Separability of SO2 from SO2/N2 mixture through sulfoxide-modified poly(vinyl alcohol) and cellulose membranes

Separability of SO₂ from mixtures of SO₂ and N₂ gases was studied for membranes of poly(vinyl alcohol) (PVA) and cellulose modified with methyl, ethyl, t-butyl, and phenyl vinyl sulfoxides. Of these sulfoxide-modified polymers, the phenyl vinyl sulfoxide-modified PVA membranes were found to give the best separation of SO₂. In the phenyl vinyl sulfoxide modified PVA membranes, the permeability coefficient of SO₂ increased with sulfoxide content while separability of SO₂ was maximum at a sulfoxide content of 23.5 mol %; the separation factor of SO₂ was about 170 at this sulfoxide content. © 1993 John Wiley & Sons, Inc.     

Comparative effects of pyrolyzed oil shale and pyrolyzed burned oil shale used as fillers in poly(ethylene‐co‐vinyl alcohol)

Pyrolyzed oil shale (POS) obtained from the pyrolysis of bituminous rock was burned in a normal atmosphere (POSB) to remove the organic phase and then used as a filler in poly(ethylene‐co‐vinyl alcohol) (EVAL). The effects of vinyl alcohol content, POSB particle size, and POSB concentration on the composite were investigated through measurement of mechanical properties. Composites were prepared in a rotor mixer at 180°C. Stress–strain plots of compression‐molded composites showed synergic behavior of the mechanical properties with low concentrations (1–5 wt %) of POSB, regardless of particle size or type of EVAL. Such behavior suggests close packing and strong interactions between inorganic filler and polymer, with the effects reinforced by the mechanical properties. It was observed that the absence of the organic phase in the modified material improved the mechanical properties of the composites. Increasing the vinyl alcohol content improved the compatibility between polymer and filler in the EVAL/POS but did not affect the compatibility in EVAL/POSB composites. The relationship of mechanical and morphological behavior in the EVAL/POS and EVAL/POSB composites indicated that different factors were at play to explain the compatibility between the EVAL and the inorganic phase. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1859–1864, 2006     

Use of pyrolysed oil shale as filler in poly(ethylene‐co‐vinyl alcohol)

The pyrolysed oil shale (POS) obtained from the pyrolysis of bituminous rock was used as filler in poly(ethylene‐co‐vinyl alcohol) (EVAL). The effects of vinyl alcohol content in the EVAL and the particle size of pyrolysed oil shale in the mechanical properties were investigated. The EVAL was prepared by hydrolysis of poly(ethylene‐co‐vinyl acetate) (EVA) with 8 and 18 wt % of vinyl alcohol content. The composites were prepared in a rotor mixer at 180°C with concentration of pyrolysed oil shale up to 5 wt %. Stress–strain plots of compression‐molded composites showed a synergic behavior in the mechanical properties for low concentrations (1–5 wt %) of POS in all particle sizes and EVAL used. Such behavior indicates a close packing and strong interactions between the inorganic filler and the polymer. Increasing of the vinyl alcohol content of EVAL improved the compatibility between the polymer and filler, but decreasing the POS particle size had no effect on the properties. The modulus and the ultimate tensile strength also increased in all concentrations of POS for both EVAL. Mechanical properties and dynamic mechanical analysis also demonstrated the compatibility between EVAL and POS. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1658–1665, 2004     

Photocatalytic deoxygenation of sulfoxides to sulfides over titanium(IV) oxide at room temperature without use of metal co-catalysts

Deoxygenation of sulfoxides was examined in acetonitrile suspensions of metal-free titanium(IV) oxide (TiO₂) under irradiation of UV light at room temperature. Experimental results indicate that deoxygenation was induced by the TiO₂ photocatalyst and that organic acids such as formic acid and oxalic acid are appropriate as hole scavengers in the photocatalytic reaction. Diphenyl sulfoxide was successfully deoxygenated to diphenyl sulfide with high yields, and the TiO₂ photocatalyst could be repeatedly used for deoxygenation without loss of activity. The present photocatalytic method could be applied for deoxygenation of various sulfoxides to corresponding sulfides, and phenyl vinyl sulfoxide was chemoselectively reduced to phenyl vinyl sulfide without hydrogenation of a CC double bond.     

