What is plastic and how is it made?

 

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Plastics are made from oil. Oil is a carbon-rich raw material, and plastics are large carbon-containing compounds.

Plastics are simply chains of like molecules, called polymers,  linked together. This is why many plastics begin with “poly,” such as polyethylene, polystyrene, and polypropylene. Polymers often are made of carbon and hydrogen and sometimes oxygen, nitrogen, sulfur, chlorine, fluorine, phosphorous, or silicon.

The first synthetic plastic was made from the plant material cellulose. In 1869, John Wesley Hyatt, an American printer and inventor, found that cellulose nitrate could be used as an inexpensive substitute for ivory. The mixture could be plasticized with the addition of camphor. Celluloid, as this new material was called, became the only plastic of commercial importance for 30 years. It was used for eyeglass frames, combs, billiard balls, shirt collars, buttons, dentures, and photographic film.

In 1951, two young research chemists for Phillips Petroleum Company in Bartlesville, Okla., made discoveries that revolutionized the plastics world. Today, the plastics they discovered—polypropylene and polyethylene—are used to produce the vast majority of the thousands of plastics products all over the world.

How does petroleum become plastic?

1. Petroleum is drilled and transported to a refinery.

2. Crude oil and natural gas are refined into ethane, propane, hundreds of other petrochemical products and, of course, fuel for your car.

3. Ethane and propane are “cracked” into ethylene and propylene, using high-temperature furnaces.

4. A catalyst is combined with ethylene or propylene in a reactor, resulting in “fluff,” a powdered material (polymer) resembling laundry detergent.

5. Fluff is combined with additives in a continuous blender.

6. Polymer is fed to an extruder where it is melted.

7. Melted plastic is cooled then fed to a pelletizer that cuts the product into small pellets.

8. Pellets are shipped to customers.

9. Customers manufacture plastic products by using processes such as the following:

Extrusion: Pellets are heated and mechanically mixed in a long chamber, forced through a small opening and cooled with air or water. This method is used to make plastic films.

Injection molding: The resin pellets are heated and mechanically mixed in a chamber and then forced under high pressure into a cooled mold. This process is used for containers like butter and yogurt tubs. (Custompart.net has a great lesson on injection molding.)

Blow molding: This technique is used in conjunction with extrusion or injection molding. The resin pellets are heated and compressed into a liquid tube, like toothpaste. The resin goes into the chilled mold, and compressed air gets blown into the resin tube. The air expands the resin against the walls of the mold. This process is used to make plastic bottles.

Rotational molding: The resin pellets are heated and cooled in a mold that can be rotated in three dimensions. The rotation evenly distributes the plastic along the walls of the mold. This technique is used to make large, hollow plastic items (toys, furniture, sporting equipment, septic tanks, garbage cans and kayaks).

know-your-plastics

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Step 8: Bye Bye Aluminium foil & plastic film

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:-O Am I serious? How could I say that about two of the cornerstones not just of storage but of baking/roasting? Waaaaaaaa, you go. Cry as much as you like but ’tis best to forego these two.

Why, you ask, why are you being so perverse? Well, in case you are not much into reading scientific papers, this is the very readable article (written by the lead scientist) on the research done into aluminium leaching into food as it is cooked. For those of you who love research papers, here is the original research which came out in 2012! Seems the media forgot to inform you…..tis obvious that measuring the size of a Kardashian bum was more important (eye rolling).

Re plastic film….I think you have already got my drift about plastic in general, right? From the way it is manufactured and the products used to manufacture it (see next post!), how these products leach into our food and finally, how this material is now polluting our natural habitats, I feel there is nothing more to say.

So, what do we do now? How do we bake, roast, store and do all the marvellous things these 2 materials afford us? You will be happy to know that alternatives do exist 😀

FullSizeRender-2Have you heard of baking paper? It works brilliantly to either put at the bottom of your roasting trays or over whatever you are roasting. I tend to oil my roasting trays really well or use ceramic/metal trays which don’t really need lining, just a bit of elbow grease. Another thing I do is to put bacon over tender chicken breasts or roasting meats, which also beats having to use paper ( or aluminium foil). Voila, problem solved.

Now…how about storing our foods in the fridge, without foil or film- “Is this possible” you asked in hushed tones? Apart from the stainless steel and glass storage containers (see previous post), here are some more ideas:

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Leftover food items can be stored in ceramic bowls with a plate as a lid in case you don’t have glass/stainless steel storage containers or have run out. I cover the yoghurt I make with denim lids from trousers that I hemmed (yay, being short has its uses). Kitchen towels work well as covers of food items too.

How to remove pesky labels and glue from jars

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I like to recycle ie reuse ALL my glass jars when I do buy stuff in glass. But how to remove those pesky labels? A good soak in hot water or hot water and soap helps but in most cases, the glue/gum remains on the glass, doesn’t it? Grrrrr. Nail varnish remover and paint thinner are two VERY unecological ways to do away with the labels – banish the thought! (Can you imagine this chemical gunk going down our drains, into the sewers and eventually into the oFullSizeRender-2ceans?). So I tried salt, thinking that its abrasive nature would help AND, it does to some extent but not enough for that perfect and clean glassy look. So I thought about using the ash I harvest from my barbecues (I actually sieve the leftover coals once they have cooled- is that crazy?) and guess what? Ash and wire wool work wonders and within seconds, the toughest glue/gum comes off without a scratch on the glass! Hallelujah!

If you don’t have recourse to ash, salt will have to do. Scrub away!

I have come up with my own pretty labels to affix to these jars, for the freezer or fridge or plain storage or to fill with oils or as wax or..but I digress.

UPDATE: A word to the wise: a lot of labels are now stickers so, before wetting them or steaming/boiling/grating etc, why not try peeling them off? Believe me, it makes the job a whole lot easier!

Step 6: Get rid of plastic storage containers for meals

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Plastic storage containers sometimes erroneously and generically called Tupperware ( that’s a brand!) – are they Good? Bad? or plain Ugly?

UGLY! No euphemism or gentle way to say this – STOP USING THEM! As mentioned in my previous post, many plastics used for food and beverage storage are potential sources of Bisphenol A or BPA which is a plasticiser, used to make clear, hard plastic. A group of researchers from the Institute of Environmental Medicine in Stockholm, Sweden recently reviewed all the research (46 studies) on whether BPA is toxic to the developing nervous systems of newborns. They concluded that even though the studies have been conducted according to standardized protocols, the research “…may overlook sensitive effects of BPA, and possibly other potential endocrine disruptors, especially in female offspring.” In addition to developmental toxicity, BPA has also been linked to obesity in children and adults as well as to cardiovascular disease, diabetes, reproductive disorders, breast cancer, and more. Brrrrrrr

And for those of you who heat your food in them, ARE YOU OUTTA YOUR MIND? Even those stating that they are microwave safe- just transfer your food to a ceramic or glass plate to heat it. Please! Heat makes the plastic leach it’s chemicals into the food. Here is an American Scientist article on it for you to have a look at and raise your eyebrows in shock and horror.

So, what do you do with the tuppers/ plastic storage containers you already have? No point throwing them away for they can’t be cleanly recycled, if you do find a place that recycles them. You could give them away, use them to store non-food items like crayons, meds or whatever or better still, store them in a dark, dark corner of your home and never, ever use them again.

And …now what? :-O

Here is an alternative made of stainless steel and which is ideal for travel too:

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Here is an alternative made of glass and perfect for storing your meals in the fridge:

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With a glass lid
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With a metal lid