Number Of Ethylene Oxide Units Research Articles

A systematic derivatization technique for characterization of ethoxylates by GC and GCMS

AbstractEthoxylation is one of the common industrial process in which ethylene oxide (EO) is added to compounds containing active hydrogen atom (OH, COOH, SH, NH, etc.) to form surfactants. Alcohol ethoxylates are a major class of non‐ionic surfactants composed of an alkyl chain combined with few EO units. They are widely used in homecare products, personal care products, textiles, oilfield, construction, lubricants, food, paper, leather. The analysis of these ethoxylates possess several challenges since they contain ‘n’ number of EO units (n > 1). With increase in “n,” the product becomes more and more viscous and the boiling point increases making it difficult to analyze by normal gas chromatography (GC) technique. This paper describes a method of derivatizing these ethoxylates so that they can be eluted on a high temperature GC. BSTFA (N, O‐bis (trimethylsilyl) trifluoroacetamide) is used as the derivatizing agent (silylating agent). The ethoxylate combines with BSTFA to form the corresponding trimethylsilylated (TMS) product, which have comparatively lower boiling point. Thus, we detect trimethyl silyl product, which is the resemblance for the ethoxylated product. In this paper, we present a quantitative GC method for the ethoxylates of a few simple alcohols (2‐ethyl hexanol, glycerin), and complex vegetable oils (castor oil). The products formed during the reaction have also been identified on a gas chromatograph coupled with mass spectrometer (GCMS). GCMS shows the mass corresponding to the TMS derivatized product. The derivatization technique not only helps in increasing the volatility of these compounds but also improves the chromatographic efficiency, selectivity, and enhances the detectability.

Effect of ethylene oxide unit number in bis-EMA on the physical properties of additive-manufactured occlusal splint material.

To investigate the effects of the number of ethylene oxide units in bis-EMA on the physical properties of additively manufactured occlusal splints. Seven experimental materials containing bis-EMAs with three and 10 ethylene oxide units (BE3 and BE10, respectively) were prepared at different BE10 content rates (BE10-0%, -20%, -30%, -40%, -50%, -60%, and -80%). Half the specimens of each material were aged in boiling water. Flexural strength (FS), flexural modulus (FM), fracture toughness (FT), microwear depth (MD), degree of conversion (DC), water sorption (WSP), water solubility (WSL), color difference between non-aged and aged series (ΔE), and translucency (TP) were evaluated. All the evaluated properties other than FS and MD were analyzed by 1-way ANOVA and Tukey's post hoc analysis, while FS and MD were analyzed by Kruskal-Wallis's test and Bonferroni correction (α=0.05). BE10-80% revealed the lowest FS (P < 0.01 for BE10-0%, -20%, and -30%) and FM (P < 0.01, for all), while revealing the highest DC, WSP, WSL (P < 0.01 for all) and TP (P < 0.01 for all other than BE10-60%). BE10-50% showed the highest FT (P < 0.01 for all). BE10-50%, -60%, and -80% revealed significantly lower ΔE than others (P < 0.01) and lower MD than BE10-0% (P < 0.05). Regardless of the BE10 content, FS, FM, and FT decreased with aging. The number of ethylene oxide units affects the physical properties of additively manufactured occlusal splints. The higher number of ethylene oxide units in bis-EMA enhanced the microwear resistance, DC, WSP, WSL, color stability, and translucency, whereas it deteriorated the FS and FM.

Hydrophobic Porous Liquids with Controlled Cavity Size and Physico-Chemical Properties.

Developing greener hydrometallurgical processes implies offering alternatives to conventional solvents used for liquid-liquid extraction (LLE) of metals. In this context, it is proposed to substitute the organic phase by a hydrophobic silica-based porous liquid (PL). Two different sulfonated hollow silica particles (HSPs) are modified with various polyethoxylated fatty amines (EthAs) forming a canopy that provides both the targeted hydrophobicity and liquefying properties. This study shows that these properties can be tuned by varying the number of ethylene oxide units in the EthA: middle-range molecular weight EthAs allow obtaining a liquid at room temperature, while too short or too long EthA leads to solid particles. Viscosity is also impacted by the density and size of the silica spheres: less viscous PLs are obtained with small low-density spheres, while for larger spheres (c.a. 200nm) the density has a less significant impact on viscosity. According to this approach, hydrophobic PLs are successfully synthesized. When contacted with an aqueous phase, the most hydrophobic PLs obtained allow a subsequent phase separation. Preliminary extraction tests on three rare earth elements have further shown that functionalization of the PL is necessary to observe metal extraction.

