Synthesis, Characterization and Corrosion study of new Copolymers

Two new copolymers (T 1 , T 2 ) were prepared, namely (Undecyl acrylate). (Pentadecyl acrylate). With (2-acrylamido-2-methylpropane sulfonic acid. )The prepared compounds were identified by (FT-IR, 1 H-NMR, 13 C-NMR, CHN).The copolymers were study as corrosion inhibitors for carbon steel in (HCl) solution (1M) where the corrosion rate was measured by weight loss method. The weight loss measured indicate that the copolymers (T 1 , T 2 ) were prevent and efficiently (93.3,97.3%) corrosion of inhibitors respectively at a time (2 h), concentration (1M) and a temperature of 30 °C.

aqueousenvironment reduces the rate of metal wastage.The inhibitors especially that, the organic ones work byan adsorption mechanism.The resultant film of chemisorbedinhibitor is then responsible for protection either byphysically blocking the surface from the corrosionenvironment or by retarding the electrochemical processes.The main functional groups capable of forming chemisorbedbonds with metal surfaces are amino (-NH 2 ), carboxyl (-COOH) and phosphate (-PO 3 H 2 ) although otherfunctiongroups or atoms can form by coordinate bonds withmetalsurfaces.Sanyal (7) and Abd El-Maksound (8) in their reviewshave given a vivid account of organic compounds used ascorrosion inhibitors including their classification andmechanism of action.Raja and Sethuraman (9) has given acomprehensive review of natural products as corrosioninhibitors for metals in corrosive media.Naturalproducts otherwise tagged "green were uses as corrosion inhibitors" hasbeen advocated because of the cost, toxic nature andenvironmentally unfriendliness of inorganic and organiccorrosion inhibitors.they are readily available, cheap and a renewable source of materials.The use of polymers as corrosion inhibitors has attractedconsiderable attention recently.Polymers are used ascorrosion inhibitors because, through their functional groupsthey form complexes with metal ions and on the metalsurface these complexes occupy a large surface area, therebyblanketing the surface and protecting the metal fromcorrosive agents present in the solution (10).The inhibitivepower of these polymers is related structurally to the cyclicrings, heteroatom (oxygen and nitrogen) that are the majoractive centers of adsorption.The present work presents a review of copolymers ascorrosion inhibitors, which completed to the previous our work for various metals in various aqueouscorrosive environments.investigatedusing weight loss measurements, galvanostaticpolarisation studies, electro permeation studies and a.c.impedance measurements (11,12).The polymer acts predominantlyas an anodic inhibitor.Hydrogen permeation studies and a.c.impedance measurements clearly indicate a very effectiveperformance of the compound as a corrosion inhibitor.Theadsorption of the compound on the mild steel surface obeys Tomkins's adsorption isotherm.

2.1.Synthesis of Copolymers T 1 ,T 2
The copolymers surfactant were prepared by mixing (2 g, 0.01 mol) 2acrylamide-2-methylpropane sulfuric acid dissolved in (10ml) DMF with (3g, 0.01mol) Undecyl acrylate (T 1 ) and (3.2g, 0.01mol) Pentadecyl acrylate (T 2 )in a (250ml) circular flask and the reaction was heated at a temperature of 75-80°C in the presence of nitrogen gas and a little benzoyl peroxide was added as a polymerization initiator with continuous stirring for (3-4 hrs), then the product was left to cool and a mixture of diethyl ether was added for the purpose of washing, drying and disposal.Excess solvent.As in scheme (1).

2.2.Wear velocity measurement
By taking rectangular pieces from the N-80 carbon steel models (with dimensions of (46cm, 3cm, 19cm) for each length, width and thickness, respectively,for the purpose of checking by weight loss measurement method, then the models were washed with dilute hydrochloric acid solution.The dimensions of the carbon steel model N-80 were measured by Venire to calculate the surface area of the model (length, width, thickness).Then , was weighed using the four decimal places sensitive scale.The model was immersed in the edible medium (1M hydrochloric acid) for two hours.And then it was cleanedThe model after extracting it from the medium, eating it with a piece of cotton, removing the erosion products.Weigh the model after cleaning and drying.Calculate the erosion velocity using equation (1).Then the experiment is repeated after adding the corrosion inhibitors in concentrations (0.01,0.02,0.03M) to the edible medium.And at different temperatures (40,50,60) 0 C and time (2hr).Rcorr = wear velocity gm.cm -2 .hr - ∆W = weight loss gm S = surface area cm 2 t = time (hr).

Characterizations 3.1.Infrared spectrum of the two copolymer inhibitors.
The infrared spectrum of the T1 copolymer inhibitor was characterized by the presence of a wide band at the range (3444 cm -1 ) which represents the NH band -(amide.It appeared broadly because of the hydrogen gas.While a sharp band appeared for the group (C=O) ester at a range of (1728 cm -1 ) While a sharp band appeared for the group (C=O) Alameda at a range of (1658 cm -1 ).The CH 2 group bent bundle appeared at a range of 1469cm-1.A group beam (S=O) was distinguished at a range of -1 1388 cm.A bundle of group (S-O) appeared in a range of (1041 cm -1 ).The amplitude oscillation beams of a group (C-O) appeared at a range of (1118 cm -1 ).As for the signal at the site (3140 cm -1 ) it belongs to the (C-H) Alphabet group.as in the figure (1).

