Radiation resistant plastics 

Depending on the application, plastics can come into contact with different types of radiation, which under certain circumstances can have radiation effects on polymers. The spectrum of electromagnetic radiation ranges from radio waves, with a longer wavelength, through normal day light, with its short wavelength UV radiation, to extremely short wavelength X and gamma rays. The shorter the wavelength of radiation, the higher the susceptibility of a plastic to damage.

Electromagnetic radiation

Electromagnetic radiation is a form of radiation that includes visible light, radio waves, gamma rays, and X-rays, in which electric and magnetic fields vary simultaneously. The dissipation factor is an important characteristic to be considered in situations where plastics may potentially be exposed to such electromagnetic waves. It describes the proportion of energy that can be absorbed by the plastic â€“ otherwise known as polymer radiation absorption. Specific attention should be paid to plastics with a high dissipation factor, as they are less suitable for use in high-frequency and microwave insulating applications. The following plastic materials have been proven to have greater resistance to electromagnetic radiation:  

Ionizing radiation

Ionizing radiation consists of particles such as X-rays or gamma rays that have sufficient energy to cause ionization in the medium through which it passes. Ionization occurs when tightly bound electrons are removed from the orbit of an atom, causing the atom to become charged. An understanding of radiation technology for polymers can be necessary for applications in medical diagnostics, radiation therapy, sterilization of articles and in test instrumentation, as well as in radioactive and other radiant environments. The high energy radiation in these applications often leads to a decrease in the elongation characteristics and the development of brittleness in a polymer.

The overall service life of a plastic is dependent on the total amount of radiation absorbed. Materials like PEEK and polyimide show good resistance against gamma radiation and X-rays. By contrast, PTFE and POM are very sensitive and are therefore less suitable for applications that involve exposure to radiation.

The illustration below provides an overview of which are the most radiation resistant polymers within the Ensinger shapes portfolio. Here you can see a full list of radiation resistant plastics and evaluate, for instance, PEEK radiation resistance vs. PTFE radiation resistance. Information relating to the resistance of plastics should only be considered as a point of reference, as different parameters play a co-determining role (geometry, dose rate, mechanical stress, temperature or ambient medium). Actual testing for your specific application is always recommended.

Ultraviolet radiation

Weather influences, but in particular UV radiation in outdoor applications, can have a negative impact on the optical and mechanical properties of plastics. Black colouration of plastics is a good way of protecting them against the influence of weather. Otherwise, the material group of fluorinated polymers such as PTFE and PVDF demonstrate particularly good UV stability in their natural state. Click here to find out more ...