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N_Cook N_Cook is offline
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Default What causes white plastic cases to yellow?

msg wrote in message
ernet...
Greetings,

I would appreciate a discussion on what environmental factors
cause white plastic equipment cases (which thermoplastics are used
I don't know) to yellow to a sickening hue. I have a number of
devices that only in one room of the house have suffered this fate
over the last several years in storage. Some have been in boxes
and others in the open. The room is darkened with no solar
illumination and only occasionally are CFL lights used. One
device only yellowed on the surface facing the ceiling. There
is no smoking in the house and very little (only occasional)
fry-pan cooking at a low temperature.

What chemistry is involved here? Could carpet composition or
fire-retardant treating do this?

Michael


I've always assumed it was a surface oxidation process or from airbourne
acids. It can often be cut back with oven cleaner but any legends etc are
lost doing that. White paint goes yellow, paper goes brown in a reaction
with airbourne acids.

perhaps try sci.chem

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