Well, How to bring back plastic to white color .... :-(

Xeratul · 03-31-2024, 10:19 PM

Hi,

NaOCl is great to clean surfaces, ... but with special cares.
By accident, I forgot the liquid on a plastic surface. It is likely some PP (window area).
I wanted to clean it with Javelo, i.e. sodium-hypochlorite-bleach, which is an alkaline inorganic chemical compound with the formula NaOCl.

I forgot it during about 1 hour.

The surface turned now to yellow, sadly.
see; https://i.postimg.cc/0jnDyM2W/yellow-comp.png

Is there any chemical compound that can bring the plastic back from yellow to white color? Hard question.

Kind regards

smallpond · 04-02-2024, 07:44 AM

Doubtful that you can do this by chemical means. If it is a thin surface layer, you can try Simichrome or some other fine abrasive to polish it off.

Xeratul · 04-02-2024, 08:18 AM

Quote:

Originally Posted by smallpond

Doubtful that you can do this by chemical means. If it is a thin surface layer, you can try Simichrome or some other fine abrasive to polish it off.

https://en.wikipedia.org/wiki/Brasso

thanks !! I will try Simichrome

rokytnji · 04-02-2024, 08:33 AM

On motorcycle repaired plastics. I use steel wool first for the scratches. Then I have my rubbing compound paste made with mineral oil and stick of abrasive in a crock pot.

Works on borked aluminum also.

valeoak · 04-02-2024, 11:01 AM

Hydrogen peroxide and UV light is useful for retrobrighting ABS plastics (see, e.g., this video from the The 8-Bit Guy). However, this method tackles yellowing caused by photo-oxidation of the plastic polymers. I don't think it will be effective against oxidising from bleach.

I agree with smallpond to try an abrasive cleaning technique.

Xeratul · 04-03-2024, 12:29 AM

Quote:

Originally Posted by valeoak

Hydrogen peroxide and UV light is useful for retrobrighting ABS plastics (see, e.g., this video from the The 8-Bit Guy). However, this method tackles yellowing caused by photo-oxidation of the plastic polymers. I don't think it will be effective against oxidising from bleach.

I agree with smallpond to try an abrasive cleaning technique.

Hydrogen peroxide is a good idea, yeah. Acetone maybe too?

But, damaging the PP layer can be dangerous, like polishing. Maybe there is a PP top layer or ABS, I dont know what it is, and below another thing, like wood. it is on window edge (inside)

Hydrogen peroxide, I recall has some effects.

Actually, it is just NaClO type of compounds (*) that put themselves into the molecular arrangement, and bit more.