Are Bioplastics Finally Ready for Take Off?

Bioplastics, especially biodegradable or, to be more precise, compostable bioplastics, have been in use for the past 20 to 25 years. Initial expectations were high — they became the "great white hope" of the plastics industry — but price, performance, availability, and applicability relegated these materials to specific niche markets, such as flexible packaging or agriculture.

The lack of knowledge also raised nomenclature problems. How biodegradable plastics degrade, especially under what conditions, caused confusion among many companies, where it was thought that these plastics would disintegrate spontaneously after a certain period of use.

In the end, it was not clear if there was less interest in biodegradable plastics than initially thought or if total capacity stayed low because existing production satisfied market needs.

Global bioplastics production breaks 2-million-tonne barrier

In the last decade, the production of biodegradable plastics showed low annual growth rates, rarely exceeding 1.5 million tonnes per year. But in 2022, global bioplastics production — biodegradable and non-fossil-based plastics, bio-PE, and bio-PET, for example — surpassed the barrier of 2 million tonnes, with biodegradable plastics accounting for 1.2 million tonnes, according to a report on the European bioplastics market.

This change in the production of biodegradable polymers may be related to a new mentality toward the circular economy and the EU plastics strategy, which was presented by the European Union in 2018 and emphasized the approach of re-introducing more recycled plastics and non-fossil-based plastics. These policies are aligned with the positive public perception of bioplastics.

The report estimates that global production will jump to 5 million tonnes by 2025, including 2.5 million tonnes of biodegradable plastics that will grow to 3.5 million tonnes by 2027. These figures are consistent with the new bioplastics facilities (mainly PLA) that big players such as NatureWorks, Futerro, and LG-Chem are building. PLA, therefore, will become the main driver of the biodegradable plastics industry. New developments in PLA for higher temperature applications are also expected.

PHA-based bioplastics an alternative to polypropylene

The production of PHA-based bioplastics is also expected to increase. PHA biodegradability in soil and a relatively high service temperature make these polymers more suitable to replace commodities such as polypropylene. PHA has many possibilities in the field of copolymers because they provide a wide range of properties and improve the flexibility of these materials. Unlike PLA, PHA bioplastics are “open-code” polymers, and a significant number of startups are basing their business on the development of new polymers and compounds in this family of plastics. (PHA can be obtained in many ways using different bacteria and carbon sources, hence the open-code analogy. PLA needs lactide, which is only provided by a handful of suppliers.)

Demand for the most used biodegradable plastics, such as starch-based blends, has remained the same despite overall forecasted growth, given that their thermal and mechanical properties have relegated these materials to agriculture and bag production. However, the position of these plastics is well-established and new companies are entering the market because of easy access to new sources of starch.

The bioplastics market traditionally oriented toward extrusion has a great deal of potential, especially with molded parts for consumer goods and, in the mid-term, with household appliances, textiles, and automotive applications. Bioplastic compounding will play an important role in modifying the selected polymers and improving their mechanical and thermal properties through the addition of additives, fillers, or natural fibers, the ideal reinforcing agents for these kinds of materials and other polymers to develop tailor-made blends for specific applications. The automotive industry is currently more likely to use “natural” polymers such as bio-PA.

Regulations will dictate uptake of biodegradable plastics

As occurred 40 to 50 years ago, when many recyclers become compounders and started developing special compounds for their customers and plastics started gaining ground on conventional materials such as wood, glass, metal, and paper, something similar could happen now with bioplastics. A new breed of compounders who modify PLA, PHA, and other bioplastics could drive a shift away from conventional polymers in some applications.

However, biodegradable plastic compounds must deal with the issue of compostability. Depending on what is added to a bioplastic, its compostability can be affected, along with its field of applications. Compostability standards, therefore, should be a priority when designing a new compound, and assessment by certified labs is highly advisable. End users also must be taught that compostability conditions cannot be achieved when something like a vacuum cleaner is made with PLA or PHA parts.

Besides compounders, masterbatch producers can also penetrate a potential market by working with biodegradable polymers as carrier resins and using natural fillers and natural additives.

Because conventional polymers are ubiquitous, market penetration by biodegradable polymers will depend on new regional policies and whether or not the scarcity of resources affects the availability of traditional polymers, especially in Europe, a densely populated region with low resource availability.

Biodegradable plastics have always raised ethical issues, given that different types of food products — starch, sugar, and so forth — are used in their production. The fact that this can be seen as a negative has led to more research in polymers based on agro-forestry waste, new polysaccharides, and new building blocks for the polymerization of existing polymers such as PLA, PHA, PBAT, and PBS. These natural-based building blocks can also be used in new polymerization methods for reactive extrusion and the development of polymers such as PLA, PCL, PBS, and PGA.

Global and regional policies, public perception, the support of the big players with new materials, and the geo-strategic situation are creating a scenario where the position of bioplastics can be strengthened. Economies of scale, in turn, will lower costs, leading to the final step of definitive implementation of biodegradable plastics in our economy.