Because it contains a very high diversity of proteins, natural cuticle also occurs in different thicknesses and degrees of rigidity or flexibility, depending on where it occurs in the insect's body. The researchers found that, by controlling water content during fabrication of Shrilk, they could reproduce these wide variations in stiffness of natural insect cuticle, resulting in a range of materials from highly elastic to highly rigid.
The chitin component of natural cuticle can be difficult to work with because of its low solubility. Chitosan, a more soluble, highly deacetylated form of chitin, is already approved for use in wound dressings by the US Food and Drug Administration. Fibroin from silk is also widely used in surgical sutures. This combination of attributes, in addition to its biocompatibility, means that applications for Shrilk could include suturing wounds that must bear high loads, such as for hernia repair, or as a scaffold for tissue regeneration. Other applications as a cheap, environmentally safe alternative to plastic include packaging that degrades quickly. The fact that the new material is as tough and strong as aluminum suggests that it might have applications in industrial or transportation applications as well.
Chitosan/silk combinations have been attempted before for medical applications that require both high strength and biocompatibility, but the strength of the combined materials was disappointing. One possibility for this is the fact that previous combinations were disorganized conglomerates that did not reproduce the laminar structure of chitin and protein layers found in natural insect cuticle.
Jack, I think that's a good point. But I believe the analyst's point was that it's better to start and do the research instead of not do it, and be stuck in the same boat, only now it's later and the need for replacements is even greater. I also get the impression that instead of a single answer, we're going to have multiple answers. I'd be pretty surprised if any individual bioplastic was suited either by volume or by its nature and characteristics, to substitute for all the petro-based plastics we currently use.
I don't think we can ignore the volume issues juse because it is a new technology. While this might currently be seen as a proof of concept, the fact is that the long term plan is to make it more common rather than being used only as a special application. It would not make sense to go far down the development route and then say that we have this great product but the raw materials don't exist, so never mind.
SparkyWatt, thanks for the answers. I just interviewed Freedonia Group analyst regarding a bioplastics study they just completed and he pointed out that right now, bioplastics represent only about 1/1000 of the plastics we use. He said we're so far away from even putting a dent into plastics consumption with bio-alternatives that it doesn't make much sense to worry about how to reach those volumes. I tend to agree.
And I concur with your comments on EVs and fossil fuels.
On the plastics thing, there are two things about this that people often miss. First, not all plastics are petroleum products. Many of the plastics we use today (although not nearly most) are agricultural or forestry products. Products like this are renewable as well. The second issue has to do with supply and demand. Let's say that shrimp grow at a rate that will easily supply 30 pounds of meat or so per person per year. It is really probably several times that, but I am reasonably sure it isn't 10 times that. Now if you try to supply 100 pounds of tails and shells per person per year, you are vastly overfishing.
Renewable resources, properly managed, will continue to be available for the foreseeable future, but only at a particular rate. That is the general problem with solutions like ethanol, biodiesel, and bioplastics. They will be available forever, but only in limited quantities. Usually those limited quatities aren't enough. That is why I don't see Shrilk displacing plastics in the near future, even if it does live up to all of its promises. There just won't be enough materials available for it to take over.
The article talked about the materials being "abundantly available", and that is no doubt true when you look at it from the point of view of starting an industry and launching products. However, that is a long way from meeting our appetite for plastics.
On the EV's. The basic goal here is to eliminate the use of fossil fuels. Right now the fossil fuels are used in two major ways, electricity generation and transportation. To eliminate the use of fossil fuels, their use must be eliminated from BOTH major areas (as well as the minor ones that pop up here and there). EV's eliminate one of the major components of the transportation sector. Because they aren't completely efficient, they are TEMPORARILY driving up the use of fossil fuels; that is a temporary problem. The longer range problem that needs to be solved is electricity generation. When electricity is no longer based on fossil fuels, EV's won't drive the use of fossil fuels either. Problem solved.
SparkyWatt, I don't see why an abundance of shrimp shells and silk can't help replace plastic, since these are natural, renewable resources. Can you elaborate a bit on what you meant?
Otherwise, I think your comment about EVs' electricity coming from carbon producing sources being a temporary problem is an interesting one. It has also seemed to me that some of our solutions are bound to be interim, or based on interim energy sources, while we solve longer-term problems, and that solving those longer-term problems will eliminate the short-term ones.
Can you spell out more what you mean in this case? Why will this EV-related problem go away when we solve longer term problems, and which longer-term problems did you mean in this case?
This sounds like a really useful material, although I did not fully understand about the degrading process. Even better is the source of material, totally renewable. OF course there is quite a transition to be made in going from a laboratory discovery to a commercially viable product.
But clearly there is a possibility for the stuff to find a niche application, at the least.
Also agreed. I think there are many avenues to pursue. I mentioned geothermal. Fusion would be great, if we can lick it. They all take a big investment, but many are doable. It is more a problem of will and investment than of possibility.
What I get tired of is people slamming EVs because the electricity comes from carbon sources. That is a temporary problem. That link in the carbon-free chain is solved. Instead of complaining about the temporary problems, let's solve the other links. Then the temporary problems go away, too.
Well, I doubt that an abundance like being a waste product of shrimping would allow shrilk to replace plastics. On the other hand, it will be a while before it ramps up to that level and I wouldn't be surprised if the components were good candidates for synthesizing. That is an encouraging idea.
"Transparent aluminum" anyone?
On the EV front. I don't worry about the EVs running on coal produced electricity. The fact that electricity can be produced other ways makes EVs a step away from fossil fuel dependency. They are a link in the chain that is (at least nearly) solved. Solving the dependency of the source is a separate problem. When "carbon free" electricity is solved, the whole problem will be solved. Without EV's solving the electricity problem still leaves the vehicles to be solved.
Personally, I don't understand why more attention isn't being given to geothermal energy. We are sitting over 230,000,000,000 cubic miles of hot lava. That should be enough energy to last us a very long time (shoot, it is enough to vaporize the entire skin of the earth and everything on it without even burping), and with minimal environmental consequences. I know that we have to drill a very deep hole to get at it, so the investment isn't cheap. The technology to harvest it isn't trivial either (but it is fairly well understood). The results of the effort will be a nearly unlimited energy source. Why isn't it getting more press?
Good point on the whole lifecycle consideration, Ann. I just did an short article for Green Scene that looks at efforts by Kraft Foods to improve sustainable all the way back to the farms that produce their raw materials.
The sustainability from raw materials through recycling is getting considered more often these days.
That whole consideration brings up the question of how EVs compare to traditional vehicles when you figure in the likelihood that the electricity is produced by burning coal.
Producing high-quality end-production metal parts with additive manufacturing for applications like aerospace and medical requires very tightly controlled processes and materials. New standards and guidelines for machines and processes, materials, and printed parts are underway from bodies such as ASTM International.
Engineers at the University of San Diego’s Jacobs School of Engineering have designed biobatteries on commercial tattoo paper, with an anode and cathode screen-printed on and modified to harvest energy from lactate in a person’s sweat.
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