I'm a hobby enthusiast that loves to play with electronics so my major is not in chemistry, there for I'm hoping that this forum is the right place to find aid in this question.

I've searched day in and day out, and when someone refers to "epoxy" with "extreme high temperature tolerance" they're generally speaking about 200-300°C, which to me isn't that much.

I can understand that depending on the context that is a lot, but there has to be something that is actually "extreme" in the sense that it can tolerate up to 1000 °C since formula 1 cars typically hit around 1000°C at the end of a break line and typically the thickness and heat dispersion of the setup just can't take more because of the limits within FIA.

So my question is, what is the technical term for high temperature epoxy's and what other options is there if not?

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    $\begingroup$ Siloxanes are available as bicomponent resins and there are siloxanes withstanding 300 Celsium. I'm very sceptical about polymeres stable at 500+ celsium for prolonged time. While some polyacrilonitrile-derived materials (pyron) can withstand extreme heating for some time, they still degrade over time. In case you want carbon-derived material, most likely you'll have to carbonize it moving to reinforced carbon. Various ceramics, glass and castable materials can be a valid alternative if stability above 300 C is required. $\endgroup$ – permeakra Dec 30 '14 at 16:22
  • $\begingroup$ Thanks martin! @permeakra thanks for reminding me that my "it's all the same" isn't applicable hehe, sorry for this confusion. My intentions are to use either carbon fiber if it can withstand the heat or fiber glass strands and glue those strands in a epoxy or some sort that can withstand 500 or even 1000+°C. $\endgroup$ – Torxed Dec 30 '14 at 16:33
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    $\begingroup$ @Torxed Carbon fiber certainly can withstand 1000 C as long as it is not exposed to air, otherwise it may start to oxidize... Slowly. Common glass fiber will not withstand such temperatures, it would fail somewhere between 500...700 I think. I don't think you'll find commercially available binary resing able to withstand over 300 C, but maybe you can use ceramics? Though it will require a proper furnace to use. $\endgroup$ – permeakra Dec 30 '14 at 16:39
  • $\begingroup$ Can someone recommend a good 300 degree resin? -- I'm having trouble finding anything that is rated above 100 degrees Celsius... $\endgroup$ – BrainSlugs83 Oct 23 '17 at 23:10
  • $\begingroup$ According to Wikipedia Formula 1 disk brakes are made of carbon-reinforced carbon. $\endgroup$ – JanKanis Dec 20 '17 at 9:29

To succinctly answer your question, yes. However, they are not epoxies, and typically not available to a hobby enthusiast.

  1. There is no such thing as a high temperature epoxy. The maximum service temperature of epoxies is around 200 C on a good day.

  2. Higher temperature resin systems for 250 a 300 C are typically BMI-resins. These are rigid, thermoset plastics used in aerospace for composite airframe structures. BMI resins can be two-part, but are typically high-temperature thermal cures.

  3. The next level of heat resistant resins are polyimides. These can range from 300 C to about 450 C operational temperatures. However, it depends highly on the application. Some thermoplastic polyimides will not thermally degrade until 600 C, but have a much lower softening temperature (Tg). Thermosets will maintain rigidity, but will begin to thermally decompose at a lower temperature. However, depending on the application, polyimides can carbonize to form carbon-carbon structures: https://www.techbriefs.com/component/content/article/tb/pub/techbriefs/materials/27033. Polyimides are not two-part systems and require high temperature (250-380C) cures.

  4. Silicones. These are things like the fireplace sealant. They are not really high temperature, but will crystalize into ceramic-type structures at very high heat. They can be one or two-part. Things like this are typically used for glues, think space shuttle tile, and not composites, or as a precursor for carbon-ceramic composites.

  5. There are some next generation hybrids, like polysiloxaneimides that are two part. They are mixtures of polyimides and ceramic silicones. Good for temperatures from about 300 C up to about 1200 C, but poor performance in the mid-range.

  6. Carbon-carbon and carbon-ceramic. Made from polyimdes or silicones, these resins are fired at high temperatures (1000C+) to form ceramic-like materials capable with withstanding temperatures from 900 C to above 2500C. Two parts in the sense it is really a two-part manufacturing process.

When it comes down to it, there are a lot of options, including a few I didn’t cover like PEEKs and PBIs and Cyanate Esters. Most of these are not available to normal humans though, and there is a reason they tend to be reserved for aerospace and space applications. At the lower end of the BMI resins can cost hundreds a gallon, high-temperature polyimides can stretch into thousands per pound, and then all of these typically require special processing equipment, handling and safety measures. High temperature composites are not typically used on F1 cars as they are too expensive and not allowed by regulations - excluding exhaust systems and carbon-ceramic brakes. You also run into the problem that these high-temperature materials are not ‘consumer’ goods. So, unless you have access to a major university or corporation, there is no way to actually buy them.

