If it could be shaped, would chitin from giant insects make decent body armor?

Question

I found a previous question on using chitin from giant insects to make weapons and armor, but the answer left out something I had considered for the medieval fantasy setting I'm developing. The answer suggested that the chitin pieces would not likely fit the shape of a humanoid race and would need to be fastened together into something akin to lamellar armor.

Weapons and armor from chitin

What I had wanted to explore was the possibility of being able to reshape pieces of chitin from these giant insects, allowing for a properly fitted set of armor to be made (as well as more styles than just looking like the creature the materials were harvested from.)

Maybe something of an alchemical process that makes it pliable for a short time, allowing it to be shaped. This also could allow for several pieces to be shaped and glued together to make a thicker piece of armor. I imagine the lower density might make it useful for some light armor. Probably not as good as a set of steel platemail.

My question is, if chitin was upscaled to a form that could be shaped into usable body armor, would it be useful in combat? How would it stack up against other forms of armor from the medieval period? At the very least, would it be useful as an alternative armor for people in regions where there is limited access to metal? Or would they be better off with other materials like hide and wood?

Clarification: I'm aware that giant insects wouldn't normally be able to exist. This is a fantasy setting, so I'm not too worried about that. I'm just interested in the mechanical properties of chitin itself and its usefulness as armor.

Answer 1

Hard answer: Chitin is very heavy.

The reason we don't encounter giant insects in the real world, is that exoskeletons are too heavy. The cube-square law says that, even though a small creature can support an exoskeleton. . . .

. . . a creature 5 times longer has a 125 times heavier shell, but is only 25 times stronger. This is why we only get big arthropods in the sea, where the water does some of the lifting for them.

The earliest forms of complex life were arthropods and molluscs. Both have heavy shells. This is the main reason vertebrates did so much better on land.

Edit: As pointed out, another limitation on giant insects is how they don't use lungs and are unable to pump oxygen deep into the body.

In order to make your chitin armor realistic you must first solve the problem of realistic giant insects.

Failing that I suggest woolen armor.

This is called a gambeson. It is a big uncomfortable woolen blanket that is pretty resistant to slashing blows ((especially from jagged weapons) but not so much piercing. Do you think you could cut through your bed duvet in one swing? Thought not.

Historically gambesons were worn under metal armor but also on their own since metal was expensive.

Maybe you could make a helmet out of several large crabs or insects stuck together? It would be pretty heavy compared to its protective value, but it's only a helmet and not a full body cover.

Soft answer: Sure

If I were doing this, I would say the technique is to grind up insect/snail/crabshells and with some secret ingredients to make a gluey paste that is then soaked onto fabric. It forms a plasticky but breathable layer that is much less clammy than a gambeson and is better protection against piercing.

Answer 2

from what i get from google, chitin is a good material for composite, i dont know chemistry or how to create composite armor but maybe this help?

warning, as i mention, i dont know anything regarding chemistry, and i may end up give link or cite a misleading information. so put a grain of salt in what i put here.

from:https://en.wikipedia.org/wiki/Chitin

Chemistry, physical properties and biological function

The structure of chitin was determined by Albert Hofmann in 1929.[3]

Chitin is a modified polysaccharide that contains nitrogen; it is synthesized from units of N-acetyl-D-glucosamine (to be precise, 2-(acetylamino)-2-deoxy-D-glucose). These units form covalent β-(1→4)-linkages (like the linkages between glucose units forming cellulose). Therefore, chitin may be described as cellulose with one hydroxyl group on each monomer replaced with an acetyl amine group. This allows for increased hydrogen bonding between adjacent polymers, giving the chitin-polymer matrix increased strength.

