Liquid-Induced Modification of Powder Coatings

Many Cl are liquid-phase. The application technology of inhibited coatings depends on the character of their interaction with polymer materials. 

Polymer powders absorb well, as a rule, liquid Cl. Most crystalline polymers are insoluble and cannot be plasticized at room temperature. Therefore, adsorption of a liquid on powder particles results in their coagulation and noticeable reduction of powder friability. Impregnation of encapsulated Cl eliminates, to some extent, this drawback but raises the price of the coatings and limits their application range [67]. 

The presence of liquid and plasticizing Cl in the coatings improves a number of aspects of their performance. Firstly, their presence reduces residual stresses, which are the main reason of untimely cracking and exfoliation from the substrate. In addition, the elasticity modulus and hardness of the coatings diminish, while the elasticity and relative elongation increase. Moreover, the inhibited coatings display much higher adhesion than non-inhibited ones. 

A method of obtaining anticorrosion coatings containing a liquid inhibitor reducing adhesion of the coating to the metal substrate has been patented [69]. To improve adhesion, a primary layer of the initial thermoplastic polymer is first applied onto the substrate under technological regimes optimum for 

Dosed treatment of a powder layer deposited on the substrate with a Cl aerosol turned out to be highly convenient for the introduction of liquid inhibitors into polymer coatings. Polymer particles can be treated by a liquid Cl directly during jet deposition (Fig. 3.32) or during electrostatic powder application. In the latter case, the properties of the electrically deposited layer are altered. 

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