الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The aromatic diisocyanate is highly reactive towards the air moisture even at room temperature and resultant carbon dioxide bubbles led to undesired several defects of the applied polyurethane coatings. Due to the high chemical reactivity of the vinyltrimethoxy silane (VTMS), we applied it as moisture scavenger in the polyurethane coatings to prevent the diisocyanate-moisture reactions, which also proved by the kinetic studies. The higher activation energy in the presence of the VTMS showed a fast and safe reaction even under high temperature and high relative humidity conditions. The vinyltrimethoxy silane successfully prevented the CO2 bubbles and improved both the hardness and gloss of the final coating, hence; keep the coatings attractive without any defects.Incorporation of 3-triethoxysilylpropyl succinic acid anhydride TESP-SA as a core material into the alkyd polymer through multi-steps chemical reaction enhanced the mechanical properties as well as gloss retention and longtime yellowing resistance characteristics of the alkyd polymers. The reaction between TESP-SA, Trimethylolpropane and acid mixture was described in a detailed scheme, followed by the acid value, and confirmed by 13C NMR analysis and FTIR measurements. It is also concluded that this type of modifications improved the thermal stability of the final coating. Incorporation of sodium feldspar as a functional filler into polyurethane coatings enhanced the mechanical properties such as hardness; where increasing the percentage of sodium feldspar by ratios 2, 4, 6 and 8% led to proportional increment in hardness values. Further addition of sodium feldspar 10% led to decrease in hardness. Incorporation of sodium feldspar yields a smooth surface which kept the intensity of reflected light without any scatters and also kept gloss without significant decrements.
The coating thickness was increased when the sodium feldspar dosage increased from 0 to 10%. By increasing the film thickness, the polyurethane component percentage at certain cross section of the coating layer decreased. This explanation was clearly confirmed FTIR measurements. The VOCs content was decreased when the sodium feldspar dosage increased from 0 to 10%. The replacement of volatile solvent (xylene) by sodium feldspar increased the solid content in the final coating, thus, decreased the organic emissions. It was concluded that VOCs is inversely proportional to the sodium feldspar dosage. Addition of 2, 4 and 6 % sodium feldspar to the coating formulation indicated the enhanced the coating hydrolysis resistance. Otherwise, addition of 8 and 10 % sodium feldspar to the coating formulation negatively affected the coating hydrolysis resistance.