Divinylbenzene Content Research Articles

Pore size tuning of poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) hypercrosslinked polymers: Insights from molecular simulations

In this study, we present an atomistic simulation study of several structure-property relationships of hypercrosslinked polymers (HCPs) synthesized using styrene (STR), vinylbenzyl chloride (VBC), and divinylbenzene (DVB). Molecular simulation samples were prepared using a virtual polymerization algorithm, Polymatic, with DVB contents ranging from 0 to 50 mol%. The HCP polymerization algorithm and the models were validated by comparison with experimental data: BET surface area, pore volume, H2 and CO2 loading in 2% DVB samples. Furthermore, the simulated trends in BET surface area and pore volume were in good agreement with the experimental data; both surface areas and pore volumes increased with increased VBC-DVB crosslinking. The same virtual polymerization approach was utilized to study the effect of DVB on the structure and thermodynamic properties of HCPs. Our results demonstrate that DVB mol% significantly altered the structural and gas (H2 and CO2) adsorption properties of the sample. Finally, though our data demonstrated that structural properties can be tuned at the atomistic level by varying the DVB mol%, they did not exhibit a significant improvement in the performance of H2/CO2 gas separation applications.

Emulsion-based pressure sensitive adhesives from conjugated linoleic acid/styrene/butyl acrylate terpolymers

Free radical emulsion terpolymerizations of conjugated linoleic acid (CLA), styrene (Sty), and butyl acrylate (BA) were performed at 80°C. Terpolymers were characterized for composition, conversion, molecular weight and glass transition temperature, latexes were characterized for viscosity and particle size while adhesives were characterized for tack, peel strength, shear strength, storage modulus, loss modulus and tan delta. One impurity commonly found in CLA, oleic acid, was shown to influence the reaction kinetics significantly. Adhesive performance was tuned using divinylbenzene (DVB) crosslinker to keep the terpolymer molecular weight in a desired range. By using a constrained mixture design, the influence of terpolymer composition, chain transfer agent (CTA) concentration, DVB concentration, molecular weights, viscosity and particle size on tack, peel strength and shear strength was investigated. The final forms of the resulting empirical models allowed the creation of 3D response surfaces for pressure sensitive adhesive (PSA) performance optimization.

Esterification of levulinic acid with butanol over ion exchange resins

Alkyl levulinates are biobased chemicals with a great number of applications and great biofuel potential for blending to conventional diesel or gasoline. The present work focuses on the liquid-phase synthesis of butyl levulinate (BL) by esterification of levulinic acid (LA) with 1-butanol (BuOH) using a set of acidic ion-exchange resins. Experiments were performed at 80°C and 2.5MPa in a batch reactor by using an initial molar ratio AL/BuOH of 1/3 and a catalyst loading of 0.8%. It has been found that BL could be successfully obtained over ion-exchange resins with a selectivity higher than 99.5%. LA conversions ranged from 64% (Amberlyst 46, macroreticular, surface sulfonated) to 94% (Dowex 50Wx2, gel-type resin, conventionally sulfonated) at 8h reaction time. By comparing their catalytic behavior, it was seen that resins morphology plays a very important role in the synthesis of BL making easier the access of reactants to acid sites. Accessibility of LA and BuOH to acid centers was high over highly swollen and low polymer density resins. Thus, gel-type resins with low divinylbenzene (DVB) content have been found as the most suitable to produce BL, e.g. Dowex 50Wx2, Dowex 50Wx4 and Purolite® CT224. Among them, Dowex 50Wx2 (2% DVB) is the most efficient catalyst tested.

