biodegradable plastics logo on the base of a plastic item with soil rubbed off to expose the logo

From Concept to Compost: Addressing the Challenges of Biodegradable Plastics

The field of biodegradable plastics R&D has experienced rapid growth and progress. The promise these materials hold, if properly harnessed, is a significant reduction in plastic pollution, coupled with an enhancement in the sustainability of associated products and processes. But the road to achieving this sustainable future faces technological, environmental, and socio-economic challenges.

Our previous article on bioplastics offered a comprehensive overview of the history, composition and commercial state of bioplastics. In this article, we will unpack the challenges and uncertainties surrounding biodegradable plastics research and development.

Understanding biodegradable plastics

Biodegradable plastics represent a broad category of materials with one shared characteristic – the ability to degrade into natural elements under specific environmental conditions, resulting from the activity of microorganisms. However, the rate and degree of this degradation can vary depending on the type of biodegradable plastic, its composition, and environmental conditions.

Among degradable plastics, there exist different types that each hold unique properties. Polylactic Acid (PLA) or Polyhydroxyalkanoates (PHA) plastics are the most common types of biodegradable plastic. These materials, derived from renewable resources, are intended to break down in composting conditions. Oxo-degradable plastics are sometimes labelled as biodegradable but are not, in fact, bioplastics – these are fossil-fuel-based plastics with degradable additives included. Oxo-degradable plastics fragment into small pieces when exposed to sunlight and oxygen, but do not fully degrade into compost as biodegradable plastics do, and may leave microplastic particles behind.

sweet packaging made of PLA blend plastic

Packaging for a sweet, produced from PLA blend bioflex material

Confusion and misinformation often arise due to the lack of a universally accepted definition of biodegradable plastics. Biodegradability can take different forms, and does not necessarily equate to environmental benignity.

The most common biodegradable plastics are designed to be composted in industrial composting facilities where the microorganisms necessary to break them down are present in large quantities. The microorganisms degrade the plastic into carbon dioxide, water, and biomass.

Not all biodegradable plastics break down in every environment. Temperature, humidity, and the presence of specific microorganisms can impact the degradation process. Biodegradable plastics designed for industrial composting may not biodegrade in a home composting setup or in the natural environment, thus adding to plastic waste.

Understanding these nuances is critical to navigate the challenges and uncertainties associated with biodegradable plastics.

The promise and potential 

At the forefront of biodegradable plastic’s promise is the potential to decrease the waste and carbon footprint generated by plastic production. Many biodegradable plastics are derived from renewable resources, presenting an opportunity to mitigate the use of fossil fuels in plastic manufacturing. Moreover, for some biodegradable plastics, the broken-down materials return to the ecosystem as beneficial compost.

Consumers largely express positive attitudes towards biodegradable plastics. A study by W.L. Filho, J. Barbir, I.R. Abubakar, A. Paço, Z. Stasiskiene, M. Hornbogen, et al., ‘Consumer attitudes and concerns with bioplastics use: An international study,’ suggested a general optimism about bioplastics in the consumer market, with buyers supportive of the potential of bioplastics to reduce plastic pollution, indicating a readiness to embrace more sustainable choices.

This is a market with a high value potential and significant investment from industry. According to an AP News report of August 2022, market data platform i3 Connect showed global investment in bioplastic manufacturing reached $500 million in the first three months of 2022, exceeding the previous high of $350 million in the last quarter of 2021.

A report by Coherent Market Insights, ‘Bioplastics Market 2022–2030’, estimated the value of the bioplastics market in 2021 at $1 billion (approx. £809 million). The growth rate of the bioplastics market was said to be around 14.8%, with the value expected to reach $3.5 billion (approx. £2.8 billion) by 2030. An August 2022 report by Zion Market Research placed the estimate much higher, forecasting a market value of $29 billion by 2028.

Table 1 shows the current biggest players in the global biodegradable plastics market.

Key global players in the biodegradable plastics market

Table 1 Key global players in the biodegradable plastics market

In 2022, several major companies expanded their investments in bioplastics. One such example is NatureWorks, which is building a $600 million plant in Thailand to increase its production capacity by 50%. This is one of the biggest names in bioplastics, especially in the UK, where tea manufacturer PG Tips recently switched from polyester tea bags to bags made with a compostable mix of cellulose and a thin layer of NatureWorks’ PLA.

However, the market isn’t devoid of reservations. Consumers need assurance about the true biodegradability of these products and their cost-effectiveness compared to conventional plastics. If biodegradable plastics are to fulfil their promise, these concerns must be transparently addressed, and the products must deliver on their environmental and economic expectations.

