Highly crosslinked poly(glycidyl methacrylate-co-divinyl benzene) particles by precipitation polymerization

Stable and smooth surface poly(glycidyl metharylate-co-divinylbenzene) (GMA-co-DVB) microspheres composed of various concentrations of DVB from 20 to 90 mol% in acetonitrile medium were prepared without a significant coagulum by precipitation polymerization. The number-average diameter of the microspheres linearly increases from 2.63 to 3.34 μm and the particle size distribution becomes narrower by decreasing the uniformity from 1.10 to 1.02 with the DVB concentration from 20 to 90 mol%. The yield of polymerization increased from 28.9 to 79.7% with the DVB concentration as well. The FT-IR spectrum shows the characteristic peaks at 1725-1650 cm⁻¹ assigned to the confirmation of the polymerization between GMA and DVB. No glass transition temperature and the onset of the thermal degradation temperature at higher temperature indicate that the poly(GMA-co-DVB) is crosslinked; this is evidenced by the swelling ratio measurement relevant to the crosslinking density of the poly(GMA-co-DVB). The swelling test suggested that the poly(GMA-co-DVB) particles would be a core/shell type structure composing of a highly crosslinked DVB rich-phase in the core part and slightly crosslinked GMA rich-phase in the shell part.     

Transport of nickel and copper against a concentration gradient through a carboxylic membrane,based on poly(vinyl chloride)/poly(methyl methacrylate-co-divinylbenzene)

Carboxylic exchange membranes were prepared from poly(vinyl chloride)/poly(methyl methacrylate-co-divinylbenzene) (PVC) [poly(MMA-co-DVB]. Transport of nickel and copper against a concentration gradient through the membrane was investigated by using a system containing NiCl₂ or CuCl₂ aqueous solution on the left side (L) and mixed solution of NiCl₂ (or CuCl₂) and HCl on the right side (R) of the membrane. It was found that nickel and copper were actively transported through the membrane from the L to the R side during the first 5 h of the experiments. The rate of transport of the ions increased with increasing H⁺ ion concentration on the R side and the initial concentration of the metals ions on both sides. The highest rate of transport was observed when 0.1 mol/L MeCl₂ on the L side and 0.1 mol/L MeCl₂-0.5 mol/L HCl on the R side were used. The nickel and copper transport fractions were 34 and 24%, respectively. © 1996 John Wiley & Sons, Inc.     

Preparation and oil-absorptivity of crosslinked polymers containing stearylmethacrylate, 4-t-butylstyrene, and divinylbenzene

Summary The crosslinked polymers, poly(stearylmethacrylate-co-divinylbenzene) [CP(SMA-co-DVB)] and poly(t-butylstyrene-co-divinylbenzene) [CP(tBS-co-DVB)], and CP(SMA-co-DVB)/PtBS IPNs, were prepared by the polymerization of corresponding monomer pairs in the presence of BPO. The structures and thermal properties of CP(SMA-co-DVB), CP(tBS-co-DVB), and the IPN were determined by FT-IR, DSC, and TGA. The oil-absorptivities of CP(SMA-co-DVB) and CP(SMA-co-DVB)/PtBS IPN decreased with increasing concentrations of DVB and tBS, respectively. The highest oil-absorptivities of CP(SMA-co-DVB) and the IPN(PtBS: 25%) were 615 % and 330 %, respectively. The toluene absorptivity of the synthesized polymers decreased in following order: CP(tBS-co-DVB) > CP(SMA-co-DVB) > IPN(PtBS: 25 %) > IPN(PtBS: 50 %) > IPN(PtBS: 75 %) at immersion above 60 min. Received: 4 November 1999/Revised version: 13 December 1999/Accepted: 15 December 1999     

Preparation of Chelating Resins Containing a Pair of Neighboring Carboxylic Acid Groups and the Adsorption Characteristics for Heavy Metal Ions