Synthesis and characterization of PANI-DBSA/DVB composite using roll-milled PANI-DBSA complex

A roll milled complex of Polyaniline (PANI) and Dodecylbenzenesulphonic acid (DBSA) is used with a cross-linked polymer Divinylbenzene (DVB), to prepare a conductive thermoset matrix with good environmental stability at room temperature. Upon heating, thermal doping of PANI-DBSA and curing of DVB occur simultaneously. Different amounts of DVB are used to prepare different samples and their properties are determined. Electrical & mechanical properties are measured. It has been shown that the electrical properties and mechanical properties of the composites are inversely proportional. It is demonstrated that the flexural modulus increases with an increase in DVB content, while the conductivity increases with an increase in PANI-DBSA content. The composite using roll-milled PANI-DBSA complex has shown better stability but lower electrical and mechanical properties as compared to the composite prepared using centrifugally mixed PANI-DBSA complex. An environmentally stable PANI-DBSA/DVB conductive thermosetting matrix is introduced in this work. FTIR spectra and UV–vis–NIR spectra are obtained to explain the effect of roll milling on PANI-DBSA and also the effect of DVB concentration on the composite. Thermal stability of the composites is determined using TGA analysis. The morphology of the samples is studied using SEM and the conductivity behavior is explained.

Using intra-microgel crosslinking to control the mechanical properties of doubly crosslinked microgels.

Microgels (MGs) are crosslinked polymer particles that swell when the pH approaches the pKa of the constituent polymer. Our earlier work showed that concentrated MG dispersions can be covalently interlinked to form macroscopic hydrogels, which are termed doubly crosslinked microgels (DX MGs). Here, we study for the first time the effects of intra-MG crosslinking on the swelling of the MGs and the mechanical properties of the DX MGs. The MGs were synthesised by emulsion copolymerisation of ethyl acrylate (EA) or methacrylic acid (MAA) and divinylbenzene (DVB). The latter was a crosslinking monomer. For comparison, MGs were prepared where DVB was replaced by either 1,4-butanediol diacrylate (BDDA) or a 1 : 1 mixture of both DVB and BDDA. The MG swelling behaviours were studied by dynamic light scattering; whereas, the DX MG mechanical properties were studied by dynamic rheology and uniaxial compression measurements. Inclusion of DVB within the MGs resulted in both highly swelling MGs and highly ductile DX MGs. The average strain-at-break value for the DVB-containing DX MGs was 76% which represents the highest value yet reported for a DX MG prepared using commercially available monomers. It was also shown that good tuneability of the DX MG properties could be obtained simply by controlling the DVB and BDDA contents within the MG particles. Analysis of the swelling and compression data enabled relationships between the volume-swelling ratio of the MGs and either the modulus or strain-at-break values for the DX MGs. These relationships also applied to a DVB-free system prepared with a low BDDA content. An interesting conclusion from this study is that the DX MGs can be thought of mechanically as macroscopic MG particles. The results of this study provide design tools for improving DX MG ductility and hence increasing the range of potential applications for this new class of hydrogel.

Optical properties of CCA films prepared with poly[styrene-co-sodium 1-allyloxy-2-hydroxypropane sulphonate] particles

In this study, we investigated the optical properties of CCA films prepared with poly[styrene-co-sodium 1-allyloxy-2-hydroxypropane sulphonate] particles via soap-free emulsion polymerisation. Experiments were performed by adjusting the several reaction factors such as styrene concentration, sodium 1-allyloxy-2-hydroxypropane sulphonate concentration, polymerisation temperature, initiator and divinylbenzene concentration. All latexes showed uniform spherical particles and they showed a size range of 160–550 nm. All CCA films prepared with self-assembled array showed the respective shiny structural colours from their photonic crystals. It is found that the changes in such polymerisation factors greatly affect the number of particles and particle diameter and refractive indices. Refractive indices and the reflectivity increased with sodium 1-allyloxy-2-hydroxypropane sulphonate concentration, on the other hand, and decreased with divinylbenzene concentration.

Monodispersepoly[BMA-co-(COPS-I)] Particles by Soap-Free Emulsion Copolymerization and Its Optical Properties as Photonic Crystals.

