A Strategy for Synergistically Plasticizing the Melt Processing of Polyvinyl Alcohol Using a Green Molecule: Reconstructing Hydrogen Bond Networks With Renewable Trehalose

Poly(vinyl alcohol) (PVA) is a biodegradable polymer with poor melt processability. This intrinsic property necessitates energy‐intensive, solvent‐dependent processing methods. This study introduces a green strategy using trehalose, a non‐toxic disaccharide, as a “molecular director” to reconfigure PVA's hydrogen‐bond network. Combined with glycerol and PEG400, trehalose acts as a rigid “hydrogen‐bond reconfiguration center.” It competitively replaces PVA–PVA hydrogen bonds with stronger PVA–trehalose interactions. The interaction energy ranges from 29 to 31 kJ/mol. This synergistic mechanism increases free volume by 36.69%. Consequently, melt viscosity at 230°C is reduced to 1/15 of that of pristine PVA. A quantitative power‐law model ( R 2 = 0.996) links free volume to viscosity, enabling predictive processing design. This work identifies a molecular mechanism by which a carbohydrate motif regulates hydrogen‐bonded polymer networks and provides an applicable approach for tuning the dynamics and melt behavior of strongly associated polymers.