Challenges and uncertainties 

Several key challenges and uncertainties are currently faced by companies involved in the development and commercialisation of biodegradable plastics.

Unclear definitions and standards

There is a lack of universally accepted definition and standards for biodegradable plastics. This leads to confusion and uncertainty about their environmental benefits. Without a clear and globally recognised definition, it is difficult for consumers and producers alike to distinguish between truly biodegradable plastics and those that aren’t. This lack of clarity can potentially lead to mislabelling and misuse of the term ‘biodegradable,’ thereby eroding consumer trust in these products.

Potential environmental impact

There’s still a degree of uncertainty about the full environmental impact of biodegradable plastics. More research is required to understand the long-term effects of these materials on the environment, both during production and after disposal. There are also concerns that some plastics labelled incorrectly as biodegradable plastics, in particular oxo-degradable plastics, may release harmful pollutants as they decompose, and the impact of these materials on marine life is not yet fully understood.

Plastic waste in the ocean

Marine plastic contamination

Lack of existing infrastructure

One of the most prominent challenges is the lack of appropriate infrastructure to manage biodegradable plastics. There aren’t enough composting facilities yet to can handle the volume of materials required to eliminate conventional plastic use, which makes it hard for consumers to dispose of biodegradable alternatives in an environmentally friendly manner.

Additionally, because biodegradable plastics can’t be recycled with traditional plastics, they require separate collection and processing, which adds to the complexity and cost of waste management. This means many biodegradable plastics end up in landfill or the ocean instead of a composting facility. In a natural environment, most types of biodegradable plastic still take decades to biodegrade and will pose a threat to animal life in the meantime.

High cost and low availability

The production of biodegradable plastics is currently more expensive than that of traditional plastics. This price difference may make biodegradable plastics less appealing to manufacturers and consumers alike. In addition, biodegradable plastics are not as widely available as their conventional counterparts, which limits their use in large-scale manufacturing.

Potential durability issues

Biodegradable plastics may not offer the same level of durability as traditional plastics, limiting their applicability in certain scenarios, such as packaging for long-lasting products or in the automotive and aerospace industries where plastic parts must stand up to heavy wear.

Consumer perceptions

Despite general positivity, there are consumer concerns regarding bioplastics’ actual biodegradability, cost, availability, and clear labelling. Assuring consumers that bioplastics are truly biodegradable and cost-competitive with conventional plastics is a challenge that needs to be addressed for broader acceptance and usage.

In addressing these challenges, research and development projects (and the funding to conduct them) will play a crucial role in improving biodegradable plastics’ properties, lowering their production cost, and understanding and mitigating their environmental impact. Likewise, regulatory bodies will need to establish clear standards and guidelines for what constitutes a biodegradable plastic material to address unclear definitions and standards and improve consumer trust and perceptions.

What happens when biodegradable plastics are not properly disposed of?

The aim is for biodegradable plastics to fully decompose, leaving no detrimental residues or microplastics behind. However, as an increasing number of ‘sustainable plastics’ enter the market, consumers are confronted with the challenge of choosing the right products and determining the appropriate disposal methods for each one.

According to a research paper published by the Royal Society of Chemistry (RSC), the present lack of clarity surrounding the disposal of biodegradable plastic products, coupled with insufficient infrastructure for handling them at the end of their life cycle, can result in some biodegradable plastics causing unintended harm rather than benefiting the environment.

In an RSC survey of British consumers, over half of respondents did not recognise the European Bioplastics trademark, a label which identifies industrially compostable packaging (certified according to standard EN 13432). Only 25% of respondents correctly identified the symbol as meaning packaging was compostable.

The European Bioplastics trademark

Lack of awareness of what labels like this mean indicates that consumers do not know how to correctly dispose of products marketed as bioplastics – some may incorrectly believe it is environmentally sound to dispose of biodegradable plastics with household waste sent to landfill, misunderstanding the conditions and length of time required for this type of plastic to degrade – without the right conditions, this can be years, and the materials will present the same risks of marine entanglement as posed by conventional plastics in the meantime.

In the worst case, some consumers may incorrectly dispose of biodegradable plastics with recyclable materials, which can have disastrous contaminating effects on the recycling stream.

The diagram below, from the RSC, offers examples of intended end-of-life routes for plastic materials, alternative sustainable end-of-life routes that respect their intended use, and other end-of-life destinations that are environmentally harmful or make their potential environmental benefits redundant.

