Plastics are used in various industries and can be found throughout life. However, their diversity makes plastics unique; different types of plastics have unique properties, advantages, and disadvantages.
But there are many types of plastics. Some are reusable materials, while others are hazardous and require immediate disposal.
Identifying Plastic Types
Based on the types of general-purpose plastics, about 70% of global production is concentrated in six main polymer types.
- (PET): Commonly used in beverage bottles and food containers.
- (HDPE): Milk, detergent, and plastic bags.
- (PVC): Floors, flooring, and window frames.
- (LDPE): Plastic bags, cling film, and bottle caps.
- (PP): Yogurt containers, heating containers, and bottle caps.
- (PS): No-wash utensils, CD cases, and instant noodle bowls.
How do you quickly identify plastic materials?
Appearance Identification:
You can tell the type of commodity plastics by looking at their Resin Identification Code (RIC). (usually located on the bottom)
Of course, you can find out what type of plastic material it is by looking at its color, transparency, etc. For example, PET is usually very transparent, HDPE is opaque, PVC is milky white, LDPE is very thin, PP is usually translucent or colored, and PS is usually clear or foamed.
Density Identification:
You can measure a plastic material’s density or specific gravity by weighing it in water.
The density of water, 1 g/mL, is the reference. However, this method is very limited; you need to use similar-sized pieces of plastic to measure, and except for PVC and PP, the difference in density between plastics is not very big; other plastics are difficult to observe by this method.
Burning Identification:
You can burn a small piece of plastic in a safe, ventilated area; different plastics have different burning characteristics that can help you identify them.
PET： Burns with dripping, the flame color is yellow with blue edges, the smell is burnt rubbery, burns fast, and black smoke.
HDPE： Burns with dripping, the flame color is blue with yellow top, the smell is paraffin, and the burning speed is fast.
PVC： No drops when burning, the flame color is yellow with a green edge, the smell is hydrochloric acid, and the burning speed is slow, producing white smoke.
LDPE： There are drops when burning, the flame color is blue with a yellow top, the smell is paraffin taste, and the burning speed is fast.
PP： There are drops when burning, the flame color is blue with a yellow top, the smell is diesel flavor, and the burning speed is slow.
PS： There are drops when burning, the flame color is yellow, the smell is styrene and rubber flavor, and the burning speed is fast.
How different types of plastics affect the environment
Plastics usually biodegrade over 500 years. In addition, plastics contain harmful chemicals during decomposition, which can leach into the soil and oceans and cause ecological damage.
Disposable bags, plastic straws, or pieces of plastic are exposed to creatures in the ocean, which are harmed when they eat them and cannot treat the wounds. They can only be rescued by wildlife organizations.
About 8% of the world’s oil is used to make plastics, of which less than 1% is recycled, but it takes millions of years to produce oil, and the need for renewable resources is urgent.
Finally, one of the most harmful aspects of plastic is the risk of microplastics leaching into soil and water. These particles are so tiny that they cannot be easily recycled. Not only do they damage good soil and crops, but they are also highly toxic and can cause bodily harm if ingested.
