Routes to improve the strengthening of paper with aminoalkylalkoxysilanes

Aminoalkylalkoxysilane copolymers (co-AAAS) have the ability to simultaneously deacidify and strengthen paper documents. Nevertheless, despite enhancing tensile strength, they generally fail improve folding endurance of degraded groundwood pulp-rich papers. Focusing on that specific type papers, several ways overcome their lack reinforcement were investigated. Promoting polymerization AAAS using catalysts thermal steps was one them. A monitoring with FTIR spectroscopy showed step most efficient in speeding up hydrolysis polycondensation 3-aminopropylmethyldiethoxysilane (AM) monomer aqueous solutions. The progress two-steps reaction terms degree polymers then studied in-situ after heating paper, Cross Polarization—Magic Angle Spinning 29Si solid-state NMR, shown be enhanced as well. other optimization route explored stabilize before treatment. Our previous research had presence oxidized groups hampered strengthening. Sodium borohydride, a known bleaching agent conservation, used prior AAASs treatment decrease amount carbonyls paper. reduction compared mechanical properties (folding strength) upon lignocellulosic including three newsprints dated 1911–1923. use sodium borohydride led significant improvement samples, an unprecedented result. It enabled at same time counteract yellowing induced by build larger alkaline reserve.