Understanding bioplastics

Updated: Jun 28, 2021

A major source of confusion still for consumers trying to make better choices, barePack explains what they really mean - and whether they really are the solution to single-use plastics.

With a growing demand from concerned consumers for environmentally friendly packaging, bioplastics are expected to witness the highest compound annual growth rate of 20.9% by 2023.

📷Credit: Brian Yurasits | Unsplash

We will look at the definition of bioplastics shortly, in order to really explain why they can fall into different end-of-life categories. The three most thrown-about terms "compostable, biodegradable and oxo-degradable" are interchangeably used, leaving many non-plussed consumers to believe they are synonymous, which they, of course, are not. This not only has serious consequences on whether they are disposed of correctly, but it also prevents consumers from making informed choices that actually reflect their intentions (often good ones). The major confusion stems from the fact that the prefix "bio" - meaning "relating to living things"- in bioplastics is generally misunderstood as defining what the plastic is made from. So let's look at that for a start.

Bio-based vs. biodegradable

Before you can understand biodegradability, oxo-degradability, and compostability, comes the necessity to grasp the notion of bioplastics which are in fact a fanily of plastics of all kinds of plastics, either sourced from biomass (living matter) and/or result in biomass (through metabolization). Thus bioplastics fall into three categories

1. Fully/partially bio-based and non-biodegradable

2. Petroleum-based and biodegradable

3. Fully/partially bio-based and biodegradable

Biodegradation is the process of decomposing material over time into inorganic compounds, CO2, methane gas (another greenhouse gas, much more potent than carbon dioxide), and water by the enzymatic action of microorganisms. Because plastic biodegradability is linked to the actual material's chemical properties (and not the source it was made from), biodegradable plastic can be petroleum-based. You see now where this starts to confuse most people. In a nutshell, traditionally, we used fossil fuels (petroleum) to get the carbon source necessary to manufacture plastics. Now, there's an alternative that you can get carbons from plants which on the face of it seems like a more sustainable option because we could grow more plants, making it a renewable source of carbon, unlike the oil and gas. Hence bio-based plastics.

Biodegradable vs. Oxo-degradable vs. Compostable Plastics

Essentially, everything can biodegrade, but the speed at which it is able to break down is determined not only by the material itself but in large part the environment in which it occurs.

So should disposables simply be biodegradable?

Labeling products as biodegradable, a fantastic marketing opportunity, is not informative nor transparent. What defines compostability is the speed at which, under specific conditions, the biodegradation happens. And ultimately, it does nothing to resolve the problem of the accumulation of waste and litter.

The only way today you can determine the degradability of a plastic today is by looking for specific certified labels on the products you buy. Without certifications, it is virtually impossible to verify claims on biodegradability made by manufacturers who are willing to appease consumers and improve their branding image.

Certified compostable plastics

These have been tested and certified by a third party to adhere to the industry standards (these vary depending on geography, and we currently do not have one in Singapore but can rely on the USA ASTM D6400 in the USA or European EN 13432. To pass the certification requirements, the 90% of the material must have biodegraded within 180 days and after 6 months, the resulting compost must be free of toxins or anything else that could threaten the environment it could be sold to (farming, landscaping, etc) for application. These rules are very strict for food applications as biodegradation should not occur during the period over which the plastic is in contact with foods.

However, the catch here is that these certify compostability in industrial composting facilities - only. This is due to the well-controlled parameters including heat and oxygen levels that are required for the composting to happen efficiently (or at all) - nothing your home vermi-compost could offer. We currently don't have municipal collection for compostable items here in Singapore, so any domestic waste would end up in a general waste bin and incinerated either way.

And what about oxo-degradable?

These fall into a different category altogether as neither bioplastics or biodegradable, these conventional plastics have been mixed with an additive that simply makes them break down into smaller plastic particles faster (but do not break down on a molecular or polymer level) so that they appear to be biodegrading. This has caused much concern around the health and environmental impacts of micro-plastics (especially in marine environments) and has led over 150 organisations, including some of the world's most influential brands, to address governments globally to forbid oxo-degradable plastic packaging.

Single-use, remains single-use

So now's all said and done, what is the future of biodegradable plastics? In truth, the future could be bright for biodegradable and compostable packaging businesses. The impact on our environment will largely depend on how well we learn to differentiate them, in order to separate the compostable from the biodegradable and recyclable, which is a challenge of significance given that today we are still incapable of efficiently sorting plastics we have used for over half a century. The main advantage is that the virgin material, if fully bio-based, can be carbon-neutral as the plants act as carbon sinks during their growth, storing the carbon effectively until we harvest them. We are far today from having any kind of landscape for recycling bioplastics.

Recycling conventional plastics therefore might seem like a better idea - on the surface once again. By all means, durable plastics should be recycled, but it is the 40% of plastics used for packaging that is the growing concern. The feasibility of plastic recycling is closely tied to the price of historically volatile oil prices as well as the success and speed at which we discover new technological breakthroughs (that are still at an early stage today), making it hard to predict exactly how well we could work on a recycling waste at scale, globally. The waste-recovery capital required to achieve significant recovery rates are a fraction of those annually invested by the global petrochemical and plastics industry, and itself not the problem.

The bottom line

Plastics-waste, if plastic demand follows its current trajectory, will grow from 260 million tons per year (2016) to 460 million tons by 2030 taking what is already a crisis to an irrevocable situation. No matter how much we transform our waste to create fertilisers for instance, we have to take into account the space needed for this, the energy in composting and new adequate recycling facilities for new plastics, and the overall expenses both in dollars and in environmental impact of sourcing, transforming, and redistributing waste. Single-use is the problem, and replacing disposable plastics with more sustainable but still disposable alternatives does nothing to challenge the consumer mindset. So bioplastics for durable plastic application (long term use and reusable) YES - non durable plastic application (disposable, single-use) NO.

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