3.2.Infrared spectrum of the T 2 copolymeric inhibitor.
The infrared spectrum of the T 2 copolymericinhibitor was characterized by the presence of a wide band at the range (3456 cm -1 ) which represents the amide (NH) band.It appeared broadly because of the hydrogen gas.While a sharp band for the (C=O) ester group appeared at a range of (1718 cm -1 ).While a sharp band appeared for group (C=O) Alameda at a range of (1664cm -1 ).The CH2-group flexural package appeared at a range of (1467cm -1 ).A group beam (S=O) was distinguished at a range of (1388cm -1 ).A beam of a group (S-O) appeared in a range of (1041cm -1 ).The amplitude oscillation beams of a group (C-O) appeared at a range of (1116cm -1 ).As for the signal at the site (3321cm

Figure (2) IR spectrum of the T 2 copolymer 3.3. 1 H-NMR spectrum of the T 1 copolymer
The figure (3) show that there is a signal at ppm (7.8ppm) that belongs to the proton of the sulfonic group, and a signal at the position (7.9ppm) that belongs to the proton of the (NH) group, and the signal that appears at the position (2.9ppm) belongs to the (CH 2 -) group linked With a sulfonic group, there is an indication at the 2.5ppm site that belongs to the two (CH-) groups present in the polymeric chain.As for the sign of the two groups (CH 2 -) of the polymeric chain appeared at the site (1.5ppm) while the group (CH 3 -) present in the compound appeared at the site (0.8ppm).

Figure (3) 1 H-NMR spectrum of the T 1 copolymer 3.4. 1 H-NMR spectrum of the T 2 copolymer
Figure 4 shows that the signal at ppm (7.8 ppm) belongs to the proton of the sulfonic group, the signal at position (7.3 ppm) belongs to the (NH) group proton, and the signal at position (2.2 ppm) belongs to The group (CH2-) is associated with the sulfonic group, and the indicator is located at a position (2.8 ppm) belonging to the two groups (CH-) present in the polymeric chain.As for the sign of the two groups (CH2-) of the polymeric chain, it appeared at the site (1.17 ppm), while the group (CH3-) appeared in the compound at the site (1.04 ppm).

13 C-NMR spectrum of the T 1 copolymer
We notice from Figure (5) the appearance of a signal at the site (167ppm) belonging to the carbon atom in the ester carbonyl group.As for the amide carbonyl group, it appeared on the site (162ppm).There is a signal at (35ppm) belonging to the quaternary atom carrying the two groups of the same, while the signal at the position (34ppm) belongs to the carbon atom of the group (-CH 2 ) within the polymeric chain as well as in the remaining butyl group.As for the signals within the range (25-35ppm), they belong to the carbon atom groups (-CH 3 ) present in the compound.6) the appearance of a signal at the site (167ppm) belonging to the carbon atom in the ester carbonyl group.As for the amide carbonyl group, it appeared on the site (163ppm).There is a signal at (35ppm) belonging to the quaternary atom carrying the two groups of the same, while the signal at the position (34ppm) belongs to the carbon atom of the group (-CH 2 ) within the polymeric chain as well as in the remaining butyl group.As for the signals within the range (10-20ppm), they belong to the carbon atom groups (-CH 3 ) present in the compound.

. Estimate the proportions of the elements
The proportions of (C, H,N) elements were estimated for the prepared polymeric surfactants, and through them we could infer the validity of the prepared compositions if the calculated percentage of (C, H, N) was close to its calculated theoretical value as shown in the table (1 ).
Table ( Study of the effect of temperature on the corrosion rate of carbon steel and weight loss in an aqueous solution of hydrochloric acid at a concentration of (1M) by a weight loss method with and without inhibitors.
Study of the corrosion rate of carbon steel in aqueous solution of acid (HCl) at a concentration of (1M) by weight loss method in the absence of inhibitors: Measurement of the corrosion rate of carbon steel alloys of an aqueous solution of hydrochloric acid at a concentration of (1M) for two hours.and temperatures from 30-60°C.Through the results obtained, it was noted that the weight loss is directly proportional to the temperature to which the metal is exposed in the acidic solution.As in Figure (11) and Table (3).It was observed that the amount of weight loss increased from (0.0923) at a temperature of 30°C to (0.0146) at 40°C.But at a temperature of 50°C, the weight loss became (0.0237).Whereas at 60°C the weight loss was (0.0281) when the time (2hr) was set.While the average corrosion rate of carbon steel at a temperature of 30°C (11x10 -7 ) became.At 40°C it was (13x10 -7 ).While at 50 0 C (15x10 -7 ). at 60°C (17x10 -7 ).