A many-body dissipative particle dynamics parametrisation scheme to study behaviour at air-water interfaces.

In this article, we present a general parametrisation scheme for many-body dissipative particle dynamics (MDPD). The scheme is based on matching model components to experimental surface tensions and chemical potentials. This allows us to obtain the correct surface and mixing behaviours of complex, multicomponent systems. The methodology is tested by modelling the behaviour of nonionic polyoxyethylene alkyl ether surfactants at an air/water interface. In particular, the influence of the number of ethylene oxide units in the surfactant head group is investigated. We find good agreement with many experimentally obtained parameters, such as minimum surface area per molecule; and a decrease in the surface tension with increasing surfactant surface density. Moreover, we observe an orientational transition, from surfactants lying directly on the water surface at low surface coverage, to surfactants lying parallel or tilted with respect to the surface normal at high surface coverage. The parametrisation scheme is also extended to cover the zwitterionic surfactant lauryldimethylamine oxide (LDAO), where we provide good predictions for the surface tension at maximum surface coverage. Here, if we exceed this coverage, we are able to demonstrate the spontaneous production of micelles from the surface surfactant layer.

Novel epoxy-terminated macromonomers and their polymerization for synthesis of bottle-brush type amphiphilic block copolymers.

Architecture of polymers has vital implications for their physical properties and applications. In this study, synthesis of a series of novel epoxy-terminated macromonomers namely Ep-DEGMME, Ep-TEGMME, Ep-EGMEE, Ep-EGMBE, and Ep-EGMHE is reported. The synthesized macromonomers vary in number of ethylene oxide units and length of the alkyl group. These macromonomers are first homopolymerized by anionic ring-opening polymerization for synthesis of homopolymers of a molar mass range. Subsequently, these macromonomers with different lengths of two segments (alkyl group and ethylene oxide units) are copolymerized with other monomers for synthesis of bottle-brush type architectures. In the first case, di- and tri-block copolymers of Ep-EGMBE are synthesized while using MeO-PEG or PEG as a macroinitiator; the resulting block copolymers have hydrophilic handle and hydrophobic brush. On the same lines, block copolymers of Ep-TEGMME with ε-caprolactone have hydrophobic handle and hydrophilic brush. The synthesized block copolymers are comprehensively characterized by SEC and liquid chromatography at critical conditions. The analysis reveals the successful synthesis of block copolymers while providing information on relative total molar mass, and individual block lengths of the block copolymers, along with amount of unwanted homopolymers in the sample.

A molecular study on the behavior of polyethoxylated alkyl ethers surfactants in a water/n-alkane interface

Advanced oil recovery in oil/water and water/oil emulsions is a scientific and technological challenge, and efficient technologies depend on the water/oil interface properties. Due to their amphiphilic nature, surfactants are used to modify these interfacial properties to increase oil recovery and stabilize droplets in emulsification processes. Poly-(oxyethylene) alkyl ethers are a class of non-ionic surfactants often used as reference detergents due to their relatively simple structure compared to typical commercial surfactants. This tunable structure allows a design to tailor the substance’s properties to the desired application. Here, we conduct molecular dynamics simulations to obtain both macroscopic and microscopic properties of water/n-heptane interfacial systems in the presence of these surfactants. We evaluated the effect of both temperature and modifications to the structure of the surfactant model, varying the number of ethylene oxide units in the head group. We verify that their structural properties are specific to maximize stabilizing interactions such as hydrogen bonds with water molecules, adopting a folded structure and parallel orientation in regards to the interface. We analyze the Potential of Mean Force (PMF) that shows the affinity of the surfactant to the interface is enhanced as the number of ethoxylated units increases, which is related to the decrease in interfacial tension.

