Heat-resistant plastics are constantly evolving and are increasingly used in traditional and advanced industrial applications to improve performance and durability. Plastics are often not considered to be a heat resistant material. The fact is, however, that there are entire families of high performance plastics (high temperature materials) that can withstand sustained operating temperatures ranging from over 150 °C to over 300 °C, depending on the operating conditions. The continuous service temperature (DGT) is defined as the maximum temperature at which plastics in hot air lose no more than 50 % of their initial properties after 20,000 hours of storage exposure (according to IEC 216).
The continuous service temperature (DGT) is defined as the maximum temperature at which plastics can be exposed to hot air have not lost more than 50% of their original properties after 20,000 hours of storage (according to IEC 216).
To compare plastics in terms of service temperatures, the heat deflection temperature is often used.The heat deflection temperature (HDT) indicates the temperature at which a test specimen deforms to a certain extent under bending load. This mechanical test is used to determine short-term heat resistance and is used purely as a method of comparison of plastics. It distinguishes between materials that can withstand light loads at high temperatures and those that lose their rigidity over a narrow temperature range.
High temperature materials, which are characterised by high glass transition and melting temperatures, are most suitable when, among other things, a substitute for metal is sought. At the same time, they offer the superior properties of polymers, including sliding friction properties, light weight and chemical resistance. These advantages can be maintained even under sustained high temperature operating conditions. High temperature polymers are available first as unmodified heat-resistant materials and second as modified high performance thermoplastics.
By adding reinforcing materials such as glass or carbon fibers, stiffness and heat resistance can be improved and additional dimensional stability can be achieved. This is possible due to lower thermal expansion, which can reach the levels of some metal alloys. Plastics with carbon fiber reinforcement currently represent the most interesting solutions when operating conditions require extreme stiffness and exceptional mechanical properties with the lowest possible weight, for example in aerospace or automotive applications.
For applications requiring high abrasion and wear resistance or a low coefficient of friction, these engineering plastics offer superior performance in combination with lubricants such as PTFE and graphite. The good electrical insulation properties common to these thermoplastics can also be modified to achieve static dissipative or electrically conductive grades.