Study of corrosion rate in an aqueous solution of acid (HCl) at a concentration of (1M) by weight loss method in the presence of inhibitors:
The corrosion rate was studied in an aqueous solution of hydrochloric acid at a concentration of (1M) at a time (2hr) in the presence of inhibitors (A, B) at concentrations (0.01, 0.02, 0.03) as Tables (4) and ( 5).And figures ( 12) and (13).Weight loss results.Drift speed rate and Rcorr.The fraction of the metal surface covered with inhibitor particles (θ) and the inhibition efficiency (IE%).Which is obtained in the presence of inhibitors, where the percentage of inhibition efficiency was calculated through the following equation  Figures (12) to (15) show that the amount of weight loss with the presence of inhibitors is less compared to the absence of inhibitors.We also find that with increasing temperature, weight loss will increase with constant time (2hr).The results showed that the amount of weight loss increased from (0.923) at a temperature of 30°C to (0.281) at a temperature of 60°C in the absence of inhibitors.In the presence of inhibitors at a concentration (0.03 M) and at a constant time (2hr), the weight loss increased from (0.0402) at 30°C to (0.0706) at 60°C in the presence of inhibitor A. Inhibitor C, the amount of weight loss increased from (0.0184) at 30°C to (0.0709) at 60°C.As for the rate of velocity, it has been observed that the rate of corrosion of carbon steel with the presence of inhibitors is lower than in the absence of inhibitors.
Corrosion rate of carbon steel in solution (HCl) (1M) at 30°C with time constant (2hr) and in the absence of inhibitor (11x10 -7 ) while inhibitors are present to (5x10 -7 , 2.33x10 -7 ) respectively at a concentration of (0.03M).While at 40°C in the absence of the inhibitor and at a constant temperature (2hr) the corrosion rate was (13x10 -7 ).While in the presence of dampers (A, B) to (4x10 -7 ، 3.68x10 -7 ) at a concentration (0.03M) but at 50°C in the absence of damper and at constant temperature (2hr) the wear rate was (15x10 -7 ) While in the presence of inhibitors (A, B) to (2.08x10 -7 , 4.67x10 -7) respectively at a concentration of (0.03 M) but at 60°C in the absence of the inhibitor and when the temperature is constant (2hr) the corrosion rate was (17x10 -7 ) while in the presence of inhibitors (A, B) to(4.49x10 - , 4.50x10 -7 ) respectively at concentration (0.03 M)As for inhibitor A, it decreased from 93.3% at 30°C to 88.3% at 60°C.As for inhibitor C, the inhibition efficiency decreased from 97.3% at 30°C to 89.8% at 60°C.Table (4

Figure ( 11 )
Figure (11) Weight loss and corrosion velocity of carbon steel alloy in acidic medium (HCl) with concentration (1M) as a function of temperature in the absence of inhibitor
Figures(12) to(15)  show that the amount of weight loss with the presence of inhibitors is less compared to the absence of inhibitors.We also find that with increasing temperature, weight loss will increase with constant time (2hr).The results showed that the amount of weight loss increased from (0.923) at a temperature of 30°C to (0.281) at a temperature of 60°C in the absence of inhibitors.In the presence of inhibitors at a concentration (0.03 M) and at a constant time (2hr), the weight loss increased from (0.0402) at 30°C to (0.0706) at 60°C in the presence of inhibitor A. Inhibitor C, the amount of weight loss increased from (0.0184) at 30°C to (0.0709) at 60°C.As for the rate of velocity, it has been observed that the rate of corrosion of carbon steel with the presence of inhibitors is lower than in the absence of inhibitors.Corrosion rate of carbon steel in solution (HCl) (1M) at 30°C with time constant (2hr) and in the absence of inhibitor (11x10-7 ) while inhibitors are present to (5x10 -7 , 2.33x10-7 ) respectively at a concentration of (0.03M).While at 40°C in the absence of the inhibitor and at a constant temperature (2hr) the corrosion rate was (13x10-7 ).While in the presence of dampers (A, B) to (4x10 -7 ، 3.68x10-7 ) at a concentration (0.03M) but at 50°C in the absence of damper and at constant temperature (2hr) the wear rate was (15x10 -7 ) While in the presence of inhibitors (A, B) to (2.08x10 -7 , 4.67x10-7) respectively at a concentration of (0.03 M) but at 60°C in the absence of the inhibitor and when the temperature is constant (2hr) the corrosion rate was (17x10-7 ) while in the presence of inhibitors (A, B) to(4.49x10 - , 4.50x10-7 ) respectively at concentration (0.03 M)As for inhibitor A, it decreased from 93.3% at 30°C to 88.3% at 60°C.As for inhibitor C, the inhibition efficiency decreased from 97.3% at 30°C to 89.8% at 60°C.Table (4 ) represents the weight loss, the rate of corrosion speed, the part covered by the metal surface with inhibitor particles, and the percentage of inhibition for carbon steel alloy N-80 in HCl solution at a concentration of (1M) at different temperatures and time (2hr) in the presence of inhibitor A

Figure ( 13 )Figure (14) Average wear rate of carbon steel as a function of concentration in the presence of
Figure ( 13 ) percentage of inhibition efficiency as a function of concentration in the presence of inhibitor A - 1 ) it belongs to the (C-H) Alphabet group.as in the figure ( 2)