Separation of water/ethanol mixture through poly(acrylonitrile-co-acrylic acid)/poly(ethylene oxide) membranes by pervaporation

The separation of water/ethanol mixtures was investigated by poly(acrylonitrile-co-acrylic acid) and by poly(acrylonitrile-co-acrylic acid)/poly(ethylene oxide) blend membranes. The flux increased with the content of acrylic acid in copolymers and the selectivity remained constant. The marked increase of the selectivity was observed for blend membranes of a certain blend ratio, suggesting that the two polymers are partially miscible. Poly(ethylene oxide) in blends was thought to act as a plasticizer as well as a preferentially water absorbing and diffusing component. © 1994 John Wiley & Sons, Inc.     

Fine polystyrene latexes with reactive poly(ethylene oxide) –poly(propylene oxide)–poly(ethylene oxide) triblock macrosurfactants in modified miniemulsion polymerization

Polystyrene latexes were produced via a newly accessible miniemulsion polymerization where reactive poly(ethylene oxide)–poly(propylene oxide) –poly(ethylene oxide) triblock macrosurfactants were used to impart the interfacial activity during the emulsification and the reactivity in the polymerization. Through atomic force microscopy studies, it was found that the polystyrene latexes produced were extremely small to about 50 nm in a proper experimental condition, and covered richly with poly(ethylene oxide) groups. The polystyrene latexes were expected to have great applicability in the production of structured latex films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 328–332, 2002     

Properties of Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline Conductive Films: The Effect of Poly(ethylene glycol) Diglycidyl Ether

The effect of polyaniline and poly(ethylene glycol) diglycidyl ether on tensile properties, morphology, thermal degradation, and electrical conductivity of poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films was studied. The poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films were prepared using a solution casting technique at room temperature until a homogeneous solution was produced. Poly(vinyl chloride)/poly(ethylene oxide)/polyaniline/poly(ethylene glycol) diglycidyl ether conductive films exhibit higher electrical properties, tensile strength, modulus of elasticity but lower final decomposition temperature than poly(vinyl chloride)/poly(ethylene oxide)/polyaniline conductive films. Scanning electron microscopy morphology showed that the polyaniline more widely dispersed in the poly(vinyl chloride)/poly(ethylene oxide) blends with the addition of poly(ethylene glycol) diglycidyl ether as surface modifier.     

Block copolymers comprising poly(ethylene oxide) and poly(hydroxyethyl methacrylate) blocks: synthesis and characterization

Monofunctional poly(ethylene oxide) macroinitiators with a molecular weight of 2000, 5000, 10?000, 20?000 and bifunctional poly(ethylene oxide) macroinitiators with a molecular weight of 20?000 were used for the atom transfer radical polymerisation (ATRP) of hydroxyethyl methacrylate (HEMA) in ethylene glycol as a solvent. The polymerisation proceeds in a controlled way up to high conversions. The molecular weight of the obtained copolymers increases linearly with conversion. A high rate of polymerisation was observed for the ATRP of HEMA. The effect of the poly(ethylene oxide) moiety on the course of the reaction is limited to solvating effects. The surface analysis of poly(ethylene oxide)/poly(hydroxyethyl methacrylate) block copolymers by means of atomic force microscopy in tapping mode using phase imaging shows phase separated domains with characteristic features related to the volume fraction of the respective blocks.     

