Scalable production of polyamide-6/graphene composites with enhanced electromagnetic shielding and thermal conductivity

•PA-6/FLG composite was prepared by combining mechanochemistry and scCO2.•The compatibility between FLG and polymer matrix was greatly enhanced.•The TP-σc enhanced significantly up to 29.59 S·m−1 only at 3 wt% FLG amount.•The PA-6/FLG composite showed an excellent EMI SE of 41.4 dB.•The TP- kc enhanced to up to 2.14 W m−1 K−1 with 3 wt% of Gns amount.