A. Abdel-Azim

Determination of intrinsic viscosity of polymeric compounds through a single specific viscosity measurement

Abstract A modified method based on a combination of the Huggins and Schulz–Blaschke equations is proposed which enables the determination of intrinsic viscosity [η] from the measurement of a single specific viscosity. The method has been verified for different polymer samples having a wide range of [η] values and showed a variation of

Modified unsaturated polyester resins synthesized from poly(ethylene terephthalate) waste, 1. Synthesis and curing characteristics

The depolymerization of poly(ethylene terephthalate) (PET) by alcoholysis reaction is an easy operation and gives prospects for the valorization of wastes. PET waste was first depolymerized by glycolysis reaction at different molar ratios of diethylene glycol (DEG), in the presence of Mn acetate as a transesterification catalyst. The glycolyzed products obtained were reacted with p-hydroxybenzoic acid (PHBA) and maleic anhydride (MA) to prepare modified unsaturated polyesters. The molar ratio of added PHBA was varied in order to investigate its effect on the curing characteristics of thes modified unsaturated polyesters. The data obtained revealed that an increasing molar ratio of PHBA, within the studied range of concentrations, leads to a reduction in th peak exothermic temperature (T max ) accompanied with the required delay in the curing time. The curing characteristics of these modified polyesters are not so fast anymore, which is not manageables and considered as disadvantageous from th practical point of view, showing instead a moderate speed.

Propylene oxide-ethylene oxide block copolymers as demulsifiers for water-in-oil emulsions, I. Effect of molecular weight and hydrophilic-lipophylic balance on the demulsification efficiency

SummaryA series of propylene oxide (PO)-ethylene oxide (EO) block copolymers with differentEO/PO ratios and molecular weights have been prepared and tested for their demulsification potency in breaking synthetic water-in-benzene emulsions stabilized by asphaltenes. Their partition coefficients between benzene and water were determined by means of UV absorption. NMR spectroscopic analysis was used for determining the actualPO/EO ratios of these block copolymers. The effects of hydrophilic-lipophilic balance (HLB) and molecular weight of the prepared surfactants on their demulsification efficiency were investigated. It was found that the demulsification efficiency is directly proportional to both HLB and molecular weight.ZusammenfassungEine Reihe von Propylenoxid (PO)-Ethylenoxid (EO) Blockcopolymeren mit verschiedenenEO/PO-Verhältnissen und Molekulargewichten wurden hergestellt und auf ihre Effizienz bezüglich des Brechens von durch Asphalt stabilisierten synthetischen Wasser/Benzol-Emulsionen untersucht. Ihre Verteilungskoeffizienten zwischen Benzol und Wasser wurden mittels UV-Spektroskopie ermittelt. DasPO/EO-Verhältnis wurde NMR-spektroskopisch bestimmt. Die Effekte von Hydrophilie-Lipophilie-Gleichgewicht (HLB) und Molekulargewicht auf die Effizienz der Wirkung wurden untersucht. Das Emulsionsbrechungsvermögen ist direkt proportional zu HLB und indirekt proportional zum Molekulargewicht.

Effect of Crosslinker Functionality on Swelling and Network Parameters of Copolymeric Hydrogels

WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW Crosslinked xerogels comprising N-vinyl-2-pyrrolidone (VP) and butyl acrylate (BA) with different weight fractions of BA ranging between 0.1 and 0.3 were prepared by g-ray initiation copolymerization using different concentrations of either hexa- or tetrafunctional crosslinking agents. Methylene bisacrylamide (MBA) was selected as tetrafunctional crosslinker, while 1,1,1- trimethylolpropane trimethacrylate (TPT) was used as a hexafunctional crosslinker. The concentration of both crosslinkers ranged between 0.5% and 2%. Thin disks of the prepared copolymers were swollen in deionized water at 294K. The final equilibrium water content, volume fraction of polymer and swelling capacity were deter- mined. The effective crosslinking density Ve, the average molecular weight between the crosslinks Mc and the polymer-water interaction parameter were determined from stress-strain measurements. For different composi- tions of VP/BA, the linear relations between theoretical crosslinking densities Vt and Ve were established. The efficiencies of MBA and TPT crosslinking agents towards VP-BA copolymers were determined.

Propylene oxide-ethylene oxide block copolymers as demulsifiers for water-in-oil emulsions, II. Effects of temperature, salinity,pH-value, and solvents on the demulsification efficiency

SummaryThe effects of temperature, NaCl concentration (salinity),pH value, and solvents on the demulsification efficiency of propylene oxide (PO)-ethylene oxide (EO) block copolymers in the breaking of synthetic water-in-benzene emulsions stabilized by petroleum asphaltenes have been thoroughly investigated. The demulsification efficiency of the studied polymeric surfactants was found to increase with increasing temperature and decreasing salinity of the aqueous phase. A neutralpH value of the aqueous phase of the emulsion was found to be optimat for efficient demulsification. Water and water compatible solvents were found to be the best solvents for the prepared demulsifiers with respect to demulsification properties.ZusammenfassungDie Einflüsse von Temperatur, NaCl-Konzentration,pH-Wert und Lösungsmitteln auf die Fähigkeit von Propylenoxid-Ethylenoxid-Blockcopolymeren (PO-EO), durch Asphalte stabilisierte Wasser-in-Benzol-Emulsionen zu brechen, wurden eingehend studiert. Die Wirksamkeit der untersuchten polymeren oberflächenaktiven Substanzen steigt mit steigender Temperatur und sinkendem Salzgehalt der wäßrigen Phase. Am besten verläuft die Demulsifikation bei neutralempH-Wert. Wasser und vergleichbare Lösungsmittel eignen sich am besten zur Erzielung einer hohen Wirksamkeit der verwendeten Emulsionsbrecher.

