Graphene, possible non-battery uses in bicycles?

[spinningmagnets]

Hey Chalo. There have been some bold claims about graphene, so I went back to see where I picked up the bit about it making CF frames lighter. In the fourth post down on the first page of this thread, there is a video link and the 4:20 mark shows the host claiming that Dassi is using oxygen-doped graphene. The weight per volume is not stated, but they are claiming that this type is 200 times stronger than steel. If we accept that the true figure is closer to 20 times stronger than steel, then perhaps they are making the frame tube-walls half as thick to achieve a weight savings.

If that is the paraphrased truth of the situation, then the frame would be much lighter, while still being measurably stronger. Each manufacturer that designs a CF/G frame could adjust the weight and strength factors up or down to find a sellable balance.

Some riders who want CF are fearful of how easy they are to crack in a relatively minor fall. If you triple the damage resistance with no weight savings, there is an existing market for that alone. If a few grams can be shaved away for bragging rights, then an enterprising company could cater to the "Koenigsegg" crowd.

I can see now that I worded that claim poorly, thanks for correcting me. Also, thanks to rborger73 for that video link.

 

[cycleops612]

Now you want someone blocked because he disagree with you ? Or maybe it is because you find him rude and obstinate ? Then I am sorry to say that you are very close competition, that is a remarkable achievement in such a short posting history.

It is not another thread that you need to start, it is another forum. Imagine your own forum that you control alone, where your opinions are the only truth allowed.

I may not agree, but would fight to the death for your right to say it - churchill

yep - i recant on agreeing w/ exile, but deliberately wasting folks time and courtesy with broken record, off topic axe grinding is no small matter.

banning loonies from meetings is hardly the preserve of fascists?

oddly, i am now finding his comments reasonably sensible.

i shall bear the ignore function in mind in future.

 

[cycleops612]

That's not how this forum works.

Its rare to have a thread being split, not because its rarely needed, but because its a PITA and nobody wants to do it. The original thread was about spokeless wheels with integral hubmotors, A couple of posts about Graphene is one thing, but a couple of pages sof OT sort of demands to be its own thread.

As far as blocking Chalo, anyone here can block themselves from seeing his posts. There are many posters who's opinions I might disagree with on a given day, but I am comfortable with hearing what everyone has to say, and then letting the reader decide who's argument was more persuasive.

briefly, for the record, this thread is a split of the "heavy guys busting spokes on rear hubs" recent thread i mentioned. So it could have been far more tangled.

 

[rborger73]

This was always the issue with many of the forum software. Blocking still allows you to see when people quote, and you can't fully make the person disappear. I have him on ignore now, but it means he can still see my posts, reply to my posts, and still be a horrible nag. He has been an annoyance since my first thread or two. If you go back and look at my project threads he has always be an annoyance. All he has said about my projects, failed to come true. lol

 

[rborger73]

Oh and to MadRhino.. Dude I've been a webmaster since the late 90s. Owned and ran sites back then, and installed Phpbb when it was still in early beta on sites. I'm not about to try to setup a new forum when ES is already here. The good people are still here, but there is no way to keep the most annoying people to fully stay out of threads you make. Ignore is a piss poor feature. Blocking where the person sees nothing you post, and can't post in your threads is far superior. There used to be some good add ons for Phpbb, but I haven't messed with forum software since FB came out. You're better off these days with a FB group attached to whatever site you run. But being able to block someone on this forum from posting in your threads, is a much better option. :wink:

 

[Chalo]

There have been some bold claims about graphene, so I went back to see where I picked up the bit about it making CF frames lighter. In the fourth post down on the first page of this thread, there is a video link and the 4:20 mark shows the host claiming that Dassi is using oxygen-doped graphene. The weight per volume is not stated, but they are claiming that this type is 200 times stronger than steel. If we accept that the true figure is closer to 20 times stronger than steel, then perhaps they are making the frame tube-walls half as thick to achieve a weight savings.

The problem with claims about graphene's strength is that they characterize the bulk properties of the material, but the unit size of the individual pieces of material is less than a thousandth of a millimeter in the largest dimension. That's too small for the structural properties of the material to come through in a composite mixture.

To make an analogy, 1/8" ball bearings are made from super hard, super strong steel whose properties you can characterize. Cookie dough has another set of much lesser structural properties. Let the ball bearings stand in for the sub-microscopic particles of graphene, and let the cookie dough stand in for epoxy resin.