Abstract

For the functional enhancement of chelating resins containing carboxylic acids, copolymer beads were prepared by suspension polymerization of styrene (St), methyl methacrylate (MMA), and divinylbenzene (DVB) in the presence of toluene as diluent. The phenyl rings of the beads were directly chloromethylated, and the carboxylic ester groups of the beads were converted into hydroxymethyl groups by reduction followed by chlorination to give chloromethyl groups, respectively. The chelating resins containing a pair of neighboring carboxylic acid groups (NCAGs) were obtained by the alkylation of chloromethyl groups in copolymer beads with diethyl malonate in the presence of sodium hydride followed by hydrolysis using aqueous alkali solution. Accordingly, the structural effects of the resins on the adsorption of heavy metal ions were investigated. Poly(St‐co‐DVB)‐based chelating resin containing NCAGs showed adsorption abilities toward heavy metal ions like Pb²⁺, Cd²⁺, and Cu²⁺, whereas poly(MMA‐co‐DVB)‐based chelating resin containing NCAGs showed adsorption abilities toward heavy metal ions like Cu²⁺, Cd²⁺, and Co²⁺. On the other hand, poly(St‐co‐MMA‐co‐DVB)‐based chelating resin containing NCAGs showed adsorption abilities toward heavy metal ions like Pb²⁺, Cd²⁺, Hg²⁺, Co²⁺, and Cu²⁺: a synergistic effect on the adsorption of heavy metal ions like Pb²⁺, Cd²⁺, Hg²⁺, and Co²⁺ was observed. The adsorption ability of poly(St‐co‐MMA‐co‐DVB)‐based chelating resin among three kinds of chelating resins was relatively good.     

Copper (II) transfer through carboxylic ion-exchange membranes prepared by paste method

Interpolymer carboxylic membranes were prepared by the paste method. Transport of copper through the membrane was investigated by using a system containing HCl (receiver solution) and CuCl₂ (feed solution). The transfer rate was found to be greatly affected by the membrane composition and HCl concentration in the receiver solution. A membrane based on poly(vinyl chloride)/poly(methyl methacrylate-co-divinylbenzene) with 5 wt % divinylbenzene showed the highest transfer rate. © 1995 John Wiley & Sons, Inc.     

A thin film composite membrane supported by a hydrophilic poly(vinyl alcohol‐co‐ethylene) nanofiber membrane: Preparation,characterization, and application in nanofiltration

In this study, a fabricated hydrophilic poly(vinyl alcohol‐co‐ethylene) (PVA‐co‐PE) nanofiber membrane was used as the middle support layer to prepare thin film composite (TFC) membranes for nanofiltration. The effects of the supporting nonwoven layer, grams per square meter (GSM) of nanofiber, reaction time, heat treatment, monomer concentration, operating pressure, and pH value on the separation performance of the TFC membranes were analyzed. These results show that the TFC membranes prepared with the PVA‐co‐PE nanofiber membrane can be used to filtrate different metal ions. For NaCl, Na₂SO₄, CaCl₂, CuCl₂, CuSO₄, and methyl orange solutions, the rejection rates of the TFC membrane with nonwoven polyester as the supporting layer and a nanofiber GSM of 12.8 g/m² are 87.9%, 93.4%, 92.0%, 93.1%, 95.8%, and 100%, respectively. This indicates the potential application of the PVA‐co‐PE nanofiber membrane in the preparation of nanofiltration and reverse‐osmosis TFC membranes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46261.     

Transport of cadmium and iron through a carboxylic membrane based on a poly(vinyl chloride)/poly(methyl methacrylate‐co‐divinyl benzene) system

The transport of cadmium and iron through a poly(vinyl chloride)/poly(methyl methacrylate‐co‐divinyl benzene) carboxylic ion‐exchange membrane was investigated with a system containing HCl as the receiver solution and CdCl₂ or FeCl₃ as the feed solution. Transport of the ions through the membrane depended on the H⁺ concentration in the receiver solution and the metal concentration in the feed solution. The rate of transfer for cadmium was about 35% higher than that for iron under the same conditions (0.5 mol/dm³ of HCl, 0.1 mol/dm³ of CdCl₂ or FeCl₃, and 5 h of dialysis). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 705–707, 2005     

