Ultraviolet activated substances

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In summary, the bonding agent in question is activated by an ultraviolet light, causing it to turn into a solid state after three seconds of exposure. This process, known as polymerization, is also used in modern dental fillings. The UV light creates a free radical which then causes the monomers to polymerize. This specific process requires the use of UV light as its frequency resonates with the electrons in the bonds. X-rays, on the other hand, have a frequency that is too high to induce this reaction.
  • #1
Ez4u2cit
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I recently purchased a bonding agent that is activated by an ultraviolet light (provided as part of the package). After three seconds of exposure to the UV light, the liquid substance turns rock hard. I believe they use the same process with modern dental fillings. Can anyone explain what is the physics/chemistry involved in this reaction.
 
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  • #3
Thanks. I was looking for the actual mechanism whereby the UV light induces the polymerization.
 
  • #4
The UV light creates a free radical. Then the monomers polymerize via free radical polymerization.
 
  • #5
So why UV light? Is this strictly because it is short wavelength/high energy. In which case, would x-rays work?
 
  • #6
No, the frequencies of X-rays are too high. The freqeuncy of the incident radiation has to be resonant with the electrons in the bond.
 

1. What are ultraviolet activated substances?

Ultraviolet activated substances are chemicals or materials that are designed to react or change properties when exposed to ultraviolet (UV) light. These substances can include dyes, pigments, coatings, and polymers, among others.

2. How does UV light activate substances?

UV light is a high-energy form of electromagnetic radiation that is capable of breaking chemical bonds in certain substances. When UV light is absorbed by a substance, it can cause a chemical reaction, resulting in a change in color, structure, or other properties.

3. What are some common uses of UV activated substances?

UV activated substances have a variety of applications, including inks and dyes for security features on documents and banknotes, color-changing materials for clothing and accessories, and UV-curable coatings for furniture, flooring, and other surfaces.

4. Are there any safety concerns with UV activated substances?

UV activated substances can pose potential health hazards if not handled properly. It is important to follow safety precautions and wear protective gear when working with these materials. Long-term exposure to UV light can also be harmful to the skin and eyes, so it is important to limit exposure and take breaks when necessary.

5. How can I test for the presence of UV activated substances?

There are several methods for testing the presence of UV activated substances, including using a UV light source and observing any changes in color or fluorescence, performing a chemical analysis, or using specialized equipment such as a spectrophotometer. It is best to consult a professional or follow specific testing protocols for accurate results.

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