Ahmed

Synthesis of New Thiophene Derivatives and Their Use as Photostabilizers for Rigid Poly(vinyl chloride)

Five new thiophenes, namely, N-[(3-bromo-2-methylthiophen-5-yl)methylene]-4-methoxyaniline (4a), N-[(3-bromo-2-methylthiophen-5-yl)methylene]-3,4-dimethoxyaniline (4b), N-[(3-bromo-2-methylthiophen-5-yl)methylene]-3,4-dimethylaniline (4c), 3-[(3-bromo-2-methylthiophen-5-yl)methyleneamino]-2-methylquinazolin-4(3H)-one (4d), and 3-[(3-bromo-2-methylthiophen-5-yl)methyleneamino]-2-isopropylquinazolin-4(3H)-one (4e), have been synthesized. All of these materials brought about a reduction in the level of photodegradation of poly(vinyl chloride) (PVC) films containing the synthesized thiophenes (0.5%; by weight). The results obtained showed that the extent of photostabilization of PVC in the presence of an additive was in the order 4e > 4d > 4b > 4a > 4c. For the most favorable additive (4e), the rate of appearance of infrared absorption bands of degradation products was reduced by around two-thirds, while the quantum yield of chain scission was calculated to be reduced by a factor of more than one thousand. It is suggested that the additives may help stabilize PVC by direct absorption of UV radiation and dissipation of the energy as heat or that electrostatic attraction between the additives and PVC may assist transfer of energy from excited state PVC to the additive, from where it can be dissipated.

Synthesis and characterization of transition metal complexes of 4-Amino-5-pyridyl-4H-1,2,4-triazole-3-thiol

Series of coordination complexes of Ni(II), Cu(II), Zn(II), Cd(II) and Sn(II) metal with 4-amino-5-(pyridyl)-4H-1,2,4-triazole-3-thiol, as a ligand has been successfully prepared in alcoholic medium. The prepared complexes were characterized quantitatively and qualitatively by using: microelemental analysis, FTIR spectroscopy, UV-visible spectroscopy, 1H and 13C NMR, magnetic susceptibility and conductivity measurements. This triazole ligand act as bidentate that coordination to the metal ions through sulphur and amine group. According to the spectral data of the complexes a tetrahedral geometry was suggested for these complexes except Cu (II) complexes which exhibit a square structure.

Synthesis and characterization of Schiff's bases of sulfamethoxazole

Background Schiffs bases are excellent ligands which are synthesized from the condensation of primary amines with carbonyl groups. Findings The classical reaction for the synthesis of Schiffs bases in an ethanolic solution and glacial acetic acid as a catalyst was followed in the synthesis of substituted sulfamethoxazole compounds. Conclusions Some Schiffs bases containing sulfamethoxazole nucleus have been synthesized and characterized. The present compounds are hoped to be applied in the photostability of PVC.

New Tetra-Schiff Bases as Efficient Photostabilizers for Poly(vinyl chloride)

Three new tetra-Schiff bases were synthesized and characterized to be used as photostabilizers for poly(vinyl chloride) (PVC) films. The photostability of PVC films (40 μm thickness) in the presence of Schiff bases (0.5 wt %) upon irradiation (300 h) with a UV light (λmax = 365 nm and light intensity = 6.43 × 10−9 ein∙dm−3∙s−1) was examined using various spectroscopic measurements and surface morphology analysis. The changes in various functional groups’ indices, weight and viscosity average molecular weight of PVC films were monitored against irradiation time. The additives used showed photostability for PVC films, with Schiff base 1 being the most effective additive upon irradiation, followed by 2 and 3. The atomic force microscopy (AFM) images for the PVC surface containing Schiff base 1 after irradiation were found to be smooth, with a roughness factor (Rq) of 36.8, compared to 132.2 for the PVC (blank). Several possible mechanisms that explain PVC photostabilization upon irradiation in the presence of tetra-Schiff bases were proposed.

