Mechanochemical Synthesis of Dynamic Hybrid Polymer Networks using Whole Biomass

Whole plant biomass from non-agricultural sources and waste biomass from processing agricultural products are promising feedstocks for biopolymer production because they are abundant and do not compete with food production. However, their processing steps are notoriously tedious with the final materials often displaying inferior performance and limited scope in their properties. Here, we report a strategy to integrate whole-cell spirulina, a green-blue algae, into mechanically robust hybrid biomass-polyimine networks by leveraging mechanochemistry. This strategy provides a greener synthetic approach to conventional solution-phase methods for polyimine synthesis, and it simultaneously overcomes persistent constraints encountered in biomass processing and derivatization. The hybrid algae-based materials retain recyclability imparted by the underlying dynamic covalent polymer matrix and display enhanced mechanical properties compared to their all-synthetic equivalents. These advantageous properties are attributed to differences in morphology between 1) the all-synthetic material and the hybrid materials and 2) their respective synthetic methods (solution-phase vs mechanochemical). Substituting spirulina with alternative biomass sources such as waste agricultural products also yields robust hybrid materials, thus highlighting the generality of this mechanochemical approach.