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In the present work, we present the superior corrosion inhibition properties of three plant-based products, Fraxinus excelsior (FEAE), Zingiber zerumbet (ZZAE), and Isatis tinctoria (ITAE), that efficiently inhibit the corrosion of mild steel in phosphoric acid. The anti-corrosion and adsorption characteristics were assessed using a combination of experimental and computational approaches. Weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy methods were used to evaluate the inhibitive performance of the inhibitors on the metal surface. Then, both DFT/DFTB calculations and molecular dynamic simulations were further adopted to investigate the interaction between organic inhibitor molecules and the metal surface. The protective layers assembled using the active constituents, such as carbonyl and hydroxyl groups, of the three plant-based products offer high electrochemical stability at high temperatures and robust protection against aggressive acidic solutions. All electrochemical measurements showed that the inhibition performance of extracts increased by increasing their concentration and improved in the following order: FEAE > ZZAE > ITAE. Further, these extracts worked as mixed-type inhibitors to block the anodic and cathodic active sites on the mild steel surface. Multi-level computational approaches revealed that FEAE is the most adsorbed inhibitor owing to its ability to provide electron lone pairs for electrophilic reactions. The experimental and theoretical results showed good agreement. These results indicate the possibility of replacing conventional compounds with natural substituted organic products in the fabrication of hybrid materials with effective anti-corrosion performance.

Poly (vinyl chloride) (PVC) was blended with acrylonitrile/diallyl amine derivatives [diallyl amine (DAA), diallyl amine acetate (DAAA), diallyl guanidine (DAGA)] copolymers for the improve...

Cyclopolymerization of diallylamine (DAA) onto starch backbone was studied. The graft copolymerization (St-g-DAA) occurred using redox initiators (potassium persulfate/sodium bisulfite). The graft parameters have been studied to obtain the maximum percentage graft. The percentage of graft reached 56%. The copolymer’s structure was characterized by 13CNMR spectrometer. The thermal property of the synthesized copolymer was investigated to adjust the copolymer to water treatment, which involved the removal of Cu (II) ions from aqueous solution. The removal of cations was confirmed by X-Ray diffraction (XRD) and Emission scanning electron micrograph (ESEM). Also, the (St-g-DAA) showed better antibacterial activity than native starch.

Two diallylamine salts, diallylammonium acetate (DAA acetate) and diallylguanidinium acetate (DAGA) were cyclocopolymerized in water with acrylonitrile (AN) using power ultrasound in order to prepare acrylonitrile copolymers involving thermally stable heterocyclic rings in their polymeric matrix. The structural characterization of the copolymers was performed using FTIR, $$^{13}$$ C NMR, UV/Vis spectroscopy and elemental analysis. The results revealed that the diallyl amine salts cyclopolymerized to form pyrrolidine and not piperidine rings throughout the polymeric chains. The thermal behavior of the copolymers prepared under nitrogen atmosphere was investigated using thermogravimetry, differential thermal analysis (TGA/DTA) and differential scanning calorimetry. The morphological property was also discussed using scanning electron microscopy (ESEM). The results revealed that the thermal stability of the copolymers was improved by the increase in the content of N,N-diallylammonium and N,N-diallylguanidinium acetate. The power of ultrasonic waves enhanced the homogeneity of the copolymers blend films irrespective of the copolymer compositions.

The corrosion inhibition of Al–Cu alloy in 0.5 M NaOH using various concentrations of camel urine (CU) was investigated using hydrogen evolution, weight loss, electrochemical impedance spectroscopy and potentiodynamic polarization measurements. Analysis of impedance spectra revealed that CU inhibits the corrosion of the studied alloy effectively through the formation of a protective film on its surface with a resistance increasing with increasing CU concentration. Polarization studies indicated that CU was a mixed-type inhibitor except for CU concentrations > 3 mL% where it behaves predominantly as an anodic inhibitor. Hydrogen evolution plots were analyzed using shrinking core models for solid–liquid heterogeneous systems. The resultant data revealed that after certain induction period, hydrogen evolution occurs by fast reaction followed by slow reaction and the latter is controlled by diffusion. The values of IE% obtained from hydrogen evolution and weight loss measurements were temperature dependent. Generally, the inhibitor performance decreased at relatively high temperature (60 $$^{\circ }$$ C) except for low CU concentrations (

Poly(vinyl chloride) (PVC) is modified by N-phenyl itaconimide derivatives (N-(RPh)IM) as modifying agents or graft comonomers. The resulting modified polymers or graft copolymers were characterized using FTIR and UV/Vis spectrophotometry. The thermal properties of the modified polymers were investigated using thermogravimetry (TGA), which revealed that the synthesized polymers exhibited high thermal stability, as shown from the value of their initial decomposition temperatures and the percentage of weight loss at high temperatures. The polymer modified by 4-bromo itaconimide exhibited the most thermal stability. A mechanism for the modification reaction and the graft copolymerization of PVC was suggested.

