Controls over the dimensions of waterlogged archaeological wood (WAW) upon drying are a critical issue for its conservation. Surface-initiated activator regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP) has been proven to be an effective consolidation method to increase the dimensional stability. However, the drawback of the current method is that the expansion stress generated during graft polymerization cannot be well controlled. An improved SI-ARGET ATRP system using a bifunctional monomer ethylene glycol dimethacrylate (EGDMA) to introduce a cross-linking process during the polymerization is presented in this paper. Both Pinus massoniana and Sapium sp. samples with different maximum moisture contents as 507% and 863%, respectively, show a reduced volumetric shrinkage of around 5% without any expansion phenomenon after the treatment. This method shows potential applications in the field of WAW conservation and may provide a new solution for consolidation of other organic archaeological objects as well as developing new wood-based materials.
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.
危险品化学品经营许可证（带存储）