Chemical Forums
Specialty Chemistry Forums => Citizen Chemist => Topic started by: Jman on May 30, 2016, 02:53:46 AM
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It's usually said that Natural Latex material you buy degrades over time which I assume if treated well is mainly from being exposed to oxygen in the air? Even with a silicone based polish coat on the material all the time.
At typical temps & moisture levels, is it oxygen that primarily degrades Latex? Or is it more complicated with wear & tear & molecules breaking down?
What time scales until it starts to noticeable degrade? If the material is thicker does it take alot longer?
As for acrylic plastics that store things like cd's, do they noticeable degrade in our life time from the air?
thanks
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Photodegradation (https://en.wikipedia.org/wiki/Photodegradation) is probably highly significant.
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Degradation of Pmma must be very slow, since windows are made of it, exposed to sunlight and weather, and they keep transparent for decades. Pc is more sensitive to scratches. One of them is very sensitive to solvents, which crack the surface.
Light, sure. Natural rubber is in addition very sensitive to ozone, even in tiny concentration as an atmospheric pollutant. I've seen some rubber rings degrade in few years, others stay sound for longer; possibly a matter of stabilizers, vulcanization or copolymers and blends. Tyres are loaded with carbon black, one goal is to protect against UV, they (all?) contain some natural rubber and don't degrade quickly.
Only as a feeling, I'd suppose that repeated deformations do little to natural rubber, because it's the one rubber that goes back to its original shape, and quickly. No synthetic rubber is as good for that. It would be easy to try.
Protective silicone: try it. Difficulties:
- Even silicone can't stretch as much as natural rubber
- Adhesion uses to be poor
- Silicone rubber is permeable too, and deformation won't help.
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Thanks for your help.