In this series, Jennifer Gumpert, our VP of Business Development and Operations, walks us through material terms and concepts that are used frequently, but not always understood. This week: bio-based vs. biomaterial vs. bioplastics.
With the growing emphasis on “green” materials, you may be wondering – what exactly is the difference between bio-based, biomaterial, and bioplastic?
Let’s start with bio-based materials. Bio-based materials are materials where a portion of the material is intentionally made from substance derived from living or once-living organisms. This encompasses the more obvious materials, such as wood or leather, but also includes more complex solutions such as cellulose fibers, casein (a phosphoprotein found in milk), polylactic acid (a polymer produced by industrial fermentation processes) and grease (lubricants made from vegetable oils, including soybean oil, that can replace petroleum-based lubricants) .
Biomaterials refer to a specific application of materials – those intended for medical applications. These products may be natural or synthetic and are used in medical applications to support, enhance, or replace damaged tissue or biological function. These biomaterials can be comprised of metals, ceramics, plastic, glass and even living cells or tissue and be reengineered into molded or machined part, coatings, fibers, films, foams and fabrics.
Incredibly, many biomaterials are biodegradable or even bioabsorbable meaning they are eliminated from the body once their intended function is complete. This remarkable area of science combines medicine, biology, physics and chemistry to produce life-saving and life-enhancing products such as heart valves, stents, dissolvable dressings and even lab-grown tissue and bone!
And then there are bioplastics. Traditional plastics are the result of petroleum-based raw materials – a non-renewable energy source – and can take hundreds of years to decompose. On the other hand, bioplastics, which are made from 20% or more of renewable materials – reduce the use of fossil fuels, result in a smaller carbon footprint, and decompose more quickly. Whereas traditional plastic is derived from fossil fuels, bioplastics typically fall into to main types: PLA (polyactic acid) or PHA (polyhydroxyalkanoate).
PLA is typically made from the sugars in corn starch, cassava or sugarcane. It’s industrially compostable and food safe (not all PLAs are edible)! When processed, the starches breakdown in such a way as to produce long chains of carbon molecules similar to that of the carbon chains seen in fossil-fuel derived plastics. When citric acids are introduced, the result is a long-chain polymer – known as the building block of plastic. PLA can look and behave like polyethylene (used in plastic films, packing and bottles), polystyrene (Styrofoam and plastic cutlery) or polypropylene (used in packaging, auto parts and textiles).
PHA on the other hand, is made by microorganisms that produce plastic from organic materials. These microbes are deprived of nutrients like nitrogen, oxygen and phosphorus, but given high levels of carbon. They produce PHA are carbon reserves which can then be harvested. Because PHA is biodegradable in natural environments, such as soil, marine environment and will not harm living tissue, PHA is often used in biomaterials such as sutures, slings, bone plates and skin substitutes.
However it’s important to note that bioplastics are not necessarily the perfect solution. While these bioplastics are essentially net-neutral when it comes to CO2 production, one still must balance other factors: such as fertilizers, pesticides, the use of arable land, and the infrastructure required to recycle these materials which may contaminate standard recycling streams if not properly separated.
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