Chap._200006 - disadvantage is the need to remove the...

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disadvantage is the need to remove the solvent in order to isolate the solid polymer. In this respect, it is common practice to use a solvent in which the monomer but not the polymer is soluble; the polymer (such as crystalline PE) is then obtained directly as a slurry and little further purification is necessary. * Suspension polymerization: The monomer is dispersed in water in small droplets (generally about 10 -2 - 10 -1 cm in diameter) maintained by vigorous stirring. This technique is extensively used for the free radical polymerization of vinyl monomers as discussed in Chapter 4. A monomer-soluble initiator is added and polymerization occurs within each droplet. Generally a suspension agent (such as polyvinyl alcohol or gelatin) is added to provide a protective coating for the droplets; this prevents the droplets from cohering when they are at the stage of being composed of a sticky mixture of monomer and polymer.
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This note was uploaded on 10/16/2010 for the course MATSE 441 taught by Professor Chung,tze-chiang during the Fall '10 term at Penn State.

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