Choosing a Plastic for Your Application

With so many industrial plastic options, each with different characteristics, it can be challenging to know which plastic is the best for your application.

Although there are a variety of industrial plastic materials, they can be categorized into two groups: Thermoplastics and Thermosets.

Thermoplastics

Thermoplastics can be softened and melted back to their liquid state, which also means they can be molded without damaging physical properties. They are best suitable for low-stress applications, like plastic bags.

There are numerous advantages of using thermoplastics:

• Strength
• Bendability
• Shrink-resistance
• Ability to be shaped and reshaped
• Recyclable
• Chemical resistant

There are also some drawbacks:

• Ability to melt
• Usually expensive compared to thermosets

Thermoplastics Examples

• PEEK (polyetheretherketone) can be found in piston parts, pumps, electrical cable insulation, medical implant device components and metal replacement applications. PEEK is wear resistant, mechanical and chemical resistant, and heat resistant with a maximum working temperature of 500°F. PEEK’s exceptional tensile strength, biocompatibility, low water absorption and low coefficient of friction make it a popular thermoplastic used in various applications.
• PAI Torlon has the highest tensile strength among non-filled, moldable materials. It also has a maximum working temperature of 500°F. Torlon’s high strength, low friction and great bearing characteristics make it suitable as a material for electrical connectors, bearing cages, gears and impellers.
• PEI Ultem is a strong and rigid thermoplastic used mostly in electronics and reusable medical devices because of its ability to tolerate repeated steam sterilization. Not only is it resistant to long-term exposure to heat, but it is also flame, chemical and arc resistant. PEI Ultem is often used for applications with tight tolerance and low warp.

Thermosets

Thermosets are insoluble and cannot be melted. Thermosets’ high heat resistance makes it an appropriate material for high-heat applications.

These are some of the benefits of using thermosets:

• High heat resistance compared to thermoplastics
• Structural stability
• Chemical resistance
• Generally less expensive than thermoplastics

However, thermosets also come with a couple of disadvantages:

• Cannot be molded or re-molded
• Not recyclable

Thermosets Examples

• Melamine Resin is tough, and relatively scratch and heat resistant. It is produced in a variety of colors and can mostly be found in tableware such as bowls, cups and plates.
• Unsaturated Polyester Resins are utilized in a wide range of applications, including in products with high strength. Some applications include automotive bodies, fender walls and industrial equipment housings. They are relatively low cost and can have versatile properties depending on the choice of additives.
• Epoxy Resins are often used in coating materials because of their adhesion and water and chemical resistance. They also have no odor.