Monday, June 4, 2007

paper? plastic? or corn???

From a "fact" based reply from Gristmill : when asked for more info about "plastic and petroleum, (this is cut and pasted , )
You are probably familiar with the basic types of plastic, though you may not know their science-y names, which are often abbreviated on the bottom of your household products. Polyethylene (HDPE or LDPE) is the soft one you likely encounter most, in milk jugs, shampoo bottles, plastic bags, and so forth. Polystyrene (PS) is the hard plastic that makes casings for computers and other appliances, and also the basis of the foam product we fondly (but trademark infringingly) call Styrofoam. Polypropylene (PP) is used in dishwasher-safe containers and is also the magical fiber that rugged outdoors people favor. You'll often find polyethylene terephthalate (PET) in soda bottles, and it is sometimes recycled into fleece, upholstery fabrics, and other useful materials. And then of course there's polyvinyl chloride (PVC) -- no vinyl, and that's final.

How does plastic stack up in terms of oil use?
So how much oil is consumed by this process? This is the tricky part. From what I can tell, plastic production is a bit like leather production: it's one part of a complicated harvest. When crude oil is refined, its various chemical bits are separated. Some become gasoline, some diesel fuel, some motor oil, and others the raw material for plastics. The best estimate I could find says that about 4 percent of the world's annual oil production of some 84.5 million barrels per day is used as feedstock for plastic, and another 4 percent or so provides the energy to transform the feedstock into handy plastic.
Let's say a foam cup is what you had in mind as a "typical" plastic. In a classic study that closely examined the inputs for a foam cup vs. a paper cup and found the paper cup wanting, the petroleum inputs to the foam cup were 3.2 grams. (I'll leave it to you to weigh a foam cup if you want to, because I do not have one on hand, and I want you to feel empowered and participatory.) I've also seen it described slightly differently, that it requires about 1.78 kilograms of petroleum feedstock to make a kilogram of polystyrene.
We could make and use fewer petroleum-based plastics, but I don't know how much that would cut into oil drilling. Recycling, however, does cut into energy use. According to the U.S. EPA, manufacturing new plastic from recycled plastic requires two-thirds of the energy used in virgin plastic manufacture. I have more numbers, too: one ton of recycled plastic saves 685 gallons of oil. You can find lots of these "x amount is saved when we recycle" numbers in recycling promotional literature.
Abruptly,Umbra


But it got me to thinking, I had heard recently of new things being done with and in Of all things corn again ( any wonder the price keeps going up?) . again the below article is a "curt and paste" from "The Christian Science monitor"


A new corn-based plastic disappears into the dirt
By Liz Nakazawa Special to The Christian Science Monitor PORTLAND, ORE. – When you next buy a tub of potato salad, the container it comes in may be made from another vegetable - corn.
A new line of corn-based plastics, called polylactides or PLA, has begun to land on supermarket shelves. Its strongest selling points are that it fully degrades in 47 days, doesn't emit toxic fumes when incinerated, and requires 20 to 50 percent less fossil fuel to manufacture than regular plastics.
Graphic
Making biodegradable plastic

Related stories 01/20/00
Tough as soybeans

In May, 11 Wild Oats Markets on the West Coast became the first grocery stores in North America to switch from conventional plastics to the new corn-based product, with plans to roll them out nationally into all 90 stores later this year.
As part of the roll-out, Wild Oats has installed in-store bins where customers can return their empty containers. "We then take them to an industrial composting facility and they turn the containers into compost, which we then sell in our stores to people who buy it for their gardens," says Sonja Tuitele, communications director of Wild Oats.
A European retailer has also been selling the new plastic products. IPER, a 21-store chain in Italy, has been using the packaging for a year and has expanded its use from deli departments to dairy and bakery areas.
The new plastic has a few quirks, however. The biodegradable materials won't break down in regular landfills; they have to be taken to special industrial sites and treated like compost. Nor will they decompose in home compost bins: Temperatures there don't reach the required 284 degrees F. Yet the containers will melt if filled with hot food, or placed in the dishwasher or microwave.
Cargill, an international agriculture corporation, and Dow Chemical, have a joint venture making one line of PLA. Within 10 years, says Cargill spokesman Michael O'Brian, the company expects to be making 1 billion pounds of corn-derived plastics each year. That would mean 10 percent of the nation's annual corn supply would be converted into plastics and fiber.
PLA can also be used as an alternative for molded foam products, electronic packaging, and cups. For instance, the Coca-Cola Company used 500,000 cups made from corn at the 2002 Olympic Winter Games in Salt Lake City. And instead of creating a huge trash problem, the used cups were composted and turned into dirt.
What separates biodegradable plastics from their more long-lived cousins are polymers. Plastics based on natural plant polymers, derived from wheat or corn starches, have molecules that are easily broken down by microbes; traditional plastics have polymer molecules too large and too tightly bonded together to be broken apart by decomposer organisms.
Most biodegradable plastics currently on the market are between two and 10 times more expensive than traditional plastics. Yet plastics constitute 9 percent of the 156 million tons of trash Americans generate each year, and many consumers would be willing to pay the extra costs for a replacement product that biodegrades. According to a recent survey from market research firm RoperASW, 51 percent of respondents would pay a premium of up to 10 percent for environmentally safer versions of plastic packaging.


I say, if we request it, there may be more and more alternative plastics. I can say we are already seeing some of this in the textile industry with additions like soy silk, ingeo, and bamboo. Makes me hope we can make a difference , in time.

Tip for the day: put your thermostat at 78 degrees. If your home holds temp well, and it dosent become too hot inside 78 is very tollerable. BUT if you notice it is growing increasinly hot, you may want to check the state of your roof and shingles, and the caulk around your windows.
a reasonable caulk can be as low as 2$ a tube .

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