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  • $\begingroup$ Was torn between what to mark as "solved". But this answer contained a good comparison between the different options. Thank you for taking your time to answer this and welcome to this forum! $\endgroup$ – Torxed Apr 13 at 7:40

In an oxygen-containing environment, no carbon-based polymer (which includes all epoxies) that I know of can tolerate 1000 C, at least not without significant degradation in mechanical strength.

There are two reasons for this:

One is that the carbon-carbon bonds will start to break down in large numbers at higher temperatures, and since the carbon-carbon to carbon-oxygen reaction is exothermic, if oxygen is around there will be no going back upon cooling.

The second is that even if the polymer doesn't chemically degrade, it will undergo a physical phase transition - it will melt, or at least soften. This can be compensated for by reinforcing with fiber or particles to make a composite. However, if it softens enough, a fiber composite will "delaminate" - the physical bonds holding the resin onto the reinforcment will come apart, and the composite will no longer be a composite.

Here is an interesting study that talks about both mechanisms of degradation, and lists several systems with their correpsonding melt and thermal decomposition temperatures. Polytetrafluoroethylene has the highest thermal decomposition temperature in this study, at 775 K (502 C).

Non-carbon polymers might be an option, although the tradeoff is that they are weaker and composite options are a lot more limited. Silicon-based polymers generally withstand higher temperatures than carbon analogues, but I wasn't able to find any that can approach 1000 C. Fluoro-polymers are another possibility - as you can see from the reference, they tend to have much higher stability in terms of thermal decomposition. There might be a fluoro-epoxy resin out there. One thing to keep in mind, though, is that the products of fluoro-polymer decomposition are particularly toxic and reactive, and so the applications where they could safely be used at high temperatures are probably very, very limited.

Edit in response to questions

One question regarding the "oxygen around", would this also include if layers of epoxy were applied as a extra layer ontop of the carbon or would it need to be a complete vacuum in order to prohibit oxidization?

If you had a layered carbon/polymer composite, the chemical reaction with the oxygen wouldn't start at the polymer-carbon interface, it would start at the surface exposed to oxygen. However, since the reaction is exothermic, once it starts burning, it would go quickly. The carbon would burn too at these temperatures. An inert atmosphere would prevent that reaction, but it would still thermally decompose - the difference would be that hopefully the decomposition wouldn't be as exothermic, and therefore would go more slowly. Now for epoxies, they have oxygen in the polymer structure. At high temperatures, that oxygen will react and the polymer will break apart whether there is an inert atmosphere or not.

  • $\begingroup$ Thank you for sharing! There's a lot to go on here. One question regarding the "oxygen around", would this also include if layers of epoxy were applied as a extra layer ontop of the carbon or would it need to be a complete vacuum in order to prohibit oxidization? $\endgroup$ – Torxed Dec 30 '14 at 17:10
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    $\begingroup$ The answer was pretty long so I just wrote it as an edit. $\endgroup$ – thomij Dec 30 '14 at 17:28
  • $\begingroup$ This answer my questions enough to be considered a solution to my curiosity. I will simply have to look for other ways to do my applications as there will be oxygen in the working Environment and the material will degrade to quickly. Thank you for your in-depth answer and the study you pasted. Cheers! $\endgroup$ – Torxed Dec 30 '14 at 18:50
  • $\begingroup$ I'm glad I could help - if you start another question that focuses more on your specific application, you might be able to get even better answers. There might be alternative materials/ways of doing things that you haven't considered yet... $\endgroup$ – thomij Dec 30 '14 at 20:35

Polyether ether ketone (PEEK) should be good to go up to 250 °C.

Polybenzimidazoles (PBIs) are stable up to temperatures of 500 °C, probably more. Protective suits for fire fighters are made from this material.

In order to withstand higher temperatures (nose cone of a Space Shuttle), carbon-reinforced carbon can be used.

  • $\begingroup$ Up to 250 °C is way to low for my application. 500 is also to low but not we're getting somewhere :) reinforced carbon is a valid choice so +1 for that. My concern however is the epoxy holding that reinforced carbon in place. As it's apparently the weak joint in any application because the carbon obviously can take a space trip without any harm :) $\endgroup$ – Torxed Dec 30 '14 at 16:34
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    $\begingroup$ @Torxed I'm afraid I might not have read your requirements properly enough: there is no epoxy resin left in carbon-reinforced carbon. It's more like carbon fibres embedded in layers of graphite. $\endgroup$ – Klaus-Dieter Warzecha Dec 30 '14 at 17:23

You can use fireplace sealant which can withstand 1500 °C to substitute the resin. This method works with carbon fiber but I don't know about fiberglass.

Credits: amazingdiyprojects, Integza (he build a pulsejet out of this material)


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