Lignosulfonate/silica hybrid nanoparticles as a novel biobased filler in polybenzoxazine matrix

Abstract

AbstractLignin is an abundant and sustainable resource that exhibits numerous attractive functional properties as a reinforcing agent for benzoxazine‐based composites, due to its stiffness, thermal stability, and high carbon content. However, the low quality of lignin particles dispersions associated with the weak particles‐matrix interactions reduces the reinforcement capability. In this work, hybrid lignin/silica (NaLS/SiO2) nanoparticles were obtained from sodium lignosulfonate (NaLS) and tetraethylorthosilicate (TEOS) under basic conditions. The particles were characterized by transmission electron microscopy (TEM) confirming their spherical morphology and narrow nanometric‐size distributions. The hybrid particles were incorporated into conventional benzoxazine (BA‐a) and a difuran biobased benzoxazine (SA‐dfda) to prepare nanocomposites with different mass compositions (3, 5, and 10 wt%). Morphological, mechanical, dynamo‐mechanical, and thermal properties of the obtained composites were assessed. All the materials exhibited a homogenous filler dispersion that contributed to improve the reinforcement properties. Hybrid nanoparticles proved to be an interesting alternative as a filler in the benzoxazine matrix to prepare high‐performance thermosetting composites.