Unlocking the potential of lignin as a sustainable filler for tyre and rubber industry: Challenges and opportunities

Over the past decade, the concepts of circular economy, sustainability, and sustainable development have become central to global policy discussions, emphasizing human well-being, social equity, and environmental impact reduction. Achieving a sustainable economy requires a transformation in production and consumption patterns across industries. In the rubber sector, the adoption of eco-friendly materials has gained significant attention, particularly in alignment with the Circular Economy framework, guided by the 7R Strategy (Reduce, Reuse, Recycle, Redesign, Renew, Repair, and Recover). To reduce reliance on fossil-based raw materials, researchers are increasingly exploring plant-derived, renewable, and biodegradable alternatives, such as rice husk silica, cellulose nanocrystals, lignin, and natural fibers, to replace traditional fillers like carbon black and silica in rubber compounding. Among these, lignin— abundant, biodegradable, and derived from annually renewable sources—has emerged as a promising green filler due to its low cost, lightweight, and ecological adaptability. This study investigates the partial incorporation of lignin into natural rubber (NR)/cis-polybutadiene (BR) compounds, replacing ASTM grade N660 carbon black. The effects of varying lignin dosages (5-20 phr) on the mechanical properties and processability of the rubber compounds are analyzed. Results indicate that lignin's morphology, particle size, and agglomeration significantly affect the performance of the composites. Optimization of lignin content enhances the rubber's properties, though challenges remain due to the filler’s poor compatibility with the rubber matrix. Several strategies, including high-temperature mixing, liquid-phase mixing, and surface modification of lignin, are yet to be explored to improve polymer-filler interaction and facilitate lignin's incorporation into rubber products. This work highlights lignin's potential to reduce the carbon footprint of the rubber industry, with further research needed to address compatibility and performance limitations.

Dr. Rabindra Mukhopadhyay did his B.Sc. from University of Calcutta, M.Sc. & Ph.D. (Applied Chemistry) from Indian Institute of Technology (IIT), Kharagpur, India. Started his career in the 70’s as a Faculty in Applied Chemistry at I.I.T, Kharagpur. Subsequently joined Bayer India (Rubber Chemical Division) – 1979-1987. Presently he is the Director (R&D) of JK Tyre & Industries Ltd.; Director & CE of Hari Shankar Singhania Elastomer & Tyre Research Institute, Chairman of Indian Rubber Institute. Immediate Ex- President of Indian Rubber Materials Research Institute (IRMRI). He has got more than 50 years of experience in Education, Training and Research in Rubber Science and Tyre Technology. He is a Visiting Faculty at different Universities and Institutes of National Importance in India. He has to his credit more than 200 research and Technical Papers in National & International journals and seven Patents from his research work. Under his guidance twelve scientists from HASETRI did their Ph.D. from different Universities/IITs in India. He is a fellow member of Indian National Academy of Engineers, India (FNAE), The Institution of Engineers India (FIE), Indian Rubber Institute (FIRI), American Chemical Society (Rubber Division), Indian Society of Analytical Scientists, Indian Institute of Quality etc