Materiale pentru protectia anticorosiva a fagurilor metalici din preincalzitoarele de aer rotative ale instalatiilor energetice 1.Modificarea si caracterizarea reologica a unor rasini epoxidice

摘要

Celualar bodies from the cold region of the heat exchange surface of rotatory air preheaters from energetic installations are strongly affected by sulphuric corrosion and,can be protected using heat conducting and thermally resistant coatings.Epoxy resins,mofied firstly with tall and soy fatty acids to increase their elasticity and then reacted with acrylic acid and styrene to increase chemical,heat and corrosion resistance,adherence and elasticity,correspond to the qualities required for the film-forming material.The thermal conductivity of coating can be increased by introducing finely dispersed metal powders.Rheological measurement emphasizes that the resins esterified with both kinds of fatty acids have relatively low viscosities,ranging between 3500 and 8600 mPa.s,and ideal plastic fluid behaviour;the higher the epoxy equivalent of the resin the lower the viscosity of the esters.Treatment of resins(previoisly esterifies with tall fatty acids)with the two monomers increases the viscosity and modifies the rheological behaviour,transforming it into a pseudoplastic one.The increase of viscosity is huge for the resin having lower epoxy equivalent and its behaviour becomes thixotropic.Given the high specific weight of metal powders,it is expected that this last modified resin gives the most stable film-forming disperse systems with metal powders.