In its pure, unmodified form, chitin is translucent, pliable, resilient, and quite tough. In most arthropods, however, it is often modified, occurring largely as a component of composite materials, such as in sclerotin, a tanned proteinaceous matrix, which forms much of the exoskeleton of insects. Combined with calcium carbonate, as in the shells of crustaceans and molluscs, chitin produces a much stronger composite. This composite material is much harder and stiffer than pure chitin, and is tougher and less brittle than pure calcium carbonate.[4] Another difference between pure and composite forms can be seen by comparing the flexible body wall of a caterpillar (mainly chitin) to the stiff, light elytron of a beetle (containing a large proportion of sclerotin).[5]

In butterfly wing scales, chitin is organized into stacks of gyroids constructed of chitin photonic crystals that produce various iridescent colors serving phenotypic signaling and communication for mating and foraging.[6] The elaborate chitin gyroid construction in butterfly wings creates a model of optical devices having potential for innovations in biomimicry.[6] Scarab beetles in the genus Cyphochilus also utilize chitin to form extremely thin scales (five to fifteen micrometres thick) that diffusely reflect white light. These scales are networks of randomly ordered filaments of chitin with diameters on the scale of hundreds of nanometres, which serve to scatter light. The multiple scattering of light is thought to play a role in the unusual whiteness of the scales.[7][8] In addition, some social wasps, such as Protopolybia chartergoides, orally secrete material containing predominantly chitin to reinforce the outer nest envelopes, composed of paper.[9]

Chitosan is produced commercially by deacetylation of chitin; chitosan is soluble in water, while chitin is not.[10]

Nanofibrils have been made using chitin and chitosan.[11]

and from this link regarding nanofibril :https://nanografi.com/blog/cellulose-nanofiber-also-known-as-cellulose-nanofibril/

Cellulose Nanofiber (CNF) which is sometimes also called as Cellulose nanofibril is encompassed by Nanocelluloses alongside with Bacterial nanocellulose (BNC), Cellulose Nanocrystal (CNC).

Despite the fact that BNC and NCC possess several unique properties, the advantage of Cellulose Nanofiber (to BNC and NCC) is that its biodegradable nature, low density, high mechanical properties, economic value and renewability. Nanofibrillated Cellulose can be produced at large industrial scales, with a variety of functional groups, and by a multitude of industrially attractive processes. Nanocellulose materials and specifically Cellulose Nanofiber generate an immense interest due to many exceptional properties and the capability of producing the materials from a multitude of sustainable resources.

Nanofibrillated Cellulose features outstanding intrinsic mechanical properties due to their high crystallinity (high specific stiffness and strength), attractive nanoscale dimensions, and high surface areas suitable for chemical functionalization. Nanofibrillated Cellulose allow for the formation of pure nanopapers or can be integrated into bioinspired nanocomposites leading to excellent multifunctional properties. Cellulose Nanofiber emerges as a renewable and sustainable feedstock for future biobased high-performance materials with environmentally friendly character.

Some characteristics of Cellulose Nanofiber:

Cellulose Nanofiber films have excellent gas barrier properties, and these have also been shown to be less affected by the extent of delamination as long as the barrier threshold has been reached.

Crystal structure of nanocellulose is consisting from packed array of needle-like crystals. These crystal structures are incredibly tough and their strength value is nearly eight times higher than stainless steel. Therefore, nanocellulose can be perfect building material for the future body armor studies. Nanocellulose is bendable, transparent, light and strong material therefore it can easily take place of the plastic or glass.

Cellulose Nanofiber is used in Absorbent Aerogels.
Cellulose Nanofiber is used in Flexible Screens.
Cellulose Nanofiber is used in Flexible Batteries.
Cellulose Nanofiber is used in Biofuel Industry. 
Cellulose Nanofiber is used in Body Armor Applications.

also from L.Dutch link in comment, you can also turn chitin into layered of scale armor outside of lamellar that you already mention, which from what i get is considered similar or more flexible dermal armor like.

Answer 3

If it could be shaped, it might make for expensive, good heavy armor. But all practical details will depend on how easy the chitin is to get, how easy it is to work with, and what other options exist.

The normal considerations (chitin is heavy, so organisms with chitin armor won't get all that big) can be hand-waved away even without resorting to a fantasy setting. Creatures that live underwater can bear greater weight, for example, and in a high-oxygen biome insect-style respiration is easier and operative over larger distances. Even if we don't get organisms on a scale that would allow for breastplate-sized chitin sections, armorers could achieve a lot with chitin scale and layering.

I don't know how useful it would be as large, solid plates in the first place. Even though it's a strong barrier, there are lots of practical issues. The biggest one I can think of offhand is that it isn't going to be repairable-- you can't melt it down and reforge it, nor weld on a patch, or anything else. You just have to replace the piece. Scale-style armor doesn't suffer that same drawback, as you can replace damaged sections.

