Article
Polymer Science
Rafid R. Arraq, Angham G. Hadi, Dina S. Ahmed, Gamal A. El-Hiti, Benson M. Kariuki, Amani A. Husain, Muna Bufaroosha, Emad Yousif
Summary: Poly(vinyl chloride) (PVC) has attractive properties such as low cost, acid and alkali resistance, and ease of molding, but it suffers from aging. Adding tin-cephalexin complexes to PVC can improve its stability to irradiation. This study investigates the effect of these complexes on the photodecomposition of PVC and confirms their role as stabilizers by reducing the rate of photodecomposition.
Article
Polymer Science
Angham G. Hadi, Sadiq J. Baqir, Dina S. Ahmed, Gamal A. El-Hiti, Hassan Hashim, Ahmed Ahmed, Benson M. Kariuki, Emad Yousif
Summary: Poly(vinyl chloride) can undergo degradation when exposed to radiation and high temperatures, but the addition of stabilizers, such as tin complexes of 4-methoxybenzoic acid, can inhibit this degradation and enhance its stability. By doping PVC with these tin complexes, the stability of the material under ultraviolet light irradiation is improved, resulting in reduced weight loss and molecular fragmentation.
Article
Biochemistry & Molecular Biology
Hadeer Jasem, Angham G. Hadi, Gamal A. El-Hiti, Mohammed A. Baashen, Hassan Hashim, Ahmed A. Ahmed, Dina S. Ahmed, Emad Yousif
Summary: New organotin complexes were synthesized and evaluated as photostabilizers for poly(vinyl chloride), showing a reduction in photodegradation of polymeric films when irradiated with ultraviolet light. These complexes were found to inhibit the main cause of poly(vinyl chloride) photodegradation and acted as efficient primary and secondary photostabilizers.
Article
Polymer Science
Noor Emad, Gamal A. El-Hiti, Emad Yousif, Benson M. Kariuki
Summary: Poly(vinyl chloride) or PVC has functional properties that enable its use in many industrial applications. However, it suffers from aging in harsh conditions if oxygen is present. Blending PVC with metal oxide nanoparticles and clotrimazole can enhance its photostability and protect it against photodegradation.
Article
Polymer Science
Omar G. Mousa, Gamal A. El-Hiti, Mohammed A. Baashen, Muna Bufaroosha, Ahmed Ahmed, Ahmed A. Ahmed, Dina S. Ahmed, Emad Yousif
Summary: The photostability of PVC can be enhanced by adding synthesized tin complexes, which inhibit photodegradation induced by UV irradiation; organotin with a high content of aromatics is particularly efficient in this process. Carvedilol tin complexes not only absorb UV light, but also scavenge radicals, hydrochloride, and peroxides, stabilizing PVC in the presence of UV irradiation.
Article
Polymer Science
Marwa Fadhil, Emad Yousif, Dina S. Ahmed, Alaa Mohammed, Hassan Hashim, Ahmed Ahmed, Benson M. Kariuki, Gamal A. El-Hiti
Summary: Polyvinyl chloride is susceptible to degradation when exposed to high temperatures and sunlight. This research explores the use of new norfloxacin-tin complexes as additives to inhibit the photodegradation of polyvinyl chloride. The complexes were found to effectively reduce the photodegradation of polyvinyl chloride when added at low concentrations.
Article
Engineering, Environmental
Yi-heng Lu, Bing Wang, Meng-yao Xue, Yu-wei Lu
Summary: The study found that calcium metal soap and polyol additives are replacing organotin in PVC heat stabilizers, and investigated the thermal degradation and discoloration process of stabilized PVC using isothermal thermogravimetry. Results show that organotin prolongs the thermal oxidation degradation time of PVC and provides excellent heat resistance.