So let's say there are some bricks made of cookie dough with ball bearings mixed in. The manufacturer of these bricks is boastful about how super strong the steel ball bearings are. Does the strength of the steel really matter? Does it matter that the bricks might be a little bit stronger when mixed with ball bearings than plain cookie dough? Will you use the limitations of cookie dough, or the limitations of hardened steel, when deciding what you can build out of these bricks? Would you make a lifting cable or a wrench or a drill bit out of the cookie dough and ball bearing mixture, because the steel in the bearings is of a suitable grade for these objects?

A mixture of graphene nanoparticles and plastic resin is much more like resin than it is like graphene. Until we can get vastly larger continuous pieces of graphene, that's the way it's going to stay.

 

[rborger73]

See, I know he posted, and I'm pretty sure he posted the identical bs he did before, perpetually in a rut of remaining purposely obtuse.. Really wish there was user block so they don't even see threads started by the one wanting to block.

 

[rborger73]

For those not getting it..



[youtube]Uf8d1yOKUFc[/youtube]

 

[MadRhino]

Anyone familiar with epoxy works, knows that a filling agent does improve stiffness and compression resistance. This vid shows just that and chalk instead of graphene would have demontrated the same thing. What would be useful is a comparison test between graphene and other filling agents. Every filling agent included in resins has its own properties, improvement to some parameters and a handicap to others.

 

[cycleops612]

If the Luddites here had their way, carbon frames would be made by gluing carbon fiber tubes together.

Calfee, Crumpton, and Trek OCLV frames are all made by gluing carbon fiber tubes together. There are probably more Trek carbon fiber frames out there than any other kind.

Yes, I have seen them, and I can see the simpler manufacture having attractions during this phase in the market. Its a legacy manufacturing method from metal tubing days. It works, but inevitably results in over engineering. It has the advantage of perfectly~ made tubing sections as stock material, just like traditional tube frames. I doubt many would make more intricate rigid front forks that way. It misses the point of carbon IMO.

They are walking away from the key advantage of its plasticity - to allocate material precisely and in an unrestricted form, of which there are both more and inherently superior examples of frames I am confident. My guess is freeform moulded frames prevail now, and surely will in the future, for the same reasons cast wheels have advantages.

The term "cast" btw, does not exclude moulding using plastics. Molten or press extruded metal is also "plastic".

But yes, a bad example for a nevertheless valid argument perhaps. The point remains.

 

[rborger73]

Anyone familiar with epoxy works, knows that a filling agent does improve stiffness and compression resistance. This vid shows just that and chalk instead of graphene would have demontrated the same thing. What would be useful is a comparison test between graphene and other filling agents. Every filling agent included in resins has its own properties, improvement to some parameters and a handicap to others.

If you think chalk adds the same amount of strength as Graphene, please just back out of the conversation.. Please go research before you opine again... Clearly you refuse to understand why Graphene is important. :lol:

 

[MadRhino]

Don't be a jerk again. I am saying this vid doesn't show anything else than adding a mineral to a resin does make it stiff and resistant to compression, any mineral in various load %

A very long list of fillers are used with resin, for a long time and for a lot of purposes. What we need to know, is the effect of using graphene fillers as compared to other fillers commonly used. Hardness of the filler material doesn't have a direct effect on the hardness of the finished composite, and has many other effects. Most of the fillers are added to resin in very small load % to produce some desired effect, and the result is more about how it does blend in the resin structure than about the the properties of the filler material itself.

 

[rborger73]

I have explained several times why you are drastically missing what Graphene does, when it is added to a resin.

So, are you saying chalk, does the same thing, as the strongest, hardest material on earth? A material that also adds more resilience to breaking?

You said "Hardness of the filler material doesn't have a direct effect on the hardness of the finished composite," That is patently false. And graphene isn't just the hardness.. PLEASE, as I asked, go do some research, or actually look at the links I've already supplied. You're just wrong.

 

[Chalo]

What the graphene pipe smokers are ignoring is that it doesn't matter how amazingly strong a material is, if the biggest pieces of it are smaller than the finest powders we're familiar with. It's still nano powder, and isn't strong at a scale that matters to us macroscopic folk. No matter what you glue the teeny tiny particles together with, the resulting mixture will always tell you more about the glue than about the particles.

I'd go for fumed silica over this stuff every time, because its particles are much larger and shaped to provide some mechanical interlocking that graphene can't.

 

[MadRhino]

I have explained several times why you are drastically missing what Graphene does, when it is added to a resin.

