Organic coatings types

Several classes of polymers including epoxies have been developed from 2-phenyl-l,l,l,3,3,3-hexafluoropropan-2-ol and its derivatives.1 Fluorinated epoxy resins are the key intermediates for the new types ofpractical organic coatings and plastics, which have fluorocarbon properties and convenient characteristics such as hydrophobicity, oleophobicity, light stability, low friction, and, in some cases, possibly high thermal stability. 

Khrushchev (1957) considers that the need to measure the force T has not been sufficiently well substantiated, nor has a sufficiently precise and easy in service hardness tester been developed yet for determinations of this type. However, he appreciates the usefulness of scratch hardness tests, especially at low loads, as a non-destructive technique. He recommends these methods as very useful for hardness determination of metallic layers or of materials exposed to abrasive wear under operating conditions (plastics, organic coatings, such as varnishes and paints, etc.). Scratch methods are especially important in tests of anisotropic materials where a change in scratch width is the measure of anisotropy. In static indentation methods, the indentations obtained in anisotropic materials are misformed, varying... 

Requirements and tests for Pyroxylin type NC are described in Specs listed here as Refs 51 52 and for Technical NC(for use in organic coatings) in Ref 53. Several US std tests are described in Ref 55. In Ref 49 is described detn of N content of NC by IR spectrophotometry and in Ref 55 detn of NC by chromous chloride reduction. One of the latest methods on detn of N content in NC by ferrous-titanous titration is described in Ref 44. This test will be included in the next edition of US Military Standard Spec... 

Taylor et al. conducted LEIS in a mapping mode to characterize the spatial variation in the admittance associated with various types of intentionally formed defects on organically coated metal surfaces (135). The LEIS probe used in these experiments consisted of chloridized silver wires to form Ag AgCl reference electrodes. Excitation frequencies between 100 and 1000 Hz were used for mapping admittance. The precise frequency used was selected to maximize the admittances differences observed. Admittance mapping resolved differences due to millimeter-sized defects associated with adsorbed machine oil, underfilm NaCl... 

Solution polycondensation, i.e., where the monomers and polymer are soluble in the solvent(s), is also kinetically controlled. It is closely related mechanistically to reactions in the melt, but the choice of the solvent may influence both the rate and equilibrium, and hence the molecular weight. This process is utilized commercially in the production of a variety of organic coatings and certain solution-spun fibres, e.g., certain spandex types and also very high-melting aromatic polymers. 

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