Interfacial properties of nonionic hybrid surfactant with double branches of fluorocarbon and hydrocarbon

To obtain superior surface-active properties while minimizing environmental risks, new fluorinated surfactants (F2HX-nEO) were designed to include a hybrid multi-chain with a short fluorocarbon (–CF2CF3) and nonionic ethylene oxide. They were simply synthesized by a straightforward reaction involving the addition of ethylene oxide to a hybrid fluorine alcohol, and their surface-active properties were optimized by controlling the hydrocarbon length and number of ethylene oxide units. Therefore, the desirable values of critical micelle concentration (0.3 mmol/L) and surface tension (24.3 mN/m) were obtained in spite of containing the short fluorocarbon chain. Particularly, F2HX–nEO showed excellent wetting properties on hydrophobic surfaces and very low toxicity level, which can be used in various fields as a promising alternative to long fluoroalkyl chain surfactants.

Linker Architectures as Steric Auxiliaries for Altering Enzyme-Mediated Payload Release from Bioconjugates.

Protease-activated prodrugs leverage the increased activity of proteases in the tumor microenvironment and the tight regulation in healthy tissues to provide selective activation of cytotoxins in the tumor while minimizing toxicity to normal tissues. One of the largest classes of protease-activated prodrugs are composed of therapeutic agents conjugated to macromolecular carriers via peptide motifs that are substrates for cathepsin B, and antibody-drug conjugates are one of the most successful designs within this class. However, many of these peptide motifs are also cleaved by extracellular enzymes such as elastase and carboxylesterase 1C. Additionally, some peptide sequences have little selectivity for other lysosomal cathepsins, which have also been found to have extracellular activity in normal physiological processes. A lack of selectivity or oversensitivity to other extracellular enzymes can lead to off-target release of the cytotoxic payload and subsequent toxicities. In this report, we describe an approach for modulating cathepsin-mediated release of the cytotoxic payload through steric shielding provided by the synergistic effects of appropriately designed hydrophilic linkers and the conjugated carrier. We prepared a fluorogenic model payload with a Val-Cit cleavable trigger and attached the trigger-payload to a variety of PEG-based linker architectures with different numbers of PEG arms (y), different numbers of ethylene oxide units in each arm (n), and different distances between the cleavable trigger and PEG branch point (D'). These linker-payloads were then used to prepare DAR2 conjugates with the cleavable triggers at three different distances (D) from the antibody, and cathepsin-mediated payload release was monitored with in vitro assays. The results show that structural variables of the linker architectures can be manipulated to effectively shield enzymatically labile trigger-payloads from enzymes with readily accessible binding sites, and may offer an additional strategy for balancing off-target and tumor-targeted payload release.

Effects of ethylene oxide chain length on crystallization of polysorbate 80 and its related compounds

As a result of the synthesis protocol polyoxyethylene sorbitan monooleate (polysorbate 80, PS80) is a highly complex mixture of compounds. PS80 was therefore separated into its main constituents, e.g. polyoxyethylene isosorbide esters and polyoxyethylene esters, as well as mono- di- and polyesters using preparative high-performance liquid chromatography. In this comprehensive study the individual components and their ethoxylation level were verified by matrix assisted laser desorption/ionization time-of-flight and their thermotropic behavior was analyzed using differential scanning calorimetry and X-ray diffraction. A distinct correlation was found between the average length of the ethylene oxide (EO) chains in the headgroup and the individual compounds’ ability to crystallize. Importantly, a critical number of EO units required for crystallization of the headgroup was determined (6 EO units per chain or 24 per molecule). The investigation also revealed that the hydrocarbon tails only crystallize for polyoxyethylene sorbitan esters if saturated. PS80 is synthesized by reacting with approximately 20 mol of EO per mole of sorbitol, however, the number of EO units in the sorbitan ester in commercial PS80 products is higher than the expected 20 (5 EO units per chain). The complex behavior of all tested compounds revealed that if the amount of several of the linear by-products is reduced, the number of EO units in the chains will stay below the critical number and the product will not be able to crystallize by the EO chains.