So, are you saying chalk, does the same thing, as the strongest, hardest material on earth? A material that also adds more resilience to breaking?

You said "Hardness of the filler material doesn't have a direct effect on the hardness of the finished composite," That is patently false. And graphene isn't just the hardness.. PLEASE, as I asked, go do some research, or actually look at the links I've already supplied. You're just wrong.

For what is demonstrated in this video, ANY mineral filler would. We only see that it is stiffer and more resistant to compression, if you saw something else in that vid you dreamed it.

Yes, I say the properties of the filler itself as a pure material, doesn't translate into the composite. For an example some ductile metals added to resin in very low load %, are making the resin brittle. It is how a filler integrates with the resin structure, that is affecting its properties. The solvent used and the chemical (acid) alteration of the filler material, are making this integration possible and are responsible for a big part in the properties achieved. The same mineral integrated by different means can make very different properties. It can even make opposite resuts in some parameters, when it is loded 0.5 or 3.0 %.

What I say is that a demonstation of the properties of resins loaded with graphene, has to be a series of standard tests with comparative results. Seeing a cook with two cakes on a table, doesnt tell anything about how sweet they are.

 

[rborger73]

That information is probably... tucked away, hidden, earlier in this thread, several times..

Let's go for another link.. this one has pictures..

https://openresearch-repository.anu.edu.au/bitstream/1885/108975/1/Thomsa%20Larkin.pdf

Read #5...

 

[dustNbone]

What I say is that a demonstation of the properties of resins loaded with graphene, has to be a series of standard tests with comparative results. Seeing a cook with two cakes on a table, doesnt tell anything about how sweet they are.

That sounds very much like science. Pretty sure science has been obsolete for at least a month now.

 

[rborger73]

You can spend all day reading these as well... This isn't something I'm making up... This has been proven, and studied, over and over..

https://scholar.google.com/scholar?q=graphene+strength+test+++composite&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ved=0ahUKEwj7sIurq7bSAhVIfiYKHVnYBFkQgQMIGDAA


Science? There is plenty of science, when someone doesn't refuse to actually review it..

 

[dustNbone]

I browsed the top 15 results or so from the search link you posted, and exactly zero of them have anything to do with what you'd need to build a successful wheel out of graphene.

 

[rborger73]

Right now we are talking about the increased strength of composites, or polymers when Graphene is added... mmm k?

Read page 16...

http://www.tara.tcd.ie/bitstream/handle/2262/41037/Development%20of%20stiff%2c%20strong%2c%20yet%20tough%20composites%20by%20the%20addition%20of%20solvent%20exfoliated%20graphene%20to%20polyurethane.pdf?sequence=1&isAllowed=y

 

[rborger73]

So the possibility here is Graphene infused polymer, used to bind graphene sheets together.. If you think you're going to find a scholarly paper that says "Here is how you create ebike rims out of Graphene"... :lol:

 

[rborger73]

This one also applies.

http://pubs.acs.org/doi/abs/10.1021/la101698j

"The mechanical strength of the PEDOT and graphene composite film shows 6-fold enhancement over the pristine PEDOT film. Because of the contribution of graphene layer for enhancing the mechanical strength, a 44 nm thick graphene/PEDOT/graphene could be obtained as a free-standing film by delaminating the graphene layer from the glass substrate under a weak base solution. These results imply that the graphene not only improves the conductivity and mechanical strength of PEDOT but also enables to produce a free-standing film which could find a variety of applications in the fields of organic electronic, sensors, and optoelectronics."

 

[rborger73]

And another one..

" Here we report that nanocomposites based on fully exfoliated graphene nanosheets and poly(vinyl alcohol) (PVA) are prepared via a facial aqueous solution. A significant enhancement of mechanical properties of the graphene/PVA composites is obtained at low graphene loading; that is, a 150% improvement of tensile strength and a nearly 10 times increase of Young’s modulus are achieved at a graphene loading of 1.8 vol %. The comparison between the experimental results and theoretical simulation for Young’s modulus indicates that the graphene nanosheets in polymer matrix are mostly dispersed randomly in the nanocomposite films."

http://pubs.acs.org/doi/abs/10.1021/ma902862u

Ok... so... anything else that you refuse to look into on your own, that you need your hand held for? :lol:

 

[spinningmagnets]

Some people will just never agree with you. You've made your point...let it go.

 

[rborger73]

It's an excuse to post some more facts. 8)