Glycol lignin/MAH-g-PP blends and composites with exceptional mechanical properties for automotive applications

Lightweight plastics and their composites are being increasingly used in automobiles to reduce emissions and costs, but the market demand for fossil fuel-based plastics such as polypropylene (PP) creates several environmental problems such as pollution and waste. Although replacing PP with biomass such as lignin is not a new endeavor, the vast majority of past studies reported reduced mechanical properties as lignin content increases, which limits its application in industry. Herein, blends of maleic anhydride-grafted PP (MAH-g-PP) and softwood-derived glycol lignin (GL) are successfully fabricated via a melt-mixing approach, which boast exceptional mechanical properties and thermal stability. Synergistic performance enhancement is observed when combined with carbon fiber reinforcement, which is elucidated by nanoindentation of the fiber/polymer interface. This work contributes to the development of sustainable automotive structures by efficiently combining biomass and traditional materials.