How exactly does neoprene compress (permanently) and a couple other detaily questions

[dlwalke]

After repeated use, neoprene loses its bulk. Does anyone know if this is because the gas is squeezed out of intact cells, or is it because cells, presumably at the surface mostly, rupture and release their contents. Also, does anyone know the approx diameter of the gas filled cells. Finally, isn't neoprene bubbled up with nitrogen rather than air? If so, why is that?

Thanks,
Dave

 

[spectrum]

You might find this interesting:
Wetwear - Why we only use Rubatex

Rubber is of course a porous material. Compresion and recompresion along with hanging, folding, doning and doffing all contribute to the breakdown of the cell structure.

In the case of a neoprene drysuit of the same material the density of ruptures can eventaullly make for a porous leaking suit even though there is no apparent puncture.

Much of todays material is air blown, with nitrogen in the premiums. While there may be some chemical behavior that enhances the blowing process some is probably attributed to the same properties fueling the nitrogen tire filling being touted. Bigger molecules have a harder time escaping. I belive notrogen is also less of a heat conductor hence a better insullator. Keep in mind that for the actual product the delta is on 20% of the gas content.

Pete

 

[MookieMoose]

After repeated use, neoprene loses its bulk. Does anyone know if this is because the gas is squeezed out of intact cells, or is it because cells, presumably at the surface mostly, rupture and release their contents. Also, does anyone know the approx diameter of the gas filled cells. Finally, isn't neoprene bubbled up with nitrogen rather than air? If so, why is that?

Thanks,
Dave

The gas cells in neoprene eventually loose their volume becuase rubber is lipophylic. The gas inside the cells, be it air, or nitrogen, is also lipophylic, so the gas actually disolves into the rubber, just like gas can disolve in water. When you dive, and compress the cells, this increases the driving force for the gas disolving into the rubber. When you return to the surface the gas disolved in the rubber will come out of solution, either back into the cells or out of the suit. Given enough time and enough compression/decompression cycles the cells will begin to collapse.

Cam

 

[Shawley]

so how long does it take for this process to happen?

 

[spectrum]

Depends on the suit and the depths to which it is used. Anecdotally 200 - 400 dives is when divers note that the insullation has fallen off noticably.

Pete

 

[dumpsterDiver]

I have seen suits loose bouyancy in 10-20 dives

 

[mikeguerrero]

How about the newer wetsuits that boost the usage of Elastiprene? Do they fall victim too? They are much more stretchy than convential type suits but do they hold up longer? Has any studies been done with them?

I'm talking about the Pinnacles line in particular interested in the ME-7. All this talk about compression on suits makes sense to the properties of gas in a suit but how about the Merino linning? Does that also lose it's value under compression thus losing it's efficacy of warmth?

Thanks,

MG

 

[jbb]

I have seen suits loose bouyancy in 10-20 dives

Yes, the 3mm suits are usually of cheaper neoprene in my experience - I had an O'neal that didn't last more than 50 dives - two dive trips. My 5/4 Bare seems to be holding up well after more than 60 dives. It will also depend on how deep your average depth is on your dives.