A diagram showing potential end-of-life destinations for biodegradable plastics (Courtesy RSC)

Considering issues around the practical compostability of biodegradable plastics and lack of infrastructure to support mass industrial composting of these materials, RSC research suggests that the most fitting applications for compostable biodegradable plastics are specific applications wherein collection and correct processing is easily facilitated, such as with caddy liners for food waste bins and green bins.

There are others who suggest that the end goal of biodegradable plastics R&D and commercialisation should be to make all plastic biodegradable, to account for leakage from recycling or collection systems which might otherwise generate permanent, non-degrading waste. However, it may not be feasible to design a material that can decompose in any environment – when this was attempted, in the form of oxo-degradable plastics (fossil-fuel-based plastics with added degradation additives, that degrade in contact with sunlight and oxygen), the results were poor and the potential harm to marine life from microplastics remaining in the environment that many governments have banned the sale of oxo-degradable plastics, including the UK.

Most biodegradable products rely on industrial composting conditions and treatments to degrade within a short length of time (from weeks to months, as opposed to years). Some may not be possible to biodegrade in a home composting environment, while some will degrade over an extended time period – more clarity is needed to distinguish between these materials in terms of consumer labelling and education. Better industrial composting infrastructure is also required to ensure compostable biodegradable plastics do not end up in landfill due to lack of facilities to process them.

Looking forward: R&D and innovation to address challenges

Research and development (R&D) plays a crucial role in addressing the challenges and uncertainties currently associated with biodegradable plastics. The issues presented, ranging from lack of clarity in definition, and inadequate infrastructure, to environmental impacts, all indicate a pressing need for comprehensive research, creative solutions, and technological advancements in this field.

Of prime concern is the dearth of comprehensive studies on the environmental impact of biodegradable plastics. The scarcity of data is especially concerning in marine environments where plastics, biodegradable or otherwise, cause significant harm.

Notably, despite the promise of biodegradability, these plastics can still contribute to marine litter and pose threats to marine life if not managed correctly. Rigorous scientific studies are essential to evaluate the long-term environmental impacts, both on land and in marine environments. This understanding will guide the development of plastics that truly align with the ecological balance.

R&D can also fuel innovation to improve durability and reduce the production costs of biodegradable plastics. Currently, these plastics often lack the longevity of their traditional counterparts, limiting their applications. Also, the higher production costs deter manufacturers from choosing biodegradable alternatives. However, with the continuous advancement of science and technology, the synthesis of cost-effective and robust biodegradable plastics is entirely within the realm of possibilities.

Furthermore, innovation could revolutionise composting methods and improve the biodegradability of these materials. Technological solutions can make composting more accessible, efficient, and less dependent on specific conditions, allowing biodegradable plastics to decompose even in less-than-ideal circumstances. Research should also be focused on creating plastics that biodegrade completely, without leaving any harmful residues or microplastics, or releasing greenhouse gases during breakdown.

In addition to the available post-funding under HMRC’s R&D tax credits scheme, several funding opportunities for biodegradable plastics research are currently open for applications in the UK. The majority are funded by government grants. Table 2 shows five funding opportunities currently open for submissions.

Research grants currently open for applications in the UK

Table 2 A selection of biodegradable plastics research grants currently open for applications in the UK

For the most part, with the exception of NERC’s project on the biodegradation of plastics in the environment, the criteria for these funding opportunities is focused on the development of new biodegradable polymer materials.

While the level of investment in biodegradable plastics research is promising, the role of R&D and innovation will need to extend beyond improving the physical properties of plastics to address challenges across the whole value chain, from reducing the cost of production to developing the necessary infrastructure for their disposal.

Funding from relevant organisations is also necessary to conduct projects to develop clear industry standards and labelling guidelines for biodegradable plastics. Clear, universal standards must be adopted worldwide to inform consumers about the nature of products, disposal requirements, and environmental impact. Unclear or misleading labels could result in the incorrect disposal of biodegradable plastics, undermining the benefits these materials are intended to provide.

Consumer education is another area that warrants attention. Consumers are generally positive about bioplastics, as indicated by various studies, but concerns and misconceptions exist. R&D can be undertaken to inform effective communication strategies, debunk myths, and promote an accurate understanding of biodegradable plastics, their benefits, and their limitations.

In conclusion, the field of biodegradable plastics is ripe with challenges, and opportunities for innovative companies to address them. The pathway to overcoming these challenges and leveraging the opportunities lies through rigorous research, innovative developments, and informed communication.

With strategic investment in R&D, support from government post-funding schemes such as R&D tax relief in the UK, clear regulation, and consumer education, biodegradable plastics can finally live up to their promise, becoming a viable, sustainable alternative to non-degradable, fossil-fuel-based plastics.

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