Hello and welcome for the last part of the lecture cross-linked Polymer Systems.

Today as promised we will talk a bit about the stuff that is mostly relevant for the exam.

It does not mean that you do not have to have a look on it.

No guarantees here.

However, this is what I really care about that you should take with you from this lecture.

We will walk our way through a summary of the slides and yet we have to give you impression

what is highly relevant.

Okay, sure.

So, that is the broad separation of the lecture and its content.

And if you remember, we started with what are cross-linked polymers.

So it would be quite feasible if you attended this lecture that you could name a few applications

for cross-linked polymers systems.

Like one prime example is of course the car tire where we can use the R-rovers in a very

nice compound attack product.

But however, also keep in mind that gluing with the poxies or police the resins or metacrelates

also belongs to this category and also spray paints which have a dispersion agent that

evaporates and they can also cross-link.

Also these thermoplastic elastomers and of course fiber-inforced composites with focus

on the polyester and epoxy resins.

Okay, so let's start with the first part.

Of course, there is something nobody of you should be afraid to be asked.

The classification of polymers, I think you heard that a lot of times already would be

quite embarrassing if it's a problem during the exam.

What I'm a bit thinking about is the TGA, TMTA graphs here.

Like please keep in mind polymers get soft.

When you heat them up, most polymers are almost all polymers because for sure they are

chains and chains can fall.

So almost all polymers have TG with them.

Yeah, if you heat it up further, depends a bit on what polymers in particular you're

talking about.

If it's semi-crystalline, you will have a second plateau.

If it's cross-linked and you will just have the TG, maybe a small drop until the combustion.

And of course if you have an elastomer which we were talking about a lot, you have this

curve here with this rubber elasticity plateau.

This is of key interest.

Please look up in your notes what we talked about this area here.

You can also mind the slope that's rising a bit.

It has to do with temperature and entropy.

Please be aware of that.

The fan plus the elastomer is being somewhere between, quite similar to semi-crystalline

polymer.

Of course you have two phases, soft phase and the hard phase.

This one has a higher TG or higher TM.

So it stays as a physical cross-linked point inside of your polymer.

Okay, then next step is we have to talk about how we actually get polymers.

Quick example is the generation of polyolophines.

And here we start with a veneer monomer.

We have one subitune that can vary a bit.

It can be a starine, it can be a methyl group, it can be also just hydrogen.

So you get three different polymers but all with the same base reaction.