Yellowing of Polyarylate

Question

Yellowing of Polyarylate

clandestinho (Materials)

(OP)

20 Sep 16 15:50

Hi,

I have an application where I would like to use polyarylate. It will be solvent cast into a thin film, 10 micron or there about.
My only problem with this is that Polyarylate goes from clear, transparent to yellow when exposed to UV due to some rearrangement in the polymer chain.

I haven't seen for myself how bad this is and before we start spending time and money on trials I would like to hear
if anyone knows if, and to what extent, this yellowing can be masked? I wonder if a fluorescent type optical brightener could cope with this or perhaps some other method? A free radical scavenger? a metal oxide to reflect or block the UV?

I don't need transparency in this film, it can be hazy white but not completely opaque and not any other colour.

Supplier of the resin has not been able to suggest anything but they haven't ruled it out either. Any advice will be much appreciated !

regards,
Clann

Compositepro (Chemical) · Answer 1 · 2016-09-20 17:07:20

It is well know that polymer that contain double bonds, which are present in the benzene rings in polyarylene, yellow in UV light. There are UV stabilizers that could help and brighteners will help conceal the yellow, but in such a thin film the light stabilizers not will be very effective as they will be consumed very quickly. A Google search showed that this polymer is described as a transparent amber resin. If no color is important, then a different resin should be selected.

cloa (Petroleum) · Answer 2 · 2016-10-14 05:24:42

I think clandestinho wants to have some idea of how bad such a film will look after some time in the use.
clandestinho- how long in sunshine (I assume) will this film be exposed and where?

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Yellowing of Polyarylate