{"id":4253,"date":"2022-09-21T20:22:00","date_gmt":"2022-09-22T01:22:00","guid":{"rendered":"https:\/\/sybridge.com\/?p=4253"},"modified":"2024-01-24T13:34:29","modified_gmt":"2024-01-24T19:34:29","slug":"uv-resistance-qualities-polypropylene-and-nylon","status":"publish","type":"post","link":"https:\/\/sybridge.com\/uv-resistance-qualities-polypropylene-and-nylon\/","title":{"rendered":"Examining the UV Resistance Qualities of Polypropylene and Nylon"},"content":{"rendered":"\n

Originally published on fastradius.com on<\/em> September 21, 2022<\/em><\/p>\n\n\n\n

There are countless thermoplastics on the market today, from acrylic<\/a> to polyetherimide<\/a>. Polypropylene and nylon are two other thermoplastics commonly used in manufacturing, so it\u2019s important to understand the qualities of each before you consider these materials for your next project.<\/p>\n\n\n\n

Polypropylene is a capable, low-cost crystalline thermoplastic<\/a> often used in medical equipment<\/a>, food containers<\/a>, packaging, and water pipes. It\u2019s most commonly used with the injection molding<\/a> or CNC machining<\/a> manufacturing processes, but it\u2019s also possible to 3D print<\/a> polypropylene. However, before you decide to 3D print your parts using polypropylene, it\u2019s important to note that it does tend to warp more easily than many other 3D printing materials, and there may be more suitable options<\/a> depending on what you\u2019re making.<\/p>\n\n\n\n

Likewise, nylon is also compatible with 3D printing, injection molding, and CNC machining, and is used across industries to manufacture everything from rope to engine components. It can be shaped into several different forms, including sheets, fibers, filaments, and films, and is often used in place of low-strength metals.<\/p>\n\n\n\n

As you can see, nylon and polypropylene are versatile plastics with multiple benefits. However, designing parts for outdoor use requires selecting the right UV-resistant or UV-stabilized plastic<\/a>, so it\u2019s important to consider each material\u2019s UV qualities to ensure your end product can withstand prolonged exposure to sunlight without breaking down. In this article, we\u2019ll go over the UV resistance qualities of nylon and polypropylene to help you make an informed material choice.<\/p>\n\n\n\n

What is UV-resistant plastic?<\/h2>\n\n\n\n

If your part will spend a significant amount of time outside or otherwise be exposed to sustained levels of UV radiation, you may want to use a plastic resistant to UV rays. For example, you may have seen some stadium seats, automotive parts, and lawn chairs suffer from discoloration, a loss of visual clarity, and\/or a reduction in mechanical strength and impact resistance; this is because they were made out of a plastic with low UV resistance. Exposure to UV light can also make plastic parts more brittle and susceptible to breakage, cracking, deformation, or disintegration.<\/p>\n\n\n\n

While almost no material is entirely resistant to UV light, some can absorb UV radiation. Adding stabilizers or additives<\/a> can improve UV resistance for plastics that can\u2019t absorb UV light. These non-UV-resistant materials produce free radicals (atoms with an unpaired electron), which can break down intermolecular bonds, negatively impact mechanical properties, and cause plastics to wear down.<\/p>\n\n\n\n

Polypropylene UV resistance qualities in manufacturing<\/h2>\n\n\n\n

Polypropylene<\/a> is an extremely tough yet flexible and lightweight material. It is resistant to mold, bacteria, water, oil, rot, electricity, and chemicals. However, polypropylene isn\u2019t the best option for products that live outside or are regularly exposed to sunlight because it\u2019s deeply affected by exposure to UV radiation. Specifically, it\u2019s susceptible to UV wavelengths of 290 \u2013 300 nanometers, 330 nanometers, and 370 nanometers. Exposure to high-intensity UV radiation for as few as six days can cause polypropylene to lose up to 70% of its mechanical strength, resulting in very brittle parts.<\/p>\n\n\n\n

Polypropylene products will generally break down after a few months of direct exposure to sunlight, as the radiation will excite photons and create free radicals. However, using additives and coatings can help protect polypropylene parts from sunlight. For example, zinc oxide or titanium oxide fibers can block and absorb UV light, reducing the polypropylene\u2019s exposure to UV radiation and extending the part\u2019s life. Similarly, designing a polypropylene part with protective seals can help it better withstand sunlight, though getting polypropylene to bond with other materials can be difficult as it has little to no absorption tendencies and is quite slippery.<\/p>\n\n\n\n

Even with additives, polypropylene will degrade quickly compared to naturally UV-resistant plastics<\/a> like acrylic<\/a> or high-density polyethylene (HDPE)<\/a>. Thus, we recommend against its use for products that will receive extended exposure to direct sunlight.<\/p>\n\n\n\n

Nylon UV resistance qualities in manufacturing<\/h2>\n\n\n\n

Similarly, nylon is susceptible to degradation when exposed to UV radiation for prolonged periods, as UV light creates free radicals that impact nylon\u2019s properties. When exposed to sunlight for a prolonged period, nylon parts will weaken and fade in color. Nylon is sensitive to UV wavelengths of 290 \u2013 315 nanometers.<\/p>\n\n\n\n

However, there are several nylon variations<\/a> which offer varying degrees of UV resistance. For example, nylon 6\/6 is less resistant to UV rays than nylon 6 or nylon 12<\/a>. Thus, it\u2019s important to consider each nylon variation\u2019s mechanical strength, temperature resistance, abrasion resistance, and water resistance in addition to your product\u2019s intended application when deciding which type of nylon to use for your project.<\/p>\n\n\n\n

Choosing between polypropylene and nylon<\/h2>\n\n\n\n

Neither nylon nor polypropylene is particularly resistant to UV light, but polypropylene will likely degrade faster upon consistent exposure to UV radiation. However, you can boost both polypropylene UV resistance and nylon UV resistance with:<\/p>\n\n\n\n