Modification of cellulose nanocrystals as reinforcement derivatives for wood coatings

• Published in: Progress in organic coatings Vol. 77; no. 4; pp. 813 - 820
• Main Authors: Poaty, Bouddah, Vardanyan, Vahe, Wilczak, Luana, Chauve, Gregory, Riedl, Bernard
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2014
• Subjects: Cellulose nanocrystal; Derivatives synthesis; Dispersion; Mechanical properties; Nanocomposites; Wood coating; Mechanical properties; Wood coating; Cellulose nanocrystal; Nanocomposites; Dispersion; Derivatives synthesis
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2014.01.009

•A simple chemical modification of cellulose nanocrystal (CNC) is proposed for an improved reinforcement additive for water-based wood coating.•Characterizations and an overall coherence about the chemical structure, size and water wettability of modified nanoparticles are established.•AFM, gloss and haze analyses indicate a better dispersion of CNC derivatives in coating and a good retention of esthetic properties from this resultant coating.•Induction of better abrasion resistance characteristics to nanocomposite coatings by the CNC derivatives after a preparation of the acrylic UV curing type. Cellulose nanocrystal (CNC), an emerging renewable nanomaterial, was subjected to carbon chains grafting in order to improve its dispersion and its ability to transfer its rigidity properties into less polar matrixes, especially acrylic wood coatings. Chemical modifications used to this purpose are required to be simple, not affecting the CNC main structure and compatible or synergistic to oligomer reticulation inside the targeted UV-waterborne formulation. Those modifications were carried out using either alkyl quaternary ammonium bromides or acryloyl chloride. These new chemical functionalities, not inducing deep structural changes in modified CNCs, were highlighted through nuclear magnetic resonance, infrared and nitrogen content analyses. CNC derivatives were better dispersed in aqueous acrylic coating as suggested by atomic force microscopy, with a mean surface roughness falling from 9 to 6nm on the coatings containing unmodified and treated CNCs, respectively. For mechanical evaluations, the coatings including various CNC derivatives were applied on sugar maple wood, a much appreciated material as indoor timber or wooden furniture which requires an efficient surface protection. The abrasion tests indicated that the modified CNCs confer a higher scratch resistance, with an improvement from 24% to 38% for coatings containing CNC derivatives over those with unmodified CNC.