Automotive Bioplastics in automotive applications By Daniela Rusu, Séverine A.E. Boyer Marie-France Lacrampe, Patricia Krawczak Ecole des Mines de Douai, Department of Polymers and Composites Technology & Mechanical Engineering, Douai, France Nowadays, polymeric materials represent approximately 20 % of the total weight of an automobile, in other words 100 to 150 kg/car. This substantial need in plastics, and recent economical and ecological issues such as the increasing crude oil price, accelerated depletion of fossil resources, together with the new regulations for controlling greenhouse gas emissions and management of the end-of-life of vehicles, has encouraged the automotive industry to develop, adapt or revive some long existing more eco-friendly plastic materials and biocomposites for their modern cars. Currently bioplastics cover a wide range of materials, from commodity thermoplastics up to engineering materials and thermosetting resins. Within these bio-based polymeric materials, some are already validated for different automotive applications: it is the case for some bio-based polyamides and bio-based polyurethane foams, but also for polylactic acid formulations and fabrics. Other bioplastics with potential/validated use in automotive industry are belonging to the class of bio-based polyesters and copolyesters, starch plastics, bio-based polyolefins and bio-based thermosetting polymers such as unsaturated polyester resins or bio-based epoxies (for more details see [1]). And even if some of their present features are not yet optimal for durable automotive applications, they could offer in future real alternatives for petrochemical plastics in modern cars. Taken from Handbook of Bioplastics and Biocomposites Engineering Applications edited by Srikanth Pilla – Wiley-Scrivener 2011 (http://www.wiley.com/WileyCDA/WileyTitle/ productCd-0470626070.html). 14 bioplastics MAGAZINE [01/12] Vol. 7
Automotive The following shows three examples of bioplastics and vegetal fibre reinforced bioplastics to have an idea about the potential of these types of materials for automotive applications. Biopolyamides (Bio-PA) Polyamides (PA) are engineering thermoplastics that combine excellent mechanical properties, such as high mechanical strength and stiffness, wear properties, good heat resistance, together with chemical resistance to oils and solvents, dielectric properties, fire resistance, good appearance, and good processability. All these interesting features design them for high-end automotive applications, especially for under-the-hood car compartment. In fact, PA and PA composites represent about 10% of the plastics parts in modern cars. Until recently, the polyamides for car applications were petro-based, except the Rilsan ® PA 11 from Arkema, derived from castor oil, and already used for flexible tubing, mono-wall fuel lines and Rilperm ® multi-layer fuel lines, such as in ESD-Flex conductive fuel-pump module for General Motor car models, and for friction parts, quick connectors, pneumatic brake noses. Today, several other new bio-based polyamides appeared on the market, derived (at least partly) from renewable feedstocks such as castor beans and sugar cane. A recent example of an under-the-hood application of a biopolyamide, the DuPont Zytel ® RS, PA 6.10 (with 62.5% biobased carbon content), is the new automotive radiator end tank proposed by Toyota, Denso and DuPont Automotive consortium, and used in some 2009 Toyota Camrys vehicles. In appears that current and emerging bio-PA are promising new solutions for replacing the petrochemical polyamides, but also for extending the metal substitution in car applications, improving automotive comfort, design and insulation, and enriching the performances with fuel economy and reduced CO 2 emissions. PLA and PLA-based composites While the biopolyamides already represent themselves as engineering polymers for high-end automotive applications, PLA is a rather new polymer in automotive applications and from some aspects, still in development. For long time, this aliphatic biodegradable polyester was intended only for biomedical and packaging uses, but in the last years, new PLA-improved materials were proposed for durable applications, such as transportation, electrical applications and electronics. Up to now, PLA fibers and fabrics were proposed for floor mats, in Toyota Raum and Prius cars (2003), and for canvas roof and carpet mats in Ford Model U (2003). The more recent Biofront stereocomplex PLA codeveloped Teijin & Mazda, is intended for automotive applications such as car seat fabric, as for Mazda Premacy Hydrogen RE Hybrid vehicle, but also floor mats, pillar cover, door trim, front panel and ceiling material. Vegetal fibre reinforced PLA is another class of green materials, with current and potential car applications. For instance, Toyota is already proposing automotive applications for PLA/kenaf biocomposites, such as the cover spare wheel on Toyota Prius and Toyota Raum (2003) or the translucent roof PLA/kenaf and ramie biocomposites on Toyota 1/X plug-in hybrid concept vehicle. Castor plant Accelerator pedal made from bio-PA 6.10 (prototype) bioplastics MAGAZINE [01/12] Vol. 7 15
