CK-12 Foundation
Ck 12: Ionic Bonds and Ionic Compounds
[Free Registration/Login may be required to access all resource tools.] In the following online tutorial students will learn to explain how an ionic bond is formed when electrons are transferred from one atom to another in terms of the...
Wikimedia
Wikipedia: Polypropylene
This site from Wikipedia, the free encyclopedia, provides brief but factual information on the function of Polypropylene. A good site to get a short overview on the subject, with a few links to additional information.