Analysis of ionic and nonionic surfactants blends used for the reverse micellar extraction of Lactoperoxidase from whey

AbstractBovine Lactoperoxidase (LP), a minor whey protein, is used as an antimicrobial in cosmetic, food, and pharmaceutical preparations. Industries are in pursuit of reliable, cheap, and scalable purification methods as the conventional techniques for LP purification like chromatography and membrane separation suffer from several drawbacks. The present work investigates the selective reverse micellar extraction of LP using the reverse micellar system formed by mixing food grade nonionic (Tween, Span, and Triton series) and ionic (AOT) surfactant blends. The analysis of LP extraction efficiency was performed by varying the concentration of nonionic surfactants with a constant AOT concentration of 100 mM and the initial pH of the system. Complete LP solubilization was achieved with reverse micelles formed by 100 mM AOT and 20 mM Tween 80 at pH 8. It was found that the extraction efficiency was dependent on the chain length or the number of ethylene oxide units in the Triton surfactant tail and the carbon–carbon double bond in Tween 80 tail, that is, on oleic acid. Span series however showed poor extraction in the organic phase substantiating the lesser water content. The forward extracted LP was successfully back‐extracted into a fresh aqueous phase containing 1 M KCl at pH 10.5. The aqueous phase (whey) from the forward transfer can be further used to fractionate other whey proteins.

Coceth sulfate characterization by electrospray ionization tandem mass spectrometry

The anionic surfactants, among which are alkyl ether sulfates (AESs), are the most used class of surfactants in cleansing applications. The negatively charged head group of AESs is a sulfate moiety linked with a variable number of ethylene oxide units, i.e. a polyethylene glycol chain. The hydrophobic part of an AES is constituted by a linear alkyl chain of carbon atoms, generally obtained from natural fatty acids. Coconut oil fatty acids, including the sodium salts of coceth sulfate (CES) with chemical formula Cx Hy (OCH2 CH2 )n OSO3 Na, are widely used as feedstock for AESs synthesis. CES is added to many cleaning products and detergents defined as non-aggressive. Currently, no detailed structural information concerning the alkyl chain length x and, more importantly, the degree of ethoxylation n has been reported. A commercial standard solution of CES was characterized by tandem mass spectrometry, employing direct injection into the electrospray ionization (ESI) source of a a linear quadrupole ion trap mass spectrometer. Two series of oligomeric species, characterized by a C12 and C14 alkyl chains, i.e. [C12 H25 (OCH2 CH2 )nOSO3 ]- and [C14 H29 (OCH2 CH2 )n OSO3 ]- with n ranging from 0 to 7, were successfully identified. The interpretation of these data was very useful for CES identification in three commercial dishwasher cleaning products. Direct injection MS/MS analysis of CES revealed a well-defined molecular weight distribution and allowed the alkyl chain composition and the number of ethylene oxide units to be to identified.

The Accumulated Effect of the Number of Ethylene Oxide Units and/or Carbon Chain Length in Surfactants Structure on the Nano-Micellar Extraction of Flavonoids.

Classical extraction methods used for isolation of active substances from plant material are expensive, complicated and often environmentally unfriendly. The ultrasonic assistance micelle-mediated extraction method (UAMME), based on green chemistry principles, seems to be an interesting alternative. This work aimed to find a connection between the chemical structure of non-ionic surfactants and the efficiency of the extraction process. The effect of hydrophobic chain length and number of ethoxy groups on the quality of Bidens tripartite extracts was investigated. Several ethoxylated fatty alcohols were used: Ceteareth-20, Steareth-20, Oleth-20, Oleth-10, Oleth-5, C12-C13 Pareth-12, C12-C15 Pareth-12 and Ceteareth-12. The bioflavonoid compositions with the HPLC method was determined. The hydrophilic lipophilic balance (HLB) of studied surfactants, as well as the surface tension of surfactant solutions, were compared, to determine the explanation for the obtained differences in bioflavonoids concentration. The structural changes influenced by polyphenol extraction were monitored using Dynamic Light Scattering (DLS) measurements. In this work, probably for the first time, the connection between the chemical structure of non-ionic surfactants and the efficiency of the extraction process was found. The experimental and theoretical approach rationalized the choice of an appropriate eluent. We propose some structurally dependent factors, whose optimal value gave a high efficiency to the UAMME.

