Possible to Vulcanize Foam Rubber?

[bgagliana]

Hi all,

New to the forums and have a quick question regarding a product I'm trying to develop.

Is it possible to increase the rigidity and impact resistance of a closed cell foam rubber by a post-curing vulcanization process or similar method?

We're trying to carve custom foam shapes from a molded block of foam and increase it's rigidity and toughness after it is tooled, but maintain it's lightweight.

We have to ability to mold foam blocks and develop the post processing but get lost in the chemistry of additives, surfactants, etc...

Thanks in advance

~Brian

 

[GrahamBennett]

It is possible to increase the rigidity of a rubber foam by post curing but it all depends on the base polymer and the cure system used. If you can let us know these then, perhaps, we can help you further.

 

[bgagliana]

Hi GrahamBennett,
Thanks for the reply. Could use some advice on base material as well. Thinking EVA or some kind of expanded SBR, but my instincts say it will be a blend of different polymers to achieve a high rigidity and durability for the end product.

Our goal is to achieve a rigid closed cell foam in the 3 lbf density range. I understand rigidity and strength is a function of density but relatively light weight is essential for the application.

Any advice is greatly appreciated.
Thanks again

~Brian

 

[GrahamBennett]

Thanks for the reply. From the details you have provided I would suggest using an EPDM-based formulation. Although EPDM is more expensive compared with SBR, it does have the ability to accept very high levels of low cost fillers and extender oils resulting in low cost compounds, and is much more forgiving regarding very long cure times. Foam technology based on EPDM is highly developed, so I would suggest talking to the technical guys at Exxon-Mobil, DSM, etc.

Using EPDM has advantages - no need for antioxidants or antiozonants to be added to the formulation and there is no need for post curing if you use a sulphur/accelerator cure system.