Milovan Jotanović

Protection of Copper and its Alloys Using Corrosion Inhibitor-Literature Review

A review of the literature dealing with the electrochemical corrosion of copper and its alloys with purpose to find the most suitable inhibitor for its protection has been done. According to their chemical composition of corrosion inhibitors are divided into inorganic and organic inhibitors. Inhibition of alloying metals are possible (such as the addition of arsenic alloy components in brass, preventing its unzincanization). The paper reviews the theoretical basis of application of inhibitors to protect metals from corrosion as well as an overview of current research application of inhibitors to protect copper and copper alloys. Benzotriazole (BTA) is most often used corrosion inhibitor for copper and its alloys in acidic and alkaline solution, because of its high inhibition efficiency. The lowest concentration of inhibitor for protection of copper in various solutions was 0.05%, and for the protection of copper in contact with steel is 0.1%. On the surface of copper and brass BTA forms a protective Cu-BTA film. However, BTA is like many other synthesized organic inhibitors is very toxic and if used in very small concentrations. It turned out that the AETD, AETDA and PTAT good corrosion inhibitors of copper mixed type with the efficiency of inhibition increases with concentration. Due to the adverse effects on the environment, health and other bodies in recent times the focus of research is transferred to the inhibiting action of biological molecules or mixtures of natural compounds called „Green inhibitors“.

The influence of the nanofiller on thermal properties of thermoplastic polyurethane elastomers

Hybrid materials based on renewable resources are under huge interest of scientist nowadays. Polymer-based hybrid materials with the addition of nanoparticles are very interesting because the addition of small amount of nanoparticles significantly improves final material’s properties. Group of polymers which is suitable for use for hybrid materials preparation are polyurethanes. Polyurethanes have wide spectra of commercial and industrial applications, but for their production petroleum-based derivative is used and big efforts are still making for changing it with components from renewable resources. Thermoplastic polyurethanes were synthesized using two types of isocyanates: isophorone diisocyanate and hexamethylene diisocyanate, and the possibility of using isosorbide, instead of butanediol, as chain extender for the synthesis of thermoplastic polyurethane elastomers was investigated. NCO/OH ratio was 1.15/1 and soft segment content 50% in all samples. Also, the influence of the addition of hydrophilic and hydrophobic silicon(IV)-oxide nanoparticles, in amounts of 0.5,1, 2, and 5%, on thermal properties of the obtained green polyurethanes is determined using DSC and TG analysis. It is shown that hydrophilic silicon(IV)-oxide nanoparticles have an influence on thermal properties of soft segment in polyurethane structure, while hydrophobic ones have the influence on hard polyurethane’s segment properties, increasing Tg values. Thermal stability of polyurethanes increased with increasing the amount of nanoparticles added. FT-IR analysis showed that there is no chemical reaction between polymer and nanoparticles.