Re: [GreenYes] Compostable plastics

[don hughes <djhughes@mailbox.syr.edu>]

Dear Julie-
	I feel i must correct some misunderstandings about "plastics" and
"polymer".  The term plastic is commonly used to refer to the
petroleum-based stuff we are all familiar with.  (Actually, most plastics
are derived from natural gas as the starting material.)
	The term "polmer" is a chemical term referring to molecules which are made
up of repeating subunits (monomers).  Polystyrene is made from thousands of
styrene molecules strung together; same idea for polyethylene, polyvinvyl
chloride, etc.  Starch is also a polymer, made from repeating glucose
(sugar) units.  Celluose, the basis for all plant life, is also a polymer
based on glucose.  
	In my opinion, the biggest problems with traditional petroleum-based
plastics are: 1) they don;t break down in the environment, and 2) they come
from a non-renewable resource.  By switching back to carbohydrate-based
products (e.g. starch) we can produce materials that do break down and can
be grown rather than pumped out of the ground.  Of course it is essential
that the claim of biodegradability be demonstrated thoroughly.  Some
"biodegradable plastic" produced some 5-10 years ago turned out to be a
hoax--it did not degrade any faster.  But i think that we have to go back
to crops if we are to get off our addiction to oil and have a truly
sustainable economy.

Don Hughes
t 02:17 PM 12/26/2001 -0800, you wrote:
>    Dear Recyclers; Here's my two cents worth on compostable  plastics.
>Initially, I was very excited, but on investigation, I have changed my 
>thinking. Here's why. 1) Most compostable plastics are starch based. 
>Starch is a monomer and any "plastic" type product is a polymer. The
>process of  changing that monomer to a polymer is just as toxic and
>environmentally costly  using corn or potato starch as is changing oil into
>plastic. So what's the  advantage? Only that you are using a renewable
>resource as oppose to a non  renewable.  2) Look who is developing these
>plastic  alternatives? Cargill and Dow Chemical. Enough said.  3) Well, not
>quite enough. Lets add a few  words. Genetically modified crops. Follow the
>GMO corn trail.....  are another feel good  product. They dupe people into
>believing that choosing to use a thing once and  dispose of it is OK.
>Aaargh is what I have to say about that.  5) To sum up, compostable
>plastics are about  keeping the same old same old going. They do not
>substantially alter the  environmental picture and may in fact delay the
>changes in approach that need to  be made. Using farm land to grow
>genetically modified crops to manufacture a  product at great environmental
>cost so we can feel better about chucking out the  packaging delivering our
>burger and fries does not do it for me. OK, I'm done ranting!   Julie Daniel
>General Manager
>BRING  Recycling
>phone: (541) 746-3023
>fax: (541)  726-9894 

-----------------------------------------------------------
        Don Hughes      Dept. of Chemistry
        315-470-6597    431 Jahn Lab
			SUNY-College of environmental science & forestry
                        SYRACUSE, NY 13210
-----------------------------------------------------------
"I don't believe there's any problem in this country, no matter how tough
it is, that Americans, when they roll up their sleeves, can't completely
ignore."
				- George Carlin


******************************************
To post to the greenyes list,
email to: greenyes@grrn.org

Subscription information for
this list is available here:
http://www.grrn.org/general/greenyes.html
******************************************