vulcanized rubber

We have a lot of rubber conveyor belts out in the weather and we don't seem to have a lot of trouble with them.

Rex Dev.

it is not true!it not happen to the rubber ! i could assure !

Well, in fact it is half true: rubber breaks down over time when exposed to water but it is basically because of the glue they use to get it bond to the surface. Best example: street sweeper they lined them with rubber, to get bonded to the metal (or SS sometimes) they use glue. When all kind of material enter the bin (the speed is similar to a tornado inside the bin) most of the time the rubber get puncture and then the water get underneath the rubber: eventually it break down because of the glue failure

We use a urethane lining in some of these street sweeper because the steel has been sandblasted and the urethane get spayed directly on, the bond is much stronger.

As far as I know rubber is a stable material under normal condition like urethane, I am not aware of a failure (breaking down) if the rubber itself is just in immersion (plain water even waste water) unless another chemical is involved such aromatic or aliphatic solvent type for example. Just think how long it take to desintegrate a tire in a lake or in the sea!

Rubber drys like urethane over time and may become brittle and once again the failures I have seen were cause by another chemical, an external factor (rocks, glasses etc) or badly installed in both case. Of course if you choose the wrong type of rubber or urethane for the service you are looking for, you will end up with failure

Hope this clarify the question

That statement is likely taken out of context. It would depend on the crosslink density of the rubber, the antioxidant package used, the heat history, etc, but in general, rubber is quite weather resistant. Re urethanes, most urethanes are good for general usage, but be aware that the term "urethanes" covers a multitude of materials. For example, polyether-based urethanes, especially PTMEG-ethers, are generally more weather resistant than polyester based urethane, with polycarbonate-based polyurethane being significantly better than other types of urethanes. That's why they are usually the choice for body implants where hydrolysis by body fluids and body enzymes can hydrolyze lesser stability PUs, and polyether-based PUs are susceptable to metal-ion oxidation, etc. In addition, in general, polyurerthanes formulated with aliphatic diisocyanates are much more stable than PUs based on aromatic diisocyanates. MDI and PUs based on MDI, can suffer proton-abstraction, resulting in a --C = C--, which is susceptable to hydrolysis, free radical scission, etc.

I do know that wolves find the kind used to built inflatable boats to be tasty. That was a rough learning experience...Actually, my point is that boats are made of it so I would hope not. But that bit with the wolves really did happen.

We don't have this trouble,I don't think it is true

The tyres/tires on most private motor cars decompose more readily by wear attibutable to distance travelled and surfaces encountered than the water they encounter on the way.

Depends on the composition of the rubber....but generally speaking yes it does...

That's why tires have a date of manufacture stamped on....and a stated safe use of 6 years from that date...

https://pubs.acs.org/doi/pdf/10.1021/ie50258a012