Biodegradable blends of high molecular weight poly(ethylene oxide) with poly(3‐hydroxypropionic acid) and poly(3‐hydroxybutyric acid): a miscibility study by DSC,DMTA and NMR spectroscopy

The miscibility of high molecular weight poly(ethylene oxide) blends with poly(3‐hydroxypropionic acid) and poly(3‐hydroxybutyric acid) (P(3HB)) has been investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and high‐resolution solid state ¹³C nuclear magnetic resonance (NMR). The DSC thermal behaviour of the blends revealed that the binary blends of poly(ethylene oxide)/poly(3‐hydroxypropionic acid) (OP blends) were miscible over the whole composition range while the miscibility of poly(ethylene oxide)/poly(3‐hydroxybutyric acid) blends (OB blends) was dependent on the blend composition. OB blends were found to be partly miscible at the middle P(3HB) contents (25 %, 50 %) and miscible at other P(3HB) contents (10 %, 75 % and 90 %). Single‐phase behaviour for OP blends and phase separation behaviour for OB blends were observed from DMTA. The results from NMR spectroscopy revealed that the two components in the OP50 blend were intimately mixed on a scale of about 35 nm, while the domain sizes in the OB blend with a P(3HB) content of 50 % were larger than about 32 nm. © 2000 Society of Chemical Industry     

Poly(ethylene oxide)/poly(methyl methacrylate) blends: Influence of tacticity of poly(methyl methacrylate) on blend structure and miscibility

The influence of different configurations of poly(methyl methacrylate) on the miscibility and superstructure of poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blends was examined using small-angle X-ray scattering and differential scanning calorimetry. The blends prepared by solution casting were isothermally crystallized at 48°C. The miscibility, the melting behaviour, the glass transition temperature and the structural parameters of the blends were strongly dependent on the tacticity and blend composition. The small-angle X-ray intensity profiles were analysed using a recently developed methodology. For the poly(ethylene oxide)/atactic poly(methyl methacrylate) (PEO/APMMA) and poly(ethylene oxide)/syndiotactic poly(methyl methacrylate) (PEO/SPMMA) blends, the long period and the amorphous and transition region thicknesses increased with increase of PMMA content, whereas for the poly(ethylene oxide)/isotactic poly(methyl methacrylate) (PEO/IPMMA) blends they are independent of composition. The structural properties of the blends were attributed to the presence of non-crystallizable material in the interlamellar or interfibrillar regions, depending on PMMA tacticity. From the glass transition and melting temperatures, it has been supposed that one homogeneous amorphous phase is present in the case of PEO/APMMA and PEO/SPMMA blends and that the PEO/IPMMA amorphous system is phase-separated. The free-volume contribution to the energy of mixing for the various tactic PMMAs is hypothesized to be responsible for the difference in mixing behaviour.     

A glow discharge treatment to immobilize poly(ethylene oxide)/poly(propylene oxide) surfactants for wettable and non-fouling biomaterials

A non-fouling (protein resistant) polymer surface was achieved using an argon glow discharge treatment of a polyethylene surface which had been precoated with various poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) (PEO-PPO-PEO) tri-block copolymer surfactants. The surfactant is first deposited on the polymer surface via a solvent swelling and evaporation method. Then the coated surfactant is immobilized on the substrate surface by an inert gas discharge treatment. ESCA and water contact angle () measurements on treated and solvent washed surfaces show significant increases in both surface O/C ratios and surface water wettability (0 < 30°) compared to LDPE control surfaces, revealing the presence of PEO on the treated surfaces. A great reduction of fibrinogen adsorption on the modified surfaces is also observed for the highest PEO content surfactants. This simple surface modification process may have wide applicability to obtain wettable polymer surfaces in general, and non-fouling biomaterial surfaces in specific.     

Gas chromatographic determination of the interaction parameter of poly(ethylene oxide)/poly(methyl methacrylate) blends

Inverse gas chromatography (IGC) has been used to investigate thermodynamic miscibility of a molten poly(ethylene oxide) (PEO)/poly(methyl methacrylate) (PMMA) blend. Toluene, benzene, and chloroform have been employed as probes in pure and mixed stationary phases of these polymers. Experimental measurements have been taken over a narrow range of temperatures because of the high PMMA glass transition temperature as well as the degradation of the PEO. The interaction parameter χ₂₃ determined at 150°C is slightly negative and dependent on the interacting probe, as has been also noted in previous chromatographic studies on polymer-polymer miscibility. The last section is devoted to a model calculation, using Flory's equation of state theory. Different χ₂₃-concentration curves have been simulated, with the interaction energy parameter X₂₃ as an adjustable parameter.     

