July 03, 2020, 10:03:10 PM
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Topic: Trying to vulcanize rubber, but accelerators are not dissolving  (Read 339 times)

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ixcm12

  • Guest
Trying to vulcanize rubber, but accelerators are not dissolving
« on: January 10, 2020, 10:02:05 AM »
Hello,
I'm pretty beginner and chemistry is not something I know very good.
I have (maybe) very basic question about vulcanizing rubber.
I want to vulcanize SBR rubber with sulphur and zinc oxide.
But final rubber mould is not vulcanized (or very little bit), because sulphur and zinc oxide are not dissolved in mixture and they are settled on the bottom of mixture. I have mixed it very well, with high rpm for a long time.
My question is how I can dissolve sulphur and zinc oxide to fully react with rubber "milk".
Both zinc oxide and sulphur which I'm adding into SBR rubber "milk" are very fine grinded (don't know how big are particles, but are much smaller that an human eye can see - in one fingerprint groove it looks like a dune made of sand).
Rubber is vulcanizing at high temperatures, but also at room temperature (but slower), right?

1.What can help with dissolving? Heat? Ammonia?
2.What is better vulcanizing material instead of mainly zinc oxide, which can be dangerous to human?

BEST REGARDS
 

ixcm12

  • Guest
Re: Trying to vulcanize rubber, but accelerators are not dissolving
« Reply #1 on: January 21, 2020, 02:45:44 AM »
Hello,
I'm pretty beginner and chemistry is not something I know very good.
I have (maybe) very basic question about vulcanizing rubber.
I want to vulcanize SBR rubber with sulphur and zinc oxide.
But final rubber mould is not vulcanized (or very little bit), because sulphur and zinc oxide are not dissolved in mixture and they are settled on the bottom of mixture. I have mixed it very well, with high rpm for a long time.
My question is how I can dissolve sulphur and zinc oxide to fully react with rubber "milk".
Both zinc oxide and sulphur which I'm adding into SBR rubber "milk" are very fine grinded (don't know how big are particles, but are much smaller that an human eye can see - in one fingerprint groove it looks like a dune made of sand).
Rubber is vulcanizing at high temperatures, but also at room temperature (but slower), right?

1.What can help with dissolving? Heat? Ammonia?
2.What is better vulcanizing material instead of mainly zinc oxide, which can be dangerous to human?

BEST REGARDS


UPDATE:
I realized that sulphur I'm using is insoluble type of sulphur so any solvent can't dissolve it. If I'm not wrong, only way to react sulphur with rubber milk is heat. Yesterday's experiment when I've heated up rubber milk in oven was succesfull only in finding information that rubber milk is boiling and is not reaching temperature over ~90°C (oven was set up to >150°C - and it was measured also by independent sensor). When is rubber milk boiling, it makes big amount of bubbles and crust so it's unusable. In this case I can't heat up rubber milk over 150°C (I can make only 90°C) to start vulvanization process with (insoluble) sulphur.

Can help me some kind of pressure? But everything I do is with home tools and kitchen. So pressure can be problem (pressure can be obtained by pappin's pot, but any kind of low pressure or vacuum is problematic).

Have you some ideas what can help me?


Kind regards

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