Bioplastics are enigmatic in different industries because they possess characteristics that are so similar to regular plastics, but they aren’t. The feedstock used to create bioplastic cannot be any more different from the conventional plastic feedstock. Learn more about these in today’s blog.
Bioplastics are subjected to a wide variety of tests to ensure their durability and suitability when used in any industry. The water solubility test of bioplastic is one of these tests. Bioplastics should be able to absorb or repel water depending on their use.
Some bioplastics are designed to have bigger pores as they are manufactured into medical devices that release drugs into the skin. Bioplastics that are used, for example, in package and restaurant disposable utensils, of course, will need to have the smallest pores, so virtually no water escapes or is absorbed.
Is Bioplastic Soluble in Water?
Does bioplastic dissolve in water?
As explained earlier, bioplastics are meant to repel water when they need to, or they can be made into porous materials, too. The moisture and absorption test is a method of measuring just how absorbent a polymer or plastic is.
This may sound not very clear, of course, because the usual polymers that we encounter are certainly waterproof, and they don’t absorb water readily. It is a different matter for different manufacturers of bioplastics who have to adjust the formulations and blends of their PLA and other bioplastics to ensure that the specs of bioplastics comply with the end requirements product.
To answer if bioplastics dissolve in water, the answer is no; they don’t. If you were holding a PLA medical device meant to absorb body fluids like blood or pus, then the bioplastic will absorb water to a certain point like a sponge and then stop, as all materials would. There would be a limit as to how much water PLA can hold.
But would it readily dissolve once it reaches this limit? Certainly not. If a piece of bioplastic were thrown out to sea, it would stay there for many years without showing signs of any deep degradation. If you are wondering why this is happening, then it is really simple.
Despite having been sources from organic carbohydrates, bioplastics won’t disintegrate in water like other organic matter. The reason for this is quite simple – bioplastics are fermented and then combined with chemicals to turn into the chemical structure of polymers and monomers. Additionally, most bioplastics require a lot of consistent heat for weeks and months to start breaking down properly. That’s something that you can’t get in any body of water, or even in one drum of water. Submerging bioplastics in a vat of water won’t do anything to the organic monomers. The bioplastic may absorb some of the water, but the bioplastic will remain largely stable (physically and chemically), and no breakdown will occur.
Bioplastics also need oxygen and the presence of good bacteria to disintegrate properly. All these requirements can only be obtained in a specialized facility that provides all needed to ensure the continuous breakdown of the bioplastic chemical bonds.
During the transformation, the bioplastic’s chemical nature emerges, and it is no longer comparable to the original raw material used to produce it.
So while a detergent bottle made of corn might sound like the neatest and most organic thing in the world, it’s not. It’s made of organic matter, surely, but it has the durability of conventional plastic. One of the main reasons why bioplastics are manufactured to have zero pores is that absorbed water can weaken bioplastics’ constitution.
The weakening of the bioplastic is bad news for manufacturers who need to keep their products bone dry during shipping and subsequent storage. Imagine food packages that eventually absorb water so much that their content begins to spoil even before the customers can get to them.
Why Is Starch Used in Bioplastics?
The production of bioplastic from starch has been done for many decades now. There are no stopping manufacturers from exploiting one of nature’s biggest secrets – that you can ferment sugars or carbohydrates to eventually produce durable monomers that can serve as substitutes for petroleum-based polymers and monomers.
Companies that produce bioplastics are more likely to use starch because of the raw material’s low cost.
The stable cost of cornstarch ensures that manufacturers can remain profitable, whatever changes there are in the market. Cornstarch is categorized as organic biomass, compared to the distillates that are derived from petroleum products.
Like conventional plastic, monomers produced from organic biomass or starch can be subjected to manufacturing processes like injection molding and extrusion. These biobased plastics are resistant to heat and exhibit the same characteristics are conventional plastics in terms of durability, porosity, resistance to heat, water resistance, etc.
In short, they are the more environmentally-friendlier versions of conventional plastics that have less of a carbon footprint and are far easier to break down. Some people ask – why not just burn conventional plastics? Incineration of plastics is an option, but at what cost?
The cost of burning plastics is too high compared to just leaving them as solid waste. However, as plastic degrades physically over time due to age and exposure to the sun, the chemical runoff can poison the land and the freshwater table underneath. Plastic produces so many problems that it is no small wonder that governments want to regulate its production.
Does Bioplastic Decompose?
How do bioplastics decompose?
Bioplastics can decompose when exposed to consistent heat, oxygen, and when the bioplastic reservoir is fed with the bacteria that consume the monomers. Remove any of these factors, and the process of breaking down bioplastics can range from a few years to several hundred years, like regular plastic.
Can You Eat Bioplastic?
While PLA filament in its purest form can be eaten, we don’t recommend it. A bioplastic that has been molded into products and figurines will likely contain metal oxides and artificial dyes that are poisonous to both humans and animals. In short, there is no benefit in eating bioplastic, so don’t attempt it.