Isocyanate-functionalized starch as biorenewable backbone for the preparation and application of poly(ethylene imine) grafted starch

Abstract Reactive supports provide versatile platforms for surface decoration, affording various functional materials widely used in chemical and biological research. Considering the biodegradability, biocompatibility, and economy, starch is a suitable support media with high functionality for further chemical modifications. In this proof-of-concept study, isocyanate-functionalized starch was prepared using symmetric diisocyanates as bridging block. Its potential as a reactive platform support was evaluated from the aspects of reactivity and storage stability. Polyamine could be grafted onto this reactive support via urea linkage. The applicability of PEI grafted starch as organic base catalyst was then tested in Knoevenagel condensation as a model reaction. Moreover, the feasibility of PEI grafted starch as a scavenger was also demonstrated in the capture of acid fluorescent dye and excess electrophilic reagent. Graphical abstract