Skosana, Sifiso JKhoathane, CMalwela, Thomas2020-09-212020-09-212020-01Skosana, S.J., Khoathane, C. and Malwela, T. 2020. Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method. Polymer Bulletin: https://doi.org/10.1007/s00289-020-03100-y0170-08391436-2449https://doi.org/10.1007/s00289-020-03100-yhttps://link.springer.com/article/10.1007/s00289-020-03100-ydoi.org/10.1007/s00289-020-03100-yhttps://rdcu.be/b7hOKhttp://hdl.handle.net/10204/11586Copyright: 2020 Sprinter. Due to copyright restrictions, the attached PDF file only contains the abstract version of the full-text item. For access to the full-text item, please consult the publisher's website: https://link.springer.com/article/10.1007/s00289-020-03100-y . A free full-text non-print version of the published item can be viewed at https://rdcu.be/b7hOKLow adhesion strength of polyurethane coating to a steel substrate is often attributed to poor steel preparation. However, the ratio of diisocyanate/polyol and dispersion of fillers within a polyurethane coating matrix influence the adhesion strength, optical and corrosion resistance properties. Poor dispersion of nano-fillers in a polymer coating matrix can lead to low adhesion strength, because close packing of nanoparticles often hides the hydroxyl groups required to form polar–polar bonds with the steel surface. This study combines sonication and high-shear mixing methods with shorter mixing times to prepare polyurethane nanocomposite coatings with various clay concentrations while keeping the ratio of diisocyanate/polyol constant. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction, thermogravimetric analysis and pull-off are used to characterize polyurethane nanocomposite coatings. FTIR results confirm that sonication and high-shear mixing successfully prepare polyurethane-based coatings. TEM shows uniformly dispersed clay particles in polyurethane matrices. The adhesion strength improved on addition of 1–5 wt% C30B organoclay, with the highest improvement (34.4%) at 3 wt% loading. The corrosion resistance of polyurethane coatings was improved by the incorporation of organoclays into their matrices. Onset degradation temperature is also delayed by 4.1–8.5% as the clay concentration increased from 1 to 5 wt%.enPolyurethane coatingsHigh-shear mixingNanocompositesAdhesion strengthArticleSkosana, S. J., Khoathane, C., & Malwela, T. (2020). Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method. http://hdl.handle.net/10204/11586Skosana, Sifiso J, C Khoathane, and Thomas Malwela "Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method." (2020) http://hdl.handle.net/10204/11586Skosana SJ, Khoathane C, Malwela T. Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method. 2020; http://hdl.handle.net/10204/11586.TY - Article AU - Skosana, Sifiso J AU - Khoathane, C AU - Malwela, Thomas AB - Low adhesion strength of polyurethane coating to a steel substrate is often attributed to poor steel preparation. However, the ratio of diisocyanate/polyol and dispersion of fillers within a polyurethane coating matrix influence the adhesion strength, optical and corrosion resistance properties. Poor dispersion of nano-fillers in a polymer coating matrix can lead to low adhesion strength, because close packing of nanoparticles often hides the hydroxyl groups required to form polar–polar bonds with the steel surface. This study combines sonication and high-shear mixing methods with shorter mixing times to prepare polyurethane nanocomposite coatings with various clay concentrations while keeping the ratio of diisocyanate/polyol constant. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction, thermogravimetric analysis and pull-off are used to characterize polyurethane nanocomposite coatings. FTIR results confirm that sonication and high-shear mixing successfully prepare polyurethane-based coatings. TEM shows uniformly dispersed clay particles in polyurethane matrices. The adhesion strength improved on addition of 1–5 wt% C30B organoclay, with the highest improvement (34.4%) at 3 wt% loading. The corrosion resistance of polyurethane coatings was improved by the incorporation of organoclays into their matrices. Onset degradation temperature is also delayed by 4.1–8.5% as the clay concentration increased from 1 to 5 wt%. DA - 2020-01 DB - ResearchSpace DP - CSIR KW - Polyurethane coatings KW - High-shear mixing KW - Nanocomposites KW - Adhesion strength LK - https://researchspace.csir.co.za PY - 2020 SM - 0170-0839 SM - 1436-2449 T1 - Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method TI - Enhancing the adhesion strength of polyurethane coatings by dispersing layered silicates via sonication and high-shear mixing method UR - http://hdl.handle.net/10204/11586 ER -