تحضير وتشخيص وتقييم انواع جديدة من البولي يورثان القابلة للتفكك الاحيائي ودراسة تطبيقاتها الحيوية في اطلاق الدواء == Preparation , Identification And Evaluation of New Types of Biodegradable Polyurethane And Study Their Application In Drug Delivery
Author name:
صابرين فرحان جواد
Supervisor name:
محمد علي مطر
General topic:
Chemistry
Specific topic:
Physical Chemistry
Degree:
Master
University:
University of Al-Qadisiyah - College Of Science - Chemistry Department
Language:
English
University location:
Qadisiyah
First pages:
25T1436 - p.pdf
Abstract:
Corrosion and corrosion protection of carbon steel (C.S) alloy in seawater (3.5% NaCl) was achieved in this thesis. Three types of nanoparticles (NPs) were used to protect C.S the first silicon carbide (SiC), second alumina (Al2O3) and the third zirconium oxide (ZrO2) nanoparticles (NPs). Electrophoretic deposition (EPD) technique was applied to coating the C.S surface. Different polyacrylic acid (PAA) percentage (0.1 - 1)% were added to the suspension solution of coating by the three types of NPs, to improve the protection efficiency (PE%) for the coated C.S surfaces.The corrosion rate with respect to uncoated and coated C.S with the three above NPs were measured. Different corrosion parameters were obtained; corrosion current density (icorr), corrosion potential (Ecorr), cathodic and anodic Tafel slopes (bc,ba), protection efficiency (PE%), polarization resistance (Rp) and the surface porosity (P%). The effect of temperatures (298 - 328)K on the corrosion of uncoated and coated C.S by the three NPs in presence and absence of PAA were also investigated and therefore activation energy (Ea) and preexponential factor (A) were calculated. Thermodynamic parameters ?G, ?H and ?S for all corrosion processes were obtained. Coated C.S were analysed using atomic force microscopy (AFM) to detect the morphology of surface and the particles size of coat layers which range from 60 - 103 nm, which greater than thestarting particles.The corrosion current densities (icorr) were increased generally with increasing temperatures for all cases and icorr reduced after coated C.S by different NPs in absence and presence PAA, therefore icorr reduced from 168.88 ?A.cm - 2 to 19.45, 28.71 and 30.2 ?A.cm - 2 for C.S coated by SiC, ZrO2 and Al2O3 respectively at 298K.While the Ecorr shifted to more active potential after coated by different NPs excepting when C.S coated by SiC in presence of (0.25%) PAA in coating solution suspension where Ecorr shifted to noble direction. The protection efficiency (PE%) of all coated C.S in absence and presence of PAA showed noteworthy degree of enhancement and the PE% ranged between (85 to 99.65)% for SiC , (69 to 91)% for ZrO2 and (77 to 87.9)% for Al2O3. The surface porosity (P%) were increased with increasing temperatures for all cases. The activation energy (Ea) values for the corrosion of coated C.S by different NPs lead to higher values than Ea for uncoated C.S and the highest value was (71.936) kJ.mol - 1 obtained when C.S coated by SiC in presence of (0.25%) PAA. The free energy (?G) Values for the corrosion of coated C.S generally more negatively than uncoated and the values of enthalpy (?H) for the corrosion of coated C.S by ZrO2 and Al2O3 were less negatively than uncoated C.S while coated C.S by SiC lead to more negatively ?H values.
