Plastic is a synthetic material made from a wide range of synthetic or semi-synthetic organic polymers such as polyethylene, PVC, nylon, etc., that can be moulded into shape while soft, and then set into a rigid or slightly elastic form. The name "plastic" refers to the property of plasticity, which is the ability to deform without breaking.While other elements may be present, plastics always include carbon and hydrogen, can be made from any organic polymer, but most industrial plastic is made from petrochemicals.
The first completely synthetic plastic was bakelite, made in 1907 by Leo Baekeland, who also coined the word "plastics". Approximately, a third of plastic produced is used to make packaging, while another third is used for piping. Pure plastic is generally insoluble in water and non-toxic. However, many of the additives in plastics are toxic and may leach into the environment. Plastic is almost always mixed with additives, including colourants, plasticisers, stabilisers, fillers, etc which affect the chemical composition, chemical and mechanical properties and affect its cost.
Kinds of plastics
Plastics are classified in seven categories. If you look at a plastic product, somewhere in it will be a chasing arrow symbol with a number at the centre. These numbers range from 1 to 7 and denote the kind of plastic that particular product is made out of. These seven categories are:
Some other kinds of plastics in common use are Polycarbonate (PC), Acrylic (PMMA), Acetal or Polyoxymethalene (POM), Nylon (PA) and Acrylonitrile Butadiene Styrene (ABS). In the classification, all these fall under category #7 - OTHER.
Polycarbonate has very high impact strength compared to other plastics and are used in building structures like greenhouses. Being transparent also helps in many applications.
Acrylic is extremely transparent, scratch resistant and is used in optical devices due to its low susceptibility to damage human skin, even the eyes.
Acetal also has a very high tensile strength and what makes it useful is its high resistance to creep, ie the ability to withstand deformity due to sustained temperatures or pressure.
Nylon is used for a variety of purposes that include clothing, tyres, ropes, cordage, and other mechanical parts. It is often used as a substitute to metals due to its high strength, resistance to temperature variations, etc.
ABS is used in a variety of applications, but with the growth of 3D printing, it is coming into its own due to its strong resistance to corrosive chemicals and ability to resist high degrees of physical impacts. It is readily available and has a low melting point making it suitable for injection moulding.
Are plastics safe?
Which of these categories is safe(r)? Well, there is a rhyme to help gauge this - "1245 stay alive, 367 straight to Heaven". Plastics with the number 1,2,4 and 5 are generally safer (less toxic) than the ones with the numbers 3,6 and 7. But really, no plastic is safe. All plastics leach toxins. And this is true for plastic water bottles as well as plastic food wraps.
The chasing arrow symbol usually denotes that the product is made from recycled material or that it is recyclable. But the chasing arrows denoting the plastic category is a red herring and is just a design element and has nothing to do with recycling. May be there is a case for banning the use of the chasing arrow symbol from plastic items, unless of course they are really recyclable.
One of the big toxins in plastic is BPA or Bisphenol-A, a known carcinogen. It is found in most water bottles and in the lining of canned food containers. So, if you are giving up plastics and opting for canned food instead, you are still exposed to the very same carcinogen that the plastic you were avoiding contains. There are products labelled BPA-free, but only time will tell if the chemicals added to make the plastic BPA-free end up causing other health issues.
Does plastic biodegrade?
The short answer is NO ... in capitals. Biodegradation is a process by which bacteria transform the products into other useful compounds. As per current knowledge there is no organism on land or sea that considers plastics food ... the basic minimum requirement for biodegradation. What happens to plastic is photodegradation. When exposed to sunlight, plastics eventually become brittle and break up into smaller and smaller pieces. However, plastic remains plastic, even if a single bottle photodegrades into a million microscopic pieces. This is what is happening to plastics that find their way into the rivers and seas. However, if the plastic is buried in a landfill, nothing happens to it for centuries, since there is no sunlight for it to even photodegrade.
Every piece of plastic ever produced since 1907 when it was first produced, still exists on Earth, slowly but surely poisoning the Planet.
There is a lot of research being undertaken all over the world to find a viable answer to plastics, particularly single use plastics. There are chemicals being added to regular plastic pellets that are supposed to turn plastics biodegradable. There are alternatives being made from bananas, yucca, sugarcane, millets, etc. Polylactic acid (PLA) is a plastic made from corn, and is the most talked-about alternative. These products are still largely in the development stage and in their nascency. Once acceptance is received on a voluminous scale, costs will go down, making it more easily acceptable to people.
Visit The Green Shop to take a look at some possible alternatives that you can buy to replace your use of regular single use plastics.