What are clear aligners made of? Are they the same as Invisalign? When I try to search for clear aligners, results are usually made of articles about Invisalign. So I’m not sure if they are the same.
The aligners are made of a thermoplastic material uniquely designed for each individual. They look similar to teeth-whitening trays. Though I’m not sure what’s the difference between the material used for aligners and whitening trays.
So is the material used for aligners and Invisalign the same?
They aren’t exactly the same but I believe they use the same main component which is polyurethane resin. I guess they have their own “brands”. Some “brands” are more developed and advanced, while others have less strength and flexibility. Aligners and Invisalign basically have similar material but not the same. I’m sorry if my explanation made you more confused. I tried my best 
What I’m sure of is they all use thermoplastic material which becomes soft when heated and hard when cooled. They can be cooled and heated several times without any change in their chemical or mechanical properties. And when thermoplastics are heated to their melting point, they melt to a liquid. Source of definition: https://simple.wikipedia.org/wiki/Thermoplastic#:~:text=A%20thermoplastic%20is%20a%20material,they%20melt%20to%20a%20liquid.
It’s fine. I kinda get it now 
Thank you!
Invisalign aligners are FDA-approved and contain no BPA, BPS, latex, or gluten. If you are looking at other aligners, you can ask them directly what material they use.
Aligner providers use a thermoplastic material that doesn’t change their chemical or mechanical properties with a change in temperature. The difference between the providers is other components that they may have added to make the aligners.
Thanks for this info. I didn’t get a chance to ask this to my provider. Good to know about the material used. Is it environment-friendly? I mean, can it be recycled?
You’re welcome 
I’m not sure, but I don’t think it can be recycled. They haven’t found yet a material that can be reused.
I hope they would already develop a material that can be recycled. Since a lot of people are choosing aligners over braces, it would be a big help to the environment if they use environment-friendly products.
I’m also not sure how to dispose of the aligners after your treatment? Do we give it back to our provider so they can dispose of it themselves? Or we can just throw it in our trash bin?
I believe some clinics ask their patients to bring their aligners back after their treatment so they can dispose it properly.
Unfortunately, the trash bin is the only place for the aligners after you use them. 
"The most common way of disposing Invisalign trays is in the trash bin. Since they aren’t recyclable and can’t precisely be reused, there aren’t many other places for them besides the trash bin.
We know that it can feel frustrating tossing your plastic trays in the landfill, but there are a few things that prevent your aligners from classifying as recyclable. First, they are considered medical waste. Like any other plastic used for medical purposes, trays that have spent the last week sitting in your mouth are not technically allowed in the green bin.
Second, Invisalign is a multi-layer polymer, which means it uses a mixture of different plastics to create the exact balance of elasticity and rigidity to nudge your teeth where they need to go. It also means that it complicates the recycling process. There are roughly seven grades of plastic, each of which requires a different method for recycling. Because Invisalign fuses several different types of plastics, they can’t be sorted into one of the recycling methods. So, even if you have a few unused pairs, they may need to join the others in the trash bin. At least for now."
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In short, since aligner trays uses different plastics, it will be harder to recycle. I think we will still wait a long time until aligners can be recycled. For now, it will just add to our everyday waste. 
I wonder how long do aligners need for it to be decomposed in landfills 
Based on the article from @Kassandra’s post, I believe it will take more than a thousand years for it to be decomposed. The usual plastic takes 1000 years, so it’s similar to that. Though it may take a little bit longer because aligners use more than 1 type of plastic.
Different brands have their different plastics that they use. Others use cheaper plastics that’s why they are cheaper also.