A Multifunctionalized CO2‐Fixing Resin Transforms Paper to High‐Strength and Flame‐Retardant Plastic Substitutes

In the plastic industry, replacing petrochemical‐based polymers with naturally occurring bio‐polymers (represented by cellulose), is a very promising route to circumvent the plastic pollution issue. However, the implementation of this is severely hindered by the high water affinity and flammability of such materials. Here, a verstile non‐isocyanate polyurethane (NIPU) formulation composed of a CO2‐based cyclic carbonate compound, a reactive amino‐functionalized silicone oil concurrently capable of providing water‐resistance and a flame‐retardant moiety is designed. Compositing it with conventional cellulose paper (cellulose macrofiber network, CMN), a nonflammable and mechanically strong cellulose macrofiber network‐based biocomposite (CMN‐Biocomposite) can be easily obtained via transcarbamoylation reaction. Other than hydrogen bonding interaction among various components of CMN‐Biocomposite, the intermolecular bond exchange mechanism between the dynamic carbamate moiety and hydroxyl of the cellulose is also experimentally and computationally determined as the governing factor for the high tensile strength of up to 57.9 MPa. Additionally, benefiting from the dynamic nature of the carbamate bond, the CMN‐Biocomposite's processability and biodegradability outperform most petrochemical‐based plastics. The superiority of the proposed synthetic strategy in achieving the long‐term carbon neutrality goal by CO2 fixation and excellent performance for plastic applications make the CMN‐Biocomposite a very promising alternative to conventional plastics.