Sulfonation of macroporous poly(styrene-co-divinylbenzene) beads: Effect of the proportion of isomers on their cation exchange capacity

The influence of the proportions of the meta- and para-isomers of divinylbenzene and ethylstyrene in the degree of sulfonation of macroporous poly(styrene-co-divinylbenzene) (poly(ST-co-DVB)) beads has been investigated. The first step in this work was the synthesis of poly(ST-co-DVB) beads, with different porous structures, by variation of the proportions of cross-linking agent (%DVB) and of the volume fraction of monomers in the organic phase (Fm) of the polymerization mixture. The next step involved transformation of the polymeric beads obtained into cation exchange resins by means of hot sulphuric acid treatment. The quantitative extent of the sulfonation reaction was evaluated by measuring the ion exchange capacity (q) of each type of resin. The Design of Experiments (DOE) methodology was used to study the effects of %DVB and Fm on q and it was found that only the %DVB factor exerted a significant effect on this parameter, its influence being non-linear and negative. To obtain more reliable results, a new set of experiment was performed in which the range of %DVB values was expanded, covering from 25% to 80% DVB. The results indicated again that the influence of the %DVB factor on q was non-linear and negative; that is, an increase of %DVB in the synthesis process led to a decrease in q. Since this effect can be thought to be due to the hindered penetration of the sulfonation mixture into the very cross-linked gel-type nanoparticles comprising the beads, an attempt was made to find an interrelationship between the specific surface area (S_BET) of each type of bead and their q, trying to determine whether the sulfonation was merely a surface process. However, it was found that not only did sulfonation of the surface of the nanoparticles occur but also that the sulfonation agent penetrated into their interior. Taking these observations into account, it was suspected that one or more of the isomers present in the commercial DVB polymerize in such a way that their sulfonation is not complete. To check this possibility, the proportion of the DVB isomers and q were correlated The quantitative relationship found indicated that the absence of a completely homogeneous sulfonation of poly(ST-co-DVB) beads seems to be due to an insufficient sulfonation of the benzene rings of the para-isomers present in commercial DVB.     

Properties of Interpolymer PESS Ion-Exchange Membranes in Contact with Solvents of Different Polarities

Abstract

PESS membranes with sulfonic ion-exchange groups were prepared by chemical modification of a polyethylene/poly(styrene-co-divinylbenzene) interpenetrating polymer network with varying content of the crosslinking agent (DVB). PESS membranes were loaded with different alkali metal ions as counterions. Swelling and pervaporation properties of these membranes in contact with water and aliphatic alcohols were obtained. The obtained data show that properties of PESS membranes depend strongly on the kind of counterions, the degree of crosslinking, and the solvent polarity.     

Alteration of the refractive index of polyacrylate and poly(styrene-<Emphasis Type="Italic">co</Emphasis>-acrylate) films via molecular structure modification

The alteration in the refractive index (RI) of the polyacrylate and poly(styrene-co-acrylate) films was performed in order to produce a gradient index in the polymeric RI profiles. Such gradient is imperative especially in realizing the fabrication of the polymeric multilayer optical filters and the graded-refractive-index polymeric-based antireflection films. In this study, the highest RI obtained is 1.528 with the poly(styrene-co-acrylate) film which consists of 25 wt% of styrene (Sty), 70 wt% of butyl acrylate (BA) and 5 wt% of acrylic acid, with 8 wt% of divinyl benzene (DVB) which can be utilized to alter the flexibility or the hardness of the polymeric materials. Replacing Sty with methyl methacrylate (MMA) in the copolymer without DVB gives the lowest RI of 1.472 and a difference of RI of 0.056. The Sty copolymer system that contains 8 wt% of DVB has been identified to be one of the effective factors, which yields a refractive index of approximately 0.040 higher than that obtained from the PMMA copolymer system when the same amount of DVB was used. The incorporation of the DVB up to 8.5 wt% has resulted in an increase of the refractive index of approximately 0.013 in the poly(MMA-co-BA-co-AA) copolymer. The refractive index of the polyacrylate copolymer film does not change significantly with the increasing amount of up to 7 % of TMVS in both acidic and alkaline environment. The difference of the refractive index of the film under both mediums is in the order of 10^?3.     

