How to prevent certain plastics from turning yellow.

How to prevent certain plastics from turning yellow.

Dear Dr Chemical,
Thank you for your time.
I purchased a brand new 1990s telephone. The photos attached to the question show both models of phone. The left phone is white in appearance. The right phone is coloured yellow.

My new 1990s telephone is in its box. It is white in appearance. I would like to know how to prevent the white phone as exemplified on the left side of the photo from turning yellow as exemplified on the right side of the photo.

First I am aware that sunlight may affect the colouring of plastic.

Are there any other factors which change white plastic to yellow?

Note: I know how to reverse the yellowing process. I have successfully applied hair creme containing H2O2 on the surface of a yellowed plastic and exposing the plastic in the sun’s direction.

I want to know how to prevent the plastic from yellowing.

Thank you
Anthony of Sydney

21870cookie-checkHow to prevent certain plastics from turning yellow.

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Anthony The Koala
Anthony The Koala

Dear Dr Chemical,
Here is a site that discusses methods using chemicals containing H2O2 to de-yellow plastic. It mentions UV light from the sun causing the yellowing.

https://www.thegeekpub.com/13216/how-retrobright-works/

Again I still would like to know if there are other causes of yellowing of plastic other than the SUN’s UV.

Thank you

Dr Chemical

The problem is that it’s not UV-stabilised plastic, and yes – it’s the UV light that causes the yellowing.
So the only way that I know of is to regularly apply SPF50 sunscreen….
There may be a clear spray you can spray on that contains UV stabilisers, but I don’t know of any off the top of my head