<scp>MXene</scp>‐assisted click chemistry of L‐cysteine for the preparation of highly efficient damping materials

Abstract L‐cysteine, a bio‐based modifier with multiple functional groups (thiol, amino, and carboxyl), holds promise for polymer modification. However, its tendency to agglomerate and poor solubility in nonpolar polymers limits its effectiveness. In this study, 1,2‐polybutadiene (1,2‐PB) was intercalated within MXene layers to enhance L‐cysteine dispersibility. The intercalation allowed nanoscale distribution of 1,2‐PB within MXene sheets, while interactions between MXene's hydroxyl groups and L‐cysteine's polar groups promoted uniform dispersion in the rubber matrix. Compared with physical blending, the grafting degree of L‐cysteine is higher, thereby more effectively restricting the movement of molecular chains, which leads to an increase in the effective damping temperature by over 7°C. Additionally, due to the ionic interactions between the functional groups, the resulting composite exhibits favorable dielectric performance, with the dielectric constant increasing from 2.5 to 3.2. Experimental results demonstrate that the synergistic effect between MXene and L‐cysteine improves both the damping and dielectric properties of the resulting composites. This study presents a novel approach using two‐dimensional nanosheets and bio‐based thiols for modifying polybutadiene, offering a potential path for high‐performance functional materials. Highlights In‐situ polymerization enhances MXene distribution in the matrix. Grafting degree of L‐cysteine increases with MXene incorporation. Well‐dispersed MXene reduces L‐cysteine aggregation, enhancing mechanical strength. Effective damping temperature rises by over 7°C with MXene and L‐cysteine. Dielectric constant of composites increases from 2.5 to 3.2.