Biobased Microgel Nucleating Agent-Enhanced Polylactic Acid Fibers with High Strength, Superior Heat Resistance, and Dyeability

The intrinsic brittleness, sluggish crystallization kinetics, and poor thermal stability during dyeing severely restrict the high-performance textile applications of poly(lactic acid) (PLA). Herein, we demonstrate a facile strategy to fabricate high-strength, heat-resistant, and dyeable PLA fibers by constructing an in situ cross-linked microgel network derived from 4,4′-diaminodiphenylmethane (DDM), tannin acid (TA), and epoxidized soybean oil (ESO). The resulting DDM-TE (referred to as DDM-TA-ESO) microgels serve as efficient heterogeneous nucleating agents, significantly refining the crystallization property of PLA. During hot drawing, this 3D microgel nucleating agent acts as a structural guide, promoting the orderly orientation of molecular chains and the development of stable α-crystals. Consequently, the DDM 0.2 -TE/PLA fibers exhibit a remarkable tensile strength of 257.75 MPa, surpassing neat PLA fibers. Moreover, the reinforcement and confinement effects of the microgel network endow the fibers with superior dimensional stability (boiling water shrinkage of ∼6.7%) and enable successful dyeing using conventional aqueous disperse dyes. The dyed fibers achieve high color depth (K/S over 18.7) without the catastrophic mechanical degradation, providing a robust pathway for the industrial-scale production of biobased textiles.