Polymers Utilization of plastics

Posted by: @chaoticgood

Can someone please explain process of plastic utilization? Is it possible for such structure to decompose back to monomers?

Yes, of course, many polymers undergo thermal depolymerization - polyethylene, polystyrene and others. Another part that does not have this property can be subjected to hydrolysis

@argentum So monomer must be a small and stable compound then?

@chaoticgood monomers are usually small compared to the polymer of course

@argentum I meant if to compare it among over organic molecules

The logic is if the monomer itself will be complex it can decompose into a number of different compounds

@chaoticgood Well, here the question is relative, any organic compound can be subjected to pyrolysis at high temperatures

@argentum Well, if we are talking about pyrolysis- that's for sure. But the idea is to save structure of monomer to create polymer from it once again 

@chaoticgood Well, basically the monomer can be obtained if it is not a polycondensation polymer

@argentum Haven't quite understood you. And also wanted to underline an important difference between polymerization and polycondensetion: during polycondensation small molecules are being emitted, such as water or alcohol, whilst during polymerization molecules only bond with each over

@chaoticgood I emphasize the different nature of the structure of polymers, depending on these two processes.

Hm, talking about plastic utilization: does anybody knows what does the numbers in a recycling triangle mean?

@amalgama The number inside the triangle indicates the so-called recycling code and the type of material - for example, paper, glass or plastic. The letter abbreviation under the triangle indicates the type of material.

20-22 (PAP) - paper and cardboard. Can be recycled. 40 (FE) - tin: cans, aerosol cans. Cans can be recycled, cans are not accepted everywhere. 41 (ALU) - aluminum: beverage cans and foil. You can hand over for processing, but the foil is accepted only in St. Petersburg. 50 FOR (FOR) - wooden goods. 51 FOR (FOR) - corks from trees that are used in the creation of insoles for shoes, coasters on the table. 60 TEX (TEX) - cotton products (cotton wool, fabrics, threads). 70–74 (GL) - glass and glass containers. Cans and bottles can be recycled. 81-84 (C/PAP) - composite materials: multilayer packaging made of paper, plastic and sometimes metal. Such packaging is called "tetra pak" or "pure pak" and is used, for example, for juice and dairy products.

Pyrolysis works fine only with a quaternary polymers like poly(a-methylstyrene), poly(isobutylene) and plexiglas. It works acceptable for the amateur chemistry on benzyl compounds like styrofoam, but the amount of tar, coal and other extremely useful side products crosses out any recycling through monomer. Btw, I found that pyrolysis could be used for the clean burning of polymers -- without soot and drops everywhere. Just use an old paint can with a small hole on top of it