Suspension Copolymerization Of Styrene Research Articles

Porous polymeric antimicrobial resin containing N-halamine functional groups

An effective and easily recovered porous divinylbenzene (DVB) cross-linked antimicrobial polymeric resin containing N-halamine functional groups, poly (styrene-co-N-(t-Bu)-N-chloro-acryl amide) (PSA-N-Cl) resin, has been synthesized by a suspension copolymerization of styrene and acrylic acid and DVB, an amination with tert-butylamine and triethylenediamine (TEDA), and then a facile chlorination in diluted NaOCl solution. The as-prepared porous DVB cross-linked PSA-N-Cl resin was characterized by Brunauer–Emmett–Teller (BET) analysis, field emission scanning electron microscopy (FE-SEM), Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS). BET analysis indicated that PSA-N-Cl resin has a very large surface area (124.9m2/g) which is favorable for the quick water disinfection. Antibacterial tests showed that the as-prepared PSA-N-Cl resin possesses powerful antibacterial efficacies against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The as-prepared PSA-N-Cl resin was capable of about 7.95-log and 7.81-log reductions of E. coli and S. aureus within 1 and 3min of contact times, respectively. Also, the regenerability and preliminary storage stability of the as-prepared PSA-N-Cl resin were investigated.

Suspension copolymerization of styrene and divinylbenzene in the presence of stabilizers (starch and gelatin)

The procedure for preparing spherical particles of copolymers of styrene and technical-grade divinylbenzene in the presence of stabilizers (starch and gelatin) added to improve the process parameters was examined with the aim to develop a process for production of gel ion-exchange resins.

Synthesis and expansion characteristics of expandable styrene/methyl methacrylate copolymer beads: The effects of monomer composition and cell structure modifying aid

Parts cast of metals such as iron, using expandable polystyrene foams, may have an unacceptable amount of surface defects, such as lustrous carbon. The use of foams made of styrene/methyl methacrylate copolymers can improve the quality of foam molds and metal parts made using such molds. In this work, expandable copolymers were synthesized by suspension copolymerization of styrene and methyl methacrylate in the presence of blowing agents (pentane isomers). When the surrounding temperature was high enough to vaporize the blowing agent and soften the polymer shell, the beads were expanded. The effects of monomer composition and cell structure modifying aid (polyethylene wax) on the particle size, average molecular weight and molecular weight distribution of synthesized copolymer, pentane content and expansion properties (density, residual pentane of pre-expanded particles and cell structure) were investigated. The results showed that monomer composition had a significant effect on the copolymerization kinetic and the copolymer molecular weight. In addition, cell structure, cell size and cell size distribution of the pre-expanded particles were strongly influenced by cell structure modifying aid concentration. The effects of comonomer composition and copolymer particle size on pentane content of expandable particles were also studied.

Expandable styrene/methyl methacrylate copolymer: Synthesis and determination of VOCs by combined thermogravimetry/differential thermal analysis‐gas chromatography/mass spectrometry

AbstractParts cast of metals using expandable polystyrene foams may have an unacceptable amount of surface defects, such as lustrous carbon. The use of foams made of styrenic/acrylic copolymers can improve the quality of foam molds and metal parts made using such molds. Lost foam copolymer was synthesized by suspension copolymerization of styrene and methyl methacrylate. The polymerization was carried out in the presence of blowing agents. The decomposition products of lost foam beads were studied by a method composed of the thermogravimetry/differential thermal analysis (TG/DTA) and gas chromatography/mass spectrometry (GC/MS). With these systems, the TG/DTA data can be combined with a GC separation and MS identification methods. This combined method improves the analysis of the decomposition products of lost foam beads and enables the precise identification of the amount and the nature of volatile organic compounds (VOCs) trapped during suspension polymerization. The results obtained from the combined method were verified for the nature and amount of VOCs with the results of time‐conversion studies for copolymerization of monomers in the presence of different concentrations of blowing agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Kinetic Modeling of the Suspension Copolymerization of Styrene/Divinylbenzene with Gel Formation

