Disulfide-Induced Interparticle Adhesion of Crystalline Cellulose

Cellulose-based materials have attracted increasing attention as sustainable alternatives to petroleum-derived
plastics. However, cellulose has limited processability due to its strong intermolecular hydrogen bonding. In this
study, structurally stable cellulose composites were fabricated by incorporating α-lipoic acid (LA), a naturally
derived molecule containing dynamic disulfide bonds capable of ring-opening polymerization, into crystalline
cellulose. The crystalline cellulose was mechanically pretreated to improve its dispersibility and subsequently
blended with LA to prepare a homogeneous dispersion. The resulting dispersion was processed by two-
dimensional directional melt crystallization (2D DMC) and freeze-drying to fabricate a foam with continuous
pores, followed by hot pressing to produce various molded shapes. The formation of a chain-end stabilizer was
confirmed by ¹H NMR analysis, and three-point bending tests demonstrated improved elongation compared with
neat cellulose foam. In addition, scanning electron microscopy (SEM) revealed the co-continuous porous
structure generated through the 2D DMC process. The incorporation of LA enhanced interparticle adhesion and
structural stability, enabling the fabrication of flexible, shape-retaining cellulose-based bioplastics. This study
presents a new design strategy for improving the processability and mechanical properties of cellulose through
dynamic disulfide chemistry and demonstrates the potential for developing biodegradable cellulose-based foams.