Maleimidophenyl isocyanates adducts as versatile post-polymerization modification agents for biobased furan polymers

Abstract

Biobased furan polymers (BFPs) derived from 5-hydroxymethylfurfural (HMF) are eco-friendly polymers obtained from inedible biomass resources. Modification of such polymers is expected to expand their practical uses. BFPs have furan moieties that can react as dienophiles with maleimide, facilitating well-designed polymer reactions. Herein, we report the preparation of various maleimides using p-maleimidophenylisocyanate (PMPI), which has a highly reactive isocyanate group and a maleimide group, to modify BFP through the Diels–Alder reaction of the maleimide group. Two reactive sites in PMPI exhibit orthogonal reactivity, enabling us to achieve tailor-made modification agents. The T_g values and rheological properties of modified polymers can be tuned according to the structure of maleimide and their reaction conversion, which demonstrates the practical usability of BFP derived from furfural. The strategy proposed herein can be applied to obtain biobased materials with desirable functions and physical properties.