Synthesis and Structural Characterizations of “Core–Shell”-Type Nickel-Coated Polymeric Particles

A polystyrene seed with a narrow size distribution was synthesized by the dispersion polymerization method first, then uniformly “swollen up” and cross-linked with divinylbenzene (DVB) utilizing the dynamic swelling polymerization technique. The surface of hollow poly(styrene-co-DVB) particles was coated with nickel by the electroless plating method. The density of the synthesized “core–shell”-type conductive particle was 3.06 g/cm³, significantly lower than the density of pure metallurgical nickel of 8.91 g/cm³. Hence, the sedimentation problem, which often occurs in the blend of high-density metal fillers with a relatively low density polymer matrix, could be overcome as the metal fillers were replaced by the synthesized core–shell-type conductive particles.     

Performances of poly(vinylidene fluoride‐co‐hexafluoropropylene) ultrafiltration membranes modified with poly(vinyl pyrrolidone)

The structure and performance of modified poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐co‐HFP) ultra‐filtration membranes prepared from casting solutions with different concentrations of poly(vinyl pyrrolidone) (PVP) were investigated in this study. Membrane properties were studied in terms of membrane compaction, pure water flux (PWF), water content (WC), membrane hydraulic resistance ( R _m), protein rejection, molecular weight cut‐off (MWCO), average pore size, and porosity. PWF, WC, and thermal stability of the blend membranes increased whereas the crystalline nature and mechanical strength of the blend membranes decreased when PVP additive concentration was increased. The contact angle (CA) decreased as the PVP concentration increased in the casting solution, which indicates that the hydro‐philicity of the surface increased upon addition of PVP. The average pore size and porosity of the PVdF‐co‐HFP membrane increased to 42.82 Å and 25.12%, respectively, when 7.5 wt% PVP was blended in the casting solution. The MWCO increased from 20 to 45 kDa with an increase in PVP concentration from 0 to 7.5 wt%. The protein separation study revealed that the rejection increased as the protein molecular weight increased. The PVdF‐co‐HFP/PVP blended membrane prepared from a 7.5 wt% PVP solution had a maximum flux recovery ratio of 74.3%, which explains its better antifouling properties as compared to the neat PVdF‐co‐HFP membrane. POLYM. ENG. SCI., 55:2482–2492, 2015. © 2015 Society of Plastics Engineers     

Mechanical stability of trimethylolpropane trimethacrylate-based polymers

Trimethylolpropane trimethacrylate (TRIM) was homopolymerized and copolymerized with methyl methacrylate (MMA), glycidyl methacrylate (GMA), and acrylamide (AA), respectively, in various solvents and at various temperatures. For comparison, poly(styrene-co-divinyl benzene) [poly(S-co-DVB)] gels were selected. The mechanical stability was measured by compression of the swollen gels. The porogen served as swelling agent. The compression moduli increased with increasing TRIM concentration in the polymerization. The compression moduli of poly(TRIM) could be increased by copolymerization with low concentrations of comonomer. Low polymerization temperature decreased the mechanical strength of poly(TRIM). A good solvent increased the compression modulus. TRIM-based gels were at least as mechanically stable as were poly(S-co-DVB) gels.     

