CP–MAS NMR spectra of polyurethane–lignin blends



Solid-state high-resolution C-13 NMR spectra of lignin, a polyurethane, and their blend give information about phase structure and interactions in the blend. As the Tg values indicate, this is an incompatible blend, and values of the spin–lattice relaxation times in the rotating frame confirm tthat there are two separate phases in the blend. However, buildup of magnetization wiitthin the two phases clearly indicates some interactions between the phases, which allow transfer of magnetiization from lignin to the polyurethane.