Bioplastics and Biopolymers

It’s not easy to answer the question of What are Bioplastics? The definition of “bioplastics” is not definitive or universal because not everyone agrees on the definition.

There are two attributes related to the word bioplastics. We could say that bioplastics could be divided into two pillars:

• bio-based and bio-sourced; and / or
• biodegradable and compostable

Popular definitions evolve over time and legal definitions are usually politically and economically loaded because of the commercial consequences they will have.

Etymology reminds us that sometimes we use words in a wrong sense or that popular interpretations or conventional use of words may not be …etymologically correct.

Bio-based, Bio-sourced and Plant-based

You need carbon to make plastics and historically we’ve been using carbon originating from crude oil. These are commonly referred to as “fossil-based plastics”.

However, it’s possible to use non-fossil based feedstock to make plastic. They’re called bio-based, bio-sourced or biomass feedstock. You can find a complete list of bio-based feedstock to produce bioplastics on the following page Bioplastics Feedstock.

The Oxford Dictionary defines “bioplastics” as a type of biodegradable plastic derived from biological substances rather than petroleum. This is what we call “bio-based”. The “bio” refers to biological.

However, crude oil and fossil fuel are also from “biological” origin. They’re the residue of biological entities such as animals and plants that have been fossilised over millions of years.

Some people may claim that “Bio” may not only refer to the biological origin but also to the biological friendliness. How do you define biological friendliness? Some people may say that it has to respect the fauna, flora and ecosystems.

Some people like to look at the renewability of the feedstock. How long does it take to renew a plant and a crop versus crude oil? Plants and crops can be grown in a short period of time compared to fossil fuel that takes millions of years to fossilise.

A small quantity of fossil-based plastics may be added to bio-based plastics to make it biodegradable or compostable. Some purists claim bio-based plastics should be made with 100 % bio-based feedstock while some suppliers of fossil-based (compostable) plastics claim 60 % bio-based feedstock is enough to be branded “bio-based”.

Within the bio-based feedstock, you need to differentiate between (1) vegan and (2) animal origin feedstock

(1) Vegan or plant-based refers to plants, crops and non-animal feedstock; we could say that it refers to “flora”;

(2) Animal content refers to animal fats, milk waste, chitin, slaughterhouses leftovers, cooking oils, animal fats, etc. We could say that it refers to “fauna”.

There may be sensitivities regarding the use of animal content in the manufacture of plastics. Imagine how a vegetarian would feel if you told him that his / her packaging was made with animal fats; or tell a muslim that his packaging was made with carbon from porcine origin.

The industry came up with the term “renewable” feedstock to include vegan plastic, animal-based content and recycled plastics.

Topics such as GMO, feedstock generation and intensive agriculture may be important when it comes to selecting “responsible” bio-based feedstock.

The most important feedstock generations are the “1st and 2nd”. We refer to the first generation when crops are “explicitly” grown to produce plastics, chemicals or fuels. We refer to 2nd generation when biomass waste and byproducts are used to produce plastics, chemicals or fuels.

1st generation feedstock are more efficient in terms of production output but may be more sensitive regarding the fuel / plastic vs. food debate.

Plastics vs Polymers

When we use the word plastics, we mean polymers. When we use the word polymer, we mean a sophisticated construction made of monomers. Metaphorically speaking, I could say that monomer are two-dimensional while polymers are three-dimensional structures.

Some people may say that plastics is not a substance or material but an attribute (plasticity).

Plasticity is the name used to describe the property, feature or attribute of all materials which can deform irreversibly without breaking. The word “plastic” surgery is used when we make face lifts.

This attribute refers to the production process and not the use. We can mould a polymer to give it a specific form (ex: a plate). The polymer survived the moulding and production process because of its plasticity.

What we refer to as plastics are usually organic polymers of high molecular mass mixed with other substances (additives).

Biodegradation and Compostability

Bioplastics is the sense of “biodegradable” or “compostable” plastics refers to the ability of the polymer to biodegrade or decompose back into its natural elements under the action of bacteria or enzymes (bio-degradable). You can find an interesting article here The Degradation of Plastics and Polymer

There’s a difference between biodegradation and composting. Biodegradation refers to a process that starts without human intervention and where the residue is not necessarily compost. Composting refers to a process started by human intervention and where the residue may be defined as compost.

You can find an interesting article here What is the Difference Between Biodegradable, Compostable and OXO Biodegradable?

Applications of Bioplastics

There’s a wide range of bioplastics applications. You can find an extensive list here bioplastics applications

End of life, Lifecycle and Waste Management

An object reaches it’s end-of-life and is usually discarded when it has accomplished its initial purpose.

The billion dollar question is “what shall we do with the plastic and bioplastic waste? “

Bioplastics in the sense of “biodegradable” and “compostable” plastics refers to potential end-of-life options, namely that they will be processed through bacterial digestion.

Bioplastics in the sense of “biobased” plastics refers to the sourcing of the carbon and doesn’t necessarily include an end-of-life option.

The most known waste management options are reuse, recycle, biodegrade, compost, energy recovery or incineration and landfill.

The circular economy recommends to valorise waste in the sense as to use it as or transform it into a new feedstock.

Firstly, bioplastics needs to be sorted, collected, treated and processed for its second life. How do you differentiate between different types of bioplastics? Some packaging are made from several materials often referred to as laminates. How do we separate these layers? How do we sort them? How do we remove the labels, sleeves, glue, colorants and additives? This falls under waste management.

In the following graph, we see the decision to include fossil-based plastics that are biodegradable under the term bioplastics. This is not a universal definition, this is a political or subjective definition. This may change over time or may not be agreed upon by everyone.

Bioplastics History

• 1862 – Alexander Parkes creates the first man-made polymer from an organic material derived from cellulose. It was a bio-based plastic and was called Parkesine.
• 1926 – French scientist Maurice Lemoigne developed polyhydroxybutyrate (PHB) from bacterium Bacillus megaterium. The first bioplastics made from bacteria.
• 1907 – Leo Baekeland invents Bakelite and it will be described as a National Historic Chemical Landmark due to its importance. Bakelite was a synthetic plastic that was revolutionary for its electrical nonconductivity and heat-resistant properties in electrical insulators, radio and telephone casings and such diverse products as kitchenware, jewelry, pipe stems, children’s toys, and firearms.
• 1990 – Imperial Chemical Industries (UK) developed a bioplastic that was biodegradable. It was called named Biopol.
• 1990 – Commercial demand for bioplastics starts to develop, driven by oil price volatility and environmental concerns.

Environment

It’s difficult to measure the exact environmental impact of Bioplastics.

A popular belief is that bio-based plastics have a lower carbon footprint than fossil-based plastics. You need to consider many items to define the accurate carbon footprint including feedstock generation, transportation and processing, supply and value chain, distribution, consumption and end-of life processing.

Types of Bioplastics

• BDO 1.4 butanediol 
• Bio-based PET
• But-1,3-diene
• Bio-Epoxy
• FURFURAL
• FDCA
• LIGNIN
• PEF Polyethylene Furanoate
• PLA polylactic acid
• PHA Polyhydroxyalkanoate
• PBT polybutylene terephtalate
• PBS polybutylene succinate
• PDO 1.3 propanediol
• PU Bio-based Polyurethane
• PTT polytrimethylene terephthalate
• PA10 PA11 : bio-polyamides from oil plants (Castor)
• Bio-Polyamides

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