Let’s talk about it: Bioplastics
26. 8. 2019 | Source: BusinessInfo.cz
Efforts to lower the amount of plastic waste on our planet have brought forth innovations in areas from recycling to material production itself. These innovations promise to help us be more environmentally conscious while maintain our current consumer lifestyles. One of them comes in the form of bioplastic.
"Let´s talk about it" is a project of Unipetrol company. It´s aim is to explain various sustainable solutions, including all their benefits and drawbacks.
The prefix “bio” evokes the idea of an organic, natural material, giving an impression that the the problem has been solved. But has it really? Are bioplastics the Holy Grail of plastics or just another dead end?
The prefix “bio” makes me think of something organic or biologically degradable. What all covered under the term bioplastic?
The term bioplastic is a bit misleading, because approximately 300 types of various substances with differing characteristics get the bioplastic label. There are two main motives behind the development of bioplastics. One is the replacement of non-renewable resources, such as petroleum, in plastic production with renewable materials that can be “grown in a field”. For example, polyethylene or polyethylene terephthalate can be replaced with identical materials with the prefix bio. The prefix bio here doesn’t mean that nature can break down the material. We shouldn’t get the impression that we can throw a bio-PET bottle into the woods and nature will take care of it. At the end of their lifecycle, these materials need to go into a yellow container for plastic recycling.
At what capacity are we currently substituting conventional plastics with these bioplastics?
The current annual production makes up about 0.6 percent of total plastic production. Increasing production could compete with growing crops.
What other types of bioplastics are there?
Other kinds are biopolymers that originate from renewable sources through natural processes. This is where the second motive for bioplastic development comes into play- end of life biodegradation. These materials are developed to decompose at the end of their lifecycle, preferably with no residue, so they don’t end up as waste in our oceans.
Could you identify for me a couple of the most significant bio-bioplastics?
Thermoplastic starches such as polylactic acid are among these. Materials produced from bacterial strains with a polyhydroxyalkanoate basis are also very promising.
How long does it take for these bioplastics to decompose? Can we put them in the compost or do they require special conditions?
It’s important to say that the name bioplastic doesn’t automatically mean that a material is decomposable. We saw that with the first group. Even here there’s no guarantee of 100% decomposition. It depends on product shape and the environment the product ends up in. Suitable conditions are found in, for example, industrial composting plants which, among other things, reach very high temperatures. On the contrary, if the product ends up somewhere low in nutrients for the bacterial strain, decomposition takes longer.
So under the right conditions, these plastics decompose easily. Does that mean that using them could help us solve the current plastic crisis?
There are certainly candidates that could help. There is also one more kind of bioplastic- materials which are only bio at the end of the lifecycle. They’re known under acronym such as PBS, polyethylene succinate, PVAP and so on. These originate from a non-renewable petroleum source, but are made to be biodegradable.
Biodegradable by bacteria or by UV light?
They should be biodegradable by bacteria. Then there are plastics with a shortened lifespan, sometimes also wrongly labeled as bioplastics. These are called oxodegradable. They are conventional plastics with a pro-oxidant additive that, when exposed to UV light, increased temperature and dampness, undergo what is referred to as chemo-hydrolytic decomposition. The producers of these plastics declare that these small fragments easily degrade through natural processes. That, however, hasn’t proven to be true. On the contrary, they’ve been proven as a source of microplastics and their production has significantly decreased.
Not even bioplastics that should be biodegradable, such as PBS, always fulfill their producers’ proclamations. When we exposed allegedly one hundred percent compostable foil to field conditions for eight months, it only decomposed by about ten percent. Tests for material conditions occur in conditions that don’t necessarily exist in the real environment.
According to you, bioplastics do offer opportunities, but are not a sweeping solution. We can’t simply substitute synthetic plastics with easily degradable bio-bioplastics. The research isn’t expansive enough yet and we don’t know the environmental effects of the particles which remain after decomposition. Are there situations in which applying these innovations would bring us specific advantages?
