The Eleven Most Important Types of Plastic

One of the major innovations of the past century has been the introduction and wide adoption of plastics for many day-to-day applications that previously relied on traditional materials like metal, glass, or cotton. Plastics have revolutionized many industries for a number of different reasons to include the fact that they resist environmental degradation over time, are generally safe for human beings, are economical and widely available, and are produced with a wide variety of material properties that allow adaptation to many different applications. Here is our list of the top 11 plastics the modern world simply cannot do without:

1. Polyethylene terephthalate (PETE or PET):

PET is the most widely produced plastic in the world. It is used predominantly as a fiber (known by the trade name “polyester”) and for bottling or packaging. For example, PET is the plastic used for bottled water and is highly recyclable.

PET plastic water bottle

Polyester Fabric

Three words or short phrases to describe the major benefits of Polyethylene relative to other plastics and materials would be:

• Wide applications as a fiber (“polyester”)
• Extremely effective moisture barrier
• Shatterproof

2. Polyethylene (PE):

There are a number of different variants of polyethylene. Low and high density polyethylene (LDPE and HDPE respectively) are the two most common and the material properties vary across the different variants.

HDPE plastic container

a. LDPE: LDPE is the plastic used for plastic bags in grocery stores. It has high ductility but low tensile strength.

b. HDPE: A stiff plastic used for more robust plastic packaging like laundry detergent containers as well as for construction applications or trash bins.

c. UHMW: Extremely strong plastic that can rival or even exceed steel in strength and is used is for applications like medical devices (e.g. artificial hips).

3. Polyvinyl Chloride (PVC):

Polyvinyl Chloride is perhaps most well known for its use in residential and commercial property construction applications. Different types of PVC are used for plumbing, insulation of electrical wires, and “vinyl” siding. In the construction business PVC pipe is often referred to by the term “schedule 40” which indicates the thickness of the pipe relative to its length.

Schedule 40 PVC pipe

Three words or short phrases to describe the major benefits of PVC relative to other plastics and materials would be:

• Brittle
• Rigid (although different PVC variants are actually designed to be very flexible)
• Strong

4. Polypropylene (PP):

Polypropylene is used in a variety of applications to include packaging for consumer products, plastic parts for the automotive industry, special devices like living hinges, and textiles. It is semi-transparent, has a low-friction surface, doesn’t react well with liquids, is easily repaired from damage and has good electrical resistance (i.e. it is a good electrical insulator). Perhaps most importantly, polypropylene is adaptable to a variety of manufacturing techniques which makes it one of the most commonly produced and highly demanded plastics on the market.

Living hinge prototype cap CNC machined from polypropylene

Two short phrases to describe the major benefits of Polypropylene relative to other plastics and materials would be:

• Unique Use For Living Hinges
• Simple To Manufacture

5. Polystyrene (PS):

Polystyrene is used widely in packaging under the trade name “styrofoam.” It is also available as a naturally transparent solid commonly used for consumer products like soft drink lids or medical devices like test tubes or petri dishes.

Styrofoam peanuts

One short phrase to describe the major benefits of Polystyrene relative to other plastics and materials would be:

• Foam Applications

6. Polylactic Acid (PLA):

Polylactic Acid is unique in relation to the other plastics on this list in that it is derived from biomass rather than petroleum. Accordingly it biodegrades much quicker than traditional plastic materials.

A cup made from bioplastic PLA

Two words or short phrases to describe the major benefits of Polylactic Acid relative to other plastics and materials would be:

• Biodegradable
• DIY 3D Printing (compare PLA to ABS)

7. Polycarbonate (PC):

Polycarbonate is a transparent material known for its particularly high impact strength relative to other plastics. It is used in greenhouses where high transmissivity and high strength are both required or in riot gear for police.

A polycarbonate greenhouse

Two words or short phrases to describe the major benefits of Polycarbonate relative to other plastics and materials would be:

• Transparent
• High Strength

8. Acrylic (PMMA):

Acrylic is best known for its use in optical devices. It is extremely transparent, scratch resistant, and much less susceptible to damaging human skin or eye tissue if it fails (e.g. shatters) in close proximity to sensitive tissue.

A laser being directed through an acrylic lens

Two words or short phrases to describe the major benefits of Acrylic relative to other plastics and materials would be:

• Transparent
• Scratch Resistant

9. Acetal (Polyoxymethylene, POM):

Acetal is a very high tensile strength plastic with significant creep resistant properties that bridge the material properties gap between most plastics and metals. It is known for high resistance to heat, abrasion, water, and chemical compounds. Additionally, Acetal has a particularly low coefficient of friction which combined with its other characteristics makes it very useful for applications that utilize gears.

Acetal gears and rack

One short phrase to describe the major benefits of Acetal relative to other plastics and materials would be:

• Low Friction

10. Nylon (PA):

Nylon is used for a variety of applications to include clothing, reinforcement in rubber material like car tires, for use as a rope or thread, and for a number of injection molded parts for vehicles and mechanical equipment. It is often used as a substitute for low strength metals in applications like car engines because of its high strength (relative to other plastics), high temperature resilience, and high chemical compatibility.

Nylon rope

Two short phrases to describe the major benefits of Nylon relative to other plastics and materials would be:

• High Strength
• Temperature Resistant

11. ABS (Acrylonitrile Butadiene Styrene):

ABS has a strong resistance to corrosive chemicals and physical impacts. It is very easy to machine, is readily available and has a low melting temperature making it particularly simple to use in injection molding manufacturing processes or 3D printing.