Chiral Thiourea‐Phosphine Organocatalysts in the Asymmetric Aza‐Morita–Baylis–Hillman Reaction

A new kind of bifunctional (thio)urea‐phosphine catalyst was synthesized and applied to the aza‐Morita–Baylis–Hillman reaction of N‐sulfonated imines with methyl vinyl ketone, phenyl vinyl ketone, ethyl vinyl ketone or acrolein. Moderate to excellent ee and yields of the products were obtained under mild reaction conditions.     

Effects of ethylene content of poly(ethylene‐co‐vinyl alcohol) on diameter of fibers produced by melt‐electrospinning

Rodlike samples were made from four kinds of poly(ethylene‐co‐vinyl alcohol) (EVAL) pellets with different ethylene contents. From these rodlike samples, fibers were produced using a melt‐electrospinning system equipped with a CO₂‐laser melting device. The effects on the fiber diameter of the ethylene content and the moisture regain of the rodlike samples were investigated. Furthermore, the physical properties of the fibers were investigated. The following conclusions were reached: (i) EVAL fibers having an average fiber diameter smaller than 1 μm can be obtained using the system developed; (ii) the diameter of EVAL fiber is influenced by the ethylene content and the moisture regain of the starting rods; (iii) the laser heating does not greatly decrease the melting point and the molecular weight of EVAL; and (iv) preferred crystal orientation can be seen in electrospun EVAL fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1368–1375, 2007     

Synthesis of sulfone-modified poly(vinyl alcohol) and its application for permselective membrane of sulfur dioxide

The Michael type addition reaction of poly(vinyl alcohol) (PVA) with a series of vinyl sulfones, namely methyl vinyl sulfone, ethyl vinyl sulfone, and t-butyl vinyl sulfone, was performed with NaOH as catalyst to produce 2-(alkylsulfonyl)ethyl PVA derivatives. The high permselectivity of sulfur dioxide against nitrogen and oxygen was achieved through these sulfone-modified PVA membranes.     

Poly(ethylene‐vinyl co‐vinyl acetate)/clay nanocomposites: Mechanical,morphology, and thermal behavior

Nanocomposites of ethylene‐vinyl acetate copolymer (EVAL) with Dellite organoclay were prepared in a laboratory extruder. The extent of intercalation of the nanocomposites was studied by field emission scanning electron microscopy and X‐ray diffraction. It was established that the organoclay is well dispersed and preferentially embedded in the EVAL phase. Further, the intercalation degree of the organoclay decreased with increasing organoclay content. The mechanical properties of the nanocomposites were studied as a function of clay loading and EVAL type. The nanocomposites exhibited enhanced thermal stability as seen in thermogravimetric studies. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Effect of Poly(vinyl pyrrolidone) on Antifouling Properties of Asymmetric Poly(ethylene‐co‐vinyl alcohol) Membranes

Poly(ethylene‐co‐vinyl alcohol)/poly(vinyl pyrrolidone) (EVAL/PVP) blend membranes with antifouling properties were prepared by nonsolvent induced phase separation. Residual PVP in the sample was calculated by infrared spectroscopic data and confirmed by thermogravimetric analysis. The effect of residual PVP on hydrophilicity and permeation characteristics of the membranes was evaluated. Porosity and equilibrium water content of the membranes were influenced by the addition of PVP. The effect of protein fouling on flux using bovine serum albumin as a model system was studied in detail. The residual PVP content could enhance the antifouling property of the membrane. All membranes proved to have sufficient mechanical strength to withstand pressure‐driven filtrations.     