AbstractSummary: Experimental and theoretical studies concerning the suspension copolymerization of styrene with divinylbenzene are reported. Experiments were carried out in a batch stirred reactor, at 1.2 dm3 scale, and extended beyond gelation in order to synthesize insoluble material. Looking for real time information concerning the building process of such materials, these polymerizations were In‐line monitored using a FTIR‐ATR immersion probe. Polymer samples collected before and after gelation were Off‐line characterized using a SEC/RI/MALLS system allowing the measurement of monomer conversion, average molecular weights, MWD and also the z‐average radius of gyration. The weight fraction of insoluble material (gel) was measured for samples with different reaction times. The experimental program has included the study of the influence of key polymerization parameters on the dynamics of gelation and some properties of the resulting networks, namely the initial mole fraction of crosslinker and the initial proportions between monomers and inert diluent. Variable n‐heptane/toluene mixtures were used within this purpose. These experimental observations were complemented with theoretical studies using a general kinetic approach allowing the prediction of MWD and z‐average radius of gyration before and also after gelation. Comparison of the experimental measurements with these predictions is being exploited to develop modeling tools useful for the design of operating conditions allowing the improvement of the performance of the final products.

Modification of styrene-divinyl benzene copolymers using monoacrylates as ter-monomer

Porous styrene-divinyl benzene (St-DVB) copolymers were synthesized by incorporation of cyclohexanol during copolymerization. It led to copolymers of high porosity, high surface area and high % swelling. However these copolymers exhibit very poor compressive strength. Therefore they have been modified by terpolymerization in order to achieve styrene-DVB copolymers of adequate compressive strength with high surface area and % swelling. These terpolymers were synthesized by suspension copolymerization of styrene, DVB and variable amount of monoacrylates in presence of cyclohexanol as a diluent. Methylacrylate, ethyl acrylate, butyl acrylate, methylmethacrylate and glycidyl methacrylate were taken as ter-monomers for the present study and influence of these ter-monomers on formation of porous structure of the copolymer was investigated by % swelling, surface area, bulk density, compressive strength measurement and surface morphology. Incorporation of ter-monomers resulted into increased compressive strength and bulk density with adequate surface area and % swelling with the increased content of monoacrylates. Further at constant ter-monomer concentration, physical properties and thermal stability of the ter-polymers were found to be in the order: MMA > MA > EA > BA > GMA.

Effects of crosslinking agents and inert diluents on the characteristics of crosslinked polystyrene copolymers

AbstractThe suspension copolymerization of styrene with various vinyl crosslinking monomers, that is, dimethacrylates and divinylbenzene, was carried out with poly (vinyl alcohol) as the suspending agent. The effect of the crosslinking monomers on the characteristics of the styrene copolymers was also studied, and the styrene–divinylbenzene copolymers were found to be the most thermally stable. Inert diluents were added during styrene and divinylbenzene copolymerization to achieve porous, crosslinked polystyrene. Furthermore, the influence of the diluents on the formation of porous styrene–divinylbenzene copolymers was investigated by surface area, pore volume, pore diameter, apparent density, swelling percentage, and compressive strength measurements and the surface morphology. It was observed that among the inert diluents studied, cyclohexanol was the most effective diluent, leading to the styrene–divinylbenzene copolymer beads with maximum porosity. A surface morphology study of the polystyrene copolymer beads supported the porosity in these copolymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Synthesis and Catalytic Activity of Polymer Supported Schiff Base Complexes of Copper(II) and Iron(III) Ions in Comparison to Unsupported Complexes