Article
Polymer Science
Noor Naoom, Emad Yousif, Dina S. Ahmed, Benson M. Kariuki, Gamal A. El-Hiti
Summary: Polyvinyl chloride (PVC) is a widely used thermoplastic that undergoes photodecomposition when exposed to harsh conditions. The addition of methyldopa-tin complexes can enhance PVC's resistance to UV-induced deterioration. These complexes act as radiation absorbents, coordinate with polymeric chains, and scavenge radicals, peroxides, and hydrogen chloride.
Article
Polymer Science
Marwa Fadhil, Emad Yousif, Dina S. Ahmed, Benson M. Kariuki, Gamal A. El-Hiti
Summary: Polyvinyl chloride (PVC) is a synthetic polymer widely used in our daily life, but its useful lifetime can be shortened due to photodegradation, which also produces toxic products. Therefore, finding additives to reduce the photodecomposition of PVC is important. In this study, new levofloxacin-tin complexes were synthesized and tested for their ability to reduce PVC photodegradation. The results showed that these new additives effectively reduced the photodegradation of PVC by absorbing ultraviolet light and quenching reactive species. They were more effective than previously reported organotin complexes.
Review
Polymer Science
Krzysztof Lewandowski, Katarzyna Skorczewska
Summary: This article provides a literature review on the recycling of PVC, including mechanical recycling and feedstock recycling methods. It also introduces the characteristics of PVC and its potential in the circular economy.
Article
Polymer Science
Fiona J. Horne, John J. J. Liggat
Summary: The degradation of poly(diethylene glycol terephthalate) (PDEGT) under accelerated aging conditions was investigated using simulated sunlight and UV lamps. Various spectroscopic techniques were employed to determine the extent of degradation. The results indicate that PDEGT degrades more significantly than poly(ethylene terephthalate) due to the susceptibility of the ether linkage. The diethylene glycol sequences do not act as photochemical weak links but serve as additional sites for secondary free radical chemistry.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Review
Polymer Science
Digvijayee Pal, Debabrata Konar, Brent S. Sumerlin
Summary: Poly(vinyl ketones) (PVKs) have been extensively studied for their unique photochemistry and photodegradation properties under ultraviolet (UV) light. PVKs rapidly undergo photodegradation through Norrish type I or Norrish type II reaction mechanisms, and the side-chain carbonyl moieties can be easily modified by nucleophilic addition reactions. These properties make PVKs versatile scaffolds for generating functional materials. This review provides an overview of synthetic routes to access well-defined PVKs, their photochemistry and photo-degradation pathways, as well as recent and potential applications of these photodegradable materials.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Materials Science, Characterization & Testing
Emaad T. B. Al-Tikrity, Anaheed A. Yaseen, Emad Yousif, Dina S. Ahmed, Mohammed H. Al-Mashhadani
Summary: This study investigates the use of three new Schiff bases as photo-stabilizers for poly(vinyl chloride) to resist photo-decomposition. The additives were found to reduce the elimination of hydrogen chloride molecules and act as free radical scavengers or peroxide decomposers, thus inhibiting photo-degradation.
POLYMERS & POLYMER COMPOSITES
(2022)
Article
Polymer Science
Carlos M. R. Abreu, Talita C. Rezende, Armenio C. Serra, Ana C. Fonseca, Rebecca Braslau, Jorge F. J. Coelho
Summary: A new strategy of internal plasticization of PVC was achieved by copolymerization of VC with n-BA and OEOA. The effect of solvent, initiator, polymerization temperature, and VC/n-BA/OEOA ratios on Tg of the resulting copolymers was investigated. The internally plasticized PVC copolymers showed lower Tg values than predicted, indicating effective plasticization of PVC. Under optimized conditions, different degrees of internal plasticization could be achieved by varying the initial monomer ratio. Importantly, the plasticizing moieties were covalently bonded to the polymer, resulting in no migration during extraction.