In order to study the surfactant-free emulsion copolymerization of benzyl methacrylate (BMA) with sodium 1-allyloxy-2-hydroxypropane sulfonate (COPS-I) and the resulting optical properties, a series of experiments was carried out at various reaction conditions such as the changes of BMA concentration, COPS-I concentration, BMA concentration under a fixed COPS-I amount, initiator and divinyl benzene (DVB) concentration. All the latices showed highly monodispersed spherical particles in the size range of 144~435 nm and the respective shiny structural colors from their colloidal photonic crystals. It is found that the changes in such polymerization factors greatly affect the number of particles and particle diameter, polymerization rate, molecular weight, zeta-potential, and refractive indices. The increase of number of particles led to the increased rate of polymerization and zeta-potential of the latices, on the other hand, to the decreased molecular weight. Refractive indices and the reflectivity increased with COPS-I concentration, on the other hand, and decreased with DVB concentration. Especially, refractive indices of the resulting poly[BMA-co-(COPS-I)] colloidal photonic crystals showed much higher values of 1.65~2.21 than that of polystyrene, due to the formation of core-shell shaped morphology. Monodisperse and high refractive index of poly[BMA-co-(COPS-I)] particles prepared in this work could be used for the study in photonic crystals and electrophoretic display.

Formation of semi-IPN membrane composed of crosslinked SPS-[PVdF-co-HFP/Nafion] for application in DMFC: A fine tuning between crosslinker and initiator

The semi-interpenetrating (semi-IPN) membrane composed of crosslinked sulfonated polystyrene (SPS) within the host blend of PVdF-co-HFP (Polyvinylidenefluoride-co-hexafluoropropylene) and Nafion has already been tested as a promising polymer electrolyte membrane (PEM) in terms of improved water uptake, proton conductivity and electrical efficiency for application in the direct methanol fuel cell (DMFC). These desired results have generated further curiosity about a fine tuning between the contents of divinyl benzene (DVB) as a crosslinker and azobisisobutyronitrile (AIBN) as an initiator for the optimization of PEM characteristics. It has been observed that an increase in AIBN content leads to an acceptable degree of water uptake, swelling ratio and proton conductivity in PEM, while higher DVB content causes declined methanol crossover, leading to higher membrane selectivity. These two opposing effects are optimized in terms of proton conductivity, tensile strength and membrane selectivity for the membrane consisting of 0.4 wt% of AIBN and 1.2 wt% of DVB. Moreover, the maximum power density obtained for the membrane having optimum selectivity is 56 mW cm−2, when analyzed at 90 °C. These results indicate that one can achieve a high power density in comparison to Nafion by fine tuning the contents of initiator and cross-linker during the synthesis of the semi-IPN membrane.

Rational design and preparation of dibenzothiophene‐targeting molecularly imprinted polymers with molecular dynamics approaches and surface‐initiated activators regenerated by electron‐transfer atom‐transfer radical polymerization

ABSTRACTNine molecular dynamic simulations of molecular‐imprinting prepolymerization systems were performed to investigate the effects of the type and concentration of crosslinkers (CLs) on key template (T)–functional monomer (FM) complexes. Subsequent analyses revealed that the system with divinylbenzene as the CL had the most stable T–FM complexes, and the mass percentage concentration of divinylbenzene in the prepolymerization system was 9.4%. Nine corresponding imprinted polymers were synthesized by the coupling of the surface‐initiated activator regenerated by electron‐transfer atom‐transfer radical polymerization technique with the hierarchical‐imprinting technique to validate the reliability of the simulation results. The structural properties of the optimal adsorbent were characterized by IR spectrophotometry, scanning electron microscopy, and nitrogen sorption measurements. The Langmuir isotherm fitted the equilibrium data best, and the kinetic data (within 30 min) were well described by the pseudo‐second‐order model. Meanwhile, the prepared adsorbent displayed a higher selectivity to dibenzothiophene compared with other analogs. Finally, the adsorbent was successfully applied for the deep desulfurization of the gasoline sample. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42629.

