A Volkswagen project engineer says that use of lignin as a thermoplastics filler offers “an enormous lightweight potential” for large volume auto production. Use of lignin in car parts dates to 2006 by a German company called Tecnaro, but only for exotic parts such as steering wheel substrates.
“A (polypropylene) compound filled with up to 30 percent lignin powder offers a 20 percent weight reduction compared to traditional filled PP compounds assuring the same mechanical performance,” said Hendrik Mainka of VW in a presentation at the Society of Plastics Engineers’ Annual Technical Conference (Antec) held in March in Orlando, Florida. Costs would be reduced as much as 30 percent through replacement as fillers such as glass, talc, carbon black, aluminum oxides, and silicates.
Paper production generates about 60 million tons of lignin a year as a waste product. Lignin makes plant cell walls fibrous and hard and is the second most common organic material on earth (after cellulose), with about 20 billion tons being formed each year by photosynthesis
Mainka’s technical paper reported his research showing the specific technical properties of lignin compounds, and the enhancements possible through use of a compatibilizer. The best values were measured with 20 percent lignin content and MAH compatibilizer.
He did not comment on specific commercial plans that VW may have for use of lignin in series production.