Blends composed of poly(N‐isopropylacrylamide) and an ethylene/vinyl alcohol copolymer: Thermal and morphological studies

Blends of poly(N‐isopropylacrylamide) (PNIPAM) and an ethylene/vinyl alcohol copolymer (EVAL) were obtained through casting from dimethyl sulfoxide (DMSO) solutions and phase inversion in 50/50 DMSO/H₂O solutions. The miscibility and morphology of the PNIPAM/EVAL blends were investigated with thermal and morphological analysis. Differential scanning calorimetry indicated that the crystallinity of EVAL decreased with increasing PNIPAM content and that the blends cast from DMSO/H₂O solutions were miscible in the melt state. Measurements of the melting point depression allowed the determination of the interaction energy density (B) and Flory–Huggins interaction parameter (χ₁₂) with the Nishi–Wang equation. The negative B and χ₁₂ values obtained were examined in terms of the specific intermolecular interactions between the polymers. Scanning electron micrographs revealed that blends obtained by the casting method led to dense membranes, whereas the phase‐inversion method rendered typical macroporous membranes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 501–505, 2004     

Polymeric decontaminant: N,N‐dichloro poly(styrene‐co‐divinyl benzene) sulfonamide—synthesis,characterization and efficacy against simulant of sulfur mustard

N,N‐Dichloro poly(styrene‐co‐divinylbenzene) sulfonamide (1) reacts with 2‐chloro ethyl phenyl sulfide (2), a simulant of sulfur mustard (SM), at room temperature, yielding corresponding nontoxic sulfones and sulfoxides in aqueous as well as aprotic medium. The decontamination reaction was monitored by gas chromatography, and products were identified by gas chromatography–mass spectrometry. N,N‐dichloro poly(styrene‐co‐divinylbenzene) sulfonamide was synthesized by three steps from a commercial starting material sulfonate cation‐exchange resin and characterized by FTIR, and TGA, and compressive strength by universal testing machine. The positive chlorine content of this polymer was checked by standard iodometry titration. The synthesized positive chlorine compound is observed to be a promising against a simulant of SM, chiefly in the situation where use of aqueous medium is precluded. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Similarly sized protein separation of charge‐selective ethylene‐vinyl alcohol copolymer membrane by grafting dimethylaminoethyl methacrylate

Similarly sized protein separation was investigated using a charge‐selective membrane, which prepared by grafting dimethylaminoethyl methacrylate (DMAEMA) onto ethylene vinyl alcohol copolymer (EVAL) membrane. Bovine serum albumin (BSA) and bovine hemoglobin (BHb) was used as model proteins. P(DMAEMA), the weak cationic polyelectrolyte with ionizable tertiary amine groups, contributed to the charge‐selective separation for BSA and BHb. At pH 6.0, the grafted EVAL membrane surface was positively charged and BSA was negatively charged, while BHb was positively charged. The BSA was adsorbed onto the membrane surface due to electrostatic interaction and the BHb passed through the membrane into the permeate. The charge‐selective behavior resulted in the separation of the similarly sized protein. The maximum separation factors of static adsorption separation for model protein and binary mixture were 32.4 and 37.2, respectively. In the dynamic separation process, the maximum separation factor value was 6.2. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46374.     

Gas transport properties of poly(3-hydroxyoxetane)

Gas transport properties for poly(3-hydroxyoxetane) (PHO) were measured for five gases at 35°C. While PHO has very low gas permeability coefficients, they are larger than those reported for polyacrylonitrile (PAN), poly(vinyl alcohol) (PVA1) and copolymers of ethylene / vinyl alcohol (EVAL) for all gases tested except He. The permeability coefficients for PHO and EVAL are well correlated with the density of hydroxyl groups along the chain. Extrapolations to PVA1 give values that agree well with those estimated by Salame using the Permachor method. It is suggested that some of the reported experimental values for PVA1 are in error. © 1993 John Wiley & Sons, Inc.     