The polymer supported metal complexes of N,N′‐bis(acetyl acetone)o‐phenylene‐diamine (ACPDA) Schiff base were synthesized by suspension copolymerization of styrene and allyl chloride in the presence of divinyl benzene (DVB) as cross‐linker and azobisisobutyronitrile (AIBN) as initiator at 70±0.1°C and then ACPDA Schiff base and metal ions were loaded on the resulting polymer beads. The cross‐linked density in polymer beads was varied by taking different concentrations of divinyl benzene in the reaction mixture. The polymer beads were characterized for their cross‐linked density, size (φ), density (ρ), degree of swelling (%S w ) and loading of ACPDA Schiff base and metal ions. The polymer beads prepared with 1.5 mmol of DVB (Type III) had a sufficient amount of allyl chloride (4.90 mmol, 0.367 g) and showed optimum loading for ACPDA Schiff base (1.96 mmol g−1) and metal ions. The structures of copper(II) and iron(III) ions complexes (ACPDA‐M) and their loading on polymer beads (P‐ACPDA‐M) was characterized with spectral analysis. The catalytic activity of unsupported and polymer supported ACPDA Schiff base complexes of copper(II) and iron(III) ions was evaluated by studying the rate of decomposition of hydrogen peroxide. The rate of decomposition (Rp) of hydrogen peroxide varied linearly with a concentration of hydrogen peroxide and catalyst, but varied inversely with hydrogen ions concentration. Finally reaction steps for decomposition of H2O2 were proposed and a rate expression was derived considering the experimental data.

Preparation and characterization of micron‐sized magnetic microspheres by one‐step suspension polymerization

AbstractMicron‐sized magnetic microspheres with different functional groups were prepared by one‐step suspension copolymerization of styrene, divinyl benzene, and methyl methacrylate in the presence of oleic acid‐coated magnetic nanoparticles. In the present work, we used benzoyl peroxide as an initiator and poly(vinyl alcohol) (PVA‐1788; degree of polymerization: 1,700; degree of hydrolysis: 88%) as a stabilizer. We also added acrylamide (AM) monomer in the aqueous phase and methacrylic acid (MAA) in the oil phase. The morphology and properties of the resulting magnetic microspheres were examined by optical micrographs (OMs), vibrating‐sample magnetometer (VSM), and Fourier transform infrared spectrometer (FT IR). The results showed the three products have uniform and spherical form with superparamagnetism and well dispersion. Moreover, we found that monomer AM had a little contribution to the copolymerization, and MAA could strikingly decrease the diameter of the final microspheres. The magnetic microspheres with functional groups could be linked well with the IgG‐FITC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Determination of the relative importance of process factors on particle size distribution in suspension polymerization using a Bayesian experimental design technique

AbstractThe use of a Bayesian experimental design technique to determine the relative importance of factors that control particle size distribution (PSD) in suspension copolymerization of styrene and divinylbenzene is reported. Six factors and two responses are considered in this study. The experimental trials are of the two‐level factorial type designed with a Bayesian method. The experiments were carried out in a 5‐L pilot plant reactor. The matrix of variances of the parameter means (the prior knowledge) was estimated with the use of a preliminary compartment‐mixing (CM) model for PSD in suspension polymerization and our subjective judgement (process understanding). The responses, mean particle size and coefficient of variation, were calculated from distributions obtained with a Coulter particle counter. The results of this study provided the criteria needed to guide the future improvement of our CM‐PSD model in a balanced and effective way. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5577–5586, 2006

Suspension copolymerization of styrene and divinylbenzene: Formation of beads

AbstractSuspension copolymerization of styrene and divinylbenzene (DVB) was carried out using benzoyl peroxide as initiator and magnesium hydroxide as suspending agent in water at 80°C under nitrogen atmosphere to produce styrene–DVB copolymer beads. These beads were characterized by infrared spectroscopy, thermal gravimetric analysis, and scanning electron microscopy. Porosity generated in styrene–DVB copolymer beads by incorporation of solvents in the polymerization system was confirmed by SEM micrograph, apparent density, swelling measurements, and Brunauer, Emmett, Teller surface area. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3559–3563, 2006

Suportes poliméricos para catalisadores sulfônicos: síntese e caracterização

Suportes poliméricos foram sintetizados por meio da copolimerização de estireno (S) e divinilbenzeno (DVB) em suspensão aquosa na presença de misturas diluentes constituídas por tolueno e n-heptano, solventes esses considerados como bom e mau para o polímero respectivamente, em composições variadas. Foram usados dois teores de DVB (60 e 80%) e dois graus de diluição (100 e 200%). Os suportes foram caracterizados no estado seco e no estado inchado e suas propriedades foram relacionadas com os parâmetros de síntese. No estado seco, os copolímeros foram analisados quanto à densidade aparente, à área específica, ao volume de poros e à morfologia. No estado inchado foi observado o comportamento dos copolímeros em tolueno e em n-heptano. Neste trabalho são comentadas as vantagens do uso desses suportes para a preparação de catalisadores sulfônicos e se faz uma comparação entre esses catalisadores e os catalisadores homogêneos convencionais comumente usados em sínteses orgânicas.

