The growing use and waste of plastic is one of the biggest environmental problems the world is currently experiencing. Despite an anticipated increase in the deployment of recycling systems, humans generated 460 million tons of plastic in 2019, and usage will continue to climb.

The developing carbon capture and utilization (CCU) sector suggests a solution for both problems by exploiting rising carbon dioxide (CO₂) emissions as the feedstock to produce lower-carbon, biodegradable polymers. The prospects and difficulties of establishing this suggested circular carbon economy are examined in the new IDTechEx paper "Carbon Dioxide (CO₂) Utilization 2022-2042: Technologies, Market Forecasts, and Players."

Turning waste into usable polymers

CO₂ can be turned into polymers in at least three primary ways: electrochemistry, biological conversion and thermocatalysis. This is the most developed CO₂ use technology. The gas can be used directly to make CO₂-based polymers, most notably biodegradable linear-chain polycarbonates (LPCs), or indirectly by making chemical precursors (such as methanol, ethanol, acrylate derivatives or mono-ethylene glycolLatest ways CO2 can be utilized. Source: IDTechEx [MEG]) for polymerization reactions.

Polypropylene carbonate (PPC), polyethylene carbonate (PEC), and polyurethanes are all LPCs that are made from CO₂ (PUR). CO₂-based polymers have a big market in PUR, which is used in electrical components, compost films, foams, and the biomedical and healthcare fields. CO₂ can make up up to half of the weight of a polyol, which is one of the principal parts of PUR. CO₂ and cyclic ethers are mixed together to make polyols, which are alcohols with two or more reactive hydroxyl groups per molecule (oxygen-containing, ring-like molecules called epoxides). After that, the polyol is mixed with an isocyanate to create PUR.

In new technologies, electrochemistry or microbial synthesis can be used to make the chemical building blocks for CO₂-based polymers. Even though CO₂ can be converted into chemicals through electrochemistry, this process is still in its early stages. Biological pathways, on the other hand, are more developed and have reached the early commercialization stage. Because of recent improvements in biological engineering and process optimization, chemoautotrophic microorganisms can now be used in synthetic biological routes to turn CO₂ into fuels, chemicals and proteins.

Some research left to do

Even though it seems like a good idea to use waste greenhouse gases as raw materials, there are many questions about the effectiveness of each CO₂ utilization route. Will it really cut down on emissions? What are the economic and pragmatic problems that make it hard to sell? Can it be scaled up to do something about environmental issues? IDTechEx answered some of these difficult questions in their report. The study focused not only on CO₂ use in the polymer and chemical industries, but also in oil recovery, building materials, fuels and increasing biological returns.

Since the demand for plastics shows no sign of abating, a circular carbon economy that encourages the petrochemical industry to use waste CO₂ as a substrate could be an effective way to keep people's current standard of living.