PET is one of the most widely used and recognizable packaging materials for beverage and food applications. However, amid concerns from some sectors regarding low recycling rates in some parts of the world and the spread of microplastics, Caroli Buitenhuis of Green Serendipity argues that now might be the time to look into biobased alternatives. 

Europe demands zero fossil resources for packaging in 2050. In addition, packaging must become fully recyclable, preferably to be able to reuse the recycled material for packaging again.

If a PET food packaging is entirely made of mono-material, properly collected, sorted and recycled, it can be re-used as a raw material for food or beverage packaging. But… reality shows that in more than 80% of the countries worldwide packaging is hardly or only partly collected, sorted and recycled. These systems will also not be fully developed in 2050, simply due to a lack of infrastructure and business models. In addition, landfill and litter will still widely exist in 2050.

Bottle of the future

What does the future of PET look like? Can we manage without fossil-based PET? Are there other suitable materials that can take over the characteristics of PET and contribute to a more sustainable and fossil-free future? When looking at alternatives, it is important to make a solid choice for the longer term.

Let’s take the PET bottle as an example. The ‘bottle of the future’ should be made of fossil-free CO2-neutral sustainably produced renewable raw materials. Alternatives can be based on biomass, biowaste, microbes or even CO2/methane. The raw materials must not compete with food or feed and contribute to a healthy biodiversity and regeneration of our soil.

Also important is that the bottle of the future can be recycled in multiple ways and preferably with less energy than the current PET bottle. Furthermore, the recyclate should be reusable for new bottles while maintaining food safety.

In addition, the bottle should be biodegradable when needed (if littered or landfilled) without leaving behind harmful persistent microplastics for next generations. By biodegradable we mean that the bottle can serve as food for micro-organisms for their energy supply within the period of one generation (max 25 years). So that we do not leave irreversible damage for future generations and the environment.

Three options

Which alternative materials meet these stringent requirements? We give an overview of three options.

PLA (PolyLactic Acid) is currently made from corn or sugar cane. But there are also already many developments to produce the lactic acid from waste streams from i.e. paper or textile recycling or from algae and even from methane and CO2! It can be used to make bottles that can be recycled mechanically and chemically (with less energy than PET recycling). Next to being recyclable, PLA is also a biodegradable polymer. It does not disappear very quickly because the right temperature, humidity and bacteria are needed at the same time, but it will disappear within 1 generation if it ends up in the wrong place.

PLA is also a ‘biocompatible material’ which means it can be broken down naturally within our body (PLA is for this reason also used for implants and wound sutures). PLA bottles can be particularly suitable for replacement of PET water bottles at stations, on-the-go stores, in cities, events (fast-moving circulation). Suitable for still water, juices, dairy drinks. Not suitable for carbonated drinks.

PEF (PolyEthylene Furanoate) promises to be an excellent alternative to PET. It is currently made of agri crops but the used glucose can also be made from cellulose from biomass residue streams, think sawdust from trees for the paper industry or from forest management. PEF has much better barriers to oxygen and water vapor than PET, which makes it much more suitable for carbonated drinks. In addition, PEF has excellent mechanical and chemical recyclability. And although PEF is absolutely not a biodegradable polymer, it can break down hundreds of years earlier than PET, should it end up in the wrong place.

PHAs (PolyHydroxy Alkanoates) are a class of natural materials that have existed in nature for millions of years. These materials are similar to other natural materials such as cellulose, proteins and starch. PHAs are produced by microorganisms and can be made anywhere in the world from almost any possible biomass residue or waste stream but also, for example, from used frying oil or even from sewage sludge or methane.

In terms of production and properties, the material can be compared to polyethylene (PE) or polypropylene (PP), but with the advantage that it is not fossil-based and that it is both recyclable and biodegradable. And the biodegradability of PHA is particularly special because in addition to the fact that this material is, just like PLA, biocompatible, it has also been proven that it breaks down better than cellulose under the same conditions in nature, even in water! The first PHA water bottles are already available on the market. Suitable for still water or short shelf life drinks, not carbonated.

Recycling of bioplastics

PET bottles are currently recycled mechanically and chemically. The same is possible for the mentioned biobased materials PLA, PEF and PHA. In the first place, it is already tested that these new materials can be sorted by material type. Then the sorted bottles can be recycled mechanically and/or chemically using current equipment for sorting, washing, shreddering and i.e. depolymerization. In addition, a new recycling technology is being developed: ‘Torwash for bioplastics’. Contaminated and multimaterial packaging can be fed into this system and the building blocks for new food-safe materials can be recovered.

Room for innovation

Currently, we are still stuck in fossil-based packaging and systems that are no longer appropriate for the future. There must be room for innovations. Both in terms of materials and systems. We must not only look at the business model of the current waste industry but also decide what is good for our future generations and planet. Making the right choices will also lead to new sustainable business models. And it may take some time but the era of PET packaging comes to an end….

This article was submitted to independent scientists prior to publication.

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