Biobased plastics provide a solution to a problem that we are all familiar with. Current plastics are mostly derived from petroleum-based feedstock and thus inevitably introduce carbon to the environment that was previously stored in underground fossil reservoirs. In contrast, biobased plastics are made from feedstock derived from biological sources and thus only introduce carbon content that was already present in the environment. In essence, they provide a closed loop for carbon. Additional benefits can be attributed to the possibility of making biobased degradable polymers that don’t pollute the environment further because they simply compost into useable components for organisms. In the first part of this series, we will give a generalized introduction to biobased plastics, with following parts touching on opportunities for processing.
The biobased market currently has a production capacity of 2.1 Mton and is projected to rise to 2.8 Mton in 2025. The current polymer market is responsible for the production of 357 Mton of plastics and thus the biobased plastics provide a production share of 0,6% of global capacity1 (Figure 1). Packaging currently provides the largest application bioplastics by contributing to approximately 47% of its use2.
Figure 1: Biobased polymer market with degradable and non-degradable polymers in 2020
note: Adapted from: European Bioplastics – Bioplastics Market Data (2020)2
The biobased plastic market suffers from a convoluted problem that appears to be self-reinforcing. The market is limited in scope and thus the global production of biobased plastics is of a small scale compared to the petroleum-based market. In this way it suffers from problems originating in economy of scale. The demand for biobased plastics is low and thus the global production is low. In turn, this means that the demand for biobased plastics is low DUE to the low global production. This is offset by a steady increase in market size. Another problem presents itself in the reputation bioplastics have with regard to processing. In short: difficult. However, this is not necessarily the case for all biobased plastics or even for plastics that are considered “difficult” to process. Bio-PET, for example, is also a biobased plastic due to the origin of the fact that its feedstock is derived from biomass. Bio-PET shows the exact same composition as petroleum-based PET and thus is no different with regards to processing. Other biobased polymers such as PLA, PHA and cellulose/starch polymers are potential candidates for the replacement of petroleum-based packaging and thus certain techniques, such as plastic extrusion, blow moulding and thermoforming are applicable processing steps. The reputation for PLA and PHA in this regard is generally considered to be subpar due to, amongst other things, thermal instability. However, there are plenty solutions available to counteract this during processing and, in some cases, thermal instability is an opportunity itself. In the subsequent parts these solutions will be illustrated for the biobased degradable plastics.
Tiseo, I. Annual production of plastics worldwide from 1950 to 2020. Statista https://www.statista.com/statistics/282732/global-production-of-plastics-since-1950/ (2021).
European Bioplastics. Market update 2020: Bioplastics continue to become mainstream as the global bioplastics market is set to grow by 36 percent over the next 5 years. https://www.european-bioplastics.org/market-update-2020-bioplastics-continue-to-become-mainstream-as-the-global-bioplastics-market-is-set-to-grow-by-36-percent-over-the-next-5-years/ (2020).