Does Nature’s own Bioplastic already exist?
Did you know that the country of the Philippines alone produced more plastic waste in the year 2019 (366,300 tons) than the mass of the Empire State Building (365,300 tons)!?
Studies estimate there are now 15–51 trillion pieces of plastic in the world’s oceans, as well as countless more rotting away in our landfills or releasing toxins in our incinerators. 108 million metric tons of CO2 emission per year are produced and emitted due to our single-use plastic problem.
BUT
What if I told you there’s already a potential solution to this problem? A waterproof, natural, and biodegradable material made by the world’s most skilled engineer- Nature.
Problem: Plastic Waste
Solution: Allotropes and Feathers
That sounds like a bunch of random buzzwords, right? Let me show you how they’re all interconnected to potentially replace the use of plastics without having to let go of its benefits (durability, flexibility, waterproof nature)
Allotropes.
Different versions of the same element or molecule
Carbon is the universal building block for life as we know it. Its ability to form complex, stable molecules with itself and other elements, mainly hydrogen, oxygen, and nitrogen, is unique. [1] Carbon’s importance comes primarily from the enormous variety of structures it can form due to its unusual four valence electrons [2]. The great variety of structures formed from carbon, from chains and rings to three-dimensional macromolecules, are primarily stable within a broad temperature range. The versatility of carbon is further enhanced by its ability to form double and triple bonds, which alters the chemistry and geometry of the molecule as well as its temperature-dependent fluidity.
Carbon is an extremely light and versatile material that, depending on the local bonding of the constituting carbon atoms, has hugely varying properties. Allotrope refers to one or more forms of a chemical element that occur in the same physical state. The different forms arise from the different ways atoms may be bonded together.
Elements transform from one allotrope to another in response to changes in temperature, pressure, and even exposure to light. Allotropes often form spontaneously. Usually, the first solid allotrope to crystallize from a solution or melt is the least stable one. [3] [4] [5]
This versatility that can be seen in Carbon helps it form allotropes like Diamonds (tetrahedral lattice), Buckminsterfullerene, Amorphous Carbon (non-crystalline), Graphite (sheets of hexagonal lattices), Graphene (two-dimensional honeycomb lattice), Carbon nanotubes, etc.
Allotropism can also be seen in
- Phosphorous (White phosphorus, Red phosphorus, Violet phosphorus, Scarlet phosphorus, Black phosphorus, Diphosphorus)
- Oxygen (Dioxygen, Ozone, Tetraoxygen, Octaoxygen )
- Arsenic (Yellow, Gray, Black)
- Tin (α-tin or gray tin, β-tin or white tin, γ-tin, σ-Sn)
- Iron Allotropes (ferrite, austenine, hexaferrum) [6]
Feathers.
They seem very…normal, don’t they? Here’s a little flashback: When I was around five, I refused to believe that feathers, especially peacock ones, were actually from birds. Because
a) How could something that blue be natural? (Since we don’t see much of the color blue in nature. Here’s a really cool explanation about why)
b) I used to think feathers were made in factories because their stem (called a calamus or quill) looked like plastic. How could something that looked so much like the toxic plastics we’ve been trying to avoid be grown from birds?
Looks like five-year-old Chandhana was onto something.
The Calamus attaches feathers to the bird body, mainly made of Keratin and the remains feather pulp. This part of the feathers looks like a straw- it’s waxy and hollow, with the added advantage of being biodegradable.
There’s another thing that’s interesting about the formation of feathers- Keratin. It is similar to Carbon and its allotropes, even though it isn’t an element.
Keratin is composed of 18 amino acids. The most abundant amino acids are cysteine, serine, glutamic acid, glycine, threonine, arginine, valine, leucine, and isoleucine. [7]
These amino acids bond differently to form versions of Keratin with varying characteristics.
- Hair: Properties -> High tensile strength, Thin, Degradable
- Nails: Properties -> Low tensile strength, Hard, Waterproof, Degradable
- Feathers (Calamus): Properties -> High tensile strength, Hollow, Waxy, Degradable
Questions I’m working towards answering:
- What if we can synthetically recreate the calamus of bird feathers to serve as a substitute for plastic products?
- What causes Keratin’s physical and structural differences, and how can we utilize their versatile property in biomedical innovation?
Sources and Citations
[1] Dirk, SM., Irwin, L.N. 5. Building Blocks of Life. In: Life in the Universe. Advances in Astrobiology and Biogeophysics, vol 3. Springer, Berlin, Heidelberg. https://doi.org/10.1007/10825622_5
[2]https://med.libretexts.org/Bookshelves/Anatomy_and_Physiology/Book%3A_Anatomy_and_Physiology_(Boundless)/2%3A_The_Chemical_Building_Blocks_of_Life
[3] https://sciencenotes.org/what-is-an-allotrope-definition-and-examples-in-chemistry/
[4] IUPAC (1997). “Allotrope”. Compendium of Chemical Terminology (2nd ed.) (the “Gold Book”). doi:10.1351/goldbook.A00243
[5] Threlfall, T. (2003). “Structural and thermodynamic explanations of Ostwald’s Rule”. Organic Process Research & Development. 7 (6): 1017–1027. doi:10.1021/op030026l
[6] Jensen, W. B. (2006). “The Origin of the Term Allotrope”. J. Chem. Educ. 83 (6): 838–39. doi:10.1021/ed083p838
