial dominated by secondary solid
high–molecular-weight molecules. These molecules
atoms or ions of a foreign species are located in the
cal representation showing the OF POLYMERhave either a linear (chain) structure or a
2.9 THE STRUCTURE
a given composition as a
three-dimensional network structure.
An important class of conduction
intrinsic materials consists of large molecules called macromolecules. A
Electrical conduction in pure
subset of macromolecules are those that are formed by linking together a large number of
semiconductors composites Composite
identicalpolymer-matrixsuch as Si, Ge, and GaAs. systems in a
units, or mers. These molecules, called polymers, for “many mers,” offer
variety ofinvariant matrix material is a contain covalent bonds within the
useful the reaction
scence that persists more
which properties. Although all polymers polymer. there are zero
A reaction is which
molecules, they may have either primary or secondary bonds bridging the macrous is removed.
degrees of freedom.
polymorphic Allotropic; capable of more atomic scale
molecules. We have elected to introduce the concept of a polymer in thethan one
structure chapter since the distinction between the two major subclasses of polymers is
crease in electrical
crystal structure. A process in which ions of light
based on the type of bond between adjacent polymer chains.
elements such as boron and nitrogen are As an to impinge
The structurally simplest polymers are A process...
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