Materials Database and Search Engine Covers Over 20,000 Items

MatWeb ( http://www.matweb.com/ ) is a database covering over 20,000 materials including metals, plastics, ceramics, and composites. You can search by keyword or do a limited amount of browsing.

I searched for "plastic" and got the maximum 200 results (if you use a common search word MatWeb will only display the first 200 results.) The results provide only the name of the material (for example, "Superplastic Zinc (Zn-22Al), As-Rolled - Longitudinal Properties.")

Click on one of the names and you'll get a page of information about the material, including subcategory, close analogs, keywords, and composition. The page also includes physical, mechanical, thermal, and electrical properties for the item.

In addition to materials information this site also has a conversions tool, weight calculator, and link list. Worth a look.

Posted to Science-Engineering