Biobased Polymers: A Sustainable Alternative?

[ACSGCI]

Dr. Bryony Core, Senior Technology Analyst at IDTechEx

We live in the age of plastic. Our lives have become so enmeshed with it that it is becoming impossible to avoid in day to day life. Its uses are myriad: saving lives in medical devices, reducing carbon dioxide emissions by light-weighting vehicles, and packaging food to prevent it from spoiling. But it wasn’t always this way: mass production started to ramp up in the 1950s, and ever since supply has grown exponentially to reach 348 MT produced in 2017 alone.[1] This wouldn’t be a problem, were it not for the fact that the lifespan of plastic typically far exceeds the time spent using it, as well as its synthesis from non-renewable hydrocarbon feedstocks.

One of the central issues with plastic is that it won’t readily decompose, instead being ground into ever smaller fragments, or “microplastics”. Academic investigation into the prevalence of contamination has revealed that plastic is indeed everywhere: microplastics have been found in tap water, in the air and in soil. Following an onslaught of recent news coverage depicting the scale of the problem, plastic pollution now occupies a very prominent position in public consciousness. One proposed solution is to incinerate waste plastic to avoid its longevity in the environment. However, burning these carbon-rich sinks only serves to release carbon dioxide into the atmosphere, adding to greenhouse gas emissions.

Considering the significant downsides of plastics produced on the current scale, what are the options? Recycling at their end of life is one route to managing waste; however, recycling infrastructure is far from perfect and mechanical recovery methods output ever poorer materials until incineration or landfill are the only options left. Alternatively, another potential solution lies in replacing petroleum-based polymers with biobased polymers, which have been partially or completely derived from a renewable biomass feedstock.

Biobased polymers can be chemically identical to petroleum-based polymers, and therefore act as “drop-in” replacements, or they can have entirely new chemistries. They can both directly substitute incumbent materials and offer the potential for improved performance. Furthermore, they partly answer the complications raised above: produced via photosynthesis, biomass locks in carbon dioxide from the atmosphere and is a carbon sink. As a result, biobased polymers represent a means to substantially reduce associated greenhouse gas emissions over their lifecycle compared to current polymers.

In addition, their unique chemistries present novel properties: several biobased polymers are also biodegradable or compostable and can be metabolised by microorganisms in the correct conditions. NatureWorks and Corbion have developed poly(lactide) (PLA), a compostable polyester, with a combined global production of over 225 kT annually. Challenging to produce economically from petrochemicals, biobased PLA is used in emerging applications such as biocompatible drug delivery systems, cell scaffolding and 3D printing, as well as displacing materials in consumer goods packaging.

Despite the opportunity presented by biobased polymers, and customer demand for greener products, production has been slow to get off the mark. Transitioning proof of concepts out of the laboratory and into an industrial fermentation facility is fraught with technical complexity and high CAPEX. Coupled with a chronic shortage of investment, production at scale has been hindered to date; innovators are exposed to volatility in the price of crude oil, resulting in many ventures ceasing operations in recent years.

Is there a future for biobased polymers? Biobased or not, these polymers still require robust waste management processes, but they do offer a partial solution to the issues of curbing carbon dioxide emissions as well as avoiding waste leaking into the environment. Addressing the funding shortages which have stifled growth, the EU has made €80 billion available under the Horizon 2020 project as part of its updated Bioeconomy Strategy which promotes circular economy initiatives. Based on these factors, IDTechEx projects that biobased polymers will play an increasingly important role in the plastics industry, and that the market size for biobased polymers will grow to 2.7 Mt by 2023, as barriers are addressed and demand for more sustainable materials grows.[2]

[1] “Plastics- The Facts 2018”, Plastics Europe, www.PlasticsEurope.org
[2] “Biobased Polymers 2018-2023: A Technology and Market Perspective”, IDTechEx, www.idtechex.com/biopoly