Treatment of paper biodeterioration by fungi: An NMR approach to the preservation of human history

Barrulas, Raquel Alexandra Valadares

http://hdl.handle.net/10362/63791

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Autores

Barrulas, Raquel Alexandra Valadares

Orientador(es)

Corvo, Marta

Resumo(s)

The main goal of this dissertation was to develop a new class of materials in order to provide an improved solution to clean fungal staining in paper. Initially a screening of favourable interactions between pigment model compounds and ionic liquids (ILs) was accessed through Nuclear Magnetic Resonance (NMR) protocol. The most promising IL moieties were incorporated into polymer matrices. The final products were tested against contaminated paper samples. The NMR approach allowed profiling the molecular interactions prevailing between ILs with cations such as 1-butyl-3-methylimidazolium ([BMIM]+), 1-ethyl-3-methylimidazolium ([EMIM]+), 1-butyl-2,3-dimethylimidazolium ([BDMIM]+), 1-benzyl-3-methylimidazolium ([BZMIM]+); and anions such as chloride, trifluoromethanesulfonate ([OTf]-), dicyanamide ([DCA]-) and tricyanomethanide (TCN]-), and model compounds (naphthalene, L-DOPA, veratrole, alizarin and quinizarin) with identification of the structural features in the IL pair responsible for the preferential interactions. The ILs [EMIM][TCN], [EMIM][OTf] and [EMIM][DCA] exhibited better interaction abilities with stronger interactions – hydrophobic and π-π stacking interactions. The monomers with cations [ETVIM]+ and [BVIM]+ as well as with anions [DCA]-, [OTf]-, bromide and [NTf2]- were synthetized and polymerized afterwards, with very high yields. Hydrogels derived from polymeric ILs (PILs) and agarose and/or PVP were obtained. The efficacy of the hydrogels obtained was tested on contaminated paper samples with A. niger, C. cladosporioides, P. chrysogenum and F. oxysporum. The most promising results were obtained with hydrogels with poly([ETVIM][DCA]) and poly([BVIM][OTf]) against P. chrysogenum and A. niger, respectively.