Aldehyde-functionalization of chitin nanocrystals via SI-ARGET ATRP of lignin-derived monomers
Tongjun Yang, Rongli Li, Mingtao Ding, Hong Yu, Lihua Zhang, Haibo Xie
Abstract
Chitin nanocrystals (ChNCs), prepared from a down-sizing process from chitin, have recently captured great attention to access sustainable nanomaterials . The surface modification of ChNCs is crucial to regulate the surface physicochemical properties and introduce specific functions, thus satisfying their diverse applications. In this study, aldehyde-functionalized ChNCs (ChNCs-PVMA) with enhanced hydrophobicity were developed via surface-initiated activators regenerated by electron transfer for atom transfer radical polymerization (SI-ARGET ATRP) of a lignin-derived polymerizable aldehyde monomer , vanillin methacrylate (VMA). The monomer conversion was determined by 1 H NMR spectroscopy of the reaction mixture based on the change of the relative ratio of VMA and solvent signals. The prepared ChNCs-PVMA were systematically characterized by FTIR, CP/MAS 13 C NMR, XPS , XRD , DSC , TGA , and TEM. The dispersibility of ChNCs and ChNCs-PVMA in water and DMF was evaluated by dynamic light scattering and visual observation, indicating good dispersion of ChNCs-PVMA in organic solvents . Furthermore, based on the available aldehyde groups, the ChNCs-PVMA was reacted with amino acids via Schiff base reaction, demonstrating a rich follow-up chemistry towards diverse functions by the reactive aldehyde groups.