Have you noticed how there’s so much more plastic around these days? Particularly in supermarkets. Your food can have up to two or three plasic containers/bags/wrappings etc.
So I was wondering (as I’m sure countless others have done before) is there a substitute we could use instead of plastic? Something that is still waterproof yet bio-degradeable?
Note that “plastics” is a catchall term for a huge number of materials. Lot’s of different base compounds hooked up in polymer chain. Pretty much any new replacement for plastic bags will also be a plastic made up from a different base material.
There are plastics made from corn-derived polymers that are biodegradable. But keep in mind that nothing biodegrades in a landfill, biodegradable plastics are not recyclable, etc. To make a dent in plastic waste you have to a large composting facility to breakdown biodegradables or ordinary recycling such as the current (unmet) demand for plastic pop bottles for carpeting.
OTOH, biodegradable bags might help reduce the production of “plastic forests”: trees suffocating in bags blown into their branches. A real headache in many regions.
There are more factors to consider than that. How stable is it over time? To heat? Cold? Exposure to light? Will the wrapping leech into the food? Will it contain the food (a liquid?) as we want it to? Is it easy and efficient (cost/environmentaly) to produce in mass quantities? etc etc
I agree that many MANY companies use too much plastics/wrapping in a lot of products, and that there are definitely ways to reduce the amount used. Plastics (and there are many kinds) have been shown to have properties that are useful and, in some cases, beneficial. They are durable and the wide varieities of polymers out there mean that we can have many different types of products, more or less “designed” to fit a specific need, such as a pop bottle or a prosthetic limb. There isn’t really a good substitute. I mean, plastics ARE the subsitutes for wood and glass and metals.
Plastics aren’t biodegradable, but a lot of things that are just wouldn’t be good for what we want to use it for (e.g. food storage). One thing to note, however, is that plastics ARE recyclable - its just that very few people know this or try to do it, and it is complicated by the fact that each plastic type (HDPE, LDPE, PPE, PETE, etc) needs to be recycled separately, since mixing them causes them to not be as good.
Short of drastically changing the lifestyles of a good proportion of the world, the “solution” is more an awareness one than in finding a substitute, IMHO. Make companies use less, and invest money into proper recycling programs and facilities, and attempt to reduce consumption, if at all possible.
By definition plastics can never be replaced.
Hm, that definition is missing something.
Plastic is a generic term for polymers, particularly synthetic polymers.
I have heard constantly (I’ll look for a cite) that what is made out of plastic nowadays used to be made of hemp, as far as fabric-like items.
So if we were suddenly to ran out of oil, but managed to find an alternative energy source, would we still be in trouble in terms of plastic supply?
You can avoid having to use any plastic bags in a supermarket by buying a set of cloth bags and using them for all your grocery purchases. Such sets include smaller bags for produce. I’ve found that I can avoid having to be given a plastic shopping bag for my purchases in many stores by simply refusing the bag that I’m offered. If I were more consistent about bringing my cloth bags into all stores, I could avoid nearly all the plastic shopping bags that I’m offered. (The few bags I get from stores I find ways to use for other things.) If everyone were to do that, it would reduce the amount of unrecyclable materials more than trying to find some substitute for plastic would.
Another way to recycle plastics is by recovering the energy from them i.e burning them.
Materials recycling of plastics can quite often be both economically and environmentally unprofitable.
As mnemosyne mentioned above there are quite a lot of different types of plastics used for different purposes and in order to recycle the material you have to separate them by type which can be quite costly both in terms of energy and labour. One cannot just thrown in some old shampoo bottles into the melter and get useful plastic out of it. You have to get rid of residue from whatever was in the container and any other contaminants it may have picked up. This process often requires the use of both energy and cleaning chemicals which have a negative impact on the environment. If these negative impacts are greater than the positive benefits of not having to produce new plastic, incineration with heat recovery is often the environmentally and economically best option.
If we were to incinerate plastics on a large scale, what about air pollution? No incinerator is fully efficient (as is obvious from Thermodynamics) and no filter is fully efficient (ditto).
What would we end up with in terms of dispersed and solid waste?
Where I shop (France) plastic has been replaced by paper in several cases. For example, beer bottles are sold in 6-(or 8 or 10 or…)packs wrapped up not in plastic, but in cleverly folded paper. (Held together without any glue or staples! Isn’t that clever!).
