Michigan State University

Saeid Nikafshar

Mojgan Nejad

The disclosure relates to a polyurethane prepolymer and corresponding crosslinked network polymer incorporating lignin as a natural polyol in the polyurethane system. The polyurethane prepolymer includes a reaction product between an isocyanate, lignin, and a cyclic alkyl carbonate. The reaction product includes (i) free isocyanate groups and/or free hydroxyl groups, (ii) urethane linking groups between residues of lignin aliphatic hydroxyl groups and the isocyanate, (iii) ester linking groups between residues of lignin aromatic hydroxyl groups and a ring-opened form of the cyclic alkyl carbonate, and (iv) optionally urethane linking groups between residues of the ring-opened cyclic alkyl carbonate and the isocyanate. The polyurethane polymer can be a networked, crosslinked polymerization product of the prepolymer reaction product, for example in combination with a lignin curing agent. The polyurethane polymer can be used as a coating on a substrate, an adhesive joining multiple substrates, etc.

Lignin-based polyurethane prepolymers, polymers, related compositions, and related methods

The disclosure relates to encapsulated UV (ultraviolet) stabilizer/absorber nanoparticles, which nanoparticles limit or prevent the migration of UV stabilizers/absorbers to the surface of a coating in service and/or which otherwise preserve the UV-resistance properties of the UV stabilizer for a longer period once incorporated into a UV-protective coating. The nanoparticles each include a clay or other nanotube encapsulating body such as a halloysite nanotube (HNT) and a UV stabilizing material within the interior cylindrical volume of the nanotube encapsulating body. The UV stabilizing/absorbing material can include one or more of lignin, a biomass extractive, a phenolic biomass material, and an organic UV stabilizer. The encapsulated UV stabilizer nanoparticles can be incorporated into a polymer composite as a heterogeneous phase distributed throughout a continuous polymer matrix. The polymer composite can be applied as a coating or film to an underlying substrate to form a corresponding coated article.

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East Lansing, MI, United States of America

Saeid Nikafshar