Which plastics for tomorrow?
Bio-based: a source of confusion
They are the height of fashion! In these times where saving the planet is becoming a global priority, the plastics industry is often accused of the worst. It is worth recalling, though, that it only uses 4% of the oil consumed around the world. This being said, many manufacturers, including some of the largest, are increasingly looking into plastics of vegetable origin, called bio-based plastics. So what does this word mean? Bio-based plastics are the product of plant chemistry, and therefore of a renewable source. Unlike traditional plastics made from fossil carbon, bioplastic polymers are fully or partly produced from plant carbon. A bioplastic may be manufactured from whole plants, from starch extracted from grains (wheat or corn) or potatoes, from glucose derived from starch, or from vegetable oil. Many people often confuse bio-based and biodegradable, and this causes much ambiguity. A plant-based plastic is not necessarily biodegradable. And surprisingly, the contrary is also true because some oil-based plastics are in fact biodegradable
The revolution of bio-based plastics. Really?
Let's tear down some common misconceptions. No, bio-based plastics are nothing new. In fact, they are older than those made from hydrocarbons. Celluloid, for instance, is now considered to be the very first artificial plastic. It was invented in the United States in 1856 by skilfully mixing the cellulose nitrate from cotton with camphor from, as its name suggests, the camphor tree. Special mention should also be made of galathite, a polymer developed in the late 19th century by a French scientist who found a way to make the casein in milk (one of its proteins) insoluble by adding formaldehyde. It was one of history's first thermosetting polymers. Plants were also given a starring role during the crisis in the 1920s. Henry Ford and his team of chemists manufactured a new plastic from soybeans. Polymers, therefore, are in no way exclusively linked to hydrocarbons.
Manufacturing plastic, as previously stated, primarily requires carbon, and many raw materials contain it! Fossil resources are the first port of call simply because they are so simple to extract, they remain cheap to transform and are abundant.
Niches seeking to grow
The expected decrease in oil resources and the increase in prices that accompany it, the fight against global warming and saving the environment are encouraging the search for alternatives to petrochemical products. In the plastics industry, where manufacturers are seeking to reduce their dependence on oil and improve their brand image, efforts have been made since the year 2000 to develop bio-based plastics, a new range of plastics from renewable sources. In 2012, the global production capacity of bio-based plastics represented 0.5% of all plastics produced throughout the world. According to the European Bioplastics manufacturers' grouping, their production capacity should increase by around 400% in the coming years. They would then account for 2% of the total production of plastics.
The use of renewable sources, such as biomass or organic methane, is an alternative to the use of fossil fuels. Polylactic acid, for instance, can be produced from the lactic acid extracted during the fermentation of starch-rich agricultural by-products. Many "bio-based" plastics could be manufactured from cellulose, vegetable oil and even the casein in milk. The only question that remains is that of whether it is economically viable?/p>
PLA joins the party"
There are two different types of renewable polymers: the polymers with a structure identical to their fossil counterparts such as polyethylene (PE) derived from sugarcane for instance, and those with an innovative structure which is different to the known polymers. This is the case of PLA (polylactic acid), derived from corn starch, for instance. It is the first bio-based alternative to polyethylene. Polylactic acid is derived from the fermentation of starch. They are bacteria which synthesise the lactic acid and transform it into polylactic acid. PLA is currently being tested in many different applications.
Nothing is that easy
Appearance-wise, PLA looks very much like PET and could disrupt PET bottle recycling chains, or even make them impossible. This lack of distinguishing features between PLA and PET would require considerable investments in order to refine sorting techniques. One of the solutions for managing the end-of-life of PLA products is the Loopla recycling process developed by the Galactic company. The process enables PLA products to be reconverted into lactic acid by eliminating the other components. This would still require specific collections, such as during major events in which only PLA bottles and cups are used.
PLA also has biodegradability characteristics that could be exploited, but care must be taken as certain methods of biodegradation generate methane, a greenhouse gas that is 23 times more powerful than CO2.
The way forward is not as obvious as it may have seemed. However, research is moving forward and the bio-based plastics industry is recent enough that it can be given time to come up with new solutions. Their novelty and the pressing competitive environment should lead to progress rapidly being made as regards the environmental impact of these new materials./p>
From black gold...
Considered to be largely responsible for global warming, CO2 has just found its defenders. They are Japanese, Norwegian and American, and all belong to separate research centres intent on making the gas a key component of a future polymer. Plastics are mainly comprised of carbon, like CO2. So why not make plastics with the carbon dioxide already present in the atmosphere? The idea has been floating around for around a decade, and that was the time it took for these teams to come up with a way of extracting the CO2 from the air. Even better, the carbon is captured near water treatment and energy production plants, where the air is particularly loaded with carbon. The gas is then converted, using the process of biocatalysis, into a liquid polymer that can then be converted into a plastic.
...to transparent gold
As proof that the technology has created interest, Dell recently launched a pilot project aimed at making the protective covers for its portable computers entirely from this new polymer in the United States and Canada. In China, plans are being made to install pollution vacuums to recover as much raw material as possible. German manufacturer Bayer even managed to go one step further by producing polyol, a polyurethane foam until recently made from petro-sourced plastic, from CO2. Initial tests are very encouraging as this innovative foam is able to reach the same level of quality as traditional polyol.