Polyoxyalkylenated amines for breaking water‐in‐oil emulsions: effect of structural variations on the demulsification efficiency

In the present work, different aliphatic and aromatic amines were ethoxylated after a previous propoxylation (PPPEA) with different degrees of propoxylation and ethoxylation in order to obtain polymeric surfactants having different hydrophilic–lipophilic balance (HLB) values. The influence of the structural variations in the prepared PPPEA on their efficiency as demulsifiers for water-in-oil emulsions was investigated. Synthetic water-in-benzene emulsions stabilized by petroleum asphaltenes was utilized for the completion of this study. The actual propylene oxide (PO)–ethylene oxide (EO) ratios of the PPPEA under investigation was elucidated via 1H NMR spectroscopy. It was found that each demulsifier practices a maximum demulsification efficiency at an optimum concentration. At this concentration, the demulsifiers’ molecules were believed to form a monolayer by adsorbance at the benzene–water interface. The influences of the number of aromatic rings in the molecule, the degree of substitution in the aromatic rings, the number of amine groups, the number of PO–EO chains and HLB on the demulsification efficiency were accomplished.

Preparation and properties of two‐component hydrogels based on 2‐acrylamido‐2‐methylpropane sulphonic acid

WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW Xerogels comprising 2-acrylamido-2-methylpropane sul- phonic acid (AMPS) and acrylic acid as well as AMPS and acrylamide crosslinked with hexafunctional cross- linking agent have been prepared by catalytic initiation polymerization to complete conversion. Different percen- tages of hexafunctional crosslinker, 1,1,1-trimethylolpro- pane trimethacrylate, were used to prepare crosslinked copolymers having different degree of crosslink densities. The crosslinked copolymers were swollen in water to equilibrium. The volume fraction of polymer, the swelling capacity and the equilibrium water content were obtained. Low conversion polymerization was used to determine the reactivity ratios of both monomer pairs. Fourier transform spectroscopy was utilized to measure the molar ratio of copolymers constituents.

Estimation of the compatibility of poly(ethylene glycol)/poly(ethylene oxide) blends from dilute solution viscosity measurements

Abstract The intrinsic viscosities of poly(ethylene glycol)/poly(ethylene oxide) (PEG/PEO) blends have measured in benzene as a function of blend composition for various molecular weights of PEO at two different temperatures (293.15 K and 303.15 K). In order to predict the compatibility of polymer pairs in solution, the interaction parameter term, Δb, and the difference between the intrinsic viscosities of the polymer blends and the weight average intrinsic viscosities, Δ[η], of the two polymer solutions taken separately are used. The effects of both temperatures and molecular weight of the blend components on the extent of compatibility was elucidated.

Synthesis and Evaluation of Some Polymeric Compounds as Pour Point Depressants and Viscosity Index Improvers for Lube Oil

Abstract In the present study, some polymeric additives were prepared and used as pour point depressants and as viscosity index improvers for lube oil via copolymerization of maleic anhydride and vinyl acetate with different esters of acrylic acid. The molecular weights of the prepared copolymers were determined by GPC. The efficiency of the prepared compounds as pour point depressant and viscosity index improvers was investigated. It was found that the efficiency of the prepared compounds as pour point depressant increases with decreasing the concentration of the prepared polymers, increasing the chain length of alkyl groups, and increases with decreasing the molecular weight. The efficiency of the prepared compounds as viscosity index improvers increases by increasing the concentration of these additives and by increasing the molecular weight of the polymer.

POLYOXYALKYLENATED AMINES FOR BREAKING OF WATER-IN-OIL EMULSIONS STABILIZED BY ASPHALTENES AND CLAY

ABSTRACT The main objective of this paper is lo emphasize the efficiency of synthesized polyo.xyalkylenated amines (PPPEA) having different hydiophilic-lipophilic balance (HLB) values in breaking synthetic water-iu-benzene emulsions stabilized by both pelroleum asphaltenes and clay (EAC). It was found that the presence of clay and asphaltenes in a certain ratio (1:1 summing 0 5 wt / vol. % with respect to the total emulsion volume ) offers maximum emulsion stability. This was attributed to the effect of asphaltenes in converting water-wet particles (such as clay) into oil-wet panicles, which then act as emulsifying agents for waler-in-oil emulsions. This explains the synergistic effect resulting from the mutual interactions between asphaltenes and clay in stabilizing Eac. It was found that the most efficient demulsifiers for breaking Eac are the aromatic PPPEA having low HLB. This is attributed to the capability of the aromatic PPPEA demulsifiers lo form well developed interactions with the aromatic asphaltenes. This enhanced interaction will drag the asphaltenes and clay from the interlace increasing the demulsification efficiency.