View Single Post
  #1   Report Post  
Posted to sci.electronics.repair
msg msg is offline
external usenet poster
 
Posts: 412
Default What causes white plastic cases to yellow?

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