Characterization of Anion Exchange Membrane Containing Epoxy Ring and C–Cl Bond Quaternized by Various Amine Groups for Application in Fuel Cells

Anion exchange membranes were synthesized from different compositions of glycidyl methacrylate (GMA) and vinylbenzyl chloride (VBC), with constant content of divinyl benzene (DVB) by radical polymerization using benzoyl peroxide (BPO) on non-woven polyethylene terephthalate (PET) substrate. Polymerized membranes were then quaternized by soaking in trimethylamine (TMA), triethylamine (TEA), tripropylamine (TPA), and 1,4-diazabicyclo [2.2.2] octane (DABCO). Characteristics of membranes were confirmed by Fourier transform infrared spectroscopy, water uptake, ion exchange capacity, ion conductivity, thermal, and alkaline stability. The results revealed that membranes quaternized by TPA and DABCO showed high affinity when GMA content was 15 wt% and 75 wt%, respectively. IEC and ion conductivity of membranes quaternized by TPA were 1.34 meq·g−1 and 0.022 S·cm−1 (at 60 °C), respectively. IEC and ion conductivity of membranes were quaternized by DABCO were 1.34 meq·g−1 and 0.021 S·cm−1 (at 60 °C), respectively. The results indicate that the membrane containing GMA 15 wt% quaternized by TPA showed the highest thermal stability among membranes and exhibited high ion conductivity compared to existing researches using GMA, VBC, and DVB monomers.

Self film‐forming and opaque hollow latexes fabricated via seeded emulsion polymerization followed by alkali post‐treatment

ABSTRACTIn order to obtain novel hollow latexes with both opaque and self film‐forming properties, the four‐layer core/shell latex particles—sequentially consisting of a high carboxyl‐containing soft core, a transition layer, a rigid supporting layer, and an outermost film‐forming layer—are first designed and prepared by emulsion polymerization, and then treated with alkali to fabricate self film‐forming hollow latexes. On the basis of the previous research on the three‐layer core/shell latex, influences of the composition and thickness of the film‐forming layer on the properties and morphologies of the four‐layer core/shell and the final hollow latexes are investigated. Results show that under optimized conditions with butyl acrylate/styrene (BA/St) mass ratio of 2/1, divinyl benzene (DVB) content of 1 wt %, and core/film‐forming layer mass ratio of 1/6 in the film‐forming layer preparation, the final hollow latex particles exhibit best morphology considering both light scattering efficiency and film‐forming capability at room temperature. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42541.

Mechanical and electrical properties of PANI-based conductive thermosetting composites

Polyaniline (PANI) is one of the most studied intrinsic electrically conductive polymer in recent years. In the present work, PANI-based conductive composites have been prepared using dodecylbenzenesulphonic acid (DBSA) as a dopant and divinylbenzene (DVB) as a cross-linking polymer to enhance the rigidity. In this mixture, DBSA acts as the dopant of PANI as well as the curing agent of DVB, and this means that doping and curing of the composite occur simultaneously. PANI–DBSA mixture has been prepared by physical mixing using centrifugal mixer. The ratio of PANI and DBSA has been kept constant in weight ratio 30:70. Furthermore, DVB content has been varied to prepare the different samples. It has been found that with the increase in DVB content, a good dispersion of PANI–DBSA/DVB solution is achieved. However, significant improvement in the electrical conductivity of the samples is observed with the increase in PANI content. Mechanical flexural test has been performed on the prepared samples using a three-point bending configuration. It has been found that the flexural modulus and brittleness of the prepared samples increase with the increase in the content of DVB in the composite. Morphology of the composite surfaces has been also studied and it has been found that low concentration of DVB results into a poor dispersion and hence agglomeration of PANI–DBSA in composite can be seen clearly in the images.

Network and swelling parameters of cross-linked octadecylacrylate-co-acrylic acid copolymers based on divinyl benzene cross-linker

Authors describe the network structure of octadecylacrylate (ODA)-co-acrylic acid (AA) cross-linked with divinyl benzene (DVB). Crosslinked xerogels comprised of ODA/AA, with ODA molar composition ranging from 50 to 90%, were synthesised by radical initiation copolymerisation in different concentrations (1–10%) of DVB utilising either bulk or suspension techniques in two solvents. Atomic force microscopy images of the xerogels reveal a variety of porous morphologies. The average molecular weight between the cross-links and polymer-toluene interaction parameter of xerogels were determined from swelling measurements. The efficiency of DVB as a cross-linking agent for ODA/AA was also determined. An increase of concentration of AA in the copolymers enhances the thermal stability of the copolymers at elevated temperatures determined by thermogravimetric analysis (TGA). Moreover, the increase in AA concentration increases the average molecular weight between cross-links and thus enhances swelling of the copolymer by toluene; this is true for any of our copolymerisation procedures.

