What are Drop-In Bioplastics?

What are drop-in bioplastics and smart drop-ins? What are their advantages and differences? What are the polemics?

The dictionary defines a drop-in as “one who casually  drops  in, as  to  visit  or  obtain an appointment.”

Types of Bioplastics Drop-Ins

The popular term is “drop-in bioplastics” while the technical term is “bio-based drop-in chemicals”. The “bio-based” will usually be dropped out of the technical term, so we’ll have “drop-in bioplastics” and “drop-in chemicals”.

The production process to make (bio-based) chemicals are called pathways. There are two types of drop-in chemicals:

  • drop-in bioplastics or (bio-based) drop-in chemicals
  • smart drop-in bioplastics or smart (bio-based) drop-in chemicals

A drop-in bioplastics is a kind of “bio-similar” copy of the petrochemical plastics but it’s made from biomass instead of fossil-oil. The drop-in bioplastics uses the same pathway as the petrochemical plastics. The advantage is that the drop-in bioplastics can be used almost immediately without any major technology or equipment investments and the testing period is also limited. To put it simple: the user can replace the fossil-based chemicals by drop-in chemicals while using the same machinery and equipments.

Examples of drop-ins bioplastics include bio-Ethylene, bio-polyethylene (bio-PE),  bio-propylene (bio-PP), bio-polyethylene terephthalate (bio-PET)

Smart drop-ins are identical to drop-ins with the important difference that they’re better than their fossil-based counterparts. The production process or pathway to produce smart drop-in chemicals are usually more efficient and smarter than the “regular” pathway used by the petrochemical and drop-in bioplastics. Drop-in chemicals have to fulfil at least two of the following criteria to be called smart drop-ins:

  • the pathway uses less biomaterials (better use of  raw materials);
  • the pathway requires less energy (a higher energy-efficiency);
  • the pathways are faster (time-to-product is better);
  • the pathways are less complex (less steppingstones needed to reach the final results);
  • the pathways are less toxic (less toxic materials are used or created as by-products of the production process).

Examples of smart drop-ins include Acetic acid, acrylic acid, adipic acid, aniline, butadiene, 1,4-butanediol, isoprene, PA (6,6), polybutylene succinate, 1,3-propanediol, succinic acid.

Difference between Drop-ins Bioplastics and Petrochemical Plastics

There are 2 important differences between drop-in bioplastics and their fossil-based or petrochemical counterparts: the price and the environmental footprint.

The drop-in bioplastics are more expensive than the original fossil based plastics. There are several reasons, including:

  • Economy of scale: the fossil-based plastics industry have a much larger production and processing capacity and can thus produce plastics at a much lower price.
  • R&D: the fossil-based plastics industry is much older than the bioplastics industry and more has been invested in the R&D of fossil-based plastics than in (drop-ins) bioplastics.
  • Price of raw material can be influenced by state aid, international organisations and transport: the state aid towards the oil industry is different than towards agriculture. The price of oil is impacted by organisations such as OPEC while the price of biomass is impacted by waste and agricultural policies and subsidies. Other mechanisms that may impact the price include production quotas and minimum prices. Oil can be transported through pipelines while biomass is usually transported in trucks.

There are no theoretical differences between drop-ins and petrochemicals when looking at the end-of life options. However, there’s a difference when looking at the greenhouse gas emissions. When you pump out oil, you bring potential new CO2 in the atmosphere. This potential CO2 becomes a reality when you incinerate the plastics. In the case of bioplastics (drop-ins) the CO2 that is released during incineration had been been captured by the plant during its growth. No additional CO2 is brought into the atmosphere with drop-in bioplastics.

Open questions and Polemics

  • Should there be policies to support drop-in bioplastics by making them more competitive than their petrochemical counterparts?
  • Are there still policies making petrochemicals more competitive? If yes, are they still justified?
  • Should policymakers make a difference between drop-ins and smart drop-ins?
  • Should policies set a hierarchy between CO2 reduction, efficient use of resources, end-of-life options, efficient use of land, innovation, competitiveness and employment? Which one is more important according to you? Why?


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