The term “radiation” encompasses the whole broad spectrum of electromagnetic wavelengths – from long radio waves to extremely short gamma rays – as well as ionizing radiation. Knowing the types of radiation your plastic components will be exposed to will help you choose the plastic material with the appropriate degree of radiation resistance.
Electromagnetic radiation is a form of radiation in which electric and magnetic fields vary simultaneously, and includes visible light (UV radiation), radio waves, gamma rays, and X-rays. Typically the shorter the wavelength the more likely a plastic is to sustain damage. If your plastic parts will be exposed to electromagnetic radiation, you must consider the plastic’s dissipation factor (the proportion of energy that can be absorbed by the plastic). Plastics with a high dissipation factor are less suitable for high-frequency and microwave insulating applications.
The best plastics for electromagnetic radiation include:
Ionizing radiation is when particles such as X-rays or gamma rays have sufficient energy to cause ionization in the medium through which they pass. (Ionization is what occurs when tightly bound electrons are removed from an atom’s orbit, causing the atom to become charged.) Plastics used for radiation therapy, medical diagnostics, sterilization of testing instruments, and other radioactive and radiant environments are most likely to encounter this type of radiation. If a plastic does not have ionizing radiation resistance it can become brittle and experience a decrease in its elongation characteristics.
The service life of a plastic will depend on the total amount of radiation absorbed, geometry of the part, dose rate, temperature, and mechanical stress. However, PEEK and polyimide offer reliable ionizing radiation resistance, with PPS and PVDF also performing well under certain conditions.
Ultraviolet (UV) radiation is the most common type of radiation that plastic components used in outdoor applications encounter. UV radiation can have adverse effects on both the visual appearance and mechanical properties of plastics, causing them to:
UV radiation resistance is typically achieved by adding black coloration (generally carbon black), UV stabilizers, or protective coatings. Adding carbon black is a low-cost, effective way to create UV resistant plastics. Or you can choose fluorinated polymers – such as PTFE (Teflon®) and PVDF – which have very good UV radiation resistance in their natural state.
Whether you need a plastic part that can endure prolonged sun exposure or an FDA approved medical device, Reading Plastic can produce your high-quality plastic parts quickly and accurately. Have a particular job in mind? Request a quote today and our expert staff will help you determine which radiation resistant plastic is right for your application.
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