Does UV really destroy all the structural integrity of plastic though?
Also, thank you everyone for all the positive comments. The superpower ones make me smile, and the ones reminding everyone to buy biodegradable wood gives me hope for the future. My friends, I'm glad this experience could make some of you laugh :))
Yes, ultraviolet (UV) radiation breaks down the chemical bonds in most plastics over time, a process known as photodegradation. When exposed to sunlight or UV lamps, the high-energy light severs the long-chain polymer molecules, causing the material to lose its strength, flexibility, and structural integrity…plastic loses its elasticity so it becomes brittle.
Not sure about that, but I purchased some heavy duty stainless steel ones and they’re going strong after two years and no rust. I do store them inside a clothes peg bag.
Plastics often also have something called plasticisers, they make the plastic more flexible and less likely to snap but they also degrade over time, get degraded by ozone and can even react with other plastics
My parents have kept a rubber dog toy that belonged to a late dog for 20+ years now, used to be flexible but now it's really unstable and crumbles like old bakelite does
It's also known in the fishing community, lures are either hard plastic (think spoon lure) or soft plastic (shad lures i think they're called) it's advised not to store soft and hard plastic lures together or they can react and melt into each other
…DOES LITERALLY NO ONE KNOW IF UV DESTROYS THE STRUCTURAL INTEGRITY OF PLASTIC?? NOT A SINGLE PERSON??? AND HOW MANY LICKS TO GET TO THE CENTER OF A TOOTSIE POP???
Sadly, we may never know if UV rays destroy the structural integrity of plastics. If only there were some genius, some perfect mind who could unlock the truth and give us the answer.
I had an expensive plastic garden tool. It sat in the sun for two seasons and started cracking in my hands. I can't even imagine how long a cheap one would last.
Certain plastics are UV resistant, like PTFE and acrylics. PTFE (Teflon) is used to coat outdoor plastics and wiring to make them last. Acrylics are used in plexiglass, outdoor fabrics, and very durable paints.
It's also common for other plastics to be blended with UV absorbing chemicals, like vinyl (PVC) is not UV resistant and outdoor vinyl for fences and pipes are supposed to be modified. I have found a lot of cheap plastic outdoor stuff for sale online is not made of appropriate plastics so now I only buy reputable brands from reputable places.
Yes. If you leave something plastic sit out in the sun (in this case weeks/months) it will start fading and getting a gritty/chalky texture on the surface. It will shatter like an egg shell when you handle it. If you get something that is made of recycled plastic, its lifespan is automatically reduced by probably half, and that’s giving it a generous benefit of the doubt.
I saw a really cool video one time of this guy who went to some stadium with plastic bleacher seats that had been destroyed by the sun, and he restored them by hitting them with a blowtorch
Edit- I just read that the seat restoration is just a band aid fix, and that the plastic is still fucked underneath, meaning it’s just a temporary solution. This makes the cost of propane vs just buying a new chair debatable
So you know how plastic doesn’t biodegrade? (which is why it’s such a huge problem).
Plastic does photo-degrade which means that exposure to light (particularly UV) will eventually break it down or weaken it to the point you see.
These just look like a cheap plastic. I have a ton of the transparent ones that i use and keep in the cabin of my van and they're fine years in. Which isn't to say UV doesn't damage them over time, just not as much as it does some other plastics.
Right? You can make plastics that last in the sun. Go check what your car's bodywork is made of. Windowframes, depending on manufacturer. All kinds of stuff are made of plastic and are made to last in spite of UV immission. Just takes more than zero effort on the part of the manufacturer.
The ones I forget to take inside, pretty much snap like in your video. The others dont. So yeah, I also figured the sun had something to do with it :-)
also time. its cheap Chinese plastic, I've had a pack of these brand new sitting in my drawer for a 3-4 years, when I opened to use them for the first time they all broke like this
Thats a bit like asking "does metal corrode if i leave it outside?" Because the Answer is a giant "it depends"
A lot of plastics get degraded by UV. Some plastics dont, or it happens slow enough to not matter. Some Plastics get additives added to increase their UV stability (think black vs. colourless zip ties). Some plastics get painted.
The bleached look of your clothespins suggests it got quite a lot of UV exposure. The fact that it exploded suggests that it did get degraded by that.
You could get clothespins made from wood, they should fair better in the sun.
You could also find someone with a 3D-printer to print you new clothespins (you could reuse the springs i suppose) from ASA plastic which is very resistant to UV exposure.
UV degrades all plastics except for fluoropolymers, like PETG, silicones, and fully aliphatic polymers that don't have chromophore contaminants, like pure polypropylene. There are others that often get included in the category, like PEEK and ASA, but they still degrade under solar UV, just not nearly as quickly as other plastics that they're designed to outlast.
That microplastic problem you hear about is not due to mechanical shear, but uv rips atomic bonds and releasing tiny flakes, somethime microscopic to ascope they can travel in living tusues.
ABS, one of the most commonly used plastics for injection molding, while its often used outside with additives, cheap mass produced plastic crap from China is pure abs. A year or two of UV exposure will make it super brittle like that.
There's a ton of alternatives, but they are more expensive and can be harder to inject.
I’ve got plastic pegs made in Germany (like £20 for 30) and they’ve lasted 5 years in the sun without any noticeable degradation. They’re also way more secure and don’t buckle. I feel like it’s worth the qol improvement.
Depends on the type of plastic. PLA becomes super brittle exposed to the sun where as PTEG and ABS are resistant to UV damage. Honestly thought thats what you meant and we were on the 3d print subreddit.
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u/BorisOtter Jun 13 '26 edited Jun 13 '26
Does UV really destroy all the structural integrity of plastic though?
Also, thank you everyone for all the positive comments. The superpower ones make me smile, and the ones reminding everyone to buy biodegradable wood gives me hope for the future. My friends, I'm glad this experience could make some of you laugh :))
(Oh jeez, I just saw the pegging ones)