Analysis of networks based on styrene and divinylbenzene containing iron anchored using variable pressure scanning electron microscopy

There is great demand for the development of composite materials containing small metal or metal oxides particles, owing to their variable properties and wide application. However, microscopic evaluation of these materials using high-vacuum scanning electron microscopy is difficult because the samples must undergo a series of preparation steps to reach a high image quality and to avoid becoming shrunk inside the microscope vacuum chamber. Thus, in this study, we used variable pressure scanning electron microscopy to evaluate the morphology and iron distribution on the surface of magnetic microspheres based on poly(styrene-co-divinylbenzene). These materials were obtained by suspension copolymerization of styrene and divinylbenzene in the presence of fine iron particles. Energy-dispersive X-rays were also used to analyse distribution of the iron particles. The results indicate that, under the conditions used, magnetic microspheres with a relatively narrow size distribution were formed. Moreover, the micrographs show that agglomerated iron particles appeared only on the microsphere surface.

Polymer‐immobilized N,N′‐bis(acetylacetone)ethylenediamine cobalt(II) Schiff base complex and its catalytic activity in comparison with that of its homogenized analogue

AbstractFor the preparation of a heterogenized N,N′‐bis(acetylacetone)ethylenediamine cobalt(II) Schiff base complex, first crosslinked polymer beads were prepared by the suspension copolymerization of styrene (48.97 mmol, 5.1 g), allyl chloride (48.97 mmol, 3.746 g), and divinyl benzene (DVB; 1.75 mmol, 0.228 g) in the presence of azobisisobutyronitrile (0.9 × 10−3 mmol, 0.15 g) as an initiator at 23 ± 0.1°C under an inert atmosphere. The copolymerization of styrene, allyl chloride in the presence of gelatin (0.75 g), bentonite (2.0 g), and boric acid (2.5 g) produced beads of different crosslinked densities corresponding to the concentration of DVB in the reaction mixture. The amount of allyl chloride in the prepared beads varied from 5.40 to 7.40 mmol g−1 of beads with the amount of DVB varying from 2.0 to 0.8 mmol in the reaction mixture. A quadridentate Schiff base (acen) was prepared with ethylenediamine (5.0 mmol, 0.3 g) and acetylacetone (10.0 mmol, 1.0 g), and it was used to obtain a homogenized and heterogenized Co(II)(acen)2 complex. The extent and arrangement of the Schiff base (acen) in the crosslinked beads depended on the availability of DVB in the reaction mixture. The amount of DVB in the reaction mixture influenced the extent of cobalt(II) ion loading, the degree of swelling, the porosity, and the pore size in the prepared beads. The beads (type IV) prepared with 1.75 mmol (0.228 g) of DVB in the reaction mixture showed a degree of swelling of 9.65% and efficiencies of loading and complexation for cobalt(II) ions of 49.4 and 85%, respectively, in comparison with beads obtained at other concentrations of DVB in the reaction mixture. The structure of free and polymer‐supported Co(II)(acen)2 complexes was verified with IR, UV, and magnetic measurements, which suggested a square planar geometry for the complexes under both conditions. The catalytic activities of the homogenized and heterogenized Co(II)(acen)2 complexes were compared by the evaluation of the rate constant (k) for the decomposition of hydrogen peroxide. The heterogenized Co(II)(acen)2 complex showed a high catalytic activity for the decomposition of hydrogen peroxide (k = 2.02 × 10−4 s−1) in comparison with the homogenized Co(II)(acen)2 complex (k = 4.32 × 10−6 s−1). The energy of activation for the decomposition of hydrogen peroxide with the heterogenized Co(II)(acen)2 complex was low (38.52 kJ mol−1) in comparison with that for the homogenized complex (73.44 kJ mol−1). In both cases, the rate of decomposition of hydrogen peroxide was directly proportional to the concentration of hydrogen peroxide and cobalt(II) ions. On the basis of experimental observations, a rate expression for the decomposition of hydrogen peroxide was derived. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1398–1411, 2003

