I may add dicumyl peroxide. AIBN is typically used below 100 deg C or even lower.

Hi Darryl,

High temperatures more than 120C with AIBN most probably not suitable due to explosion.

Having said that with radical initiators and high temperature there is not much of a choice. Perhaps tert-Butyl hydroperoxide or Cumene hydroperoxide be an option.

I may add dicumyl peroxide. AIBN is typically used below 100 deg C or even lower.

Use the nomogram from Gyorgy's pdf. That will help you for  a big part.

But there are more things; what kind of monomers do you want to polymerize? Do you mind branching due to H-abstracting/grafting reactions.  This is so much depending upon your choice of monomers, the initiator, the temperature, the actual monomer conversion, the presence of material that may influence the radical polymerization/side reactions. 

AIBN is not suitable radical initiator at temperatures you are intending to operate. 

i agree with MR juorgy AIBN is not suitable initiator , you can use dibenzoyl peroxide at  high temperature

VAm-110 (2,2'-Azobis(N-butyl-2-methylpropionamide）, Wako Chem.) can be used at 110 C same as AIBN at 60 C.

Dibenzoyl peroxide can be used at high temperature, however, it's difficult to control the speed of initiation same as at 60 C. 

Dibenzoyl peroxide is known to generate benzene as by-product.

And a report on the material itself, wrt evaluation of the carcinogenicity and genotoxicity :

http://www.gezondheidsraad.nl/sites/default/files/201224Dibenzoyl_peroxide.pdf

Take a real good look at Gyorgy's pdf and after a choice look what is known in literature on the choices you've made which for for your work.  You know the materials/process et al the best so that will help with the pdf/the literature to make up the balance for your final choice.

Use minor amounts on AIBN. 

The half-life-time of AIBN at those temperatures is only some seconds. Di-tert-butylperoxide, Trigonox 101 or Dicumylperoxide are suitable initiators for those temperatures. You can google "list of peroxides" to get an overview about the decay temperatures of initiatores.

Use AIBN and 80 degree centigrade not more then that for polymerization

I quite agree with Samir Zaweri. To my best understanding, you are running thermal polymerization at elevated temperatures, and you only want to compare the rates with that of a radical polymerization. Therefore using AIBN at temperatures of or below 80*C is ideal, the temperatures you choose for the thermal initiation should be far below that of thermal to be able to appreciate the effect of the radical initiator. Besides AIBN is void of chain transfer reaction which is very likely to come in with those types of monomers you are working it.

@ Burkhard Koehler:"You can google "list of peroxides" to get an overview about the decay temperatures of initiators."

That's not needed....  Gyorgy Banhegyi first answer contains also that list.

The choice is also very much dependent upon your process, e.g. batch use or dosage of monomers. Dosing monomers might give you somewhat more freedom in your ini choice.

Better read a good handbook on radical polymerization, e.g the chapter (nr 3) from Per Zetterlund et all, see Google book link, but there are many more (good) books:

https://books.google.nl/books?id=kk9c5xQZERUC&pg=PA118&lpg=PA118&dq=aibn+initiator+byproducts&source=bl&ots=8yMPmZSgY0&sig=m8l8vk93EeeUfvQO3BJxIPqchio&hl=en&sa=X&ved=0ahUKEwimpdG1jdHJAhUFLw8KHct4DzsQ6AEITjAJ#v=onepage&q=aibn%20initiator%20byproducts&f=false

Here's a list of common oil-soluble azo-type initiators that are commercially available: http://www.wako-chem.co.jp/specialty/oilazo/index.htm

A couple of them are more appropriate for your temperature range.

Dear Darryl Boyd

Many criteria apply while choosing a particular kind of AIBN type Initiator , which depends on the kind use , duration and other thermal conditions; if you ignore these set of  preconditions, AIBN may become ineffective.    

Add your answer

I thank everyone for the responses.  This has been a very fruitful and productive exchange of knowledge!

Hi additionally this two links can help you to know half lives of various initiators including AIBN.

www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Aldrich/General_Information/thermal_initiators.pdf

http://ce.sysu.edu.cn/echemi/polychem/uploadfiles/%E8%87%AA%E7%94%B1%E5%9F%BA%E8%81%9A%E5%90%88.pdf

Find it empirically. Start lab experiments with a very low mass (volume) of a monomer  with a low amount of AIBN. Find an appropriate concentration of AIBN under a hood. 

AIBN is probably the most useful radical initiator for beginners in the field of polymerization as well as professionals. It is relatively stable & safe and can be used at the typical temperature range 60-100 oC. I used it at lower temperatures (40 – 60 oC) for a certain purpose & it worked well.

It is true that free radical polymerization can be risky but the research work, itself, may be ruined. At higher temperatures (above 120 oC), the decomposition of AIBN becomes too fast & the polymeric chain may be broken after the AIBN is consumed since another initiation step is not available for this chain reaction polymerization (i.e. one will get anything except a polymer !).  

I do not know your monomer or oligomer, At such high temperatures polymerization can be spontaneous. If not, try minor amount of AIBN or benzoyl peroxide.