Don't Sweat It! These 4 High Temp Plastics Can Take the Heat

Posted by Katie Gerard on 09.22.2014

When choosing a heat resistant plastic, it is important to pick the best material for the job required in order to avoid costly damages. heat resistant plasticsMore and more, these high temperature plastics are taking the stage because they are light, versatile alternatives to metal, ceramics and older-generation polymers. Some plastics have permanent operating temperatures of more than 150° C and often use special reinforcing materials, such as glass fiber, glass beads or carbon fiber, to increase heat distortion resistance and rigidity. Adding PTFE, graphite and aramid fibers considerably improves sliding friction characteristics while the addition of metal fibers and carbon provides improved electrical conductivity. 

But how do these high temp plastics compare to other types of materials? Ceramics are extremely strong, showing considerable stiffness under compression and bending. One of the strongest ceramics has a bend strength similar to steel and can retain strength up to 900° C. However, these materials are brittle and may break when dropped or undergo sudden temperature changes. Ceramics are also resistant to corrosion in harsh environments but have lower electrical and thermal conductivity. Metals also have high mechanical strength and better electrical and thermal conductivity than ceramics. Metals can also be deformed or cut into new shapes without breaking, but they are vulnerable to corrosion.   

Let’s take a look at the four most popular heat resistant plastic materials:

1. Vespel ®

Without a doubt Vespel ® can take the heat. This non-melting polyimide can withstand repeated heating up to 300° C without altering its thermal or mechanical properties, making it a popular choice for jet engines, industrial machinery, cars, trucks, and other vehicles. 

Depending on the filler material (Unfilled, 15% Graphite, 40% Graphite, 10% PTFE and 15% Graphite, or 15% Moly), Vespel ® can withstand 350 hours of 398° C heat, losing only 50% of its initial tensile strength: 12,500 psi (unfilled base resin) reduces to 6,000 psi. This loss is due almost entirely to oxidative degradation.  The parts will perform in inert environments, such as nitrogen or vacuum, with negligible loss of properties over time.

2. Torlon®

Torlon®, a polyamide-imide, offers Nylon 6/6’s room temperature properties at 204° C, with exceptional long-term strength and stiffness up to a continuous 260° C.  Torlon® is an effective alternative to metal in high temperature friction and wear applications. It has outstanding resistance to wear, creep, and chemicals, including strong acids and most organic chemicals, and is ideally suited for severe service environments. Torlon is typically used to make aircraft hardware and fasteners, mechanical and structural components, transmission and powertrain components, as well as coatings, composites, and additives.

3. Ryton ® 

Also known as Polyphenylene sulfide (PPS), this organic polymer can be molded, extruded or machined to high tolerances with a maximum service temperature of 218° C. It has not been found to dissolve in any solvent at temperatures below about 200° C. Along with Vespel, Ryton® PPS compounds have a UL 94 V-0 flammability rating without any flame retardant additives, meaning burning stops within 10 seconds on a vertical specimen.

4. Noryl

A blend of polyphenylene oxide (PPO) and polystyrene (PS), Noryl is a rare example of a homogeneous mixture of two polymers.  The inclusion of PS increases the glass transition temperature above 100° C, making Noryl stable in boiling water.

Noryl has a maximum service temperature of 105° C and a melting point of 154° C. These properties make it useful in the production of solar panels, because solar panels in the summer only reach 45° C. It also has unusually low water absorption, with values as low as .07%, making it an excellent electrical insulating material.

Heat Resistant Plastics Material Properties
Plastic
Tensile strength
at 26° C
Flexural strength
at 26° C
Max service
temperature
Melting Point
Vespel
8,750 psi
16,000 psi
300° C
none
Torlon
27,847 psi
35,390 psi
260° C
none
Ryton
21,755 psi
25,800 psi
218° C
none
Noryl
9,200 psi
7,400 psi
105° C
154° C

Did I miss your favorite temperature resistant plastic?  Please share in the comment section below. 

Interested to learn more about the heat resistance of specific plastics? Check out our High Performance Material Guide.

Download the Guide to High Performance Plastics!

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