It wouldn’t surprise me if the science on this is divided, especially because conditions (and the shape of the object) vary so much. It seems very plausible that a thin injection molded PLA cup could break down really fast in a sunny pond in a warm climate, but a thick 3D printed object buried in the ground somewhere with a cold clinate could take many decades.
Anyway, it sounds like it’s maybe not as bad as I thought, but it’s still not good to treat it like typical biodegradable materials. Especially when pla microplastics are still harmful despite being shorter lived.
A 3D printed PLA object would degrade faster than an injection molded one. Because the layer lines provide much, much more surface area for bacterial infiltration.
I read a study about that specific thing once but I searched just now and can’t find it (from my phone). I’ll search again when I’m back at my PC later so I can give you a link but… That makes sense, right?
For plastics like PET and ABS microbial breakdown doesn’t occur but with PLA and PHA it does. The more surface area, the faster it can be broken down.
Whereas with ABS and PET, the more surface area, the faster it will turn into long-lasting microplastics.
I think the 80 year figure was for PLA, as PET lasts well into the 100s of years (450 is the number I’ve seen)
This article claims 80 years https://3dinsider.com/is-pla-biodegradable/ but I haven’t taken the time to do proper research about this.
It wouldn’t surprise me if the science on this is divided, especially because conditions (and the shape of the object) vary so much. It seems very plausible that a thin injection molded PLA cup could break down really fast in a sunny pond in a warm climate, but a thick 3D printed object buried in the ground somewhere with a cold clinate could take many decades.
Anyway, it sounds like it’s maybe not as bad as I thought, but it’s still not good to treat it like typical biodegradable materials. Especially when pla microplastics are still harmful despite being shorter lived.
A 3D printed PLA object would degrade faster than an injection molded one. Because the layer lines provide much, much more surface area for bacterial infiltration.
I read a study about that specific thing once but I searched just now and can’t find it (from my phone). I’ll search again when I’m back at my PC later so I can give you a link but… That makes sense, right?
For plastics like PET and ABS microbial breakdown doesn’t occur but with PLA and PHA it does. The more surface area, the faster it can be broken down.
Whereas with ABS and PET, the more surface area, the faster it will turn into long-lasting microplastics.