Why bother? (alternatively, it has to be worth it)

That isn't meant to be a snarky question. It will only be useful armor if it can provide acceptable protection at a cost in effort, time, and materials that is favorable compared to other options. The alchemy-like method makes that very difficult to estimate (or, conversely, easier to assert, since it's a fantasy technique in the first place!).

As I recall from my biochemistry courses, chitin is a polysaccharide (a sugar, though certainly not a table sugar) with a particularly tight angle of rotation that makes it very resistant to solvents, like water. You're not going to be able to work chitin at all like you would work metal or leather, so the alchemy which makes it possible is whatever you imagine it to be and it works however you imagine it should work.

With that in mind, secondary effects of the giant-chitin become important. If it makes the chitin easier to work with, might it cause the armor to lose its most important properties if sprayed onto combatants during a battle? Even if it can be worked, how much time and effort does it take to make a set of chitin armor versus other options, such as chainmail, full plate, wood armor, boiled leather, or quilted armor? If the armor is so good, how are people killing the insects already covered in it, and why would a person wearing it fare better?

tl;dr: If it can be shaped to be appropriate armor for a human, it's probably going to be better than being unarmored in many situations. How useful it would be is a function of how much better it performs than the next-best option available to the people that would be making it, and how much more or less effort it requires than the next-best option. And even then, practical concerns might make plate less desirable than other choices, like scale.

This is all fantasy, so you can definitely contrive a situation in which chitin armor is a practical choice and a situation in which it is the best choice. But a situation like that will have less to do with the chitin than it has to do with all of the non-chitin options available.

Answer 4

It should work, not great but usable.

Now it is not going to be as strong as metal armor, few things are, but it will be as strong as real worn armor, like paper, lacquered wood, and hide armor. Interestingly Chitin is actually considerably stronger when dried, so proper treatment can toughen it up.

It is light with a density similiar to aluminum. Its ultimate tensile strength is pretty bad (80 MPa when dry) but no worse than acrylic sheeting(70MPa), which you could still make usable armor out of. It is lighter (by density) than bronze or iron the choice metals for armor by a wide margin. The major problem is its resistance to torsion is shit, comparable to Polyethylene, so you need a decent thickness to do any good (but any terrestrial chitinous organisms will have said thickness) but that means it is not actually any lighter than metal armor (but not likely any heavier) while preforming much worse.

But if you have a race that does not have access to metal armor it would be usable if not very durable. People made real armor out of worse materials. Unless you find a piece the prefect size you are probably looking at scale armor made from cut pieces, although finding pieces that can be cut to the perfect size for arm or leg guards could be possible.

Answer 5

Think scale, not plate.

As several others have noted, chitin is fairly light. However, it is also quite brittle. If someone hits you with a sword, it will chip and crack rather than dent. You want lots of smaller pieces to limit the extent of this cracking, which also allows more flexibility in combat as a side effect. After the battle, your smiths will just replace the damaged scales and the armor is good as new.

Alchemical apprentices might be limited to flattening chitin to make scales en masse for smiths, whereas masters could shape it into things like helms and swords that need one thick, solid piece because scale doesn't suit those applications.

Answer 6

Most answers confuse things like "it'd be heavy for a large insect" with "it would be heavy.

Chitin would be around 1370 kg/m^3

Steel, assuming I have the right type, is 7900 kg/m³, about 6x heavier.

So let's assume insects evolved differently. In ye oldy days Earth had a higher oxygen content and for example the Arthropleura existed, a chitin covered millipede with 2.5m in length. If such insects had evolved a different way to breathe, say a bird lung system (birds also have ridgid chests) they would have been able to get pretty darn big again.

The limiting factor would be energy consumption. It would be possible for a human to live in a plate armor in the right climate despite the weight, but getting the daily food into you while wearing that won't be pleasant (assuming every human wears one all the time). So it should be possible for insects to get big too if the food is available, especially since an external skeleton has some solid advantages in power generation. It's why a Crab can pinch a lot harder than a human. Survival of the fittest, not the strongest! And a big chitin covered insect would just need so much more food to keep going than a lighter internal skeleton animal

So we get to the actual armor part now.

The Moh's hardness of Chitin is 7 to 7,5. That of steel is 4 to 4,5. This isn't a great way to judge the strength though as it's just a qualitative measure from 1 to 10 not an actual "this can handle more total force". Moh's isn't good for comparing industrial use.

