Effect of Lignin‐Derived Graphene on Glass Transition Temperature of Polymethacrylates

ABSTRACT Synthesis of graphene‐containing polymethacrylates was performed by radical polymerization of methacrylate monomers with 1 wt.% of commercially available graphene or lignin‐derived graphene. Among the synthesized polymethacrylates, the glass transition temperatures ( T g s) of poly‐MMA, poly‐PhMA, and poly‐ tert ‐BMA containing both graphene compounds were higher than those of the corresponding polymethacrylates without the graphene compounds, owing to the restricted molecular motion of the polymer chains by graphene compounds. Experimental results and DFT‐calculated differences in rotational barrier energy suggest that the higher the intrinsic mobility of the monomer substituent, the more effectively the graphene compounds restrict the motion of polymer chains. Additionally, the T g ‐enhancing effects of both graphene compounds were also observed in the networked copolymers. These findings indicate that the lignin‐derived graphene compound can function as an effective additive for improving the thermal stability of polymers, comparable to its commercial counterpart.