1. Modification of Paper Surface by All -Lignin Coating Formulations.
- Author
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Pinto, Patricia I. F., Magina, Sandra, Fateixa, Sara, Pinto, Paula C. R., Liebner, Falk, and Evtuguin, Dmitry V.
- Subjects
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LIGNINS , *CONTACT angle , *ATOMIC force microscopy , *SURFACE energy , *SURFACE coatings , *FREE surfaces - Abstract
All-lignin coating formulations were prepared while combining water-soluble cationic kraft lignin (quaternized LignoBoost®, CL) and anionic lignosulphonate (LS). The electrostatic attraction between positively charged CL and negatively charged LS led to the formation of insoluble self-organized macromolecule aggregates that align to films. The structures of the formed layers were evaluated by atomic force microscopy (AFM), firstly on glass lamina using dip-coating deposition and then on handsheets and industrial uncoated paper using roll-to-roll coating in a layer-by-layer mode. Coated samples were also characterized by optical microscopy, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (SEM/EDS), and contact angle measurements. It was suggested that the structure of all-lignin aggregates is the result of the interaction of amphiphilic water-soluble lignin molecules leading to their specifically ordered mutual arrangement depending on the order and the mode of their application on the surface. The all-lignin coating of cellulosic fiber imparts lower air permeability and lower free surface energy to paper, mainly due to a decrease in surface polarity, thus promoting the paper's hydrophobic properties. Moderate loading of lignin coating formulations (5–6 g m−2) did not affect the mechanical strength of the paper. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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