الفهرس 
INTRODUCTION
HISTORICAL BACKGROUNDOnly 14 pages are availabe for public view
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Abstract
Copper has an excellent electrical and thermal conductivities, good corrosion resistance and mechanical workability. It is widely used in heating and cooling systems. Corrosion of copper can lead to many problems, the most being per formation that may result in coolant leakage. Scales and corrosion products have negative influence on heat-transfer, causing a decrease in heating efficiencies of the copper structures. The use of inorganic or organic inhibitors is one of the most practical methods for protection against corrosion of metals and their alloys. Most well-known organic inhibitors such as those containing nitrogen, sulphur, oxygen atoms and aromatic rings ,So, this work aims to synthesis of a new corrosion and scale inhibitors based on acrylic acid derivatives and evaluation their inhibition efficiency on the copper corrosion in sea water. This work includes three main parts:
THE FIRST PART:
Synthesis of Compounds Used
Condensation reactions of acrylic acid with ethylene diamine were carried out. To the formed product poly ethylene oxide were added to give three different inhibitor (I-III).also for diethylene triamine and triethylene tetramine, The purity of the products was checked by FTIR and elemental analysis.
THE SECOND PART:
Study the Surface Activity of the Synthesized Surfactants
Surface activity was studied for the synthesized inhibitors by setting some properties such as surface tension (γ), critical micelle concentration (CMC), maximum surface excess concentration (Гmax) and minimum surface area per molecule (Amin).
THE THIRD PART:
Evaluation of the Prepared compound as Scale and Corrosion Inhibitors Using Different Techniques
1. Weight Loss Studies
The weight losses of copper in sea water (in mg cm-2) with and without the addition of inhibitors were determined at different immersion times. It was found that the inhibition efficiency of all these compounds increases with increasing its concentration. The maximum inhibition efficiency for each compound was achieved at 500 ppm and further increase in concentration did not cause any appreciable change in the performance of the inhibitors. The percentage inhibition efficiency was found to be in the following order:
III > II > I
2. Different Electrochemical Measurements
A. Open Circuit Potential Measurements (OCP)
The variation of the OCP of the copper electrode as a function of the period of exposure in the absence and presence of various concentrations of the inhibitors were measured against a saturated calomel electrode (SCE). It was found that the potential of copper electrode immersed in sea water tends toward more negative potential firstly, giving rise to short step. By addition of inhibitor molecules to the aggressive medium produces a slightly positive shift in Ecorr due to the formation of a protective film on the copper surface.
B. Potentiodynamic Polarization Measurements
The results of potentiodynamic polarization for copper dissolution in sea water with and without different concentrations of inhibitors have been investigated. The polarization curves indicated that both anodic metal dissolution and cathodic reduction reactions were inhibited when the inhibitors added to the sea water, where the Tafel lines are shifted to more negative and more positive potentials with respect to the blank curve by increasing the concentration of the inhibitor. This behavior indicates that the undertaken additives act as mixed type inhibitors. It was found that the inhibition efficiency increased with increasing inhibitor concentration.
C. Electrochemical Impedance Spectroscopy Measurements (EIS)
The corrosion behavior of copper immersed in sea water in the presence and absence of the synthesized inhibitors was investigated by EIS after immersion in solutions for 4 h. The results of EIS indicate that the increase of inhibitors concentrations leads to increase the charge transfer resistance (Rt) and decrease the double layer capacitances (Cdl), which indicates that these compounds act as corrosion inhibitors through adsorption on the surface of the copper.
It was found that the data obtained from the electrochemical techniques are in good agreement with that obtained from weight loss technique. Since, the percentage inhibition efficiency was found to be in the following order:
III > II > I
3. Evaluation of acrylic acid derivatives as scale inhibitors
The present work was extended to establish the effectiveness of acrylic acid derivatives as scale inhibitor for calcium sulfate deposition in synthetic cooling water. The laboratory procedures were carried out as described in the experimental part. The percentage inhibition efficiency was calculated as follow:
Scale inhibition efficiency % = (Cai - Cab \ Cac- Cab) × 100
where Cai = Calcium ion concentration for the sample treated with the inhibitor after precipitation
Cab = Calcium ion concentration in the blank solution after precipitation
Cac = Calcium ion concentration in the blank solution before precipitation
The obtained results are listed in table (6) and graphically shown in fig.(10) it is clear that the percentage inhibition efficiency increase by increasing the inhibitor, reaching 90% at 125 ppm.
4. Scanning Electron Microscopy (SEM)
The SEM results, indicated that the presence of 125 ppm of acrylic acid derivative in the synthetic cooling water minimize the deposition of large amounts of calcium sulfate. (29),because ,it has a crystal distortion effect and a threshold effect (30).by this way , the acrylic acid derivative molecules can be adsorbed on copper surface, imparting it alike charge and thereby causing the particles to remain in suspension, because of charge repulsion. In addition, the polymer can distort scale crystals by disruption their lattice structure and normal growth patterns. The inclusion of relatively large irregularly shaped polymer in the scale lattice tends to prevent the deposition of a dense uniformly structured crystalline mass on the metal surface.
5. Energy Dispersive Analysis of X-Rays (EDX)
The results of EDX, reveal that the curve of iron atom (Fe) in the presence of 450 ppm of the inhibitor (IV) less than in the absence of the inhibitor, which indicates that the surfactant inhibitor layer formed on are strongly attached to the carbon steel surface, and thus leads to a high degree of inhibition efficiency.
At the end of the thesis, the relation between the surface properties of the investigated surfactants and their corrosion inhibition efficiency IE % were studied.