Rapid functionalisation of cellulose-based materials using a mixture containing laccase activated lauryl gallate and sulfonated lignin

Abstract

An innovative method has been developed for the surface hydrophobisation of cellulose-based materials by coating it with a functionalised solution (FS), in which sonicated lauryl gallate (LG, dodecyl 3,4,5,-trihydroxybenzoate), sulfonated kraft lignin, and the enzyme laccase play a pivotal role. The rapid treatment with FS increases the hydrophobicity of cellulose sheets considerably. The FS retention on the paper surface was analysed as a function of refining and application of additives. The properties of the functionalised sheets were assessed by the water-drop test (WDT), and the surface free energy (SFE) was determined via contact angle (CA) measurements in a goniophotometer. WDT resulted in long absorption times of up to 4000 s and CA values were around 130°. Functionalised solution modification of eucalyptus paper sheets decreased SFE essentially from 55 mJ m-2 to 10 mJ m-2. ATR-FTIR suggested that FS was grafted onto the cellulosic sheets. The stability of FS and the control solutions were characterised by Z potential and light scattering measurements. The functionalised solution method is a one-step roll-to-roll process, which is easy to perform also in industrial application without additional investments. It has a potential to substitute the traditional hydrophobing processes.