An aqueous approach to functionalize waterlogged archaeological wood followed by improved surface-initiated ARGET ATRP for maintaining dimensional stability

Abstract

A previous study on consolidation of waterlogged archaeological wood (WAW) via surface initiated ARGET ATRP of the cell walls has shown its potential of maintaining the dimensional stability. But the defects lie in the unsuitable initiator immobilization methods and polymerization conditions, which impedes its application. Therefore, we are proposing a novel functionalization method for initiator immobilization in water or water/ethanol solution and an improved thermo-initiated ARGET ATRP system. First, mercaptoethylamine (MEA) was used to functionalize WAW with amino groups in water under circumneutral conditions. Then, quinone-based initiators reacted with those amino groups realizing its immobilization. Finally, by using less active reductants such as ascorbic acid 2-glucoside and glucose, monomer, catalyst, and reductant were able to permeate into the WAW samples at room temperature and polymerization was initiated by heating to 60 degrees C (for ascorbic acid 2-glucoside) or 80 degrees C (for glucose). Both satisfying uniformity and dimensional stability (77.0-85.1% ASE) can be achieved through the described approach. Moreover, the described functionalization methods may also provide reference for WAW consolidation material designs and applications in other lignocellulosic materials in the future.