I can find various hardness mentioned, like 24kg/mm-2 for chitin (up to 33kg/mm-2, such as in this article: https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=7cb6ffd0c569ccf66d8e316c147aef446ef3cbc3) but not anything that can easily be comparable to how steel is rated (Brinell, Vickers etc).

So going by the Moh's hardness, Chitin is pretty darn good as a plate armor. Lighter and yet more resistant to damage, at least scratch damage. Frankly if Chitin also crumbles when for example a mace hits it it's even better. Blunt force trauma is the trump card to all armor as you can still break the bones of someone inside plate armor by hammering it, not to mention that denting it is not a fun experience for the wearer. If chitin cracks and crumbles it will absorb a lot more force and protect the wearer from the blow, if only once.

Chitin armor would be a good option. Light and likely be pretty good. The only problem I'd see is brittleness making it fall apart a lot faster than regular armors in extended battles.

Answer 7

From https://en.uesp.net/wiki/Morrowind:Chitin

Chitin is a type of light plate armor which is constructed by laminating several layers of insect shell glued with organic resins. The design is superior to Western leather armor as it is lighter and more comfortable. It is easily found throughout Vvardenfell, but is most commonly favored by Ashlander tribes. The book Ice and Chiton tells a story of its benefits.

Chitin weapons are similarly created from the laminated shells of creatures to produce strong but flexible weapons, typically serrated to create a more damaging edge.

Chitin is used elsewhere in the Elder Scrolls series, might be worth looking at how it works there.

Answer 8

In a fantasy setting, I find nothing in the concept of using giant insect chitin as armor, jarring me out of my of suspension of disbelief.

Accepting the premise that giant insects exist. And if the chitin is like our own, It is composed of organic microfibrils. Many different compositions, from insect shells, aquatic crustaceans and even fungus. I see it could be used as an analog for plastics or resins. Bones and seashells have been used as armor in places where metals are not available. I see no reason why it could not be as good as boiled leather armor, even for the most pessimistic critic.

Even where metals are available, perhaps wearing this armor is preferable. It could certainly be much lighter, not as hot, or restrictive. Not to mention, that perhaps the culture that uses it may exist in an environment that is favorable to non metallic armor. Swamp? Marine? perpetual rain? We really don't know what the true properties of a giant insects caprice would be. A Coconut crab or large Maine lobster is about the extent of our real world experience.

The construction of the armor is trivial. Alchemists in any self respecting fantasy setting can find a way to render it moldable into to any style or form one could wish. Even outside of this, sane or kozane could be shaped from the plates like traditional Samurai armor.

https://en.wikipedia.org/wiki/Japanese_armour

Leather and or iron scales were used to construct samurai armour, with leather and eventually silk lace used to connect the individual scales (kozane) from which these cuirasses were now being made. The artistic decoration of ō-yoroi reached its peak around the time of the Genpei War at the end of the Heian period.

Ultimately, it is up to how the creator of the world to say how useful it is. Is it as tough as full steel plate armor? Probably not, but is almost certainly not as heavy. Not as susceptible to corrosion. Also there is something to be said of armor that is resilient and somewhat forgiving rather that unyielding and hard. and maybe looks badass, which is worth twice the cool points.

PS: I rembert this critter from my D&D days. One of the bastards ate my donkey! (RIP Roger.): Ankheg

Answer 9

Chitin is soluble in acids, bases, and can be made pliable in hot water.

As long as you can get large enough pieces of chitin, then dunk them in a barrel of potash, apple vinegar or hot water, you should be able to make them pliable enough to be pressed into shape in a mold. This can work pretty well if your starting point is a big, relatively flat plate of chitin.

What if all you have are smaller, weirdly shaped pieces? The best option is to boil the chitin completely in vinegar, or for a cooler version, in Formic Acid already produced by giant ants :) This would form something similar to chitosan glue, which then could be poured into molds, or into flat sheets and laminated.

Also consider this: if you have giant insects, you would likely have giant insect SILK, which can be combined with chitin glue into a laminate that has better tensile strength than kevlar and better compressive strength than medieval steel.

And now for a bonus: both chitin and silk have tremendous flexible strength. You could make awesome laminate bows and crossbows with it !