UV-Resistant Plastics
Long-term exposure to the sun’s UV rays can have negative effects on a wide variety of materials. UV exposure breaks down chemical bonds in polymers, causing the material to wear down and disintegrate over time through a process known as photodegradation. Photodegradation contributes to a loss of impact and tensile strength, making the material brittle and prone to cracking or breaking, as well as reducing its ability to resist changes before irreversible deformation.
There is a range of plastic materials that offer varying degrees of UV resistance, some of which require stabilizers or additives to enhance their ability to withstand UV exposure. However, no material is completely UV resistant.
UV-Resistant Plastics Offer Various Benefits for Applications
Favored across various industries, UV-resistant plastics feature material properties that deliver advantages for outdoor applications. They are used in transportation, agriculture, construction, science, energy, recreational, residential, and a variety of other industrial applications for high-quality solutions that can withstand long-term UV exposure. UV-resistant plastics have distinct characteristics for benefits in plastic applications that spend a significant amount of time outdoors, such as:
- Increased durability to withstand the effects of prolonged UV exposure
- Performs reliably through maintaining mechanical properties, like tensile strength, elasticity, and hardness
- Features enhanced longevity due to durability and retention of mechanical properties
- Resists discoloration and fading to preserve aesthetics, original color, and appearance
- Cost-effective through extended lifespan and reduced maintenance or replacement
- Versatile, with various material types with distinct properties to meet specific application requirements
Common UV-resistant plastics used in precision machining include PTFE, acrylic, polycarbonate, PVDF, and Ultem®.
PTFE
With a highly stable chemical structure, PTFE, also known as Teflon®, is a low-friction material that can resist UV exposure without substantial degradation. Its carbon-fluorine bonds make PTFE highly resistant to chemical reactions and degradation caused by UV radiation, maintaining durability through its low surface energy, which prevents UV light from penetrating the material. PTFE offers a wide range of utility through beneficial features, including high-temperature tolerance, chemical resistance, in addition to UV resistance.
Acrylic
One of the few manufacturing materials that is inherently UV resistant, acrylic has a molecular structure that contains carbon-carbon bonds, which are more stable and less prone to degradation from UV exposure. Acrylic’s material composition absorbs or reflects UV rays, preventing the material from breaking down. However, acrylic is a rigid and brittle material that should not be used for load-bearing parts or applications requiring long-term durability.
Polycarbonate
Naturally absorbing and dissipating UV radiation, polycarbonate is strong and incredibly impact resistant. This material is tolerant of temperature fluctuations with a molecular structure that prevents UV damage, including yellowing, cracking, or degradation for a combination of material properties favorable in various safety applications. Polycarbonate is generally more expensive than other UV-resistant materials due to its exceptional durability, longevity, and resistance properties.
PVDF
Also known as polyvinylidene fluoride, PVDF features a strong molecular structure that is highly stable and less reactive to UV radiation. It offers thermal stability, abrasion resistance, as well as chemical and UV resistance, partially due to its low permeability, which further resists the damaging effects of UV exposure. PVDF is available in both homopolymer and copolymer structures, where the homopolymer exhibits higher strength, stiffness, and heat deflection. Alternatively, the copolymer is less stiff but features improved impact and stress crack resistance.
Ultem®
Featuring an aromatic molecular structure, Ultem, also known as polyetherimide (PEI), has benzene rings in its polymer chain to absorb and dissipate UV radiation. It is highly valued across various industries for its beneficial characteristics, including heat resistance, mechanical strength, and flexibility, with an inherent structural strength that resists UV discoloration and material breakdown. Over time, Ultem may degrade slightly without additional protective coatings.