Resinas sulfônicas: síntese, caracterização e avaliação em reações de alquilação

Três resinas catiônicas (Amberlyst 15, Lewatit SPC 112, ambas comerciais e MLS 07, sintetizada em laboratório) foram utilizadas como catalisadores em reação de alquilação. A resina MLS 07, obtida pela copolimerização em suspensão do estireno com divinilbenzeno, foi sintetizada de modo que apresentasse tamanho médio de partícula e porosidade próximos aos da resina Amberlyst 15. MLS 07 foi modificada por meio de reação de sulfonação dos anéis aromáticos, que introduziu no material, grupos ativos (SO3H). As três resinas, selecionadas em duas faixas granulométricas, foram caracterizadas por adsorção de nitrogênio (área específica, volume de poros e diâmetro médio de poro), por microscopia eletrônica de varredura (morfologia) e quanto a sua capacidade de troca iônica. Os catalisadores foram utilizados em reações de alquilação de tolueno com álcool benzílico. Foi observada a influência de parâmetros como: tamanho médio de partícula, morfologia, tipo de catalisador e temperatura na conversão do álcool benzílico e na seletividade da formação do produto de interesse, benziltoluenos (orto, meta e para). Os dados obtidos mostraram que as resinas Amberlyst 15 e MLS 07 apresentaram melhor performance quando comparadas com a Lewatit SPC 112 que apresentou menor atividade e seletividade no produto de interesse em todas as condições de reação utilizadas. Esse resultado pode ser atribuído principalmente à menor área específica desse material em relação às das outras duas resinas.

Synthesis of Styrene-Allylchloride Copolymer Supported Cobalt(II) Schiff Base Complex and Its Catalytic Activity

N,N′-bis(acetylacetone)o-phenylenediamine cobalt (II) Schiff base complex and its polymer bound analogue have been prepared and characterized for their structure and catalytic activity. To prepare heterogenized analogue of the cobalt (II) complex, a new crosslinked functional polymeric beads were prepared by suspension copolymerization of styrene (48.97 mmol, 5.1 g), allylchloride (48.97 mmol, 3.746 g) and divinylbenzene (1.50 mmol, 0.195 g) in the presence of azobisisobutyronitrile (9.0×10−4 mmol, 0.15 g) as initiator at 25±0.1°C under inert atmosphere. The beads of variable crosslinked densities were prepared by varying the amount of divinylbenzene in a reaction mixture from 0.80–2.00 mmol. The beads prepared with 1.5 mmol of divinylbenzene contained 4.90 mmol (0.367 g) of allylchloride as found with the chlorine content in the beads. These beads have shown optimum degree of swelling (4.83%) and maximum attachment of N,N′-bis(acetylacetone)o-phenylenediamine Schiff base (1.96 mmol g−1 of beads). These beads have also shown maximum loading of cobalt (II) ions on polymer anchored Schiff base (1.37 mmol g−1 of beads). The spectral and magnetic measurements have suggested a square planar structure for cobalt (II) complex both in homogeneous and heterogeneous state. The heterogenized cobalt (II) complex has shown an enhanced rate of decomposition of hydrogen peroxide with low activation energy (42.37 kJ mol−1) in comparison to a homogenized complex (63.59 kJ mol−1). The rate of decomposition has been found to be directly proportional to the concentration of hydrogen peroxide and cobalt (II) complex. A suitable rate expression has been derived for the decomposition of hydrogen peroxide.

