The Three Basic Types of Plastic Bags and Alternative Production Method

This source summarizes two main points. When and how the plastic bag was created and the chemicals involved as well as the method used. Plastic shopping bags were made from one of three basic types: high-density polyethylene (HDPE), low-density polyethylene (LDPE), or linear low-density polyethylene (LLDPE). These materials and methods were first discovered and used by Karl Ziegler and Giulio Natta. They discovered a method that uses a transition-metal catalyst, in which polymerization would initiate. They won a Nobel prize for this in 1963. As William Carroll, a polymer chemist said, ""With the possible exception of a little lubricant to help in extrusion, plastic bags are pretty much just the native polymer."" The only other things you add to plastic bags are pigments, to change the color of the bags. They suggest that we can make plastic bags out of starch, which can be found in potatoes and corn. This makes bags biodegradable, although it does make the production of plastic bags much more expensive.  


http://pubs.acs.org/cen/whatstuff/stuff/8238plasticbags.html