Effect of organo clay content on proton conductivity and methanol transport through crosslinked PVA hybrid membrane for direct methanol fuel cell

In the present study, crosslinked poly(vinyl alcohol) (PVA) membranes were prepared using poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA) (PVA:PSSA_MA = 1:7). The PSSA_MA was used both as a crosslinking agent and as a donor of the hydrophilic group (–SO₃H and/or –COOH). The hybrid membranes were prepared by modified clay such as Clay Na⁺, Clay 30B, and Clay 15A. The thermal, water uptake, proton and methanol transport properties of the hybrid membrane were found to be sensitive to the clay type and content. The hybrid membrane with Clay 30B shows higher proton conductivity than other hybrid membranes due to hydroxyethyl group. The membrane with Clay 15A showed the lowest methanol permeability due to lower specific gravity than other clay. Compared to the membrane without modified, the PVA/PSSA_MA/Clay 15A containing 4 wt% of Clay 15A showed both high proton conductivity (0.023 S/cm) and low methanol permeability (2.19 × 10^?7 cm²/s).     

Poly(vinylidene-co-hexafluoropropylene) membrane modified with glass fibers and polyvinyl pyrrolidone: Mechanical and electrochemical properties

The polymer electrolytes based on poly(vinylidene-co-hexafluoropropylene) (PVDF-co-HFP) have been widely studied and applied in devices for its excellent electrochemical and mechanical properties. Here, porous PVDF-co-HFP membrane modified with glass fibers (GFs) and polyvinyl pyrrolidone (PVP) were fabricated by phase-transfer method. When the dosage of GFs exceeded 1 wt%, the composite membranes exhibited 6.11 MPa tensile strength. When the dosage of GFs and PVP reached 1% (PVP₁GF₁), respectively, the composite membranes in porous network structure possessed the highest electrolyte uptake of 251.02%, the thermal stability of 343°C and the ionic conductivity of 3.05 × 10⁻³ S cm⁻¹. Electrochromic device (ECD) was assembled with PVP₁GF₁ electrolyte, showing quick responses between the bleached and the color states within 3 s. The PVDF-co-HFP composite electrolyte was expected to be effective substitutes for liquid electrolytes used in ECDs.     

The characterisation of the polyethylene-polystyrene-divinylbenzene interpolymer cation-exchange membranes in the electrolysis of borax solutions

The synthesis and the characterization of the PE-PS-DVB interpolymer cationexchange membranes in the electrolysis of borax solutions to produce boric acid and sodium hydroxide simultaneously was carried out. The characterization of the teflon based “Nafion 324” and polystyrene-DVB based “Permaplex C-20” membranes was also performed in the same system for comparison. The DVB contents were varied between 3 – 12% (by wt. in total monomers) and the increase of the cross-links resulted in the decrease of the water contents and ionexchange capacities of the membranes. The PE present in the membrane acted as a barrier for electroosmotic water transport. The membranes with high DVB contents showed better electrolysis performance due to their low water contents and low electroosmotic water transport properties. The use of the interpolymer membrane containing 11.6% DVB resulted in high current efficiency and high sodium cation dynamic transport number and worked satisfactorily at the process conditions of borax electrolysis.     

Triblock SEBS/DVB crosslinked and sulfonated membranes: Fuel cell performance and conductivity

A set of styrene-ethylene-butylene-styrene triblock copolymer (SEBS) membranes with 10 or 25 wt% divinyl-benzene (DVB) as a crosslinking agent were prepared and validated. Physicochemical characterization revealed suitable hydrolytic and thermal stability of photo-crosslinked membranes containing 25 wt% DVB and post-sulfonated. These compositions were evaluated in H₂/O₂ single cells, and electrical and proton conductivities were furtherly assessed. The membranes with the milder post-sulfonation showed greater proton conductivity than those with excessive sulfonation. In terms of electrical conductivity, a universal power law was applied, and the values obtained were low enough for being used as polyelectrolytes. At the analyzed temperatures, the charge transport process follows a long-range pathway or vehicular model. Finally, fuel cell performance revealed the best behavior for the membrane with 25 wt% DVB, photo-crosslinked during 30 min and mild sulfonated, with a promising power density of 526 mW·cm⁻². Overall, the results obtained highlight the promising fuel cell performance of these cost-effective triblock copolymer-based membranes and indicate that higher sulfonation does not necessarily imply better power density.     