Alkali‐responsive membrane prepared by grafting dimethylaminoethyl methacrylate onto ethylene vinyl alcohol copolymer membrane

An alkali‐responsive membrane was prepared by grafting dimethylaminoethyl methacrylate (DMAEMA) onto ethylene vinyl alcohol copolymer (EVAL) membrane using ultraviolet (UV) irradiation graft polymerization. A subtranslucent state of EVAL membrane swelling in the DMAEMA solution was observed, and such a state enabled the passage of UV light through all the pores, inducing graft polymerization inside the pores and on the back. Attenuated total reflectance Fourier‐transform infrared spectrometer (ATR‐FTIR), X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FESEM), and energy‐dispersive X‐ray spectroscope (EDX) confirmed that the poly(DMAEMA)‐grafted chains existed not only on the top surface, but also inside the pores and on the back. Atomic force microscopy (AFM) and nitrogen adsorption analysis confirmed that the grafted chains collapsed in air, and decreased the surface roughness, surface area, and pore size of the grafted membranes. Alkali‐responsive properties of the poly(DMAEMA)‐grafted EVAL membrane (i.e., contact angle, permeability, and selectivity) were observed in the pH range of 9–10. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41775.     

Effect of vinyl and phenyl group content on the physical and dynamic mechanical properties of HVBR and SSBR

High‐vinyl polybutadiene rubber (HVBR) and solution‐polymerized styrene–butadiene rubber (SSBR) can meet the requirements of high‐performance tires due to their excellent wet skid resistance and lower rolling resistance. In this paper, the effects of the vinyl and phenyl groups and their contents on the vulcanization behavior, mechanical strength, fatigue resistance, heat resistance, and wear resistance of HVBR and SSBR were investigated, and the dynamic viscoelasticities of HVBR and SSBR vulcanizates with or without carbon black were explored by dynamic mechanical analysis (DMA). The experimental results showed that the vinyl groups contributed more to the wear resistance and fatigue resistance of vulcanizates than the phenyl groups, but the phenyl groups contributed more to the mechanical strength of the vulcanizates than the vinyl groups. The DMA results showed that the vinyl and phenyl groups could significantly improve the road‐gripping capability and wet skid resistance of HVBR and SSBR vulcanizates, but carbon black could slightly weaken the effect of vinyl and phenyl groups on the wet skid resistance of vulcanizates, and the effect of carbon black on vinyl groups was more significant. Despite the presence of carbon black, the phenyl groups contributed more heat buildup to the vulcanizates than the vinyl groups. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45975.     

新型尼龙／聚烯烃相容剂EVALM的合成及表征

通过一种可控制的非均相水解方法制备了部分水解的乙烯／醋酸乙烯共聚物－ＥＶＡＬ。得到的ＥＶＡＬ中醋酸乙烯（ＶＡ）基团的水解度可以通过溶用及反应的温度、时间来控制,而且水解溶剂的后处理比较简单,有利于连续化生产及环境保护。将ＥＶＡＬ在苯溶液中进行马来酸酐接枝,得到一种新型的尼龙／聚烯烃相容剂马来酸酐接枝部分水解的乙烯／醋酸乙烯共聚物（ＥＶＡＬＭ）,其中马来酸酐的接枝率也可以接枝反应时间来控制。通过Ｍｏ     

Structure and properties of blends of poly(ethylene-co-vinyl alcohol) with poly(styrene-co-maleic anhydride)

In the present study, ethylene/vinyl alcohol (EVAL) copolymers with different hydroxyl contents were melt mixed with styrene/maleic anhydride (SMA) copolymers. These two copolymers have functional groups capable of reacting intermolecularly, giving stable products. All EVAL copolymers were prepared from the same ethylene/vinyl acetate (EVA) copolymer by controlled hydrolysis. The blends, prepared at constant temperature and rotation speed in the rheomixer, were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermo-gravimetric analysis, as well as mechanical properties and extraction experiments. All the above measurements lead to the conclusion that a certain part of hydroxyls of EVAL have reacted with anhydride groups of SMA, leading to the formation of branched and cross-linked products. The effect of (1) the molar ratio of hydroxyl/maleic anhydride functional groups, (2) the overall concentration of the functional groups, and (3) the mixing time on the structure and properties of the blends are discussed. Emphasis is given on the influence of these factors on the tensile strength, the elongation at break, and impact strength of the products. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 983–999, 1997     

