Nlandu, Herve, Belkacemi, Khaled, Chorfa, Nasima, Elkoun, Saïd, Robert, Mathieu, and Hamoudi, Safia
Lignocellulosic nanofibres (LCNF) are nanometer additives that can be used to improve the mechanical, esthetical, optical and thermal properties of polymers in composites, packages, or coatings. Surface modification of these hydrophilic nanometer additives is needed to improve their properties and applicability in hydrophobic polymers matrix. In this work, two phenolic monomers, guaiacol and syringaldehyde were for the first time, efficiently grafted onto the exposed residual lignin of lignocellulosic nanofibres surface by a laccase from Trametes versicolor mediated reaction. Guaiacol grafted (LCNFG) and syringaldehyde grafted (LCNFS) lignocellulosic nanofibres were characterized with Fourier Transform Infra-Red (FTIR) and UV–visible techniques. Thermal and hydrophobic properties were analyzed by thermogravimetric analysis (TGA) and Water contact angle (WCA) measurements. FTIR analyzes confirmed the laccase mediated grafting of guaiacol and syringaldehyde onto lignocellulosic nanofibres. UV–visible gave evidence for the grafting of phenolic entities onto lignocellulosic nanofibres by factual data supporting experimental observations, leading to brown and orange colored grafted lignocellulosic nanofibres (LCNFG and LCNFS, respectively). TGA has shown that grafting of phenolic compounds endowed LCNF better thermal stability. WCA angle and wettability measurements showed that the surface hydrophobicity of LCNFG and LCNFS was increased after the enzymatic grafting modification. [ABSTRACT FROM AUTHOR]