The effect of ionic liquid fragment on the performance of polymer electrolytes

An ionic liquid 1‐methyl‐3‐[2‐(methacryloyloxy)ethyl]imidazolium bis(trifluoromethane sulfonylimide) (MMEIm‐TFSI) was synthesized and polymerized. Composite polymer electrolytes based on polymeric MMEIm‐TFSI (PMMEIm‐TFSI) and poly[(methyl methacrylate)‐co‐(vinyl acetate)] (P(MMA‐VAc)) were prepared, with lithium bis(trifluoromethane sulfonylimide) (LiTFSI) as target ions (Li⁺). DSC/TGA analysis showed good flexibility and thermal stability of the composite electrolyte membranes. The AC impedance showed that the ionic conductivity of the electrolytes increased with PMMEIm‐TFSI up to a maximum value of 1.78 × 10^?4 S cm^?1 when the composition was 25 wt% P(MMA‐VAc)/75 wt% PMMEIm‐TFSI/30 wt% LiTFSI at 30 °C. The composite electrolyte membrane (transmittance ≥ 90%) can also be used as the ion‐conductive layer material for electrochromic devices, and revealed excellent colorization performance. Copyright © 2011 Society of Chemical Industry     

Preparation of poly(divinylbenzene‐co‐N‐isopropylacrylamide) microspheres and their hydrogen‐bonding assembly behavior for raspberry‐like core‐corona polymer composite

Narrowdisperse poly(divinylbenzene‐co‐N‐isopropylacrylamide) (poly(DVB‐co‐NIPAM)) functional microspheres with the diameter in the range of 630 nm and 2.58 μm were prepared by distillation–precipitation polymerization in neat acetonitrile in the absence of any stabilizer. The effect of N‐isopropylacrylamide (NIPAM) ratio in the comonomer feed on the morphology of the resultant polymer particles was investigated in detail with divinylbenzene (DVB) as crosslinker and 2,2′‐azobisisobutyronitrile (AIBN) as initiator. The monodisperse poly(DVB‐co‐NIPAM) microspheres with NIPAM fraction of 20 wt % were selected for the preparation of raspberry‐like core‐corona polymer composite by the hydrogen‐bonding self‐assembly heterocoagulation with poly(ethyleneglycol dimethacrylate‐co‐acrylic acid) [poly(EGDMA‐co‐AA)] nanospheres. Both of the functional poly(DVB‐co‐NIPAM) microspheres and the core‐corona particles were characterized with scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), and elemental analysis (EA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1350–1357, 2007     

Highly selective sulfonated poly(vinylidene fluoride‐co‐hexafluoropropylene)/poly(ether sulfone) blend proton exchange membranes for direct methanol fuel cells

Proton exchange membranes (PEMs) based on blends of poly(ether sulfone) (PES) and sulfonated poly(vinylidene fluoride‐co‐hexafluoropropylene) (sPVdF‐co‐HFP) were prepared successfully. Fabricated blend membranes showed favorable PEM characteristics such as reduced methanol permeability, high selectivity, and improved mechanical integrity. Additionally, these membranes afford comparable proton conductivity, good oxidative stability, moderate ion exchange capacity, and reasonable water uptake. To appraise PEM performance, blend membranes were characterized using techniques such as Fourier transform infrared spectroscopy, AC impedance spectroscopy; atomic force microscopy, and thermogravimetry. Addition of hydrophobic PES confines the swelling of the PEM and increases the ultimate tensile strength of the membrane. Proton conductivities of the blend membranes are about 10^?3 S cm^?1. Methanol permeability of 1.22 × 10^?7cm² s^?1 exhibited by the sPVdF‐co‐HFP/PES10 blend membrane is much lower than that of Nafion‐117. AFM studies divulged that the sPVdF‐co‐HFP/PES blend membranes have nodule like structure, which confirms the presence of hydrophilic domain. The observed results demonstrated that the sPVdF‐co‐HFP/PES blend membranes have promise for possible usage as a PEM in direct methanol fuel cells. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43907.