Bassam A. Sweileh

Synthesis and characterization of polycarbonates by melt phase interchange reactions of alkylene and arylene diacetates with alkylene and arylene diphenyl dicarbonates.

This work presents a new synthetic approach to aromatic and aliphatic polycarbonates by melt polycondensation of bisphenol A diacetates with alkylene- and arylenediphenyl dicarbonates. The diphenyl dicarbonates were prepared from phenyl chloroformate and the corresponding dihydroxy compounds. The process involved a precondensation step under a slow stream of dry argon with the elimination of phenyl acetate, followed by melt polycondensation at high temperature and under vacuum. The potential of this reaction is demonstrated by the successful synthesis of a series of aromatic-aromatic and aromatic-aliphatic polycarbonates having inherent viscosities from 0.19 to 0.43 dL/g. Thus low to intermediate molecular mass polymers were obtained. The 13C-NMR spectra of the carbon of the carbonate group showed that the formed polycarbonates contain partial random sequence distribution of monomer residues in their chains. The polycarbonates were characterized by inherent viscosity, FTIR, 1H-NMR and 13C-NMR spectroscopy. The glass transition temperatures, measured by DSC, of the polycarbonates were in the range 13–108 °C. The thermogravimetric curves of showed that these polymers have good thermal stability up to 250 °C. The present approach may open the door for novel polycarbonates containing other organic functional groups.

Preparation and Characterization of Poly(2,2-dimethyl-1,3-propylene oxalate) Polymer and the Study of its Metal Uptake Behavior Toward Pb(II), Cd(II), and Hg(II) Ions

Abstract Poly(2,2-dimethyl-1,3-propylene oxalate) was synthesized from oxalyl chloride and 2,2-dimethyl-1,3-propane diol. The polymer was characterized by inherent viscosity, FT-IR, XRD, SEM, 1H-NMR, 13C-NMR, DSC, and TGA. The polymer uptake behavior towards Pb(II), Cd(II), and Hg(II) ions was studied by the batch equilibrium technique as a function of pH and contact time. The adsorption isotherms of metal ions were also investigated. Column experiments were used to determine the loading capacity and study desorption of metal ions. The polymer showed high metal-ion uptake capacity towards Pb(II), but moderate capacity towards Cd(II) and Hg(II) ions. Interestingly, the polymer was found to be highly selective for Pb(II) ions at pH 5 and 25°C. The metal ion uptake properties of the polymer show fittings for both Langmuirs and Freundlich equations. The metal-bound polymer was regenerated by treatment with 1 M HNO3. Therefore, it may be employed for the removal of heavy metal pollutants in environmental and industrial applications.

Preparation of Polyester-Based Metal-Cross Linked Polymeric Composites as Novel Materials Resistant to Bacterial Adhesion and Biofilm Formation

Bacterial biofilms constitute an extremely resistant form of bacterial colonization with dire health and economical implications. Towards achieving polymeric composites capable of resisting bacterial adhesion and biofilm formation, we prepared five 2,6-pyridinedicarboxylate-based polyesters employing five different diol monomers. The resulting polyesters were complexed with copper (II) or silver (I). The new polymers were characterized by proton and carbon nuclear magnetic resonance spectroscopy, inherent viscosity, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The corresponding metal complexes were characterized by differential scanning calorimery and infrared spectroscopy. The amounts of complexed copper and silver were determined by atomic absorption spectrophotometry. Finally, the resulting composites were tested for their antibacterial potential and were found to effectively resist bacterial attachment and growth.

Synthesis of Phosphorus, Arsenic and Antimony Ylides Containing the 1,3- Dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione Fragments

The ylides Ph3E-C6H6N2O3 (7, E = P (a), As (b), Sb (c)) have been prepared through the reaction of Ph3E and 5- bromo-1,3-dimethyl-2,4,6(1H,3H,5H)-pyrimidinetrione (5-bromo-1,3-dimethylbarbituric acid) 6 in the presence of trieth- ylamine. Their characterisation was performed by nuclear magnetic resonance (NMR), mass spectrometry (MS) and ele- mental analysis.

Preparation and Characterization of Poly(bisphenol A oxalate) and Studying its Chelating Behavior Towards Some Metal Ions

Abstract Poly(bisphenol A oxalate) was synthesized by condensation polymerization of Bisphenol A and oxalyl chloride in dichloromethane under dry nitrogen atmosphere below 5°C. The resulting linear alternating polymer was characterized by inherent viscosity, FTIR, 1H‐NMR, and 13C‐NMR. The thermal behavior of the polymer was evaluated by differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The chelating behavior of the synthesized polymer towards some divalent metal ions was studied by the batch equilibrium technique as a function of pH and contact time. The isothermal behavior and kinetics of the metal ions uptake onto the polymer were also investigated. The polymer showed high rates of metal ion uptake toward Pb(II), Cu(II), and Mg(II), but low rates toward Ni(II) and Cd(II) in the measurement of metal uptake. Interestingly, the polymer was found to selectively chelate Pb(II) and Mg(II) ions in the concentration variation isotherm experiments.

