Planet 5 min
Biosourced plastics: plant carbon makes a comeback
Biomass-based plastics are an fascinating alternative to traditional plastics. They are part of the large family of bioplastics, a generic term that encompasses many things. Let's try to get a clearer picture at a time when combating global warming also involves the decarbonisation of the plastics industry.
Biosourced plastics: plant carbon makes a comeback
Biosourced plastics: plant carbon makes a comeback

Bioplastics, a story as old as the world

“Bioplastics” from ancient times

One might think that "biosourced" plastics first appeared at the turn of the millennium. However, some have been in use since ancient times. Just think of the latex ball used by Mayan pelota players. Or, even further back, the Neolithic tools assembled with plant resins, which were contemporaneous with the bituminous sealants developed in the Middle East. For a very long time, man has drawn on biomass to create everyday objects. Biomass, which is made up of living matter of plant or animal origin, produces around 172 billion tonnes of dry organic matter each year, of which less than 4% is used, mainly for food purposes. Yet it is a pool of resources from which it is possible to produce electrical energy, biofuels, gas, hydrogen for future fuel cells, and even synthetic polymers.

 

Prehistoric man already used plant polymers such as amber to make small tools.  

The first industrial plastics were also “bioplastics”

From the beginning of the industrial era, it was in biomass that chemists found the raw materials for the first artificial polymers, such as Parkesin, which was presented in London at the 1862 World Exhibition. This was the very first modern plastic. It was developed by English chemist Alexander Parkes, who was looking for a substitute for natural rubber. Obtained from cellulose, one of the main components of plant walls, this new material could be made flexible or rigid, was water-resistant, easily dyed and, above all, could be moulded at will. Thus began the era of synthetic polymers!

 

In the early 20th century, dolls were made of celluloid, one of the first bioplastics. This material was considered dangerous because it was highly flammable and was gradually withdrawn from the market.

In 1870, while searching for a substitute for ivory, John Wesley Hyatt and his brother, printers from the State of New York, came up with the idea of improving Parkesin by adding camphor.
Their experiment resulted in the creation of celluloid. This plastic material was used for billiard balls, table tennis balls, and in the film industry.
However, because it is a highly flammable material, it was considered dangerous and is hardly ever used today.

Galalith appeared in 1897 and is attributed to Auguste Trillat. It is a biodegradable polymer made from a mixture of formaldehyde and casein, the milk protein.

Its ivory-like appearance made it a great success during the Roaring Twenties in costume jewellery.
 

Some nostalgic button-makers still use it. However, this polymer could see a resurgence in its popularity thanks in particular to the work of the French company Lactips, which is using it again after having modified it to produce a water-soluble film like the one that surrounds dishwasher tablets.

 

Galalith, a polymer derived from milk casein, has had its moment of glory in the manufacture of small brooches like this ladybird.

On the other side of the Atlantic, Henry Ford dreamed of building a plastic car, which he believed would be safer and lighter than a steel car.

In 1941, he unveiled the Hemp Body Car or Soy Bean Car, a prototype comprising parts made from a plant-based plastic made from soya beans or hemp. The project was halted when the United States entered into the Second World War, despite the millions of dollars that had been invested in developing the plant-based plastic.

In 1947, a new bioplastic that made a lasting impression for its technical performance made its appearance. Its name was Rislan®, also known as polyamide 11, and it was derived from castor oil. Because it was expensive to produce, it struggled to compete economically with petroleum-based plastics. That said, such is its technical performance, and more particularly its perfect resistance to corrosive substances, UV rays, weathering, etc., that it is widely used to manufacture fuel hoses, flexible pipes for the oil and gas sector, electrical cable coverings and even high-performance shoe soles.

 

Rislan ®, based on castor oil, is one of the oldest biopolymers. This has not prevented it from finding its way into highly technical objects such as ski boots.

It would be another fifty years before the emergence of a new generation of bioplastics such as PLA or PHAs produced from the starch of plants such as corn and which we owe to the development of green chemistry in the 1990s.

For more information on PLA and PHAs, see part 3 of our feature.

 

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