The construction of Nitro -N-amino phenyl maleimide branches onto Cellulose acetate (CA) substrate by free radical graft copolymerization using benzoyl peroxide as initiator led to formation of highly thermal stable copolymers as shown from the results of gravimetric analysis (TGA). CA-g-2,4-dinitro amino phenyl maleimide exhibited higher thermal stability than the CA-g-4-nitro amino phenyl maleimide as shown from the initial decomposition temperature (To). This is due to the ability of nitro group to form hydrogen bonding with hydroxyl group of the glucopyranose ring which increases the crystallinity of polymeric matrix. The crystalline shapes representing the graft part are clearly distinct in the Emission scanning electron microscope (ESEM) morphology of the copolymer. A suggested reaction mechanism for the grafting process was also discussed.

Cellulose acetate (CA) is a natural biodegradable polymer. It forms transparent films by the casting technique. CA suffers from high degree of water permeability as well as the low thermal stability at high temperatures. To adjust the CA polymeric films to the manufacture of food packaging, its thermal and mechanical properties should be improved. The modification of CA by grafting it with N-Amino phenyl maleimide (N-APhM) led to the construction of hydrophobic branches throughout the polymeric matrix which reduced its wettability as compared to the parent CA. The branches built onto the polymeric chains had been characterized by UV/Vis, 13C-NMR and ESEM. The improvement of the thermal properties was investigated and compared to the parent CA using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), differential thermal analysis (DTA), contact angle and mechanical testing measurements. The results revealed that the water-uptake was reduced by increasing the graft percentage. The thermal and mechanical properties were also improved., {"references":["A. K. Mohanty, A. Wibowo, M. Misra and L. T. Drzal, \"Development of renewable resource-based cellulose acetate bioplastic: Effect of process engineering on the performance of cellulosic plastics,\" Polym. Eng. & sci., Vol. 43 (5), pp. 1151-1161, 2003.","V. Thakur and S. Voicu,. \"Recent advances in cellulose and chitosan based membranes for water purification: A concise review,\" Carbohyd. Polym., Vol. 146, pp. 148-165, 2016.","L. S. Nair and C. T. Laurencin, \"Biodegradable polymers as biomaterials,\" Prog. Polym. Sci., Vol. 32 (8-9), pp.762-798, 2007.","D. Briassoulis, \"An Overview on the Mechanical Behaviour of Biodegradable Agricultural Films,\" J. Polym. Env. Vol. 12 (2), 65-81, 2004.","H. Kamal and F.M. Abd-Elrahimb and S. Lotfy, \"Characterization and some properties of cellulose acetate-co-polyethylene oxide blends prepared by the use of gamma irradiation,\" J. Rad. Res. Appl. Sci., Vol.7 (2), pp.146-153, 2014.","R. Chandra and R. Rustgi, Biodegradable polymers. Progress in Polymer Science, 23 (7), pp. 1273-1335, 1998.","A. S. Abdel-Naby and S. A. Aboubshait, \"Cellulose acetate blends with acrylonitrile/N-phenyl maleimide copolymers morphological and thermal properties\". J. Therm. Anal. Calor., Vol. 114 (3), pp. 1279–1286, 2013.","A. S. Abdel-Naby and A. A. Al-Ghamdi, \"Chemical modification of cellulose acetate by N-(phenyl amino) maleimides: Characterization and properties,\" Int. J. Biol. Macromol., Vol. 68, pp. 21–27, 2014.","A. S. Abdel-Naby and A. O. Al-Dossary, Use of N-(N0-Arylamino) maleimides to Improve theThermal Properties of Poly (vinyl chloride) Through Chemical Modification and Graft Copolymerization. J. Vinyl. Addit. Technol. Vol. 14 (4), pp. 167-174, 2008.\n[10]\tAbdel-Naby, A. S. and A. O. Al-Dossary, Stabilization of poly (vinyl chloride) against photo-degradation using dienophilic compounds. J. Appl. Polym. Sci. Vol. 114, pp. 3218–3228, 2009.\n[11]\tO. A. Fridman and A. V. Sorokina. Criteria of efficiency of cellulose acetate plasticization. Polym. Sci. ser. B. Vol. 48 (9-10), pp. 233-236, 2006."]}

Wider plastic applications of poly(vinyl chloride) (PVC) has raised serious problem to the environment. Since (PVC) waste products resist biodegradation and persist in the environment for longer time. The object of this study is to blend (PVC) with biodegradable cellulose acetate to thermally support the polymer during the molding process as well as to enhance the biodegradability of (PVC) waste products. Blending of poly(vinyl chloride) and cellulose acetate (CA) in presence of N -(phenyl amino) maleimides (R-PhAM) where (R = H, 4-NO 2 ) led to improvement in the thermal stability of the blend film at high temperatures as shown from the high values of initial decomposition temperature ( T o ) determined from their thermogravimetry (TG) curves. Also, blending (PVC) with (CA) led to improvement in the mechanical properties of the blend films as compared to (PVC). The crystalline regions of cellulose acetate enhanced the elasticity of the blend films as shown from their high Young's modulus values.

