polyester, plastic bags, etc.

Important Things to Consider Regarding Biodegradable and Compostable-Plastics.

Notice here, I'm calling these materials biodegradable plastic, not vegetable starch. Many people, including myself, nickname these bags cornstarch or potato starch, but the actual make up of the bags is not just made from starch there is what is known as a polyester matrix built into the bags.

Hang on... polyester?That's plastic isn't it?!!! In short, yes it is and you do need to be aware of this, because its something some of the wholesalers tend not to mention.

However there are many forms of plastic. Plastic is the general term for a wide range of synthetic or semisynthetic polymerization products.

A regular plastic bag is made from polyethylene which has a different molecular structure to polyester.

Regular polyester is not designed to biodegrade, however there are new polyesters on the market that have been designed to biodegrade.

Put incredibly simply, the main difference between polyethylene and biodegradable polyester molecules are that the biopolyester molecules are small enough for micro-organisms to get their mouths round and digest while polyethylene molecules are too big hence they remain intact and do not breakdown in compost because nothing can digest them.The other difference is that polyester can be made from vegetable oil, it doesn't have to be made from petroleum (although a lot of vegetable starch bags still use petroleum based polyester). Technological progress means that increasingly higher percentages of renewable materials are now being used, but you should definitely ask your wholesaler about this.

Here's a really good independent paper by California State University which trialed the differing types of material on the market. website

Now, keep in mind, Polyester has many states. I looked it up because Mark brought up something that I didn't know--that the gels we use now are made of a poly carbomer. Cool! I didn't know that. I do however know that the gels that were made of gelatin never lasted very long. It's nice that they found a solution, and this article actually shows other solutions to that crazy "polyester in the landfills" problem. And the fact that at every checkout line we have 99 cent alternatives to that plastic bags that fill our landfills. Most of those are made from polyester! Check this out! Bag Information Page