Radiation grafting of poly(ethylene terephthalate) (PET) fibre,II. Hydrolysis of grafted poly(vinyl acetate) to poly(vinyl alcohol)

Poly(ethylene terephthalate) fibres grafted with poly(vinyl acetate) by γ-radiation were hydrolysed under alkaline and acidic conditions in order to obtain poly(ethylene terephthalate)-graft-poly(vinyl alcohol) fibres. In alkaline media poly(ethylene terephthalate) degraded without appreciable conversion of acetate to hydroxyl groups. During acid hydrolysis no change in tensile properties of the fibres was observed up to an extent of 50% conversion of acetate to hydroxyl groups. Further change in the tensile strength and the elongation at break was attributed partly to the grafted poly(vinyl acetate)/poly(vinyl alcohol) balance and partly to the loss due to degradation of the fibres.     

Synthesis and characterization of a poly(ether–ester) copolymer from poly(2,6 dimethyl‐1,4‐phenylene oxide) and poly(ethylene terephthalate)

A series of poly(ether–ester) copolymers were synthesized from poly(2,6 dimethyl‐1,4‐phenylene oxide) (PPO) and poly(ethylene terephthalate) (PET). The synthesis was carried out by two‐step solution polymerization process. PET oligomers were synthesized via glycolysis and subsequently used in the copolymerization reaction. FTIR spectroscopy analysis shows the coexistence of spectral contributions of PPO and PET on the spectra of their ether–ester copolymers. The composition of the poly(ether–ester)s was calculated via ¹H NMR spectroscopy. A single glass transition temperature was detected for all synthesized poly(ether–ester)s. T_g behavior as a function of poly(ether–ester) composition is well represented by the Gordon‐Taylor equation. The molar masses of the copolymers synthesized were calculated by viscosimetry. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Biodegradable polymers for use in surgery — poly(ethylene oxide)/poly(ethylene terephthalate) (PEO/PET) copolymers: 2. In vitro degradation

The degradation mechanism of a series of poly(ethylene oxide)/poly(ethylene terephthalate) (PEO/PET) copolymers, synthesized as described in Part 1¹, has been studied in vitro. The need for the development of in vitro test methods for candidate biomaterials is set down. The effect of time, temperature, pH and selected enzymes on the rate and mechanism of degradation is elucidated. The degradation products are identified. The degree of degradation was monitored molecularly by gel permeation chromatography (g.p.c.) and end-group titration techniques. The composition of the copolymers was obtained using infra-red (i.r.) and nuclear magnetic resonance (n.m.r.) spectroscopy. Mass loss and water uptake data are also given. The mechanism of degradation is shown to be by hydrolysis. The effect of ethylene oxide (EO) and ⁶⁰Co γ-irradiation sterilization on the copolymers was investigated.     

Study of ternary component polymer complexes of poly(methacrylic acid) and poly(acrylic acid) with complementary polymers

Ternary component polymer complexes have been prepared from poly(acrylic acid) and poly(methacrylic acid) with complementary polymers, such as poly(vinylpyrrolidone) and poly(ethylene oxide). The formation of ternary complexes, selective complexation, and mutual compatibility of the complementary polymers attached to the same polycarboxylic acid chain, have been studied by several techniques, such as viscometry, turbidimetry, potentiometry, conductometry, and IR spectra.     

Synthesis and characterization of multiblock copolymers containing poly(dimethyl siloxane) blocks

Multiblock copolymers of polystyrene and poly(dimethyl siloxane) were obtained by a hydrosilylation reaction between a,w dihydrogeno poly(dimethyl siloxane) and a,w-di(vinyl silane) polystyrene. Under well chosen experimental conditions the polycondensation is free of site reactions and the macromolecules formed are linear with up to 10 blocks, which corresponds to reaction of 90% of the functions initially present. The block copolymers obtained have been characterized by g.p.c. viscosimetry and light scattering.     

Poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer as a sustained-release carrier for perfume compounds

The volatility behavior of perfume compounds in poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) copolymer was investigated by means of dynamic and static headspace analyses. Suppression of the volatility of perfume compounds by EO₁₀₅PO₂₇EO₁₀₅ copolymer was markedly greater than by polyethyleneglycol. This suppressive effect may be due to micelle and gel formation of EO₁₀₅PO₂₇EO₁₀₅ copolymer. EO₁₀₅PO₂₇EO₁₀₅ copolymer is expected to be useful as a novel sustained-release carrier that maintains constant release rates for the volatility of perfume compounds over a wide temperature range.     

Miscibility of polystyrene with poly(ethylene oxide) and poly(ethylene glycol)

The intrinsic viscosity of polystyrene–poly(ethylene oxide) (PS–PEO) and PS–poly(ethylene glycol) (PEG) blends have been measured in benzene as a function of blend composition for various molecular weights of PEO and PEG at 303.15 K. The compatibility of polymer pairs in solution were determined on the basis of the interaction parameter term, Δb, and the difference between the experimental and theoretical weight-average intrinsic viscosities of the two polymers, Δ[η]. The theoretical weight-average intrinsic viscosities were calculated by interpolation of the individual intrinsic viscosities of the blend components. The compatibility data based on [η] determined by a single specific viscosity measurement, as a quick method for the determination of the intrinsic viscosity, were compared with that obtained from [η] determined via the Huggins equation. The effect of molecular weights of the blend components and the polymer structure on the extent of compatibility was studied. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1471–1482, 1998     

Investigation on Self-assembled Blend Membranes of Polyethylene-block-poly(ethylene glycol)-block-polcaprolactone and Poly(styrene-block-methyl methacrylate) with Polymer/gold Nanocomposite Particles

A block copolymer of polyethylene-block-poly(ethylene glycol) and polycaprolactone was prepared via co-ordination–insertion polymerization. Blend membranes of poly(styrene-block-methyl methacrylate) and polyethylene-block-poly(ethylene glycol)-block-polcaprolactone were used as matrix. Gold/polystyrene nanoparticles were used as nanofiller in polyethylene-block-poly(ethylene glycol)-block-polcaprolactone/poly(styrene-block-methyl methacrylate)/gold/polystyrene nanoparticles membranes. The double gyroid pattern was depicted by blend chains in polyethylene-block-poly(ethylene glycol)-block-polcaprolactone/poly(styrene-block-methyl methacrylate)/gold/polystyrene nanoparticles. An improvement of 22% in tensile strength and 54% in tensile modulus was observed with 1 wt% nanoparticle addition. Polyethylene-block-poly(ethylene glycol)-block-polcaprolactone/poly(styrene-block-methyl methacrylate)/gold/polystyrene nanoparticles 1 showed water flux of 45.2 mL cm^?2 min^?1 and salt rejection ratio of 17.5%. Efficiency of gold nanoparticles–polystyrene nanoparticles reinforced membranes in removal of heavy metal ions was 100%.     

Molar mass of poly (ethylene terephthalate) (PET) during ultimate uniaxial drawing

The changes of the average molar mass M_w, M_n, M_z, and molar mass distributions during multistep uniaxial drawing of poly(ethylene terephthalate) (PET) to achieve ultimate mechanical properties have been studied in detail by means of size exclusion chromatography (SEC) with triple detection: concentration, viscosimetry, and light scattering, using HFIP as solvent. An increase in molar mass of PET due to post‐polycondensation and/or transesterfication during drawing at a high temperature of 160 to 230°C was found. Moreover, drawing leads to crystallization and large orientation in the amorphous phase, which results in lower molecular mobility and prevents a further growth in chain length. Crazing under extreme drawing conditions occurs and affects a decrease in molar mass.     

