Bio-based PA56/GO nanocomposite fiber with 1.2 GPa strength via in situ precipitation and solvent-free polymerization

Toward high-strength bio-based polyamide 56 (PA56) fiber, we first in situ precipitate graphene oxide (GO), adipic acid and 1,5-pentanodiamine together by reaction crystallization in ethanal to obtain PA56 salt/GO particles with well dispersed GO, then prepare PA56/GO nanocomposite with PA56 salt/GO via solvent-free polymerization including solid-state prepolycondensation and melt polycondensation. Finally, PA56/GO nanocomposite fiber is prepared by extrusion drawing. With 0.2 wt% GO, the tensile strength of PA56/GO fiber reaches 1050 MPa, which is 3.3 times that of pure PA56 fiber. Furtherly, we add PA56/GO with high GO content to commercial PA56 to prepare the hybrid fiber, of which the tensile strength reaches 1248 MPa. The great improvement is mainly due to the good dispersion of GO in the whole process, which increases the heterogeneous nucleation in favor of higher and oriented PA56 crystallization.