Top 5 Heat-Resistant Plastics

In fields such as machining, manufacturing and 3D printing, plastics are widely used due to their low cost, light weight and easy processing. However, when the application environment involves high temperature or thermal shock, ordinary plastics may not be able to do the job. In contrast, metals have excellent heat resistance and can maintain strength and stability in high temperature, thermal cycles and corrosive environments. However, in many scenarios that require weight, cost or design flexibility, heat-resistant plastics have become a more cost-effective choice for engineers due to their excellent thermal properties and lightweight advantages.

This article introduces the feature of heat-resistant plastics, the differences between amorphous plastics and semi-crystalline plastics, as well as common heat-resistant materials.

What is a heat-resistant material?

Heat-resistant plastics are advanced polymers engineered to withstand extreme temperatures without degrading. Unlike conventional plastics, these materials maintain structural integrity and performance under thermal stress, making them indispensable for high-temperature industrial applications.

These specialized plastics enable breakthrough innovations in aerospace, automotive, and electronics industries. By replacing heavy metals while resisting heat damage, they reduce weight, improve efficiency, and allow engineers to design safer, more reliable products for extreme environments.

What plastics are resistant to heat?

Common heat-resistant plastics include PEEK, PEI, PAI, PBI, PTFE and PPS. These materials have excellent high-temperature stability, chemical stability and mechanical strength. The heat resistance of plastics can be examined through multiple parameters. The following are common heat resistance parameters:

• Melting Point

The melting point refers to the temperature at which the material melts from solid to liquid. For plastics, a higher melting point usually means stronger heat resistance and the ability to maintain a stable appearance at higher temperatures.

• Glass transition temperature (Tg)

The glass transition temperature is directly related to the plasticity, tensile strength and elastic modulus of the material. When the temperature exceeds this critical point, the polymer changes from a hard and brittle glass state to a soft and elastic rubber state, and the mechanical properties will be significantly weakened.

• Heat deformation temperature (HDT)

The temperature at which a polymer or plastic begins to deform under a specific load is called the heat deformation temperature (HDT). This temperature represents the highest operating temperature that the material can withstand under stress conditions and is an important indicator for measuring the heat resistance of plastics in engineering applications.

• Continuous Use Temperature (CST)

The highest temperature at which a material can maintain stable performance in long-term use. Usually lower than the melting point, it reflects the heat resistance limit of the material in the actual working environment.

• Short-term Withstand Temperature

The highest temperature that a material can withstand in a short period of time, usually used to evaluate the stability and safety of the material under instantaneous high temperature conditions.

Semicrystalline Plastics vs. Amorphous Plastics

Plastic materials are classified into two fundamental categories based on their molecular structure: semicrystalline and amorphous plastics. This structural difference significantly impacts their physical properties, processing characteristics, and practical applications across various industries.

Top 5 Heat-Resistant Plastics

1.Polyetherimide (PEI)

PEI is a high-performance amorphous thermoplastic with excellent heat resistance, continuous use temperature up to 170°C, short-term temperature resistance over 200°C. The material is amber translucent and has excellent mechanical strength and electrical insulation properties.

PEI is widely used in aerospace, medical devices and electronic products. It is commonly found in aircraft interiors, medical sterilization vessels, electronic connector housings, automotive engine compartment components, etc. Its excellent dimensional stability makes it an ideal choice for precision engineering applications.

Advantages:

• ● Excellent high temperature stability and mechanical strength
• ● Good electrical insulation and flame retardancy
• ● Good dimensional stability and chemical resistance
• ● Reusable sterilization and good biocompatibility

Disadvantages:

• ● Higher cost and difficult processing
• ● Prone to stress cracking
• ● Limited color options

2.Polyether Ether Ketone (PEEK)

PEEK is a semi-crystalline high-performance thermoplastic with a melting point of 343°C and a continuous use temperature of up to 250°C. It has excellent mechanical strength, chemical stability and wear resistance, and is known as the "King of Plastics". It can still maintain excellent performance in extreme environments.

PEEK is widely used in aerospace, petrochemical, medical implants and automotive industries. It is commonly found in aircraft engine parts, submarine oil pipeline seals, artificial joints, high-temperature bearings, etc. Its excellent biocompatibility makes it the first choice for medical implant materials.

Advantages:

• ● Excellent high temperature and chemical stability
• ● Excellent mechanical strength and wear resistance
• ● Good biocompatibility
• ● Repeatable processing and recycling

Disadvantages:

• ● Extremely expensive
• ● High processing temperature requirements
• ● High viscosity, difficult processing

3.Polytetrafluoroethylene (PTFE)

PTFE is a perfluoropolymer with unique non-stick properties and a wide operating temperature range (-200°C to 260°C). The material has extremely low surface energy, hardly reacts chemically with any substance, and has excellent corrosion resistance and electrical insulation properties.

The most common application of PTFE in daily life is non-stick pan coating. It is also widely used in chemical pipelines, wire and cable insulation, medical catheters, seals, etc. Its excellent biological inertness makes it an ideal choice for medical implant materials and food contact materials.

Advantages:

• ● Excellent chemical stability and corrosion resistance
• ● Excellent non-stick and low friction coefficient
• ● Wide operating temperature range
• ● Good electrical insulation properties

Disadvantages:

• ● Relatively low mechanical strength
• ● Large thermal expansion coefficient
• ● Difficult processing and high cost

4.Polybenzimidazole (PBI)

PBI is one of the thermoplastics with the best known heat resistance. It has no clear melting point and can be used for a short period of time at temperatures above 500°C. The material has excellent flame retardant properties and will not burn or melt in flames while maintaining good mechanical strength.

PBI is mainly used in extreme high temperature environments, such as aerospace thermal protection systems, firefighter protective clothing, high temperature filter materials, heat-resistant components of electronic equipment, etc. Its excellent heat resistance and flame retardant properties make it a key material in the field of safety protection. Advantages:

Advantages:

• ● Excellent high temperature resistance
• ● Excellent flame retardancy and thermal stability
• ● Good mechanical strength retention rate
• ● Excellent chemical corrosion resistance

Disadvantages:

• ● Extremely expensive
• ● Extremely difficult to process
• ● Single color, usually dark

5.Polydicyclopentadiene (pDCPD)

pDCPD is a thermosetting plastic prepared by ring-opening metathesis polymerization with excellent impact strength and chemical stability. The material has low density, good weather resistance and dimensional stability, and can maintain stable performance over a wide temperature range.

pDCPD is widely used in automotive exterior parts, agricultural machinery housings, electrical equipment housings, sporting goods, etc. Its excellent molding performance and surface quality make it an ideal choice for the manufacture of large and complex parts, especially for replacing metal parts.

Advantages:

• ● Excellent impact strength and toughness
• ● Good chemical stability and weather resistance
• ● Short molding cycle and high processing efficiency
• ● Low density and light weight

Disadvantages:

• ● Higher cost and difficult processing
• ● Prone to stress cracking
• ● Limited color options

Top 5 Heat-Resistant Plastics

In demanding environments, choosing the right engineering materials is critical. While there are many high-performance materials available, not all are suitable for all projects. Failure to select the right materials early on can result in high rework costs.

With decades of experience and deep expertise, LVMA has helped many companies make the right material decisions. We are happy to provide technical support for your next project.