Free volume defects and transport properties of mechanically stable polyhedral oligomeric silsesquioxane embedded poly(vinyl alcohol)‐poly(ethylene oxide) blend membranes

Polymer membrane based gas transport and pervaporation processes are fast growing areas in separation technology and have received wide attention as areas of ‘clean technology’. Mechanically stable novel polyhedral oligomeric silsesquioxane (POSS) embedded poly(vinyl alcohol) (PVA)/poly(ethylene oxide) (PEO) blend membranes were prepared by solution blending followed by casting. The addition of carboxymethyl cellulose enhanced the interfacial activities of the PVA and PEO blends. The peripheral organic substituent on POSS plays a key role in achieving compatibility with polymers whereas the rigid Si–O–Si core of POSS imparts high mechanical strength. Compared to PVA membrane, poly(ethylene glycol) and octa(tetramethylammonium) functionalized POSS embedded PVA/PEO membranes exhibit 680% and 580% enhancement in Young's modulus as well as 130% and 140% improvement in tensile strength respectively. The Einstein, Kerner and Frankel–Acrivos models were applied to compare the experimental and theoretical Young's modulus of PVA‐PEO/POSS membranes. The presence of an ethylene oxide tail on POSS as well as PEO in the blend membrane enhances the CO₂ affinity of the membrane. The presence of a hydrophilic functional group on the POSS improves the hydrophilicity of the membrane and produces more binding sites for water molecules in the membrane during the pervaporation separation of a tetrahydrofuran–water azeotropic mixture. The transport properties of the membrane are further elucidated by means of free volume defect analysis carried out by positron annihilation lifetime spectroscopy and coincidence Doppler broadening spectroscopy. © 2019 Society of Chemical Industry     

Molecular dynamics of poly(ethylene oxide) in concentrated solution

Incoherent quasi-elastic neutron scattering measurements on aqueous poly(ethylene oxide) solutions show that as the concentration of water is increased to 1:1 mole ratio of water to ethylene oxide monomer units, the polymer chain mobility is not enhanced. Increased mobility is only observed when the water content is increased beyond this ratio. The activation energy for viscous flow shows a similar behaviour, it is unchanged as the system is diluted from the melt to the 1:1 solution and as more water is added it falls sharply. Similar studies on the system poly(ethylene oxide)/toluene show that chain mobility is enhanced and the activation energy for viscous flow falls continuously, at all concentrations. The difference is attributed to the formation of polymer-water hydrogen bonded complexes in aqueous solution. High resolution data for the aqueous systems suggest that the molecular dynamics obey the scattering law predicted for the Zimm model. In the melt the behaviour changes towards the limit given by the Rouse model.     

One-pot syntheses of water-soluble poly(oxamide)s

Two kinds of water-soluble polymers were synthesized by using the poly(oxamide) polyanion generated in situ from the reductive coupling polymerization of diisocyanates induced by SmI₂. One is a nonionic polymer bearing oligo(ethylene oxide) pendants, which was obtained by treating the polyanion with α-methyl-ω-(4-bromomethyl)phenylmethyl oligo(ethylene oxide). The other is an ion-containing polymer having sulfonate moieties in the side chains, which was prepared by the reaction of the polyanion with 1,3-propane sultone or sodium 4-(bromomethyl)-benzenesulfonate. In both cases, the corresponding polymers were provided in good yields, and their solubilities were found to be dependent on the structure as well as the substitution degree. The poly(oxamide) with oligo(ethylene oxide) exhibited good solubilities in common organic solvents and was soluble in aqueous system at high level of substitution. On the other hand, the poly(oxamide) with propane-sulfonic acid showed high solubility in both acidic and basic water but was insoluble in organic solvents, while the poly(oxamide) having benzylsulfonate was soluble only in DMF and DMSO. Received: 18 October 1996/Revised: 8 November 1996/Accepted: 15 November 1996