Sulfonated polyimide copolymers based on 4,4′-diaminostilbene-2,2′-disulfonic acid and 3,5,3′,5′-tetramethylbenzidine with enhanced solubility

A new series of six-membered ring sulfonated polyimides with different combinations of two comonomers in the nonsulfonated diamine was prepared by one-step high-temperature polycondensation in m-cresol to improve the solubility of the resulting sulfonated polyimides. They are based on 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4′-diaminostilbene-2,2-disulfonic acid sulfonated diamine, and equimolar mixture of 3,5,3′,5′-tetramethylbenzidine (TMB) and 4,4′-oxydianiline, bis(4-aminophenyl)methane, or bis(4-(aminophenoxy)-4-phenyl)isopropylidene nonsulfonated diamines. The introduction of TMB comonomer in the nonsulfonated diamine resulted in a remarkable improvement in the solubility of the resulting polyimides in comparison with the corresponding single-monomer nonsulfonated diamine polyimides. Flexible, transparent, and tough membranes were prepared by solution casting method from the different polyimides. The membranes were characterized with FTIR and 1H-NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, water uptake, and ion-exchange capacity measurements. They exhibit high thermal stability and good correlation between the ion-exchange capacity and water uptake values.

Synthesis and Characterization of New Polyamides Containing Symmetrical and Unsymmetrical Thiadiazole Rings

Diamino derivatives of thiadiazole namely, 2,5-diamino-1,3,4-thiadiazole and 3,5-diamino-1,2,4-thiadiazole were synthesized and characterized. Polyamides were synthesized by condensation of the two diamino derivatives with diacide chlorides. The structures of polyamides were verified by elemental analysis, FTIR, 1H-NMR, 13C-NMR and mass spectroscopy. The polyamides possess good solubility in aprotic organic solvents such as DMF, DMAC, DMSO and NMP at room temperature. Intrinsic viscosity measurements indicate that the polyamides synthesized have moderate molecular weights. The thermal stability of these polyamides in nitrogen atmosphere is relatively good, especially for those polyamides containing phenylene ring in the backbone. Compared to the structurally related Kevlar aramide, using 2,5-diamino-1,3,4-thiadiazole and 3,5-diamino-1,2,4-thiadiazole instead of p-phenylene diamine results in reducing the melting points of polyamides to below 350 °C.

Combustion and Emission Characteristics of Straight Vegetable Oils and Diesel Fuel Blends

An experimental investigation was carried out to evaluate the performance and emission characteristics of vegetable oils blends with diesel oil as an alternative fuel. Virgin and waste frying vegetable oils of sunflower, corn, soybean and palm oils were collected and characterized with GC-FID. Nine blends of various vegetable oils and diesel were prepared. The important chemical and physical properties of the blends (including kinematic viscosity, heat of combustion, exhaust emissions (SOx and NOx), flash point, pour point, cloud point, sulfur content, density and specific gravity) were compared to those of diesel oil. Generally, there is no significant difference between the use of waste or virgin vegetable oils blends with diesel oil. Among the various blends, those containing up to 30% vegetable oils have viscosity, pour point, cloud point and density values close to those of diesel oil. These blends have approximately 95% of the heat of combustion, but have the advantages of higher flash point and lower emissions compared to those of diesel oil. Blends of 30% vegetable oils have comparable performance and emissions characteristics to those of diesel oil fuel and found to be good substitute for diesel.

pH and reduction sensitive bio-based polyamides derived from renewable dicarboxylic acid monomers and cystine amino acid

ABSTRACT New reduction biodegradable and pH-sensitive linear nonpeptidic polyamides were synthesized by interfacial polycondensation of diamines and cystine amino acid with dicarbonyl dichlorides derived from renewable dicarboxylic acids. The polymer degradability by glutathione is enhanced by the introduction of disulfide linkages, and the response to pH change is enhanced by introducing pendant carboxylic acid functions. The results of pH sensitivity tests indicated that protonation–deprotonation of the carboxylic acid group at about pH of 4.1 with cation exchange capacity 4.5 meq g−1 and the disulfide bonds in polyamides were effectively cleaved.

Synthesis and Crystal Structure of Triethylammonium 5-[(2,2-Dimethyl- 4,6-dioxo-1,3-dioxan-5-ylidene)(methylthio) methyl]-1,3-dimethylpyrimidine- 2,4,6-trionate

Triethylammonium 5-[(2,2-dimethyl-4,6-dioxo-1,3-dioxan- 5-ylidene)(methylthio)methyl]-1,3-dimethylpyrimidine- 2,4,6-trionate (6) is obtained as red-orange stable crystals by reaction of 5-[bis(methylthio)methylene]-2,2-dimethyl- 1,3-dioxane-4,6-dione (5) with 1,3-dimethylbarbituric acid (2) in the presence of triethylamine in excellent yield. The crystal structure of 6 confirms the negative charge to be localized at the barbituric-acid ring in its enolate form.