Highly tough and electromagnetic shielding poly(lactic acid)/polycaprolactone composites by imidazolium polyurethane grafted MXene and hydroxylated carbon nanotubes

Polylactic acid (PLA), a significant biodegradable polymer, is an ideal candidate for electromagnetic shielding matrix materials due to its excellent tensile strength and processability. IPU-PLA-PCL-MXene was obtained by grafting imidazole-functionalized polyurethane containing PLA and polycaprolactone (PCL) segments onto MXene nanosheets. IPU-PLA-PCL-MXene and hydroxylated carbon nanotubes (CNT-OH) were used to improve the electromagnetic interference (EMI) properties of PLA/PCL composites. CNT-OH is distributed at PCL phase and the phase interface because of the viscosity difference between the two polymer phases. IPU-PLA-PCL-MXene enhances the interfacial interactions between polymer phases, which became an effective bridge for the transfer of interfacial stress. Consequently, the elongation at break and notched impact strength of PLA/PCL/2I/8C reached 287.4 % and 64.1 kJ/m² respectively. CNT-OH and MXene form an effective three-dimensional conductive network, resulting in a substantial improvement in the EMI shielding property of PLA/PCL/2I/8C composite to 38 dB. This work provides a novel approach for highly tough and EMI shielding PLA/PCL composites.