Plastics 101 : Common Plastic types and their different uses

Plastic types are indicated on plastic products by a number (1–7) inside triangular recycling arrows.
These codes identify the type of plastic used and help determine how it can be sorted and processed for recycling. 

1. Thermoplastics:

These are plastic that can be melted and reshaped:

1-1. Polyethylene Terephthalate (PET / #1):

• Properties: clear, strong plastic that keeps air and moisture out.
• Usage: water bottles, soda bottles, polyester clothing, …

1-2. High-Density Polyethylene (HDPE / #2):

• Properties: tough, stiff plastic that resists chemicals.
• Usage: milk jugs, shampoo bottles, detergent containers, toys, …

1-3. Polyvinyl Chloride (PVC / #3):

• Properties: versatile plastic that can be rigid or flexible.
• Usage: pipes, window frames, vinyl flooring, credit cards, …

1-4. Low-Density Polyethylene (LDPE / #4):

• Properties: soft, flexible plastic.
• Usage: plastic bags, squeeze bottles, food wrap, …

1-5. Polypropylene (PP / #5):

• Properties: lightweight, heat-resistant plastic
• Usage: yogurt containers, bottle caps, microwave-safe food containers, …

1-6. Polystyrene (PS / #6):

• Properties: either clear hard plastic or white foam.
• Usage: disposable cups, foam food containers, CD cases, …

1-7. Other (#7):

• Definition: this category is a catch-all for plastics which are not listed within the recycled categories (#1- #6).
• Usage: some water bottles and food containers, certain medical devices, electronic casings, automotive parts, some food packaging. These plastics have limited recycling options.

Examples:

• PC (Polycarbonate): tough, clear plastic (eyeglasses, water bottles).
• ABS (Acrylonitrile Butadiene Styrene): strong, impact-resistant plastic (LEGO bricks, helmets).
• PMMA (Polymethyl Methacrylate) or Acrylic: glass-like clear plastic (signs, display cases).

1-8. Summary:

Below is a simple table that lists plastics, their type and their recyclability:

2. Thermosets:

These are plastics that cannot be reshaped once they are formed. 

2-1. PU (Polyurethane):

• Properties: versatile plastic often made as foam.

• Usage: mattresses, furniture cushions, insulation.

2-3. Epoxy:

• Properties: super-strong glue-like plastic. 

• Usage: glues, coatings, surfboards.

2-4. Silicone:

• Properties: rubber-like plastic that handles heat well. 

• Usage: baking molds, sealants, phone cases.

2-5. Phenolic:

• Properties: heat-resistant plastic that doesn't conduct electricity. 

• Usage: pan handles, electrical parts, countertops.

3. Plant-Based Plastics:

3-1. PLA (Polylactic Acid):

• Properties: made from plant sugars, can decompose in industrial composting. 

• Usage: compostable cups, food containers, 3D printing material.

3-2. PHA (Polyhydroxyalkanoates):

• Properties: made by bacteria, breaks down naturally. 

• Usage: medical items, packaging, agricultural films.