Hello,
I thought I would come here to ask about researchers experience with curing bismaleimide resins. I have made a few BMI's and have had a few problems with curing. Specifically, degassing and foaming around 250C.
Any feedback would be greatly appreciated. Thankyou in advance.
chris
Dear Christopher Eugene Smith ,
Although I never worked with bismaleimides, I did work with some others thermosets and I remember having some issues like yours.
The first thing I did was to analyze the resins (through DSC) to check at which temperature do they melt and at which temperature do they cure. In my case, the gap is important, since the intention was to melt the resin without curing it, mainly for the degassing stage. If this window is wide (big difference between both temperatures) you can try to degas a little bit above the melting temperature and way below the curing temperature.
If not, I remember preparing the materials under pressure. So, when curing, incorporating high pressure (I remember using a hot press at around 2.5, 3 ton) to avoid the formation of bubbles.
I hope this two insights help you a little bit.
PS: it would be great also to be sure that in your bismaleimides there is no solvent at all. Probably the foam is related to this. Again, this could be seen by DSC or TGA of the uncured resins.
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