Multifunctional Thermoplastic Paper Enabled by Plant‐Cell‐Derived Additives: A Paradigm of Paper‐Based “Modern Alchemy”

Abstract Papermaking, an ancient yet remarkable invention, hinges on the formation of a network of plant cells. With the growing demand for bio‐derived alternatives to non‐renewable resources and difficult‐to‐degrade plastics, enhancing the functional attributes of cellulosic paper is essential to broaden its applications. Here, a facile approach is introduced to upgrade conventional cellulosic paper into an advanced thermoplastic biomaterial, endowed with ductility, wet‐strength, gas and liquid barrier functionalities, and antistatic properties. The concept is grounded in the specialized area of papermaking wet‐end chemistry and chemical additives and employs plant‐cell‐derived cellulosic additives, prepared via ring‐opening‐based heterogenous chemical engineering of paper‐grade pulp with microstructurally porous cell walls comprising fibrils, which are then formed upon dissolution in an aqueous “non‐derivatizing” solvent, for engineering the paper through a process that somehow mimics the industrial surface sizing. The utilization of additives initiates a form of paper‐based “modern alchemy”, which involves the encapsulation of fibers with ring‐opening‐engineered cellulosic structures, solvent‐induced fiber annealing, bridging of interfiber gaps, film‐forming, porosity reduction, structural densification, enhanced internal bonding, paper surface smoothening, etc. The engineered paper can be facilely reshaped through hot‐pressing for 3D forming and recyclable applications. Additionally, their dissolution in a cellulosic solution yields functional additives for diverse applications, offering another avenue for recycling. This work offers insights into designing paper‐based thermoplastic materials using sustainable additives.