Aqueous bifunctionalization of cellulose nanocrystals through amino and alkyl silylation: functionalization, characterization, and performance of nanocrystals in quartz microflotation

Abstract Surface modifications of cellulose nanomaterials can be used to tailor their surface charge and hydrophilicity-hydrophobicity characteristics. Additionally, it facilitate the selective interaction nanocelluloses with other solid particles further expand applicability in different fields. For instance, nanocrystals (CNC) amphiphilic features are potential green alternatives mineral processing such as particle flotation. In present study, aqueous, one- two-step silylation CNCs amino alkyl silanes was considered create a novel bifunctionalized that contained both positively charged silane moieties hydrophobic chains. Especially, effects reaction conditions routes on were investigated, electric hydrophobicity determined. The bifunctionalization conducted by simultaneous addition an led high efficiency, grafting amount notably higher than obtained sequential reactions individual reagents. After functionalization, strongly altered, leading water contact angles up 135° CNC films. However, slightly affected ζ-potential functionalized CNCs. Due relatively low ζ-potential, orthokinetic attachment onto quartz surfaces insufficient, resulting limited flotation recovery microflotation using Hallimond tube.