ANTIMICROBIAL PROPERTIES OF COATINGS BASED ON CHITOSAN DERIVATIVES FOR APPLICATIONS IN SUSTAINABLE PAPER CONSERVATION

摘要

This paper analyses the potential of coatings based on chitosan derivatives (ChDs) to provide antimicrobial protection on paper surface, and also to substitute cellulose ethers used as consolidation/resizing materials in paper heritage conservation. The chitosan derivatives (alkyl chitosan - ACh, quaternary chitosan - QCh and carboxymethyl chitosan CCh) were applied as one or multilayer coatings of a single or a combination of two derivatives, using different support paper types. The assessment of the antimicrobial activity of coated paper samples has shown different effectiveness among the ChDs: QCh and CCh inhibited Gram-positive and Gram-negative bacteria and had moderate effectiveness on fungi, while ACh completely inhibited fungal growth, but was less effective on Gram-positive bacteria. Finally, it was concluded that optimal combinations of two ChDs in coating formulas could confer antimicrobial protection on paper surface against a broad spectrum of pathogenic microorganisms.