Article
Polymer Science
Jolanta Tomaszewska, Tomasz Sterzynski, Damian Walczak
Summary: The study investigated the thermal stability of PVC with 1 wt % of spherical porous nanosilica prepared by roll milling at various processing times. The addition of porous nanosilica was found to improve thermal stability by absorbing HCl gas produced during dehydrochlorination reaction, resulting in minor color changes and lower evolution of hydrogen chloride gas. The results showed that TGA measurements were not sensitive enough to detect PVC degradation at processing conditions below 220 degrees C.
Article
Chemistry, Inorganic & Nuclear
Benson M. Kariuki, Hanan A. Mohamed, Bakr F. Abdel-Wahab, Gamal A. El-Hiti
Summary: Unexpected ring closure of compound 3 under the action of sulfuric acid at room temperature resulted in the formation of compound 4 with a yield of 75%. The synthesized benzenesulfonic acid showed inhibitory activity against both Listeria monocytogenes and Escherichia coli, which was comparable to ampicillin and vancomycin.
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
(2023)
Article
Polymer Science
Rafid R. Arraq, Angham G. Hadi, Dina S. Ahmed, Gamal A. El-Hiti, Benson M. Kariuki, Amani A. Husain, Muna Bufaroosha, Emad Yousif
Summary: Poly(vinyl chloride) (PVC) has attractive properties such as low cost, acid and alkali resistance, and ease of molding, but it suffers from aging. Adding tin-cephalexin complexes to PVC can improve its stability to irradiation. This study investigates the effect of these complexes on the photodecomposition of PVC and confirms their role as stabilizers by reducing the rate of photodecomposition.
Article
Chemistry, Multidisciplinary
Okba Al Rahal, Benson M. Kariuki, Colan E. Hughes, P. Andrew Williams, Xiaoyan Xu, Simon Gaisford, Dinu Iuga, Kenneth D. M. Harris
Summary: In this study, the solid-state phase transition behavior of 1-iodoadamantane (1-IA) was investigated using various techniques. The results revealed complex phase transition behavior, with multiple low-temperature phases identified. Different crystals of phase A showed different phase transition pathways, indicating the presence of other factors influencing the phase transitions.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Biochemistry & Molecular Biology
Abdelmoujoud Faris, Hanine Hadni, Basil A. Saleh, Hadjer Khelfaoui, Dalal Harkati, Hassan Ait Ahsaine, Menana Elhallaoui, Gamal A. El-Hiti
Summary: In this study, twenty-seven 1,6-disubstituted 1H-pyrazolo[3,4-d]pyrimidines were tested as potential selective inhibitors of JAK3. Molecular modeling methods and statistical analysis were used to evaluate the activity and predictive ability of the tested compounds. The results showed that compounds containing the acrylic aldehyde moiety had irreversible interaction with the active sites of JAK3, indicating their potential as anti-JAK3 inhibitors for rheumatoid arthritis treatment.
JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS
(2023)
Review
Medicine, General & Internal
Kholoud Ahmad Bokhary, Razan Ibrahim Alsabih, Gamal Abdelrahman El-Hiti
Summary: This narrative review aimed to investigate the efficiency of binocular treatment for amblyopic children and compare it with standard methods. Literature search was conducted to identify studies in the field of binocular treatment for amblyopia, and the results showed that binocular treatment improved visual acuity and binocular function, reducing suppression depth extent and increasing stereopsis for amblyopic children.
JOURNAL OF THE PAKISTAN MEDICAL ASSOCIATION
(2023)
Article
Chemistry, Analytical
Keith Smith, Xiaojing Mu, Zhaoqiang Li, Andy M. Holland, J. Stuart Woodhead, Gamal A. El-Hiti
Summary: Several new acridinium esters 2-9 with different substituents on their central acridinium ring have been synthesized and tested for their chemiluminescent properties. The esters with 2,5-dimethylphenyl emit light slowly, while the esters with 2,6-dinitrophenyl and 2,6-bis(trifluoromethyl)phenyl emit light rapidly. The hydrolytic stabilities of the compounds are influenced by the substituent at the 10 position.
