Glass transition temperature and mechanical damping of spruce lignin plasticized with methylimidazolium-based ionic liquids

An isolated spruce lignin was plasticized with methylimidazolium-based ionic liquids (ILs) with varying cations and anions and the glass transition temperature (T g ) and mechanical damping of the blends were determined with dynamic mechanical analysis (DMA). The T g was found to decrease for all blends. The mechanical damping, however, was found to be maintained or decreased upon plasticization, indicating a maintained or increased mechanical rigidity. Only a combination that included the sterically hindered, strongly hydrogen-bond-accepting anion acetate increased mechanical damping. • Lignin was plasticized using ionic liquids (ILs) of different cations and anions. • While the T g was lowered, a decrease in mechanical dampening was often observed. • This discrepancy may stem from strongly interacting networks of lignin and ILs. • The choice of anion had more impact on these properties than choice of cation.