Corona charged aerosol detector non-uniform response factors of purified alcohol ethoxylated homologues using liquid chromatography.

Surfactants are used in various applications: cosmetics, pharmaceuticals, petrochemicals, environmental, etc. Many of these compounds are polydisperse, and because of this intrinsic polydispersity, it is essential to have a universal detector with a uniform response to quantify them in a simple way. Indeed, Charged Aerosol Detector (CAD) was presented as a universal detector with a uniform response. Thus, in the present study, the CAD response, in a High-Performance Liquid Chromatography - CAD configuration (HPLCCAD), was evaluated using purified alcohol ethoxylated surfactants. A semi-preparative liquid chromatography step using a Hydrophilic interaction chromatography (HILIC) bare silica column (150mm, 4.6mm, 2.6µm) was implemented to prepare eleven homologues of BrijC10, a nonionic surfactant. These homologues differed only by the number of ethylene oxide units. BrijC10 homologues were analyzed by HPLCCAD, using a HILIC bare silica column (150mm, 2.1mm, 2.6µm) to determine the HPLCCAD response factors of purified homologues. From the calibration curves (from 100 to 500mg.kg-1), their response factors were estimated: differences in response factors were observed and a maximum difference in response factors of 3.6 was obtained. Thus, it could be concluded that CAD hyphenated to HILIC separation did not present a uniform response for this homologue's distribution.

Encoding Information into Polyethylene Glycol Using an Alcohol-Isocyanate "Click" Reaction.

In this article, the capability of encoding information using a homologous series of monodisperse monomethoxypolyethylene glycols (mPEG), with a number of ethylene oxide units ranging from nEO = 5 to 8, and monodisperse linear aliphatic isocyanates containing a number of CH2 units from 3 to 7, is demonstrated. The “click” reaction of the two corresponding homologous series yielded 20 different isocyanate end-capped polyethylene glycol derivatives (mPEG-OCONHR) whose sodiated adduct ion’s nominal m/z values spanned from 360 to 548, providing an average ca. 8 m/z unit for the storage of one-bit information. These mPEG-OCONHR oligomers were then used to encode information in binary sequences using a 384-well MALDI sample plate and employing the common dried-droplet sample preparation method capable of encoding 20 bit, i.e., 2.5 byte information in one spot, was employed. The information stored in the spots was read by MALDI-TOF MS using the m/z value of the corresponding mPEG-OCONHR oligomers. The capability of the method to store data was demonstrated by writing and reading a text file, visualizing a small picture and capturing a short audio file written in Musical Instrument Digital Interface (MIDI) sequence. Due to the very large similarities in the chemical structures of the encoding oligomers and their “easy to be ionized” property, as well as their very similar ionization efficiencies, the MALDI-TOF MS signal intensities from each compound was so strong and unambiguous that complete decoding could be performed in each case. In addition, the set of the proposed encoding oligomers can be further extended to attain higher bit “densities”.

Mixed adsorption of hexadecylpyridinium bromide and Triton X surfactants at graphitized carbon black

