Colloquia

Samenvatting

Growing environmental concerns have driven the tyre industry to investigate bio-based alternatives to fossil-based carbon black as reinforcing fillers. Lignin, an abundant aromatic biopolymer and by-product of the pulp and paper industry, shows potential as a sustainable filler but suffers from poor compatibility, agglomeration, and curative absorption leading to poor in-rubber properties. This thesis investigates the reinforcement behaviour of lignin-based fillers, focusing on the role of polymer matrix selection, polymer–filler interactions, and cure response. A systematic experimental approach combined filler characterisation with in-rubber studies in SBR, BR, ENR, and NR, evaluating filler type, loading, and surface modification through cure analysis, Payne effect, and tensile testing. Ex-situ and in-situ modification strategies using commercial chemicals containing silane, thiol, epoxy, and vinyl functionalities were investigated as well. The results demonstrate that polymer polarity and backbone functionality dominate lignin reinforcement effect, with ENR showing superior dispersion and stress transfer due to enhanced compatibility and positive epoxy-related interactions. Overall, this thesis shows that the reinforcement behaviour of lignin-filled compounds is strongly influenced by interactions among lignin hydroxyl groups, curative absorption, and epoxy-containing constituents. The results presented in this thesis could pave the way for further studies on the application of lignin in rubber compounds.