I see only certain bio-bioplastics as promising for helping solve the plastic crisis. For example, thermoplastic starches can be produced from agricultural waste. If production of these materials increased, however, raw materials from waste would be insufficient and production of these plastics would start competing with crop production. According to experts, polyhydroxy alkalates, biopolymers produced from waste bacteria, are the most promising. Their production is bio-technological and occurs in a cultivated medium. The bacteria processes waste materials such as used frying oil or leftovers from first generation biofuel production. Israeli researchers have even verified highly effective production when feeding these bacteria with lysate from seaweed. However, the created biomass has to be separated from the cultivation medium. The process of polymer extraction is quite challenging and therefore their price is not yet competitive.
Ok, so that’s price. But are the final product properties sufficient to satisfy market demand?
It depends. There are very promising materials among these biopolymers, polyhydroxy alkanolates. Polyhydroxyvutyrate or polyhydroxyvalerate in particular are very promising materials whose properties and temperature resistance are comparable with, for example, polyethylene. It’s not identical and cannot be substituted across the spectrum, but we could certainly find specific situations for their application, for example in single use plastic packaging.
Can we start using such polymers in practice already?
I would beware of overly hasty solutions, though I realize there is no time to waste, the crisis is truly culminating. Regardless of whether or not bioplastics assert themselves on the market, we need to decrease the production and consumption of single use plastics right away. There are ways to support such change, for example adding fees for every small plastic baggy, like we already do with plastic shopping bags. A consumer always has the option of bringing their own sack or paying extra for the luxury of single use packaging. We should certainly start there. One way is through legislative measures…
Those don’t exist yet?
Some packaging and waste laws do exist, but their enforcement is trivial. Packaging needs to fulfill more requirements than just protection and manufacturers can always find a reason for it to be oversized. I see more hope in working with the public. Everyone needs to start with themselves. We should start providing education about low waste, responsible treatment of packaging and so on.
Should we support bioplastics through subsidies or let the natural flow of the market decide?
I’m not an economist, but I don’t think it’s an appropriate solution. The tax payer would end up paying and supporting bioplastics this way wouldn’t be educational because it would lead to lower prices and the feeling that there’s no need to limit ourselves. Furthermore, before introducing these materials onto the market we have to prepare the waste management to be able to handle them.
So if we were to introduce bio/bioplastics in bulk, the waste management system couldn’t handle it.
At this point it’d be more of a problem than a solution. If we increased bioplastic marketshare today, their presence in yellow recycling bins would go up too. The average consumer or recycling plant employee won’t differentiate them from regular plastics at first glance. They would then devalue the material intended for recycling and we would have a problem with meting recycling goals from the European Union.
Today, if a consumer throws a bioplastic product into a brown container, neither compost plant nor biofuel station owners want that waste because the material isn’t always hundred percent degradable even in their facilities. They can do more harm than good. First we need some kind of rule for certification from a responsible authority that the materials are decomposable, even outside of industrial composting plants. They also need to be easily identifiable, for example based on color.
Guest: Petra Innemanová
Mgr. Petra Innemanová, Ph.D. works at Institute for Environmental Studies (Faculty of Science, Charles University). She is focused on waste management and decontamination and works also as a sanitation technologist and research and development worker DEKONTA, a.s.
Host: Michael Londesborough
Michael Londesborough received his Ph.D in chemistry from the University of Leeds. He is chairman of the Czech Academy of Science’s Institute of Inorganic Chemistry in Řež. He collaborates on popularization projects of the Czech Academy of Sciences, Czech Television and the National Technical Museum.
Watch the interview on bioplastics with English subtitles (25 min)
Source: Unipetrol's “Let’s Talk about It” project site.
The aim of this discussion platform is to highlight areas such as the circular economy, alternative fuels, recycling, responsible production and corporate social responsibility.