Okay, willkommen to our lecture on crosslink polymer systems.

Last time we talked a bit about vulcanized natural rubber and then we made a transition

to the synthetic stuff because it's great if nature prepares it for us, but our applications

are a bit more delicate than only what nature can supply for us.

Last time I already gave you an overview about the most important synthetic elastomers.

We have the Buddha Deen rubber, which is probably the easiest one for the art rubbers.

We have the Sterene Buddha Deen rubber, which was the first really applicable synthetic

rubber.

Then we have a whole bunch of selection of more or less specialties.

In this lecture we will focus on the M rubbers, which is just a saturated main chain like

the EPM and EPDM rubbers.

Then we will have another more speciality one, the fluorinated rubbers.

It's quite a special one, but you might often encounter it because it's the most heat resistant

elastomer, so that's quite nice.

And silicone rubbers, also quite widely used for construction stuff, but also for high

tech stuff.

That's also something you will encounter in your daily life.

That's most of these sealants in these plastic containers you get in your kitchen, also

for the bicycle stuff.

Every time something is stretchable, that's probably some silicone injection molded part.

We'll also talk about the specialties Epi-Clohydrene rubber and pure urethane rubbers, as we already

talked about that before, for the resins.

We will have a look at how we can change the main chain to come from a highly crosslinked

duromere to a weakly or widely crosslinked elastomer with nice stretchy properties.

As I just announced, for natural rubber it was Nature who supplied us with the nice polymer

stuff that we then can crosslink.

So we draw this up from the Javier Basel industry, collect that one and this is then the reduced

and stabilized for latex and so on.

So we have a whole bunch of industry behind that.

Southeast Asia is very happy about that.

So we want to not rely on the natural stuff.

We have to cook it our own.

The chemists were really, really ingenious in the beginning of the last century.

These were the golden ages of chemists, where they came up with all these nice new polymers,

like the polybutadiene that we will talk about today, the styrene butadiene copolymer,

ethylene propylene copolymer, which is then the EPM rubber.

Just mix these two together.

And then a whole new class of more or less almost inorganic polymers, which is the class

of the polydimethylsiloxanes, the famously known silicones.

Again, a brief overview of history.

Last time we also talked about the natural rubber, which was used already for three millennia

by humankind.

These ones are way newer.

And to really get the research going, you first have to understand what actually makes

a rubber.

I think you're all familiar with what we need for a rubber.

Can you please name the three criterias?

Yes.

Some kind of crosslinkability?

Crosslinkability, that's correct.