Sulfobetaine-functionalized electrospun poly(ethylene-co-vinyl alcohol) membranes for blood filtration

Functionalization imparting zwitterionic sulfobetaines has been proven as the most versatile method for improving the hemocompatibility of polymers. In this study, we aimed to enhance the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) (EVAL) by photografting with a betaine N-(3-sulfopropyl)-N-methacroyloxyethyl-N,N-dimethyl ammonium betaine (SMDB). SMDB was UV-photografted to electrospun EVAL fibroporous membranes to obtain EVAL-g-PSMDB poly[N-(3-sulfopropyl)-N-methacroyloxyethyl-N,N- dimethylammonium betaine] grafted on EVAL with different extents of grafting. The functionalization was confirmed by analysis of the attenuated total reflectance–Fourier transform infrared spectra. The effects of functionalization on the morphology, wettability, mechanical properties, and hemocompatibility of the electrospun EVAL membranes were also studied by scanning electron microscopy, water contact angle measurement, universal testing machine measurement, and in vitro hemocompatibility evaluation, respectively. The findings highlight that SMDB functionalization significantly reduced protein adsorption, hemolysis, and platelet adhesion. Blood cell consumption studies projected that the SMDB-functionalized EVAL was able to capture leukocytes from blood, and hence, this system has the potential to be used as a filter medium for the selective removal of leukocytes from blood. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47057.     

PEI/EVAL blend membranes for granule neuronal cell culture

Recently we developed a novel type of membrane, based on polyethylene vinyl alcohol (EVAL), for biomedical applications. To improve the physical and biological performance of this membrane, polyethylenimine (PEI) that has been widely used as a gene transfer vector was chosen to blend with EVAL in this study. The properties and in vitro neuronal interaction of the blend membranes were investigated. Scanning electron microscopic observations show that the membranes exhibited increasingly smoother surface morphologies as the PEI content increased. Differential scanning calorimetric analysis demonstrated that EVAL was compatible with PEI at the microscopic level and the crystallinity of EVAL membrane was reduced by amorphous PEI. The surface nitrogen to carbon ratios, surface positive charges, surface hydrophilicity and surface protein adsorption were found to increase with increasing PEI content in the blend membranes as evidenced by the evidences from electron spectroscopy for chemical analysis as well as measurements of zeta potential, water contact angle, and serum protein adsorption respectively. From the morphology and viability of neurons cultured on the surfaces, it was observed that the neurons adhered, spread, grew and differentiated more onto the moderately hydrophilic PEI-containing membranes than onto the unmodified and hydrophobic EVAL. These PEI/EVAL blend membranes, which displayed high compatibility, thermal stability, moderate hydrophilicity, improved serum protein adsorption and enhanced neuronal interaction, may offer the potential to improve the healing and axonal regeneration of injured neuronal tissues.     

Gas transport in poly(vinyl-p-isopropylbenzoate): Comparison and correlation with some other poly(vinyl esters)

Gas permeability in poly(vinyl-p-isopropylbenzoate) (PVp-i-PrB) was determined by a timelag method. The transport properties were discussed from comparison with the permeability data of other poly(vinyl esters), which were studied previously. All these polymers are structurally related, and the size of a side group or the position of its substituent was changed systematically. The isopropyl group of PVp-i-PrB is attached at the para position of a phenyl ring and is the largest in size. As a result gas diffusivity and therefore permeability were increased. The effect of the substituent on gas diffusivity was explained as it increases the interchain and intrachain distances. The discussion was supported from the comparison of the density data between PVp-i-PrB and other poly(vinyl esters). The diffusion coefficients of six glassy poly(vinyl esters) were correlated at their T_g and good correlations were shown to the free volume and its fraction. On the other hand, gas solubility was little affected by the change of an alkyl group on a phenyl ring. The solubility data of PVp-i-PrB and poly(vinyl benzoate) were shown to be clearly correlated with the critical properties of the penetrants. © 1995 John Wiley & Sons, Inc.