Article
Chemistry, Organic
Bakr F. Abdel-Wahab, Abdelbasset A. Farahat, Benson M. Kariuki, Gamal A. El-Hiti
Summary: The reaction of 1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one (1) with excess hydroxylamine hydrochloride (2 mole equivalents) in dry ethanol yielded (E)-1-(5-methyl-1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)ethan-1-one oxime (2) in 86% yield. The structure of the new heterocycle 2 was confirmed using nuclear magnetic resonance spectroscopy, single crystal X-ray, and elemental analysis.
Article
Chemistry, Organic
Bakr F. Abdel-Wahab, Mohamed S. Bekheit, Benson M. Kariuki, Gamal A. El-Hiti
Summary: Equimolar equivalents of 1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole-4-carbohydrazide (1) and 2-acetylbenzofuran (2) reacted in anhydrous ethanol containing a catalytic amount of concentrated hydrochloric acid under reflux for 2 h to give (E)-N'-(1-(benzofuran-2-yl)ethylidene)-1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole-4-carbohydrazide (3) in 86% yield. The structure of compound 3 was confirmed using nuclear magnetic resonance and X-ray diffraction.
Article
Chemistry, Organic
Bakr F. Abdel-Wahab, Hanan A. Mohamed, Benson M. Kariuki, Gamal A. El-Hiti
Summary: A 1:1 mixture of compound 1 and compound 2 reacted under reflux in anhydrous ethanol in the presence of piperidine as a catalyst for 4 hours, resulting in the formation of compound 3 with 82% yield. The structure of the newly synthesized heterocycle was confirmed using X-ray diffraction and spectral analyses.
Article
Crystallography
Reham A. Mohamed-Ezzat, Benson M. Kariuki, Rasha A. Azzam
Summary: A N-(5-Acetyl-4-methylpyrimidin-2-yl)benzenesulfonamide was synthesized and characterized by single-crystal X-ray diffraction. In the crystal, π-π interactions between the phenyl and pyrimidine groups of neighboring molecules form molecular chains parallel to [010]. Adjacent molecular chains are connected by N-H...N hydrogen-bonding interactions between the pyrimidine and amine groups of neighboring molecules, resulting in a three-dimensional network.
ACTA CRYSTALLOGRAPHICA SECTION E-CRYSTALLOGRAPHIC COMMUNICATIONS
(2023)
Article
Chemistry, Analytical
Keith Smith, Xiaojing Mu, Zhaoqiang Li, J. Stuart Woodhead, Gamal A. El-Hiti
Summary: Two new acridinium triflates with a 2-(succinimidyloxycarbonyl)ethyl side arm have been synthesized and characterized. The chemiluminescence properties and hydrolytic stabilities of the newly synthesized acridinium triflates were investigated.
Article
Biochemistry & Molecular Biology
Heba E. Hashem, Abd El-Galil E. Amr, Abdulrahman A. Almehizia, Ahmed M. Naglah, Benson M. Kariuki, Heba A. Eassa, Eman S. Nossier
Summary: This study uses the nanoformulation method to prepare nanoparticles of a previously prepared compound, and investigates their cytotoxic activity and inhibitory effects against cancer cell lines. The nanoparticles show promising anti-cancer activity and improved effects on EGFR and CDK-2 / cyclin A2. They also regulate cancer biomarkers to exert their anti-cancer effects.
Article
Chemistry, Multidisciplinary
Noor Emad, Gamal A. El-Hiti, Emad Yousif, Dina S. Ahmed, Marwa Fadhil, Benson M. Kariuki
Summary: This study reports the synthesis of a new material for storing carbon emissions, particularly carbon dioxide. The metal complexes synthesized have large surface areas and pore volumes, and exhibit high carbon dioxide storage capacity.
RESULTS IN CHEMISTRY
(2023)
