Star dryer temperature for cross linking of phenolic resin bound stars

[GermanPyro]

Hello together,

 

Can anybody tell me the temperature of a star dryer when I want to dry phenolic resin bound stars? The point is the cross-linking temperature...

 

Thanks in advance

 

Stefan

Edited January 22, 2018 by GermanPyro

[rogeryermaw]

https://en.wikipedia.org/wiki/Phenol_formaldehyde_resin#Novolacs

 

says 90 C

 

Hexamethylenetetramine is a hardener added to crosslink novolac. At a temperature >90 °C, it forms methylene and dimethylene amino bridges.

 

aka hexamine. this is what we typically use in pyro to polymerize phenolic resin.

Edited January 22, 2018 by rogeryermaw

[GermanPyro]

Thank you!!!

[rogeryermaw]

you're welcome! if you haven't messed with it before, i think you will like the outcome. the stars are rock hard and the phenolic burns cleanly without altering colors noticeably. at least that is my experience.

[MadMat]

Since we are talking about phenolic here... Do you HAVE to use hexamine and do the whole cross-link curing to enjoy the advantages of using phenolic for fuel instead of, say, red gum?

[Mumbles]

I've seen some mentions of hexamine and phenolic resin cross-linking as low as .probably 60-65 C.

 

Madmat, crosslinking has basically no influence on the fuel value of phenolic resin. It just turns the composition from hard to extremely hard. To me, this gives it the most advantage when curing large comets and doing so quickly. It also has the added benefit of making it unable to be softened with alcohol.