Bioplastics were first used in cars back in the 1930s, with Japanese manufacturers being the market leaders in the industry first pioneered by Henry Ford. The past 15 years has seen a reemergence of their use as the world becomes ever more conscious of human impacts on the environment.
Plastics now represent approximately 20% of the average car’s weight, and have steadily been replacing metals over the past 50 years. They are cheaper and lighter than metal, and have favourable qualities (e.g., corrosion resistance, freedom in design, flexibility, potential recyclability, and compostability, etc.).
There are several types of bioplastics in use, but insofar as the hemp industry is concerned two are vital: natural fibres (i.e., composites) and polylactic acid (PLA).
In the case of natural fibre composites, polymers are mixed with fibres to strengthen them. The most famous example is fibreglass, yet hemp composites are nothing new since Henry Ford used them. During the 1940s, Ford designed and built a car made almost entirely of hemp plastic, while the likes of BMW, Mercedes, Audi, and Volkswagen today make use of it in door panels, dashboards, and other interior components.
Volvo particularly emphasises its advertised “vegan” interiors of its new Polestar auto line. BMW’s zippy i3 launched in 2013; it is reported to weigh 800 pounds lighter than other cars in its class, all due to hemp. The latest Porsche 718 Cayman GT4 race car uses hemp composites (manufactured by HempFlax out of the Netherlands), and even the much smaller car manufacturer Lotus seems to be experimenting with hemp-infused materials in its Eco Elise. American comedian and car collector Jay Leno made headlines when he drove a hemp-produced Renew in 2017.
Hemp lends itself particularly well to automotive bioplastics due to its high cellulose content (hemp hurds are approximately 80% cellulose), while being 3.5x stronger than petroleum-based plastics and 5x times lighter though still biodegradable.
Swedish biocomposites developer Trifilon won last year’s European Industrial Hemp Association (EIHA) Product of the Year award for its BioLite product, which is made of 30% hemp fibres and positioned as a yet lighter alternative to carbon fibre.
For its part, PLA is a relatively new biopolymer being used in the automotive industry, having traditionally been used in biomedical and packaging applications. PLA can be used for components under the hood as well as in car interiors, whether for carpeting, floor mats, or upholstery. It is slowly gathering the top market share of polyesters by offering better heat resistance, impact resistance, and UV resistance while aesthetically offering a high gloss and particularly ease to colour.
Faurecia, a French automotive parts supplier, provides the likes of Renault with some hemp-based PLA; the company expects its products to be 100% plant-based by 2023. The trend is on the rise, with pressure for wider adoption of bioplastics fueled by both consumer expectations and by the need of automakers to overhaul waste management. The problem has been growing at a compounding rate, with Technavio reporting an estimated 3% per annum rise in automotive waste. Bioplastics can alleviate that issue, with hemp bioplastics particularly well suited to do so as they are fully biodegradable.