The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Saran is derived from the polymerization of vinylidene chloride or the copolymerization of vinylidene chloride with lesser amounts of other unsaturated monomers, most often vinyl chloride or acrylonitrile. This thermoplastic polymer was first polymerized in 1920 by the Dow Chemical Company. Today, it is most often used in copolymers to form packing film, rigid pipe, and fibers. As a film, it acts as a barrier to oxygen, water vapor, grease, and liquid. About 85% of the polyvinylidene chloride produced is used as a thin layer between cellophane, paper, and plastic packaging to improve barrier performance. Saran Wrap, well known as the cling wrap designed for household and commercial use that Dow Chemical first introduced in 1949, revolutionized the food packaging industry. Today, saran films are used as a barrier package for cheese, baked goods, processed meats, and seafood.
Saran is produced by polymerizing vinylidene chloride with other monomers to form long stereoregular chains. These chains are susceptible to crystallization, giving rise to the superior clarity and excellent barrier properties of saran.