Adsorption of cationic 1-hexadecylpyridinium bromide (HDPB) and non-ionic p-(1,1,3,3-tetramethylbutyl)-phenoxypolyoxyethylene glycols surfactants of the Triton X series (Triton X-45, Triton X-100 and Triton X-305) from their single and mixed aqueous solutions at thermally graphitized carbon black (CB) was studied. It was shown that the adsorption of the non-ionic surfactant from its individual solution decreased when a number of ethylene oxide units in the surfactant molecule increased. Addition of the non-ionic surfactants increased the amount of HDPB adsorbed from HDPB/Triton X mixtures. At low solution concentrations it was found that in HDPB/Triton X mixtures, the experimental values of total surfactants adsorption are higher than the adsorption values calculated for the ideal surfactant mixtures. The composition of the mixed HDPB/Triton X adsorption layer and the parameters of the intermolecular interaction (?s), between the components in this layer, were calculated using the Rubingh-Rosen approach. It was shown that ?s parameters have negative values, which indicate notable interactions between Triton X molecules and HDPB ions in the mixed adsorption layer. It was found that the composition of the mixed adsorption layer at CB surface is notably different from the surfactants composition in the bulk solution. The mixed HDPB/Triton X adsorption layer is enriched with Triton X surfactant and the mole fraction of Triton X increases with decreasing of ethoxylation degree of its molecules.

Effect of the number of ethylene oxide units on the properties of synthesized tailor-made cationic gemini surfactants for oilfield applications

The solubility and heat stability of the surfactants are the most prominent features required for oilfield applications. Commercial surfactants such as petroleum sulfonate, polyoxyethylene ether, and alkyl benzyl sulfonate suffer because of stability issues under high salinity and high-temperature conditions. Herein, two new cationic amido-amine type poly(ethylene oxide) gemini surfactants containing lower and higher degree of ethoxylation were synthesized. It was observed that the addition of a sufficient number of ethylene oxide groups between the hydrophobic tail and the ionic head group of the cationic gemini surfactant significantly enhanced their solubility. The surfactant containing a higher degree of ethoxylation was found to be soluble in formation water and seawater. However, the surfactant with a lower degree of ethoxylation precipitated in formation water and seawater and hence was not studied further. Thermogravimetric analysis results of the surfactants containing a higher degree of ethoxylation exhibited degradation temperature above 300 °C that was greater than the typical reservoir temperature (90 °C). The structure characterization results of the aged sample of surfactant at 90 °C for 90 days demonstrated the survival of the original chemical structure, revealing a high long-time heat stability. The reduction in critical micelle concentration (CMC) was observed upon enhancing salt concentration, and the minimum CMC was noticed in seawater (3.91 × 10−5 mol/L). Rheological investigations revealed that the viscosity, as well as storage modulus, was reduced upon increasing the concentration of surfactant. The surfactant also exhibited superior foaming properties compared to the commercial surfactants. The cationic amido-amine type poly(ethylene oxide) gemini surfactants showed excellent surface and thermal properties and are potential candidates for oilfield applications such as enhanced oil recovery in harsh reservoir conditions.

Synthesis and physiochemical properties of poly(ethylene glycol)-octanol sulfosuccinates

A series of sulfonated maleic diesters with ethylene oxide groups were synthesized by the reactions of esterification and sulfonation. Maleic diesters were prepared by esterification of maleic anhydride with any one kind of poly(ethylene glycol) with different molecular weights from 200 to 1000 and isooctanol, and then sulfonated by sodium bisulfite to get poly(ethylene glycol)-octanol sulfosuccinates. Reaction temperature and time of esterification of monoester and diester, using toluene sulfonic acid as catalyst and toluene as solvent, were investigated. The surfactants synthesized are identified by FTIR and 1HNMR. Thermal analysis results identify that the investigated surfactants have a good thermal stability. The surface activity of the surfactants in aqueous solution was determined at 298 K. It was found that the critical micelle concentrations (CMC) decrease with increase of the molecular weights and the number of ethylene oxide units of the investigated products, surface tension values at the CMC (γCMC) are upward trend in general. The maximum surface excess concentration (Γmax) decreases mildly with the increasing of molecular weight of poly(ethylene glycol), and area per molecule (Amin) increases with the increasing of ethoxy chain unit. Hydrodynamic diameter of investigated surfactants increases with increasing the concentration, and decreases in general trend with increase of molecular weight of poly(ethylene glycol). Addition of salt to the aqueous solution of surfactants sharply decrease values of CMC and γCMC compared with corresponded surfactants in distilled water.

