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Author Topic: Why does plastic become brittle with time?  (Read 6807 times)

Offline chris

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Why does plastic become brittle with time?
« on: 09/01/2009 08:28:09 »
If a mineral-water bottle is re-used a number of times eventually it becomes brittle and shatters easily; this is in stark contrast to the readily-deformable behaviour of the material when the bottle was new. Why does this happen?

Chris


 

Offline lightarrow

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Why does plastic become brittle with time?
« Reply #1 on: 09/01/2009 15:21:56 »
If a mineral-water bottle is re-used a number of times eventually it becomes brittle and shatters easily; this is in stark contrast to the readily-deformable behaviour of the material when the bottle was new. Why does this happen?

Chris
Since no one answered, I try to suggest a speculative idea: maybe, as in the case of glass, it crystallizes with time because the molecules rearrange themself in a more ordered way.
I repeat: just a speculation, I haven't made any search on the subject.
 

blakestyger

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Why does plastic become brittle with time?
« Reply #2 on: 11/01/2009 11:43:09 »
Plastics degrade in UV light - but there are myriad formulae and I imagine that the rates vary.

UPVC windows carry a 10yr warranty but I suspect that all the time and expense saved in not having to paint wooden frames will be spent in replacement windows long before the wooden ones would have given out.

Regards, Eeyore.
« Last Edit: 11/01/2009 11:44:54 by blakestyger »
 

Offline erickejah

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Why does plastic become brittle with time?
« Reply #3 on: 21/01/2009 23:29:45 »
since plastic is derived from petroleum dont the temperature affects it composition?  and plastic in bottles are arrange in layers, the particles may rearrange like lightarrow said.  ::)
 

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Why does plastic become brittle with time?
« Reply #3 on: 21/01/2009 23:29:45 »

 

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