Synthesis of amphiphilic microspheres by suspension copolymerization of styrene and poly(ethylene oxide) macromonomer

AbstractAmphiphilic microspheres, ranging in size from 3 to 35 μm, were prepared by suspension copolymerization of styrene with poly(ethylene oxide) vinylbenzyl (PEO–VB) macromonomer by changing polymerization conditions. It was found that an increase in the amount of dispersant and the PEO–VB concentration resulted in decreases of the size and size distribution of amphiphilic microspheres. The morphology, size, and size distribution of amphiphilic microspheres were characterized by scanning electron microscopy. The structure of copolymer was confirmed by infrared spectroscopy, differential scanning calorimetry, elemental analysis, and X‐ray photoelectron spectroscopy. The content of the hydroxyl groups localized in the microspheres ranged from 0.05 to 0.2 mmol/g. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 333–339, 2001

Addition of Carbon Dioxide to Phenylglycidyl Ether Using Polymer-Supported Quaternary Ammonium Salt Catalysts

The synthesis of phenoxymethyl ethylene carbonate from carbon dioxide and phenyl glycidyl ether was investigated in a semi-batch reactor using crosslinked polystyrene beads containing pendant quaternary ammonium salts as catalysts. The catalysts were prepared by suspension copolymerization of styrene, divinylbenzene (DVB) and vinylbenzyl chloride (VBC), followed by quaternization using trialkylamines. The influence of VBC and DVB concentration, the structure of trialkylamine, and the type of solvent, on the catalytic behavior are discussed. A kinetic study was also carried out to better understand the reaction steps.

Synthesis and spectral characterization of surface-enriched polymer-supported phase transfer catalysts and their effects on alkylation of phenylacetone

Polymer-supported phase transfer catalysts with active sites mostly on the surface were prepared by suspension copolymerization of styrene (St), divinylbenzene (DVB), and vinylbenzyl chloride (VBC) with AIBN, followed by the quaternization of the resulting copolymer beads with triethylamine. Active sites on the surface were achieved by the delayed addition of functional monomer (VBC) to the partially copolymerized St/DVB. Polymer beads enriched with active sites were characterized by SEM, EDAX, FTIR, and ESCA. The electron micrographs showed that the exterior surface of delayed-addition functional monomer catalysts (type 1) has a large number of nodules attached to the surface compared to the smooth surface exhibited by the conventional type 2 catalyst upon the simultaneous addition of all three monomers. In the EDAX analysis up to a depth of 100 A, the surface chloride of type 1 peak intensity is greater (compared with type 2), indicating the CH2Cl enrichment on the surface. In FTIR, the peak intensities of the CN stretching (quaternary onium group) in type 1 are greater than those of type 2, confirming the evidence of more quaternization on the surface than in the bulk. From ESCA analysis to a depth of about 30 A, it was found that type 1 (beads) contains 26% and type 2 contains 14% of covalent chloride on the surface, which strongly supports the grafting of VBC on St/DVB. In the estimation found by the Volhard method, type 1 has 4.73 m eq g−1 and type 2 has 2.29 m eq g−1 of ionic chloride, thus supporting the surface grafting of VBC. The catalytic activity of these two different catalysts was tested by studying the reaction, that is, the C-alkylation of phenylacetone. The rate constants of this reaction for type 1 are almost twofold greater than those of type 2, a finding that could uphold the preceding experimental observations. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 408–418, 2000

Effect of the third acrylated vinyl comonomer on absorption and desorption properties of styrene-divinylbenzene-alkyl acrylate terpolymers, imbibing solvent on a water surface

A series of imbiber terpolymer beads was prepared by radical suspension copolymerization of styrene–divinylbenzene with varied contents of acrylated vinyl monomers, n-butyl acrylate and 2-ethyl hexyl acrylate, as the third comonomer. A DVB content of 6 wt % and a mixture of 60/40 wt % toluene/n-heptane as the diluent were used throughout this study. The influence of acrylated vinyl comonomers on bead properties and swelling properties was investigated. The imbiber beads are capable of absorption and desorption of organic solvents having solubility parameters in the range of 14.9–20.9 (MPa)1/2. Styrenic imbiber beads were swelled in a toluene/n-heptane mixture of 50% by volume and the kinetics of absorption was studied. The imbiber beads could absorb the toluene/n-heptane mixture completely within 20 min and yielded a maximum swelling ratio of 6.8. The diffusion coefficient values of these beads were in the range of 6.40 × 10−6 to 1.52 × 10−5 cm2 s−1. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 504–516, 2001