Polypropylene as scrubber material?

onetime · 21st July 2006, 18:59

Alright, so what are the pros and cons of polypropylene? I've checked out the MDSS and it seems like a pretty good choice. Is it UV stable? Any insights appreciated.

--Paul

Dutchy · 21st July 2006, 23:06

con: It doesn't react with CO2

And no its not UV stable but then again how much exposure do you expect? If it needs be it can be coated to withstand UV better.

PP is cheap but not so much a technical material. Be carefull exposing it to higher temperatures as its thermal coefficient is rather large. (E.g. PP canister and POM lid may give you trouble the moment you submerge...)
In addition 'creep' is an issue. Try to find yourself a strip of PP and submit it to a load. Leave it like that for a night. It will be longer the next morning. That's why eg PS or POM are far better 'technical plastics'.

RebreatherDave · 25th July 2006, 05:48

What about cross linked polyethylene...

Dutchy · 25th July 2006, 07:14

Better I guess.... All I meant to say is that you need to be carefull how to use it. If you make a lid make sure that the O-ring is appropriately placed. (such that the difference in thermal coeeficient doesn't create leaks nor cracks. Otherwise PP is a decent material. It can be machined, glued (if it need be) or better welded. (Which takes practise but can be done with excelent strength)

21st July 2006, 18:59	#1 (permalink)
onetime Classic KISSer #138 Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: San Antonio, TX Posts: 684	Polypropylene as scrubber material? Alright, so what are the pros and cons of polypropylene? I've checked out the MDSS and it seems like a pretty good choice. Is it UV stable? Any insights appreciated. --Paul
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21st July 2006, 23:06	#2 (permalink)
Dutchy Rene Warries Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 844	Re: Polypropylene as scrubber material? con: It doesn't react with CO2 And no its not UV stable but then again how much exposure do you expect? If it needs be it can be coated to withstand UV better. PP is cheap but not so much a technical material. Be carefull exposing it to higher temperatures as its thermal coefficient is rather large. (E.g. PP canister and POM lid may give you trouble the moment you submerge...) In addition 'creep' is an issue. Try to find yourself a strip of PP and submit it to a load. Leave it like that for a night. It will be longer the next morning. That's why eg PS or POM are far better 'technical plastics'. __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. =
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25th July 2006, 05:48	#3 (permalink)
RebreatherDave Maximum **** Current Rebreather/s: Inspiration Classic Other Rebreather/s:** Join Date: May 2005 Location: L.A., where the debris meets the sea Posts: 226	Re: Polypropylene as scrubber material? What about cross linked polyethylene...
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25th July 2006, 07:14	#4 (permalink)
Dutchy Rene Warries Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 844	Re: Polypropylene as scrubber material? Better I guess.... All I meant to say is that you need to be carefull how to use it. If you make a lid make sure that the O-ring is appropriately placed. (such that the difference in thermal coeeficient doesn't create leaks nor cracks. Otherwise PP is a decent material. It can be machined, glued (if it need be) or better welded. (Which takes practise but can be done with excelent strength) __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. =
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