Preparation and Applications of Green Thermoplastic and Thermosetting Nanocomposites Based on Nanolignin

The development of bio-based materials is of great importance in the present environmental circumstances; hence, research has greatly advanced in the valorization of lignin from lignocellulosic wastes. Lignin is a natural polymer with a crosslinked structure, valuable antiradical activity, unique thermal- and UV-absorption properties, and biodegradability, which justify its use in several prospective and useful application sectors. The active functionalities of lignin promote its use as a valuable material to be adopted in the composite and nanocomposites arenas, being useful and suitable for consideration both for the synthesis of matrices and as a nanofiller. The aim of this review is to summarize, after a brief introduction on the need for alternative green solutions to petroleum-based plastics, the synthesis methods for bio-based and/or biodegradable thermoplastic and thermosetting nanocomposites, along with the application of lignin nanoparticles in all green polymeric matrices, thus generating responsiveness towards the sustainable use of this valuable product in the environment.