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

Abstract

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.