The study of the synthesis of anticorrosive inhibitors, based on chemically modified tannins, and their use in alkyd based coatings to improve anticorrosive properties is presented in this work. Two methods of tannin modification were applied: direct method using ammonium hydroxide, ammonium hydroxide/ammonium chloride buffer or diethylenetriamine (DETA); and a two-step method including tannin modification with epichlorohydrin (ECH) in first step to produce epoxy modified tannin, ET, and further modification with heteroaromatic amines or linseed oil fatty acids (LFA) in second step. The obtained anticorrosive additives were characterized using ATR-FTIR, 1 H and 13 C NMR spectroscopies and elemental analysis. Epoxy, amino, hydroxyl, acid and iodine values of the synthesized inhibitors were determined according to standard methods. The prepared alkyd coating with tannin inhibitors was tested according to standard SRPS EN ISO 4628 method. Anticorrosive coating containing modified tannin based additive showed increased anticorrosive properties, good adhesion and coverage comparing to the coating with zinc phosphate additive. The alkyd coating films based on ET-LFA and ET modified with 2-amino-5mercapto-1,3,4-thiadiazole showed best anticorrosive results.
The innovative laboratory procedure for the synthesis of copper(II) hydroxide in the form of the aqueous suspension was developed. The reaction mechanism consists of the reaction between copper(II) sulphate pentahydrate and sodium carbonate by successive ion exchange of carbonate ions with the hydroxide ones in a multistep process. Production of copper(II) carbonate and sodium sulphate by reacting of copper(II) sulphate with sodium carbonate was followed by addition of sodium hydroxide solution whereby the product, copper(II) hydroxide, was obtained by releasing an equimolar amount of sodium carbonate. It was determined that, the equimolar reaction of copper(II) sulphate and sodium hydroxide lead to the maximal reactants exploitation. Sodium phosphate, formed in the final process stage by addition of 10 % phosphoric acid solution, acted as a copper(II) hydroxide stabilizer. High yield of the product was obtained by optimizing the synthesis parameters: reaction time, molar ratio of reactants and the reaction temperature. The obtained product was formulated to obtain a commercial product, which is used as a fungicide and bactericide.
Komercijalni aluminijum oksid u formi viskersa (Al2O3 w) i sintentizovane Al2O3 čestice proizvedene sol-gel tehnikom (Al2O3 m) korišćene su kao ojačanja nezasićenih poliestarskih smola (NZPE). Pripremljeni su kompozitni materijali sa udelom ojačanja od 0,1 mas. %, 0,25 mas. %, 0,5 mas. %, 1,0 mas. %. i 2,5 mas. %. Strukturna analiza korišćenih ojačanja i dobijenih kompozita NZPE/Al2O3 izvršena je FTIR spektroskopijom. Morfologija korišćenih ojačanja ispitana je pomoću skenirajućeg elektronskog mikroskopa (SEM). Ispitivanje mikrotvrdoće urađeno je Vikersovom metodom. Dobijeni rezultati su pokazali da je povećanje mikrotvrdoće kod kompozita NZPE/Al2O3 w do 66,4% a kod kompozita NZPE/Al2O3 m do 52,3% u odnosu na čistu poliestarsku matricu NZPE.
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