What monomer/s is Polyethylene Terephthalate, PET, made from?
For my Chemistry assignment I am writing a report on Shampoos and one of the tasks is to write about the container - Polyethylene Terephthalate. I have to talk about the chemical composition of the plastic, monomer/s it is made from, the reaction reaction and processes it is made from, and the likely shape forming process used to make the final container.
The main thing I am stuck on is what monomer/s it is made from. I have searched for the monomer/s but different websites say different things. Wikipedia says that the monomer is ethylene terephthalate. But another website says that it is made from the monomers ethylene glycol and dimethyl terephthalate, which is what ethylene terephthalate is made from. And I'm pretty sure another website says something slightly different.
If you have any idea about the monomers or any of the other stuff that would be really helpful! Thanks.
Trevor H2011-06-20T01:09:36Z
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A good guide is if you take the name of the polymer, polyethylene terephthalate, if you eliminate the poly part you get the name of the monomer. So in this case, the monomer is ethylene terephthalate. What about ethylene glycol and dimethyl terephthalate? The Wiki article , which you probably read says: "Its monomer (bis-β-hydroxyterephthalate) can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct, or by transesterification reaction between ethylene glycol and dimethyl terephthalate with methanol as a byproduct." These two feed stocks are not monomers in the exact definition of the term - they are the raw materials used to synthesise the monomer. From what I can read in the short Wiki article, the two raw materials are fed into the reaction vessel, the monomer is formed, which simultaneously is polymerised to produce the final polymer. Unfortunately industry has some bad habits, and because the two raw materials are fed into the reactor and a polymer is taken out, the two raw materials become known as the monomers - which is not technically correct.
A similar situation could exist - you can make a polymer called polybutyl acrylate. The monomer is butyl acrylate. Normally this ester is produced in a reactor which reacts butanol with acrylic acid. The butyl acrylate is sold for use in polymers. But the butanol and acrylic acid are not the monomers of polybutyl acrylate.
For your work I would stick to the monomer being ethylene terephthalate. Keep it simple.
RE: What monomer/s is Polyethylene Terephthalate, PET, made from? For my Chemistry assignment I am writing a report on Shampoos and one of the tasks is to write about the container - Polyethylene Terephthalate. I have to talk about the chemical composition of the plastic, monomer/s it is made from, the reaction reaction and processes it is made from, and the...
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Polyethelene Terephthalate (PET) is what most people know as "polyester", the stuff leisure suits, "polar fleece" and soda bottles are made from, and this is a completely different plastic from Polyethylene (PE) and Polypropylene (PP). Try the phone book under plastics, or the Thomas register.
1. No PET is not compatible with PE for a couple of reasons. Natural PP has a melting point around 170C, PET has a melting point around 260C. If you mix them you’d have to bring the mixture up above 260C. But then at that higher temperature your PE would burn and char – bad mess. Second PP is often “filled” with other opaque materials to bring out the color intensity. These fillers cause all sorts of issues when it comes to regrind. 2. PE is polyethylene it is very closely related to polypropylene. PE is one of the common materials used as a filler in PP. And this is the primary reason that PP is not commonly recycled in the US. 3. I would contact the suppliers of the virgin plastics (often called resin). These suppliers obviously sell to manufacturers that should have copious amounts of regrind. The resin suppliers probably are not going to give you the name of their customer, but if you ask nicely they might pass your name along. Or they could refer you to one of the many companies that produce regrind.