Effect of the catalytic system based on multi-walled carbon study of properties of catalysts based on cation-exchange resins for synthesis of bisphenols

Effect of fabrication conditions on the physicochemical and catalytic properties of catalysts based on cation-exchange resins was studied. It is shown that the porous structure and surface texture, mechanical and osmotic characteristics of both gel-like and macroporous ion exchangers are determined by the content of divinylbenzene in the copolymer. Effective ways to raise the activity of the catalysts were found.

Microesferas magnéticas à base de poli(metacrilato de metila-co-divinilbenzeno) obtidas por polimerização em suspensão

Microesferas poliméricas à base de metacrilato de metila (MMA), divinilbenzeno (DVB) e material magnético foram preparadas via polimerização por suspensão. Foi estudada a influência da polimerização em suspensão ou semisuspensão, concentração de material magnético e concentração de divinilbenzeno sobre as características das microesferas obtidas. As partículas poliméricas foram caracterizadas por espectroscopia vibracional na região do infravermelho por transformada de Fourier (FT-IR), microscopia eletrônica de varredura, analisador de área específica e porosimetria, espalhamento de luz e magnetometria de amostra vibrante. O material magnético também foi caracterizado por FT-IR, além de difratometria de raios X e espectroscopia Mössbauer. Foram obtidas, com sucesso, microesferas poliméricas magnéticas à base de MMA e DVB (P(MMA-co-DVB)-M), contendo partículas magnéticas tanto na superfície quanto no interior da microesfera. As partículas obtidas através de polimerização em semisuspensão apresentaram tamanhos menores e distribuição de tamanhos de partículas mais estreita que as partículas obtidas através de suspensões convencionais. Os compósitos apresentaram um comportamento superparamagnético. As microesferas magnéticas sintetizadas neste trabalho têm potencial para serem modificadas e aplicadas como resinas de troca iônica ou suportes catalíticos.

Polymeric networks based on tung oil: Reaction and modification with green oil monomers

A highly unsaturated vegetable oil (tung oil) was cationically copolymerized with a vegetable oil derived monomer, that replaces the more frequently used styrene. The synthesized comonomer was methyl ester of tung oil, obtained by transesterification of the plant oil with methanol. Alternatively, the incorporation of a green modifier, a commercial acrylated epoxidized soybean oil, was also considered. The use of any of these modifiers allowed preparing materials with an elevated content of bio-derived components.All the materials obtained presented good mechanical damping capacity, as well as dynamic mechanical properties comparable to analogous materials obtained by copolymerization with styrene. Incorporation of low concentrations of divinylbenzene in the formulations allowed increasing rigidity and glass transition temperatures (Tg) of the materials. One of the formulations prepared by copolymerization with the tung oil methyl ester presented shape memory behavior.

Mechanical and electrical properties of acrylonitrile-butadiene rubber filled with crosslinked polystyrene prepared by emulsion polymerization

In the present work, we have studied the effects of mixed emulsifier systems, sodium dodecyl sulphate (SDS — as anionic surfactant) and poly(oxyethylene) nonylphenyl ether (NP-30 — as non-ionic surfactant), on the emulsion polymerization of styrene. The crosslinked, monodispersed polystyrene (PS) particles were synthesized with a variable divinylbenzene (DVB) concentration as cross-linking agent. The crosslinked polystyrene was incorporated into acrylonitrile-butadiene rubber (NBR). The mechani- cal and electrical properties were determined using carbon black as a conductive filler and silica as non conductive filler.

