UV stabilizing of Polysulfone / polyethersulfone 3

[clandestinho]

Hi all,

can anyone suggest a way to UV stabilize polysulfone or polyethersulfone (Solvay´s Udel or Veradel) that will allow outdoor use?

I have found some evidence that benzotriazole UV absorber in 1% concentration can do something but I am not sure that it will be enough. Anyone with experience in this area?

Painting or coating the final product is not an option here. A sort of mechanical block rather than absorber could be a possibility. (TiO2 ?)


Alternatively, is there another amorphous thermoplastic which can be solvent cast into a film, with better UV and similar mechanical properties? Preferably transparent, translucent or white and without the aerospace price tag....


your help will be highly appreciated.
many thanks,

Claus

 

[Demon3]

RTP sell it:

http://www.rtpcompany.com/info/data/0900/RTP901UV.htm

Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive

http://www.plastictraining.com

 

[Demon3]

The Plastics Additives Handbook 6th Edition covers the topic as well as you can see through Google Books.

http://books.google.com/books?id=Wb...#v=onepage&q=UV stabilize polysulfone&f=false

They show results for 0.5% and 1% Tinuvin 234

Chris DeArmitt - PhD FRSC CChem
Plastic & Additives Webinars
Instant Downloads & Inexpensive

http://www.plastictraining.com

 

[patprimmer]

Both of Chris's answers are about as good as you can hope to get I think.

TiO2 can help with UV blocking, but will also alter other properties to some extent.

There are quite a few materials that might be a suitable substitute, depending on what properties you might want to retain as mechanical properties is a very broad term.

Polycarbonate and polyester copolymers or so called high heat Lexan or even aromatic nylons spring to mind as maybe possible. Polyesters are very hard to cast from solvent but I have seen it done, although I must admit it was poorly done with straight PET and I think 90% Meta Cresol? It was probably 30 years ago or more, so memories fade.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[clandestinho]

Thanks Chris, Thanks Pat,
your help with this is most appreciated.

Chris, thanks for suggesting the UV stabilized grade from RTP. I will see what they have to say and I will also look further into Tinuvin 234. It does look like a fairly modest improvement though and perhaps I just have to look for alternatives.

Pat, This is not a high temp application although a high Tg (low tensile creep) and high tensile modulus are desired properties. Also, solvent casting a film should be fairly straight forward.

TiO2 might give that extra protection but the high polarity of PSU and low polarity of TiO2 might not work well together in a solution?


Low water absorbtion is also on my wish list so nylons are probably not a very good choice. PSU has a very good set of properties, except for the UV issue.

regards,
Claus

 

[patprimmer]

Aromatic nylons while high water absorption vs other resins, have very low water absorption for a nylon, for what it's worth.

If it's not high temperature or impact, maybe acrylic (PMMA). Easy to solvent cast, very good creep, very hard, perfect UV and perfect transparency. It is brittle though.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[clandestinho]

Hi Pat,
toughness is top of the list, I forgot to mention this... Sorry.

aramids have nice properties but would be too difficult to dissolve, I think. PC or perhaps polyester copolymers, as you say, could be possible alternatives, although a step down in some of the mechanical properties. I will look into this as well.

Thanks again for your help, both of you.

 

[patprimmer]

Polyesters, even copolymers will be hard to dissolve and cast with a good clean smooth surface

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules