1
Faculty of Polymer Engineering and Color Technology, Amirkabir University of Technology
2
Faculty of Chemistry and Chemical Engineering, Malek Ashtar University of Technology
Abstract
In the field of organic coatings mechanical properties is a crucial matter. For many applications, the choice of material depends upon a balance of stiffness, toughness, processability and price. However, to choose coating systems attending to mechanical properties is unavoidable. Impact resistance is one of the most important mechanical properties of organic coatings. Impact is a complicated phenomenon and critical condition to apply stress and many aspect of it are unknown. In this paper, impact resistance of polyurethane as one of the most useful coatings, has been studied. After discussion about behavior of organic coatings against impact and stress conditions, the method to improve impact resistance of polyurethane coatings will be presented. The results have been shown that the type of polyisocynate is very important and by replacement of Hexa Methylene Diisocynate by Isophorone Diisocyanate, impact resistance increase from 60 Kg cm to 70 Kg cm. Chain extender type, its functionality and its concentration are effective to enhance impact resistance. Using hyperbranch polymers and nanoparticle are another method to improve impact resistance of polyurethane coatings up to 100 Kg cm.
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