Micellar enhanced ultrafiltration (MEUF) of methylene blue with carboxylate surfactants

Abstract Alkylethoxy carboxylates CiEjCH2COOH of variable alkyl chain length and a different number of ethylene oxide units (RLM45 and RO90) are investigated as alternative surfactants to the classical anionic sodium dodecyl sulfate (SDS) in micellar enhanced ultrafiltration (MEUF) of dissolved methylene blue (MB) model dye. After adjustment of pH to 7, where the alkylethoxy carboxylates are in their anionic form and bind MB via electrostatic interactions, a removal efficiency of about 95% was obtained for a 1 g L−1 RLM45 solution applying a 10 kDa cellulose membrane. The performance of RLM45 is comparable to SDS, but it is not influenced by the precipitation reaction that is the major reason for the good performance of SDS below its CMC. To investigate the size effect of the micelles, the molecular weight cut-off (MWCO) of the membranes was varied. For the 5 kDa and 10 kDa membranes, the MB removal for SDS is almost quantitative and slightly higher as for the alkylethoxy carboxylates. With increasing MWCO, the MB removal efficiency for SDS strongly decreases. For the 30 kDa membrane, the removal efficiency for the carboxylate surfactants is already better than for SDS. For the 100 kDa membrane, the removal efficiency for SDS drops significantly to values below 10% because of the small size of the micelles. In contrast, the micelles of the alkylethoxy carboxylates are much larger allowing for MB removal in the order of >80%.

Poly(ethylene oxide carbonates) solid polymer electrolytes for lithium batteries

Poly(ethylene oxide) (PEO) is the gold standard matrix for polymer electrolytes used in actual all-solid lithium batteries. However, PEO solid polymer electrolytes show some limitations; such as relatively low ionic conductivity and lithium transference number resulting in the actual polymer-lithium batteries operating at 70 °C. In the last years, polycarbonates (PC) have been presented as an alternative polymer matrix with superior ionic conductivity for solid batteries which may work at room temperature. In this article we systematically investigated the properties of new polymers which combine varying composition of both ethylene oxide and carbonate groups. A series of poly(ethylene oxide carbonates) (PEO-PCs) have been synthesized by polycondensation between different ethylene oxide diols and dimethyl carbonate. As a result, eight new PEO-PCs with number of ethylene oxide units ranging from 2 to 45 between carbonate groups were synthesized and characterized in terms of physico-chemical properties (Tm and Tg). These PEO2-45-PC were formulated as solid polymer electrolytes (SPE) by adding different amounts of bis(trifluoromethane)sulfonimide lithium salt. The effect of the SPE composition (ethylene oxide/carbonate ratio, salt content) on the ionic conductivity and thermal properties (glass transition temperature and melting temperature) was investigated. The optimum SPEs showing the lowest glass transition temperature led to highest ionic conductivity value of 3.7·10−5 S cm−1 at room temperature. FTIR spectra revealed the coordination between the carbonate groups in the polymer chain and the lithium salt. 7Li-19F NMR analysis T1 relaxation and diffusion coefficients measurements indicated local dynamics that correlates with the general conductivity behaviour.

Synthesis of Additives Based on Polyethylenimine Modified with Non-ionic Surfactants for Application in Phase Separation of Water-in-Oil Emulsions

Water-in-oil emulsions are formed during petroleum production. These emulsions are stabilized by natural emulsifiers present in the oil, such as asphaltenes, resins and paraffins, making their separation difficult. Various treatments can promote the breakdown of these emulsions, among them demulsification, which involves the addition of demulsifiers to promote separation of the water and oil phases. This work proposes the synthesis of demulsifiers by modification of branched polyethylenimine (PEI) with the introduction of different nonionic surfactants along the chain. Specifically, we used ethoxylated surfactants based on lauryl acid and nonylphenol, with different numbers of ethylene oxide units in their chains. The modified polymers were characterized by hydrogen nuclear magnetic resonance spectroscopy (1H NMR) and solubility tests. Demulsifier systems were prepared by dissolving the additives in two solvent mixtures: xylene:ethanol and xylene:butylglycol. These systems were applied in demulsification ...