New kinds of lignin/non-isocyanate polyurethane hybrid polymers: Facile synthesis, smart properties and adhesive applications

The increasing demand of less toxic and non-dangerous chemicals for material preparation has boosted the development of non-isocyanate polyurethanes (NIPUs). Lignin, as a kind of natural and sustainable polymer, has been employed to replace traditional petroleum-derived chemicals for NIPUs synthesis. In this work, novel lignin/NIPU hybrid polymers (LNIPUs) were facilely synthesized from lignin, bis(6-membered cyclic carbonate) (6CC) and polyetheramine. The yielded hybrid polymers not only possess distinctive mechanical and thermal performance, but also exhibit a wide variety of smart properties including shape memory, self-healing and reprocessability. In addition, the synthetic product LNIPUs show outstanding adhesive properties with an adhesive strength of up to 24.5 MPa obtained from the aluminum plates bonding. This work provides a convenient way to endow lignin-containing NIPUs with excellent properties and simultaneously opens up promising applications of the resultant materials.