High-wet-strength hierarchically split cellulose fiber-based paper enabled by ultrafine polylactic acid and densification

Cellulose fiber-based paper has aroused wide interests owing to its potentials in building robust architectures with diverse functionalities. The chemically active surface of cellulose fiber enables the flexible manipulation of interactions, but degrades its mechanical stability in aqueous solution or moisture circumstances. Therefore, a prerequisite of achieving high wet strength is to enhance the anti-swelling capability without limiting the application scenarios. Herein, we proposed a hierarchically split cellulose fiber (HSCF)-based paper with high wet strength, featuring relatively hydrophobic ultrafine polylactic acid (PLA) capping. The reliable interaction between HSCF and PLA is derived from hydrogen bonding, multiple interfaces, and densification by hot-rolling process. The optimal tensile strength and modulus of HSCF/PLA composite paper can reach 100.24 ± 6.38 MPa and 2.50 ± 0.16 GPa, and the high wet strength can achieve 45 MPa. We further showcase the application in circuit board (PCB) with low dielectric constant and loss factor, and high breakdown strength.