@Ann: I don't think it's correct to call this a thermoplastic resin -- at least, the authors don't seem to call it that in the Science article. It's crosslinked, which would make it a thermoset according to the conventional definition. The difference is that, in this material, the crosslinks can rearrange themselves by means of a reversible chemical reaction. In a typical thermoset, the crosslinks are irreversible (which is why normal thermosets have no melting point and can't be recycled).
I also don't think it's correct to say that it could be recycled by pyrolysis. Pyrolysis would mean thermally breaking down the polymer, which would probably render it unusable. (You might be thinking about composite recycling, where pyrolysis can be used to recover fibers by removing the polymer matrix). The authors mention hydrolysis or alcoholysis, which would mean chemically breaking down the crosslinks, while leaving the polymer chains intact.
The method the authors used to recycle the material was simpler -- they just ground up the material and re-molded it. It looks like the properties were not as good as the virgin material -- but they weren't that bad either, and the fact that they were able to do it at all is impressive.
This is a very interesting development in polymer science. I hope that everyone interested in this will follow the link to the Science article.
The idea of having crosslinks which can be turned on and off is a concept which is also used in self-healing and shape memory polymers. It will be interesting to see what uses people come up with for this.
Is this material being used yet? I'm very curious as to its use. Would its use be very specific? Or could it possibly have a wide range of uses? Sounds like it's much more flexible in its potential uses than materials it might replace.
I agree with Rob that the possibilities for a material of this sort are intriguing. I know this is still in the early development stage, but the project must be driven with an eye to possible applications of this kind of material and what sort of issues it might resolve. Any sense of where it might be used and what industries it might impact?
I agree with Beth. This material was probably created with a particular solution in mind. I think it's only in the electronics industry where technology is developed without a specific solution in mind. I wouldn't imagine a "solution looking for a problem" is common in materials.
@Rob: I don't think this was developed for a specific application -- this looks like basic research. (Looking at the ESPCI website which Ann links too, it would appear that basic research is their mission).
I can't emphasize enough that this is a major breakthrough in polymer chemistry. This group has developed an entirely new class of material -- a thermosetting resin with reversible crosslinks. The number of potential applications is enormous -- basically, any application where polymers are used (and probably some where they currently aren't, too).
Is it a "solution looking for a problem"? Not really; it's a solution to very fundamental problems with thermosetting and thermoplastic resins, which the authors express very clearly and succinctly in their introduction. Thermosetting resins don't flow when heated, which, among other things, means they can't be injection molded or extruded. As Ann points out, it also means they can't be recycled. On the other hand, thermoplastics don't have the dimensional stability, mechanical properties, or chemical resistanceof thermosets.
By making a thermoset which behaves like a thermoplastic at high temperatures, they have essentially solved both sets of problems. Not only that, but they have also enabled totally new manufacturing methods which couldn't even be imagined before.
It may be a few years before this class of material starts to make its way into applications. It doesn't seem like cost will be a barrier to adoption, but unfamiliarity will undoubtedly be -- this class of material fundamentally challenges what everybody thinks they know about how polymers behave. But this is a really incredible development which illustrates the value of basic research, and is certain to have a massive impact.
I would think the recyclability of it would be hampered by the fact that it would still be molded into a composite structure with fiber reinforcement. Just like painted PP/TPO is limited in recyclability, this would be too, but still it could still be molded into something useful. If it's based on currently available thermosetting resins, I would think the moldability would be comparable (i.e. low cost tooling, low pressure molding, long cycle times), so the economics would be comparable. If it functions like a thermoset during the design life cycle of the part, I thing the main benefit would be the "green" aspect of its recyclability at the end of its life cycle.
Pretty interestng, Dave. From what you're saying, I take it that the new materials has wide potential uses. Given that, it doesn't matter if a particular use was targeted in development.
I wanted to read the article but I am unwilling to sign up for the association, or even to register. I am not a "plastics professional" and don't want to be treated like one. I was hoping to extend my education a bit, and be able to be better prepared for design decisions in the future. But I am not in the plastics industry.
So why not let others read about what sounds like a great advance?
This is an interesting material. I agree that the processability of the new material should be significantly better than existing thermoset materials. The article is a little misleading in that it states that the material has glass like properties. True, the material will melt and flow like glass, but per the atricle, the materiala at room temperature is more like conventional rubber than glass.
Reading this article and others like it around the net, it looks like the folks at ESPCI ParisTech are not exaggerating when they describe their development as a "new class" of material. While it does appear to be the result of basic research, it was supported in part by the Arkema Group. I anticipate this material and its reaction chemistry will be part of a large patent portfolio. At its face, it reminds me of the fictional "Transparent Aluminum" appearing in Start Trek IV: The Voyage Home. But rather than being a metal with glass-like qualities, the fine folks at the Laboratoire "Matière Molle et Chimie" have developed a thermoset polymer with glass-like qualities. Both would be fantastically revolutionary.
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