Breaking the corrosive solvent paradigm: Scalable wet-spinning of PPTA/MWCNT composite fibers with unprecedented strength-functionality balance

Currently, the high performance and multifunctional integration of poly(p-phenylene terephthalamide) (PPTA) fibers are still facing the limitations of the use of corrosive solvents and the poor dispersion of functional fillers in the polymer matrix. Herein, PPTA prepolymers with controlled degrees of polymerization were designed as macromolecular monomers and co-dispersed with multi-walled carbon nanotubes (MWCNT) in a composite medium consisting of polar solvent and co-solvent to synthesize a high molecular weight PPTA/MWCNT (PMC) solution via in situ secondary polymerization. The non-covalent adsorption of MWCNT by the prepolymer molecules combined with a mild secondary polymerization process ensured the homogeneous dispersion of MWCNT in PPTA solution. Subsequently, the PMC solution was processed into fibers by an efficient and controllable wet spinning process, and the strength and modulus of PMC fibers were as high as 1.61 GPa and 51.5 GPa. Furthermore, the three-dimensional conductive-thermal network formed by MWCNT endowed PMC fabrics with an electromagnetic shielding effectiveness of 32.6 dB in the X-band and enhanced thermal conductivity by 58.2 % compared with pure PPTA fabrics. This work provides a scalable and environmentally benign strategy for manufacturing high-strength PPTA fibers and their multifunctional fabrics.