- Vedant Gandhi
Types Of Plastics
Consumer plastics are made from six different polymer resins, which are indicated by a number - a resin code, from 1 to 7. The number 7 plastic indicates different plastic outside of the six.
1. Polyethylene Terephthalate (PET or PETE or Polyester)
PET is mostly used for food and drink packaging purposes because of its ability to keep oxygen out. It is also capable of keeping the carbon dioxide in-store in carbonated drinks. It is a tough plastic that is discolored if you bend it. It is the most commonly recycled plastic. Egg cartons, carpets, and fabrics for T-shirts and fleeces can be created by recycling this plastic.
2. High-density Polyethylene (HDPE)
HDPE is tougher, denser, and stronger than PET. HDPE is more recyclable and stable than PET. Some studies show that HDPE when exposed to ultraviolet light leeches estrogen-mimicking chemicals into the food/drink stored within causing hormonal imbalance in the body. Milk and juice containers, shower gel bottles, detergents, and shipping containers are manufactured using this plastic. Toys, pails, traffic barrier cones, drums, and trash cans can be manufactured by recycling this plastic.
3. Polyvinyl Chloride (PVC)
PVC is the second most used plastic resin in the world after polyethylene. PVC is also the most hazardous plastic in the world. The disposal process of plastic has been declared as the cause of serious health risks and environmental pollution issues. The use of it may leach a variety of toxic chemicals such as bisphenol A (BPA), phthalates, lead, dioxins, mercury, and cadmium. Several of the chemicals mentioned may cause cancer; they could also cause allergic symptoms in children and disrupt the human hormonal system. PVS is also rarely accepted by recycling programs. This is why PVC is best to be avoided at all costs. Packaging materials, pipes, wire and cable products, blood bags, and medical tubing are manufactured using PVC. Very few products like shoe soles, boating, and docking bumpers and construction material can be manufactured using recycled PVC.
4. Low-density polyethylene (LDPE)
These plastics have the simplest chemical structure making them very easy and very cheap to process. They are very less dense, making them ideal for single-use. LDPE is very difficult to recycle and is also prone to cause health hazards. They are used to make bags for groceries, single-use cups, plastic wraps, and lid containers. They can be recycled to manufacture trash can liners, shopping envelopes, and floor tiles.
5. Polypropylene
PP is stronger than LDPE, stiffer, and resistant to heat. Although PP is considered a safe option for food and drinks, it could cause asthma and hormone disruption in humans. PP is also very difficult to recycle. It is used to manufacture medicine bottles, plastic bottles, straws, food containers, and automotive parts. Recycling PP can produce signal lights, bicycle racks, trays, and battery cables.
6. Polystyrene
Polystyrene is the styrofoam used to make egg cartons, fast food containers, toy containers, disposable cups and bowls, and bike helmets. When exposed to oily food, Polystyrene is known to leech a toxicant that can affect genes, lungs, liver, and the immune system. Polystyrene also has a low recycling rate. It is very damaging to humans and to the environment to continue using this plastic. Recycling them can only produce styrofoam packing and egg cartons.
7. Others
All types of plastics that cannot be considered under 1-6 are considered under seven. It includes Polycarbonates (PC), bioplastics, and other layered and mixed types of plastics. PC is quite dominant under this category. PC is one of the most toxic plastic types as it contains BPA (Bisphenol A). BPA is the only chemical with estrogen activity. PC was used to make baby bottles, baby pacifiers, water bottles, ketchup containers, instant formula packagings, and dental sealants. The use of PCs has been avoided because of its toxicity.
PC can cause chromosome damage in ovaries, low sperm count in males, sex reversal in frogs, neurological damage, breast and prostate cancer, infertility, cardiovascular damage, and Diabetes. On top of such huge health risks, they have very low recycled quality.
References:
Understanding plastics recycling, Natalie Rudolph, Raphael Kiesel, and Chuanchom Amunate, pg 36
https://www.open.edu/openlearn/science-maths-technology/chemistry/the-seven-types-plastic