Problem statement: The corrosion inhibition of mild steel in 1.5 M H2SO4 by Camel’s Urine (CU) addition was evaluated at five different temperatures in the range from 30-70°C by weight loss measurements. CU acts as a good inhibitor for the corrosion of mild steel in 1.5 M H2SO4. The value of inhibition efficiency increases with increasing both inhibitor concentration and solution temperature. Approach: The adsorption of CU constituents on the mild steel surface obeys the Langmuir adsorption isotherm suggesting a monolayer adsorption of CU species. Thermodynamic parameters for CU adsorption and mild steel corrosion were evaluated. The negative values of (ΔGoads) emphasize the spontaneity of the adsorption process and stability of the adsorbed layer. Results: The estimated high, positive value of ΔHoads ensures that CU species is adsorbed chemically on mild steel surface. All values of E*app for mild steel corrosion in inhibited solutions were lower than that for the uninhibited solution indicating the occurrence of chemisorption mechanism. Conclusion: The surface morphology of mild steel in absence and presence of inhibitor revealed that with increasing both CU concentration and solution temperature, mild steel surface is modified and looks smooth. Good correlation between the inhibitor constituents and its inhibitory action was obtained.

Tin, nickel, cobalt, zinc, and copper complexes of cyanoguanidine and urea were synthesized and investigated as thermal stabilizers for rigid poly(vinyl chloride) at 180°C in air. Their stabilizing efficiencies were evaluated by measuring the induction period (the period during which no evolved hydrogen chloride could be detected) and the rate of dehydrochlorination as determined by continuous potentiometric measurements, in addition to the extent of discoloration. The results clearly revealed the greater efficiency of all of the investigated metal complexes as compared to those of well-recognized reference stabilizers. The tin complex always exhibited the highest efficiency irrespective of the type of ligand used. The nickel and cobalt complexes also possessed high stabilizing efficiencies. The order of the stabilizing potency of the various metal complexes was Sn ⋙ Co, Ni ≫ Zn, Cu. Combining the ligand itself with dimethyltin-s,s′-bis (isooctyl thioglycolate), as a reference stabilizer containing a tin atom, led to a true synergism. This synergistic effect might be attributed to the formation in situ of a complex between the ligand and the tin atom. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers

Cellulose acetate (CA) was modified using N-(phenyl amino) maleimides (R-APhM) where, R H or 4-NO2. The structure of the modified polymer was characterized by 13C-NMR. The chemical modification is based on the reaction between the acetyl group of the glucopyranose ring in cellulose acetate and the proton of the amino group in N-(phenyl amino) maleimide molecule. The thermal gravimetry (TGA) was used to investigate the thermal stability of the modified polymeric samples. The modified cellulose acetate by 4-nitro (phenyl amino) maleimide (CA/4-NO2APhM) exhibits the highest thermal stability as compared to the N-(phenyl amino) maleimide (CA/APhM) and the unmodified CA. The crystallinity and morphology of the modified polymeric samples were investigated using X-ray diffraction (XRD) and emission scanning electron microscope (ESEM), respectively. The presence of N-(phenyl amino) maleimide moieties in the cellulose acetate matrix improved its mechanical property. Also, the organic nature of (R-APhM) moieties inside CA matrix reduced its wettability.

Acrylonitrile (AN) was copolymerized with itaconic acid metal complexes [Co(II),Ni(II),Cu(II)] aiming to synthetize self-colored acrylonitrile fiber. The copolymerization occurred in water at 60°C using sodium bisulfite and potassium persulfate as redox initiators. The resulting copolymers are colored and exhibited high thermal stability as shown from their TGA curves. The investigated copolymers exhibited comparable thermal stability as that of PAN. The AN/ itaconic acid Co(NO3)2copolymer was considerably the most thermal stable copolymer while that of Ni(II) copolymer was the less stable one. Cu(II) copolymer showed an intermediate stability. The data also revealed that the maximum degradation occurred after 300°C (the cyclization temperature). Thus, neither the copolymerization nor the complexation affected the nitrile oligomerization reaction. The effect of adding ammonium hydroxide solution to acrylonitrile – itaconic acid copper(II) complex copolymer on the thermal stability of copolymer was also studied.