Moldable and durable polymer with excellent UV characteristics

[pdmsgmw]

I am trying to find a polymer that can be exposed to high doses of UV constantly (tens of mW) without degredation to the polymer. I also need the polymer to be mechanically robust. Previously i have used some elastomers but they degrade and their mechanical properties fail quickly. I am not sure i need an elastomer. Are there elastomers that can withstand high UV doses? If not, what other polymers would be useful to try?

Thank you for your help.

Best,
adam

 

[Pud]

PMMA (Lucite/Perspex) is transparent to UV.

uPVC is also good with UV, although I am not sure about plasticised elastomeric flavours...

Polyesters are also good with UV (PBT/PET etc)

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[patprimmer]

Like Harry says. PMMA or acrylic is the best to UV, but it is reasonably brittle.

PET is very good but still needs stabilisers that are sacrificial in normal circumstances.

Does it need to be transparent or a specific colour?

PTFE (Teflon) is very good to UV but cannot be moulded by normal means and is at best translucent milky white.

If it can be black or solid white, carbon black or titanium dioxide pigments offer considerable permanent UV protection to the polymer matrix, but not the surface.

Transparent durable stabilisation can now be obtained with nano sized white zinc additive, but at what price? It also only protects the matrix, not the surface.

Organic stabalisers protect the surface, but they are sacrificial.

Glass fibre reinforcment protects from crack propagation caused by microcracks that form on the surface when pigments are used for UV protection, so black, glass filled gives good almost permanent protection in polymers reasonably inherently stable like PET, PBT or even nylon.

Many boat deck fittings are carbon black, glass filled, UV and heat stabilised nylon or polyester, as are automotive roof racks and overhead electric power line fittings.

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

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

for site rules

 

[tom1953]

EPDM rubber can be very resistant to UV when a significant amount of carbon black is included in the formula. EPDM is widely used for roofing, which typically will last several decades.

 

[piero70]

PMMA is perfect for UV resistance (especially if containig additional stabilization). In thermoforming applications multilayers products are used. Specifically, (hi impact) ABS is capped with PMMA to combine good mechanical properties with outstanding UV resistance, scratch resistannce and aesthetic

BR

Piero

 

[Demon3]

ASA is like ABS in having good mechanical properties but it has really good UV resistance. It retains properties and color for many years outdoors. It is even better than PVC which is why it is used as a thin layer on top of PVC for siding.

Whereas ABS is SAN with polybutadiene rubber particles in it, ASA is SAN with UV stable acrylic impact modifier particles.

See for example

http://www.lurans.com

Chris DeArmitt

"Knowledge has no value except that which can be gained from its application toward some worthwhile end."
Think and Grow Rich - Napoleon Hill

 

[unclesyd]

You might want to look at Dupont's Tedlar products for your application.

http://www2.dupont.com/Tedlar_PVF_Film/en_US/index.html

 

[Plasman10]

It depends on wat you mean by "mechanically robust" which seems to me to conflict with the use of "elastomer." If by mechanically robust you meas high strength and stiffness, especially in elevated temperature environments, PET glass reinforced and black culd be a good fit. There are some Rynite SUV (super UV stablized)grades for the solar industry that migh fit your application.

http://www.innovations-report.com/h...rated_photovoltaic_module_housing_117834.html