<![CDATA[Modern industrial developments demand coating materials that offer high heat resistance, good thermal stability, and environmental friendliness. Polyurethane (PU) is a widely used coating material due to its good adhesion and flexibility; however, it still has limitations when exposed to high temperatures. This study aims to determine the effect of varying amounts of bentonite and chitosan on the thermal stability of polyurethane composites applied as heat-resistant protective coatings. The composites were prepared by mixing polyurethane, bentonite, and chitosan using a stirring method at a speed of 200 rpm for 1 hour. The variations in the amounts of bentonite and chitosan used were 0 g, 0.4 g, 0.8 g, 1.2 g, and 1.6 g. Material characterization was performed using Fourier Transform Infrared (FTIR) spectroscopy to identify functional groups, Thermogravimetric Analysis (TGA) to determine thermal stability, Scanning Electron Microscopy (SEM) to observe surface morphology, and coating thickness testing. The FTIR analysis results showed the formation of functional groups characteristic of polyurethane, namely C-H, C=O, O-H, and Si-O-Si, indicating the successful incorporation of polyurethane, bentonite, and chitosan into the composite system. TGA testing showed that variations in the composition of the filler affected the thermal stability of the material. The polyurethane/bentonite/chitosan sample with a ratio of 1.6:1.6 exhibited the best thermal stability, with a weight loss of 22.03%, which was lower than that of the sample with a ratio of 0.8:1.6 (49.84%) and the sample with a ratio of 0:1.6 (79.08%). SEM results for the best sample showed a relatively uniform distribution of fillers within the polyurethane matrix, although some particle agglomeration was still present. Based on the research results, it can be concluded that the addition of bentonite and chitosan improves the thermal stability of polyurethane composites. The polyurethane/bentonite/chitosan composition with a ratio of 1.6:1.6 demonstrated the best performance as a heat-resistant protective coating because it exhibited the lowest weight loss during the heating process and a relatively homogeneous surface morphology.Keywords: Bentonite, FTIR, Composite, Chitosan, Polyurethane, Thermal Stability, SEM, TGA.]]>
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