Earth Day 2020: More Plastic Makes for Enhanced Sustainability in Autos

The transportation sector accounted for 28% of U.S. greenhouse gas emissions in 2018 according to the Environmental Protection Agency (EPA), which is more than any other sector including electricity generation (27%) and industry (22%). As such, reducing carbon dioxide discharges from this sector are seen as critical if global targets are to be met.

Ways of reducing emissions include opting for electric vehicles if the electricity used for charging is generated sustainably, selecting petroleum-powered vehicles with better fuel economy (SUVs and pickup trucks are big no-nos!) using public transport, cycling, and walking. And for those business travelers and jet setters, flygskam (Swedish for flight-shaming) might convince more of us to meet virtually (we are all now of course experts at Zoom and GoToMeeting in this COVID-19-constrained environment) or engage in virtual tourism, which admittedly sounds like a poor substitute. Incidentally air travel accounts for 3% of global emissions.

From hibiscus to door trim—natural fiber reinforcement in the Toyota LQ electric concept car. Image courtesy of Toyota.

LyondellBasell’s Wesseling site in Germany produced one of the first batches of bio-based PP. Image courtesy of LyondellBasell.

Once you’ve made your choice of motion, you can be assured that plastics are playing major roles in improving the operational efficiency of your preferred mode, even down to the bounce of the sole in your sneakers, perhaps even derived from an expandable bio-based thermoplastic polyurethane (TPU). Here we take a look at recent technologies that are improving the carbon footprint of automobiles.

For starters, no matter how big and fuel-inefficient your current vehicle might be, things would be a lot worse if your massive front bumper and grill were made from steel rather than plastics, like they were in the 1960s and 1970s. Plastics have contributed greatly to mitigating curb weight increases over the years as average vehicle mass has continued to rise as a consequence of more functionality being incorporated and cars themselves getting bigger globally. Think the HDPE fuel tank, the dashboard and console, interior and exterior trim and you’ll see where weight has been slashed versus non-plastic alternatives.

So what's in store for the next phase of vehicle greening? The use of bio-based plastics and reinforcements, as well as plastics with recycled content, will hopefully go some way to placating the plastics-adverse environmentalists who themselves most certainly depend on several modes of transport to get around.

Take Belgium’s EconCore, a developer and licensor of lightweight thermoplastic honeycomb core technology already employed in transport applications. The company’s latest offering is a honeycomb based on recycled polyethylene terephthalate (rPET) recovered from bottles and food packaging. An rPET honeycomb sandwich panel outperforms polypropylene (PP) honeycombs both in terms of temperature and strength performance. PP grades incorporating recycled content are also debuting, initially in appliance applications, but it seems only a matter of time before the knock on the auto industry’s door.

Several companies, including LyondellBasell and Neste, and Japan’s Mitsui Chemicals, are developing technologies for production of PP based on renewable hydrocarbons and while initial deployment may be in packaging and other non-auto applications automakers will be clamoring for such materials to boost their green credentials.

PlasticsToday marks Earth Day’s 50th anniversary April 22 with a series of articles highlighting the real efforts that the plastics industry is taking to mitigate plastic pollution and develop effective and viable sustainable solutions. You can find all of the relevant content by typing “Earth Day 2020” in the search box at the top of the home page.

Those old enough to remember the nauseating taste of castor oil will be happy to hear it has found a more productive use, specifically in the rear bumper stay of the latest Mazda 3 & CX-30 models. Polyamides in particular are engineering plastics that can be readily polymerized from biomaterials, including potentially wood-derived turpentine.

Bio-based sebacic acid, which is used to produce BASF’s Ultramid Balance PA grade, originates from the castor oil plant. The grade reportedly boasts superior performance compared to the standard s PA6 and PA66, particularly in terms of chemical resistance, and performance is something that no automaker is prepared to compromise in order to boost its green credentials.

Cellulosic resins are also making a comeback based on their green credentials. Eastman’s 42–46%, bio-based Trēva, for example, represents an alternative to polycarbonate, ABS and PC/ABS for interior automotive applications at a cost-neutral position. Besides performance, cost remains a key challenge to greater adoption of bio-based plastics in automotive and many other sectors.

Resin suppliers also need to contemplate the environmental footprint of the additives and reinforcements they employ with “green polymers” in order to complete the circle of sustainability and alternatives are fortunately available. Clariant and Neste, for example, have teamed up to develop renewable-based flame retardant, lubricant and nucleating solutions for plastic compounds.

In terms of fiber reinforcement, natural kenaf fibers have long been used sporadically in auto applications, mainly by Toyota. Not part of the food chain, kenaf is a member of the hibiscus family and is found in regions such as Southeast Asia, Bangladesh, India and Africa. Most recently, Tier 1 Toyota Boshoku teamed up with Covestro to develop a kenaf fiber-reinforced polyurethane composite material for door trim in the new LQ electric concept car developed by Toyota.

So there you have it. Any credible car of the future surely needs to incorporate a higher degree of sustainability to resonate in an increasingly environmentally-aware market, and that is going to mean more plastics not less. One day, perhaps the likes of renewables refiner Neste may envisage that the majority of the oil associated with a new car could be the waste cooking oil used to make the PP resin it uses.

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