I’m pretty sure that they used to be wrapped in plastic, but I don’t know why it changed. (Pressure from consumers, legislation or simply cheaper?)
I believe that paper / cardboard can replace plastic in a lot of the packaging industry. It’s only slightly heavier and bulkier, but is biodegradable and can be recycled either as material or energy. And I believe it’s easier to print colourful labels on.
A certain kind of paper-based molded spacer seems to have replaced a lot of the styrofoam used to package electronic equipments.
There is a material.
It is called gutta percha, and it was used in the late 19th & early 20th Centuries as an electrical insulator, for toys, dentures, walking canes, & other items.
It comes from the sap of a tropical/semi-tropical tree.
It is relatively hard & durable when cool & dry. It is fully pliable & moldable wheen submerged in near-boiling water.
Plastics only replaced gutta percha because plastics are made from what was then waste by-products of petrol refining.
BTW–gutta percha is stronger than most plastics–see it’s use in walking canes for the lame & elderly.
We could always replace plastic with what we used before it - Paper, wood, glass etc
I know of at least one company that has developed soy-based polymers. I don’t think they’re ready for widespread use yet, but they are being used in some applications.
As I mentioned in my first post, we already have (some biodegradable) plastics from corn. You don’t need oil to make plastics. Just some basic hydrocarbons and energy. Oil is merely a cheap source. Coal is also good but not as cheap, etc.
Burning plastics produce huge amounts of polutants. The energy cost to clean the smoke would negate any profitability of energy from burning them. Note that in 3rd world countries, people scrounge dumps for plastic and then burn them. Not only does this make the air of the cities much, much, worse, they are inhaling some pretty nasty stuff from their fires.
The answer to the age old question:
Paper or Plastic?
Ecologically it comes down to what we call Embodied Energy which is how much energy it takes to mine the materials, process them, convert them into the product, and deliver it to the store. This is how environmentalists compare the various products we buy.
One standard grocery store paper bag contains the same embodied energy as 100 plastic bags.
However, my answer to the question “Paper or Plastic” is always either “cotton” (which I provide), or “my two God given hands.” 999 times out of 1000 they let me take the little hand baskets out to my car. In 10 years of refusing bags I have only been refused once. I made the manager get me a cart, which he did with a smile on his face.
Interesting fact: wood is a more environmentally friendly building material than metal, concrete, or plastic, so long as it is cut down from an ecologically managed forest and it is not an endangered species.
The grocery stores in this area (there a 3 less than 5 minutes from my house) no longer even OFFER paper bags - its always plastic.
The only element that comes close to carbon w.r.t. forming chain molecules (polymers) is silicon. So most of the material are carbon based - whether plastics or paper.
I have’nt come across any other material which can equal that.
There are lots of substitutes for plastic, but as of now plastic happens to be the cheapest. You will not get a major shift away from plastics until something else becomes more attractive economicly.
It depends what kind of plastics you’re trying to burn. for instance, the various types of vinyl (PVC) contain chlorine, and will produce rather noxious fumes. Nylons (polyamides) contain nitrogen; the nitrogen oxides formed in combustion are similar to those that form smog.
On the other hand, the various types of polyethylene are simply long, sometimes branched chains of carbon and hydrogen. If you feed enough oxygen to PE, it will burn the same way as any lighter hydrocarbon, and give off heat, water, and CO[sub]2[/sub]. If not, it will be a sooty flame, and possibly release carbon monoxide – the same way an oil lamp will if the wick is turned up too high.
More information on gutta percha. Because it became hard, but not brittle, when cooled, it was used extensively to insulate undersea telegraph cables in the mid 19th century. However, it will become brittle and degrade when exposed to light and oxygen:
I’ll be generous and say “sort of”. The ultimate tensile strength of gutta percha is about 2800 psi (cite). That compares favorably to low density polyethylene (i.e., sandwich bags; 1140-3270 psi) and plasticized PVC (shower curtains; 1420-3560 psi). However, it’s a bit weaker than some other common polymers, including high density polyethylene (milk jugs; 2560-4980 psi) and epoxies (4270-5690 psi). It wouldn’t even compare to common engineering polymers like polycarbonate (7960-9530 psi) or polyamide 66 (nylon rope, 10950-11950 psi).
[cite: Osswald, Polymer Processing Fundamentals, 1998]