Poly(vinyl chloride) derivatives as stabilizers against photodegradation

Abstract The photo-stabilization of polymers derived from poly(vinyl chloride) (PVC) films was investigated. The PVC and modified PVC films were produced by the casting method from tetrahydrofuran (THF) solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl, polyene and hydroxyl indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (Φcs) of these complexes in PVC films was evaluated and found to range between 4.79 × 10−8 and 7.50 × 10−8. Results obtained showed that the rate of photostabilization of PVC in the presence of the additive followed the trend:

Determination and applications of chemical analysis to evaluate Jurassic hydrocarbon potentiality in Northern Iraq

Chemical analysis was carried out to evaluate the potentiality of rock samples having hydrocarbon characteristics, identified by chemical methods as one of the approaches to evaluate the source rocks encountered from Sehkanian, Sargelu, Naokelekan, Sarmord and Ghia Gara of (Middle to Upper Jurassic–Lower Cretaceous) stratigraphic sequence of Iraq, representing source rocks, which are recovered from oil exploratory wells Butmah-15, Ajeel-8, Makhul-2, Qarachuq (1 and 2) and TaqTaq-1 (Bm-15, Aj-8, Mk-2, Qc-1,Qc-2 and Taq-1) alternatively, located in the northern part of Iraq and also the outcrop samples extracted from the type locality at Surdash Anticline. Additional samples were taken from another exposure section of the Jurassic rocks from Banik village, those various samples represent Varity of palynofacies. The bulk of chemical analysis enables to enhance the potentiality of the source rocks, leading to believe generating tremendous amount of oil and subordinate gas promising more than earlier predictions for forming super giant oil and thermogenic gas fields in this area. The value of the production indices determines that the system of the oil in Iraq is not widely different from the depocenters of the surrounding countries. Accordingly Iraq is considered as an ideal and systematic basin that all the total petroleum system elements are available, giving indications of good source rocks, extensive reservoirs and excellent seals. Typical oil fields, which as determined by the remarkable total organic carbon exceeds 20 %, and maturation evidences accompanied with maximum temperature up to 450°C indicate obviously various values of the hydrogen and oxygen indices, kerogen type II and type III, of marine to mixed to terrestrial origin that lead to determine that the oil and gas prone Sargelu, Naokelekan and Ghia Gara were good source rocks. Meanwhile Barsarin and Sarmord were reservoir rocks. The area of study is widely promising to produce oil with condensed gas.

Photocatalytic degradation of polyhydroxybutyrate films using titanium dioxide nanoparticles as a photocatalyst

Photocatalytic degradation of polyhydroxybutyrate (PHB) polymeric films (30 μm thickness) containing different concentrations of titanium dioxide (TiO2) nanoparticles under ultraviolet (UV) irradiation (λmax = 313 nm) has been studied. The activity of TiO2 (0.001-0.005%) as a photocatalyst was determined by monitoring various functional group indices, weight loss in polymeric films and photodegradation rate constant (kd) with irradiation time. Photodegradation was found to be highly dependent on the TiO2 nanoparticles concentration and the UV irradiation time. The rate of PHB sample photodegradation was highest when the concentration of TiO2 was 0.005% (by weight) and lowest when its concentration was 0.001%.

Antibacterial Study of Some Oxazepine Derivatives

Compounds containing 1,3-oxazepine and 1,3,4-oxadiazole (5)-(8) were synthesized by microwave assisted organic synthesis method through the condensation reaction of compounds (1 to 4) with phthalic anhydride respectively. The structure of the synthesized compounds were characterized by spectroscopic methods (1H NMR, FTIR). The synthesized compounds were screened for their antibacterial activity disc diffusion method.

Synthesis, Characterization and Optical Properties of New Pvc- Amines Polymers

Poly (vinyl chloride) (PVC) react with different amines in THF to form new polymers (PVC-L). The structures of these polymers have been characterized by IR and Uv-Vis. spectrophotometry. The optical properties of pure and modified PVC were studied in the region (200-400 nm). The optical data analyzed and interpreted in term of the theory of phonon assisted direct electronic transition; it is observed that the energy is affected by doping type polymers used.

Fabrication of Novel Ball-Like Polystyrene Films Containing Schiff Base Microspheres as Photostabilizers

Polystyrene films containing a low concentration of three highly aromatic Schiff bases were prepared using the casting method. The polystyrene films were irradiated with ultraviolet light (300 h). The polystyrene infrared spectra, weight loss, molecular weight reduction and the surface morphology were examined upon irradiation. The Schiff bases acted as photostabilizers and reduced the photodegradation of polystyrene films to a significant level in comparison to the blank film. The images recorded of the surface of the miscible polystyrene/Schiff base blends showed novel ball-like microspheres with a diameter of 3.4–4.3 µm. The Schiff bases were able to endow excellent protection to polystyrene against ultraviolet irradiation.