High throughput development of one carbon molecular sieve for many gas separations

A set of CMS adsorbents was synthesized by pyrolyzing gel-type cation exchange resins (IERs) based on sulfonated poly(styrene-co-divinylbenzene). Fifteen different materials were synthesized following a design of experiments (DOE) that included variations on four factors. These factors were divinylbenzene (DVB) content, plus three factors associated with pyrolysis (peak temperature, hold time, and temperature ramp rate). Results revealed that the peak temperature has a significant impact on the micropore volume and the effective pore size of the resultant CMS adsorbents, but the other three input variables have very little impact. High throughput single gas adsorption was conducted on the fifteen CMS adsorbents using nine probe gas molecules: CO2 (kinetic diameter 3.3Å), N2 (3.64Å), CH4 (3.8Å), C2H4 (3.9Å), C3H6 (4.0Å), C2H6 (4.1Å), C3H8 (4.3Å), i-C4H10 (5.0Å), SF6 (5.5Å). Based on gas pair selectivities calculated from the single gas adsorption data, pyrolysis process boundaries were defined to make suitable CMS adsorbents with effective micropore size in the range of 3.5–4.6Å. Based on the high throughput findings, four additional CMS adsorbents were produced for the industrially significant separations: C3H6/C3H8, C2H4/C2H6, N2/CH4, and CO2/N2. Breakthrough performance of the four target gas pairs was characterized in a packed bed configuration using binary gas mixtures of the four target gas pairs. The four CMS adsorbents exhibited high separation factors, 43 for C3H6/C3H8, 10 for C2H4/C2H6, 9 for N2/CH4, and 12 for CO2/N2, illustrating the validity of the high throughput results.

The Effect of Benzoyl Peroxide and Divinyl Benzene on the Properties of Cross-Linked Recycled Polyolefin Blends

The effect of peroxide cross-linking on the properties and morphology of recycled polyethylene (PE)/polypropylene (PP) blends was characterized. The addition of benzoyl peroxide (BPO) decreased the melt flow rate (MFR) and increased the impact strength of the recycled polymer blends. Divinyl benzene (DVB) is often used as a cross-linking agent assistant. Compared with BPO modification, the addition of BPO together with DVB improved the cross-linking efficiency and further increased the impact strength of the recycled polymer blends. The effect of BPO content on the MFR and the mechanical properties was also studied with the DVB content fixed. However, chemical cross-linking slightly reduced the thermal stability of the polymer blends. The morphology of the modified and unmodified polymer blends showed that with the addition of BPO, with or without DVB, the compatibility of the PE/PP blends was improved, resulting in enhanced impact strength.

Sulfonation Process and Desalination Effect of Polystyrene/PVDF Semi-Interpenetrating Polymer Network Cation Exchange Membrane

With the classical sulfonation method of polystyrene-based strongly acidic cation exchange resins, polystyrene/polyvinylidene fluoride (PVDF) alloy particles were sulfonated to obtain a cation exchange resin, which was then directly thermoformed to prepare a semi-interpenetrating polymer network (semi-IPN) cation exchange membrane. The effects of the swelling agent, sulfonation time and temperature and the relative contents of polystyrene and divinylbenzene (DVB) in the alloy particles on the feasibility of the membrane formation are discussed. The results indicate that a favorable sulfonation degree above 80% and a suitable ion exchange capacity of 1.5–2.4 mmol/g can be gained, with concentrated sulfuric acid as the sulfonation agent and 1,2-dichloroethane as the swelling agent. The running electrical resistance and desalination effect of the prepared cation exchange membrane were measured in a pilot-scale electrodialyser and not only obviously exceeded a commercial heterogeneous cation exchange membrane, but was also very close to a commercial homogenous membrane. In this way, the authors have combined the classical sulfonation method of polystyrene-based cation exchange resins with the traditional thermoforming manufacturing process of heterogeneous cation exchange membranes, to successfully develop a novel, low-price, but relatively high-performance polystyrene/PVDF cation exchange membrane with the semi-IPN structure.