Page 167 - Academic Press Encyclopedia of Physical Science and Technology 3rd Polymer

P1: GKY/MBQ P2: GLQ Final Pages Qu: 00, 00, 00, 00
Encyclopedia of Physical Science and Technology en012i-947 July 26, 2001 11:11

Polymers, Inorganic

and Organometallic

Martel Zeldin
Hobart and William Smith Colleges

I. Morphological Classification
II. Compositional Classification
III. Inorganic Polymers of the Main Group Elements
IV. Inorganic Polymers with Transition Metals

GLOSSARY structures in which the primary valences of the atoms
are satisfied by covalent bonds and secondary weaker
Chain polymer A macromolecule composed of difunc- interactions(e.g.,vanderWaalforces,hydrogenbonds)
tional repeating units that are devoid of inter- or intra- more loosely holding the layers intact.
chain crosslinks. Silicone An organometallic polymer that contains the
Crosslink polymers Polymers containing two or siloxyl (Si O Si) unit.
more chains that are interconnected by chemical
bonds.
Inorganic polymers Polymers containing a metal or INORGANIC and organometallic polymers are
semimetal (metalloid) in the backbone of or pendant macromolecules that contain metals or semimetals
to the polymer chain. (metalloids) either in or pendant to the polymer
Molecular weight Unless otherwise stated, the number- backbone. Many of these materials have been de-
average value (M n ). signed to withstand the extremes of temperature and
Networkpolymers Giantthree-dimensionalstructuresin erosion, but still maintain the highly desirable properties
which many chains are connected through crosslinks. of oxidative stability, elasticity, electric conductivity or
Oligomers Molecules with relatively few (usually less resistivity, tensile strength, fire retardancy, low density,
than 10) repeating units in the chain. and/or inertness to solvents and chemicals. Representative
Organometallic polymers Polymers containing a metal examples are illustrated in Fig. 1.
or semimetal (metalloid) directly bonded to carbon in Inorganic and organometallic polymers are often clas-
the macromolecule. The metal may be in or pendant to sified in terms of morphological structure (e.g., chains,
the polymer backbone. sheets, and networks) and elemental composition (e.g.,
Sheet polymers Two-dimensional, layered (lamella) homoatom and heteroatom).

675