Bio-based plastics: a brief history

Wheth­er you are think­ing about bioplastics from a bio­de­grad­able or bio-based per­spect­ive, these mater­i­als are still a long way from the ‘main­stream’, which uses pet­ro­chem­ic­als. Although, they do have a long his­tory, which could help pave the way for the future.

When we talk about bioplastics, we often assume that their name derives from the fact that they are bio­de­grad­able. But they are also named after the raw mater­i­als used to make them. In fact, “bio-based” plastics (which are not neces­sar­ily bio­de­grad­able) have been around for a while. After Bakelite (1907) and PVC (1912) were cre­ated, com­pan­ies star­ted to devel­op plastics from plant-based mater­i­als, before Plexi­glass (1924) and poly­ethyl­ene (1933) came onto the scene.

Jean-Luc Dubois is sci­entif­ic dir­ect­or at Arkema, a spe­cialty chem­ic­als com­pany. He shares his know­ledge of the his­tory of bioplastics, and Arkema’s vis­ion of these materials.

Bioplastics are cur­rently exper­i­en­cing a renais­sance. How has this know­ledge been car­ried on and passed down at Arkema?

Jean-Luc Dubois: It’s true that pet­ro­chem­ic­als have long dom­in­ated the industry, but some plastics, which have been around for a long time and are still being pro­duced today, found their own niche. Such is the case for poly­am­ide-11, also known as “Nylon 11”, which is made from castor oil.

What’s inter­est­ing is that bio-sourced plastics are expand­ing today due to polit­ic­al and reg­u­lat­ory devel­op­ments, in the same way that the Nylon 11 sec­tor was green-lighted at the highest level of the French gov­ern­ment. After 1945, they wanted to sup­port the tex­tile industry and integ­rate the eco­nomy of the French colon­ies. So castor beans brought to Mar­seille  were pro­cessed there, before the industry spread to the region of Lyon. Why Lyon? Because it was a tex­tile centre. From that point on, a sig­ni­fic­ant chem­ic­al hub star­ted to grow there. Around the same time, the Sovi­ets were try­ing to devel­op some­thing sim­il­ar with ethylene.

Poly­am­ide-11 is still being made today. It is a spe­cialty poly­mer, more expens­ive than the fossil fuel-based polyamide‑6, but with a com­bin­a­tion of prop­er­ties that has won over many cli­ents. For example, it is res­ist­ant to solvent, UV and cold weath­er. In this case, the value clearly resides in the tech­nic­al aspects, rather than it being bio-based.

Are castor oil and pet­rol pro­cessed differently?

No. They are both chem­ic­ally, rather than bio­lo­gic­ally, pro­cessed. All oils con­tain a long-chain acid, which is a good raw mater­i­al that already has an import­ant chem­ic­al func­tion. In the United States, they make sec­ond­ary plas­ti­cizers from veget­able oil (lin­seed and soybean).

For this pur­pose, palm oil would be a per­fect raw mater­i­al if it weren’t for the fact that plant­a­tions com­pete with food crops and dam­age biod­iversity. Fur­ther­more, rising qual­ity of life in devel­op­ing coun­tries means that the demand for this product is grow­ing. For that reas­on, it is no longer in the run­ning to replace petrol.

The fact remains that big com­pan­ies in our industry are closely mon­it­or­ing shifts in European reg­u­la­tions, and act­ively look­ing for altern­at­ive sources to pet­rol that could pre­vent a total over­haul of indus­tri­al factories.

Arkema had been devel­op­ing a bio-based acryl­ic acid. There is a mar­ket there for man­u­fac­tur­ing paint and nap­pies. From a tech­no­lo­gic­al stand­point, it works; gly­cer­ol made using biod­ies­el and oleo­chem­istry would be a good option. But the fluc­tu­ations in the bio­fuel mar­ket led us to aban­don the project.

Anoth­er strategy involves explor­ing entirely new approaches, such as poly­hy­droxyalkanoate (PHA), a poly­es­ter made from bac­teri­al fer­ment­a­tion. But these pro­cesses are very for­eign to our industry.

On the oth­er hand, can bio­de­grad­ab­il­ity be integ­rated more eas­ily to your products?

Yes. It takes some R&D work but in terms of the indus­tri­al found­a­tions it is less com­plic­ated. That being said, we are care­ful to think about all aspects, par­tic­u­larly the import­ance of recyc­ling. Bio­de­grad­ab­il­ity has to be defined accord­ing to the envir­on­ment where the product will break down – in soil, home com­post, indus­tri­al com­post, the ocean and so on. What you need to remem­ber is that bio­de­grad­able plastic will often suc­cess­fully break down in the con­di­tions of indus­tri­al com­post facil­it­ies, at 50–70°C, but not in your every­day garden. And even in indus­tri­al com­post, bio­de­grad­able plastics slow down the decom­pos­i­tion pro­cess. As a res­ult, the industry tends to avoid it. Only a small num­ber of plastics will break down in the ocean. 

It is best to choose bio­de­grad­able plastics for product fam­il­ies where that prop­erty will be truly use­ful. Such as the pro­tect­ive mesh used to wrap the trunks of young trees, for instance, which breaks down over four or five years.

Anoth­er example is a 100% bio­de­grad­able ver­sion of the water-sol­uble film used to hold dish­wash­ing liquid, which was pro­duced by Lac­tips. It is a truly use­ful product, in that the com­pon­ents will all end up in wastewater.