One-pot preparation of hydrophobic lignin/SiO2 nanoparticles and its reinforcing effect on HDPE

Nano silica (SiO2) is usually used as a common reinforcing agent in polymer materials, in which the interfacial interaction greatly affects the mechanical properties of the composites. The reinforcement effect of silica on non-polar polymer is restricted due to their poor compatibility. In this work, amphipathic lignin modified by quaternizat ion and alkylation was used as a modifier for silica to prepare hydrophobic lignin/SiO2 nanoparticles by in-situ one-pot co-precipitation method. In alkaline solution. hydrophobic lignin and SiO2 (from Na2SiO3) were self-assembled to form nanospheres through electrostatic and hydrophobic interactions. The results showed that the lignin/SiO2 nanoparticles were highly hydrophobic nanospheres with macropores in the surface. When the lignin/SiO2 nanoparticles (10 wt%) were added to reinforce high-density polyethylene (HDPE), the mechanical properties of HDPE were improved with the strength of 24.5 MPa and the elongation of 1096%, which were increased by 10.4% and 14.3% compared with the control HDPE, because of the good compatibility and large bonding area. This work puts forward a new solution for the application of lignin in reinforcement of non-polar polymers. (C) 2021 Published by Elsevier B.V.