High TG epoxy

[phoenix221]

I am hoping someone could suggest an epoxy/resin system that has a TG in the 450F range and is compatible with carbon fiber.

Now that was the easy part, the hard part is to find an epoxy/resin system that will yield the high TG and is relatively easy to work with, i.e. which can be cured initially at 100-120F and post cured at up to 500F.

Are my requirements completely unreasonable?

 

[SWComposites]

Probably. Look into the PETI resins developed by NASA; one of them might work. You should be able to find info by searching on the NASA Langley web site.

 

[Compositepro]

450F Tg is pretty high for an epoxy. I am not aware of any that have such a high Tg and can gel at such low temperatures but it may be possible. The PETI resins have much higher Tg that you need and require very high temperature cure. They are also very expensive. Bismaleimide resins process like epoxy and have high Tg and are far less expensive than polyimides. Fibraplex has a resin that will cure as low as 250F and has a Tg of almost 700F. It is a new product so you would have to call them for info.

 

[phoenix221]

Thanks for all the reply folks...

> Look into the PETI resins developed by NASA...
Is this the type of stuff UBE America commercialized called PMR-15? It is my understanding that PMR-15 contains the toxic compound methylenedianiline (MDA). I've also found RP-46 (Unitech Corp.) but the info I am gathering indicates very complicated manufacturing processesa and high cure temperature and pressure -- 325°C/617°F and 200 psi -- are needed, plus there is off-gasing to worry about. What about phthalonitrile resins (Eikos Inc.)? Any comments on or experience with these products? ... I need something that can be processed/applied like epoxy. Many of these products seem to be available as prepregs only!

> 450F Tg is pretty high for an epoxy. I am not aware of any
> that have such a high Tg and can gel at such low temperatures

I am desperately trying to avoid having to build a hot cure mold :-(. Even the Fibraplex cure temp of 250F would require one.

 

[SWComposites]

No, PMR-15 is an old, 70's vintage, polyimide resin system. The PETI systems are much newer, and I don't hink they contain MDA. If you want a high Tg then you are going to have to cure and/or post-cure at a high temperature. Further, I doubt that you will find a high Tg wet layup resin system.

 

[phoenix221]

Just an update, I've gotten some tips offline...

PT2846A/B2 (by PTMW) - this stuff will set at room temp, then after a graduated post cure TG is claimed (by PTMW) to go as high as 425F

ABOCAST 8501-5 (by ABATRON) - they claim that set is at 90F, after a 4 hour post cure, TG is at 570F.

Anybody had any experience with these systems?

 

[MechanicalChef]

If you have any ties to someone at SpiritAerosystems/Boeing, find out what they use around the core material of the nacelles on the 777.

 

[Blackhorse007]

Wow, epoxy are not meant to have such high tempreature resistance, probably some NASA materials might be able to come in useful here. PETI is an alternative, it might be better to look for the correct supplier to get these done? Else at worse probably you might want to put one layer of fireproof or heat proof coating on top of the epoxy to help protect it?

 

[MechanicalChef]

Also, how much are you looking to acquire and what's the application?

 

[phoenix221]

Folks thanks for the renewed interest. I am currently doing some prototyping with PT2846A/B2 (by PTMW) which combined with carbon fiber should give good hig temp (500F) performance.

If this does not pan out, I'll try to steal the industrial secrets of SpiritAerosystems/Boeing

 

[Blackhorse007]

yo phoenix221 can u pls keep us posted? this is very intresting to find that there is a high tempreature resisting epoxy

THanks!

 

[Rink]

You might find this interesting-

CERAMIC MATRIX Composite Brake rotors.

http://www.wiredhat.com/braketech/tech/cmc_process.html

Rink

 

[Prabbit]

Just a word of caution. Some of the items being mentioned fall under the export controlled regulations.

 

[InnovativeComposites]

May want to consider a Phenolic resin system. JD Lincoln makes a few that you can initial cure in the range you are looking at and ahve demonstarted Tg's in the 500F range after post!

I agree with others statements that 450F is high for an epoxy.

Good Luck,

Steve

 

[MechanicalChef]

http://www.compositesworld.com/hpc/issues/2004/November/637/1

This might give you some additional avenues to research.

 

[IceKing02]

Guys and Gals,

You may want to look at these different companies for information about high temp epoxies:
1.

http://www.cotronics.com

2.

http://www.aremco.com

I'm making an exhaust system (pipe and muffler) for my ATV and have need for the high temp resistance of these epoxies. As an aside it may be useful to consider basalt sleeve material as your first layer or two if you want to do a similar project. It is able to withstand sustained temps > 1600F. Most carbon fibers that I've seen spec'd are better at 600F (please tell me if this is in error). If this works well I am considering the use of basalt sleeve to make a 4" downpipe for my diesel (where the temps routinely hit 1200F). For this application I have found ceramic-based adhesives that may be useful--don't know as I haven't gotten that far.
Please feel free to comment on the second idea as I'm just a little diabetes doctor with a case of insomnia...

Cheers,

IceKing02

 

[no2metal]

Try curing Hexcel 8552 epoxy (or any TGDDM-DDS epoxy system) at around 135c for 1 hour followed by 175C for 2 hours and finally postcure at 250C for 2.5 hours, you should get at Tg around 250C

 

[Joshmo]

Epoxies won't get you there but Polyimides can achieve a Tg of >600 degree F. The problem is that PI's have nasty cure cyles and are hard to do anything other than flat plates. PI's in a press require B-staging for 10 hours at 350 degree F and then the actual cure has a complicated ramp up cycle for 18 hours that goes up to 750 degree F.

 

[RPstress]

Hey, pheonix221: if you're still around, how did it go with the PT2846A/B2 resin?

 

[phoenix221]

The project is on a back burner. I'll post to the forum as soon as I have results