Waterborne polyurethane dispersions (WPUDs) have become a rapidly growing segment of the polyurethane coating and adhesive industry, replacing conventional solvent borne polyurethanes with their versatile and environmentally friendly structures [1,2]. Although WPUDs are used in a variety of applications due to features such as very low VOC, low viscosity, ease of application, excellent film properties, high chemical resistance, good adhesion, flexibility, and abrasion resistance, properties such as mechanical strength, exterior durability, and water resistance require improvement [3]. Crosslinkers and nanoparticles (NPs) are common components used to improve the weaknesses of WPUDs. There are many crosslinkers, including as carbodiimides, polyaziridines, and isocyanates, that react with polymer chains to create chemically crosslinked polymers which increase the end products thermal and mechanical characteristics [4].Among various NPs, nanosilica is extensively utilized in WPUD/silica nanocomposites owing to its unique properties such as good stability, high hardness, and low cost [5].
In this study, various formulations were prepared using polyether-based aliphatic WPUD with different ratios and types of nanosilicas, and crosslinkers. The formulations included two types of nanosilica: hydrophobic fumed silica and colloidal silica, as well as two types of crosslinkers: hexamethylene diisocyanate (HDI) and polyfunctional aziridine. WPUD/silica nanocomposites were prepared using the blending method, and crosslinkers added directly to the formulation. To investigate the effect of nanosilicas and crosslinkers on the mechanical, chemical, surface, and resistance characteristics of WPUDs, tests were performed and analyzed on prepared formulations or formed films, using equipment such as SEM, FTIR, and DMA.
Anahtar Kelimeler: Waterborne polyurethane dispersion, Nanosilica, Nanocomposite, Coating
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