Questions about UV light and dry plastic and rubber

  • #1
UV causes dryness of plastic and rubber and lights have UV so keeping it in the dark away from light inside boxes prevents this but notice this photo where the box where the arrows are marked the clarity q enters this region of the closed box is enough for the long term the UV of this clarity dry out plastic and rubber objects and items q are inside the box?

photo: https://ibb.co/QjD2yCK

IMG_20200808_123518.jpg

caixa-para-sapatos-preto-fosco-33x19x12-pacote-50-unidades-D_NQ_NP_779113-MLB31194899075_06201...jpg
 

Answers and Replies

  • #2
berkeman
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Welcome to PhysicsForums. :smile:
UV causes dryness of plastic and rubber and lights have UV so keeping it in the dark away from light inside boxes prevents this but notice this photo where the box where the arrows are marked the clarity q enters this region of the closed box is enough for the long term the UV of this clarity dry out plastic and rubber objects and items q are inside the box?

photo: https://ibb.co/QjD2yCK

View attachment 267545
View attachment 267546
Using my Mentor superpowers, I can see that English is not your primary language. Unfortunately, your post as translated is very hard to follow, and that's aggravated by the lack of punctuation and sentence structure.

Are you asking about how the corners of that box may let some UV light into the inside and cause problems? Are you trying to find a better box? Or are you asking how to add something to improve the UV shielding of the contents of the box? Thanks.
 
  • #3
I thought that storing a rubber and plastic item inside a closed shoe box would protect from UV, indirect sunlight entering the houses illuminating, that same light entering the shoe box in this space between the box body and the box cover ? does the light come in from the bottom upwards and when it collides on the box lid the UV light is reflected in all directions inside the box colliding with the plastic and rubber items that are inside the box?

IMG_20200808_123518.jpg


caixa-para-sapatos-preto-fosco-33x19x12-pacote-50-unidades-D_NQ_NP_779113-MLB31194899075_06201...jpg
 
  • #4
berkeman
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What are you using for your UV light detector?
 
  • #6
BillTre
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UV causes dryness of plastic and rubber
I would say that UV causes plastics and rubber molecules to break down to some extent.
(Some plastics (usually blue or black) have UV inhibitors to decrease how much this can happen.)
This is most likely an interaction between UV photons and the molecules, occasionally causing them to break.
This can cause little cracks (crazing) in the plastic or breaking it down into a powdery substance, with a rougher surface. Also brittleness.

Sunlight and various artificial light sources contain some amount of UV light.
Any light from these sources leaking through holes in your box can contain a UV component.
How much or how little UV is important to this process being a problem is something that would have to be determined for your particular use and materials.
There will probably be a point where the amount of light is so small that the damage to the plastic will not matter to you.
Presumably, the amount of UV absorption accumulated over a period of time will be reflected in the amount of resulting damage.

If you want less UV to get into your boxes:
  • block the holes (tape?)
  • keep it in the dark (or a darker area)
  • filter out the UV light in the area
  • throw a light proof blanket over light leaky box
  • in labs, we would cover things with aluminum foil (with no holes)
 
  • Informative
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  • #9
the box is made of cardboard, does the cardboard reflect UV?
caixa-para-sapatos-preto-fosco-33x19x12-pacote-50-unidades-D_NQ_NP_779113-MLB31194899075_06201...jpg
 
  • #10
BillTre
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The UV will not usually be expected to penetrate intact cardboard.
The cardbaord would have to be transparent to UV wavelengths (and apparently non-transparent in visible light, if your picture is right).
It might, however, leak in through the cracks.
 
  • #11
berkeman
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Interesting.
Are they single use?
I would guess so, kind of like the humidity sensor cards that we use in our IC packaging, but I only found these cards with a Google search, TBH.
 
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  • #13
BillTre
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Might reflect or absorb it.
 
  • #15
internal photo cardboard box
 
  • #16
Tom.G
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If visible light can't reflect into the box, most likely UV light won't be able to either. You can buy some of these inexpensive UV detection cards to check that:

https://www.newport.com/f/ultraviolet-uv-sensor-cards
Might be rather challenging to use, they fluoresce under UV so you would have to climb inside the box to find out! o_O

From the referenced link:
These viewing cards contain a phosphor-coated sensor area that emits clearly visible light when illuminated by UV sources.

Cheers,
Tom
 
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  • #17
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Might be rather challenging to use, they fluoresce under UV so you would have to climb inside the box to find out! o_O
Either he or a camera.

Btw.: UV light is not the only possible reason for polymer degradation. After some years of storage in a carton inside a locker (and thefore well protected from UV) the soles of a pair of my shoes turned into small crumbs. I suspect microbes or oxygen to be responsible for this mess.
 
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  • #18
internal photo cardboard box internal color reflect UV?
 
  • #19
berkeman
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Might be rather challenging to use, they fluoresce under UV so you would have to climb inside the box to find out!
Oh shoot. I thought they were like humidity-detecting cards, which change color when exposed to humidity (and retain that color change). Sigh.
 
  • #20
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Btw.: UV light is not the only possible reason for polymer degradation. After some years of storage in a carton inside a locker (and thefore well protected from UV) the soles of a pair of my shoes turned into small crumbs. I suspect microbes or oxygen to be responsible for this mess.
https://en.wikipedia.org/wiki/Ozone_cracking
 
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  • #21
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Btw.: UV light is not the only possible reason for polymer degradation.
Exactly. In that box common plastic would be fine for some decades, but the usual household rubber won't hold long (around half decade, I think).
 
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  • #22
cardboard box protects of UV? cardboard box reflect UV?
 
  • #23
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cardboard box protects of UV?
I don't know about reflection, but you need something at the range of x-rays to penetrate it. So yes, against UV it protects.
 

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