Mixture Of Styrene Research Articles

Preparation of core‐shell latexes for paper coatings

AbstractNovel core‐shell latices with a partially crosslinked hydrophilic polymer core and a hard hydrophobic shell of polystyrene were prepared to improve optical properties of coated paper such as gloss and brightness. These core‐shell latices were prepared by sequential addition of a monomer mixture of styrene, n‐butylacrylate and methacrylic acid. Different crosslinkers were used to form the polymer core and in the second stage styrene to form the hard shell component. In addition, attempts were made to further improve optical properties by introducing a new polymerizable optical brightener, i.e., 1‐[(4‐vinylphenoxy)methyl]‐4‐(2‐phenylethylenyl)benzene during polymerization either into the core or into the shell. The prepared core‐shell latex particles were used as specialty plastic pigments for paper coating together with kaolin as the primary pigment. The runability of paper coating formulation by either using a laboratory scale Helicoater or pilot scale JET‐coating machine was very good. The produced coated papers were printed on both sides employing a heat set web offset (HSWO) printer to study the quality of image reproduction in terms of print gloss, print mottle, print through, etc. The core‐shell latices improved the overall print quality. Furthermore, the results demonstrated that by optimizing polymer composition one can significantly enhance the optical properties and surface smoothness of coated paper. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Volumetric and ultrasonic studies of molecular interactions in binary liquid mixtures of styrene with toluene at different temperatures

This paper presents experimental data for densities (p) and ultrasonic speeds (u) of pure styrene and toluene and of their binary liquid mixtures over the entire composition range at 298.15, 303.15, 308.15 and 313.15 K. From the experimental data the excess molar volumes (V E ), deviations in isentropic compressibilities (Δk s ), and in acoustic impedances (ΔZ), were calculated for the binary mixtures over the entire composition range at all the temperatures. Moreover, partial molar volumes, V 0 φ,1 and V 0 φ , 2 and partial molar isentropic compressibilities, K 0 φ,1 and K 0 φ,1 at infinite dilution of styrene in toluene and toluene in styrene were examined. The variations of these parameters with composition of mixture suggest the strength of interactions between the component molecules under study.

A facile preparation method for self-assembled monolayers with silica particles on polystyrene-based microspheres

This paper introduces a novel and facile preparation method for creating polystyrene-based microspheres covered with micron-size silica particles-monolayers. The method is characterized by one-step suspension polymerization from a mixture of styrene and ethylenedimethacrylate containing mono-dispersed silica particles chemically modified by methacryloxypropyl trimethoxysilane. It is also described that further functionalization can be readily done by usual addition reaction with the remaining vinyl group in silica particles.

The conversion of BTEX compounds by single and defined mixed cultures to medium-chain-length polyhydroxyalkanoate

Here, we report the use of petrochemical aromatic hydrocarbons as a feedstock for the biotechnological conversion into valuable biodegradable plastic polymers--polyhydroxyalkanoates (PHAs). We assessed the ability of the known Pseudomonas putida species that are able to utilize benzene, toluene, ethylbenzene, p-xylene (BTEX) compounds as a sole carbon and energy source for their ability to produce PHA from the single substrates. P. putida F1 is able to accumulate medium-chain-length (mcl) PHA when supplied with toluene, benzene, or ethylbenzene. P. putida mt-2 accumulates mcl-PHA when supplied with toluene or p-xylene. The highest level of PHA accumulated by cultures in shake flask was 26% cell dry weight for P. putida mt-2 supplied with p-xylene. A synthetic mixture of benzene, toluene, ethylbenzene, p-xylene, and styrene (BTEXS) which mimics the aromatic fraction of mixed plastic pyrolysis oil was supplied to a defined mixed culture of P. putida F1, mt-2, and CA-3 in the shake flasks and fermentation experiments. PHA was accumulated to 24% and to 36% of the cell dry weight of the shake flask and fermentation grown cultures respectively. In addition a three-fold higher cell density was achieved with the mixed culture grown in the bioreactor compared to shake flask experiments. A run in the 5-l fermentor resulted in the utilization of 59.6 g (67.5 ml) of the BTEXS mixture and the production of 6 g of mcl-PHA. The monomer composition of PHA accumulated by the mixed culture was the same as that accumulated by single strains supplied with single substrates with 3-hydroxydecanoic acid occurring as the predominant monomer. The purified polymer was partially crystalline with an average molecular weight of 86.9 kDa. It has a thermal degradation temperature of 350 degrees C and a glass transition temperature of -48.5 degrees C.

In situ polymerization: A novel route for thermally stable proton-conductive membranes

In this paper, a new solvent-free route for preparing proton-conductive membranes is proposed. Flexible and fiber-supported polymer electrolyte membranes, as potential proton exchange membranes, were readily obtained by in situ polymerization of a homogenous solution that consisted of bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO, polymer)–monomer mixtures of styrene (ST) and divinylbenzene (DVB), which was pre-cast onto SEFAR PETEX fibers. Factors such as the components of the casting solution and the sulfonation time, were fully investigated. The membrane structure and components were confirmed by FTIR-ATR spectra and SEM-EDXA images, and the thermal stability was examined via TGA and DrTGA. The membrane exhibited a proton conductivity of about 0.07 S/cm at 100% humidity and at room temperature, which is close to that of Nafion 117 at identical conditions (around 0.08 S/cm), whereas its thickness (about 120 μm) was less than that of Nafion 117. The tensile strength and the elongation at the break of the membrane were 31.2 MPa and 71%, respectively, which are several times higher than those of Nafion (about 6.16 MPa tensile strength and 36% elongation ratio). The dimensional change ratio of the membrane between the wet and dry states was below 3%, which is much lower than that of Nafion 117. The membrane showed a high thermal stability up to 400 °C. The method can be applied to other compatible systems of (aromatic) polymers and (aromatic) monomers.

Volumetric, ultrasonic, viscometric and refractive index behaviour of binary mixtures of styrene with ethylalcohol and chlorobenzene at different temperatures ( T = 298.15 K to 313.15 K)

This paper presents experimental data for densities, ρ, viscosities, η, ultrasonic speeds, u, and refractive indices, n, of pure styrene (STY), chlorobenzene (CB), ethylalcohol (EA) and of their binary liquid mixtures over the entire composition range at 298.15, 303.15, 308.15, 313.15 K. The uncertainties in density, ultrasonic speed, viscosity, and refractive index measurements are ± 0.0001 g cm − 3 , ± 0.15 m s − 1 , ± 0.003 mPa s, and ± 0.0002 units, respectively. From these experimental data, excess molar volume, deviations in isentropic compressibility, viscosity and in refractive index and internal pressure are calculated for all the binary mixtures, over the entire composition range. The apparent molar volume, V ϕ ,2, and apparent molar compressibility, K ϕ ,2, of CB and EA in styrene were also calculated. Partial molar volume, V− ϕ ,2 0, and partial molar compressibility, K− ϕ ,2 0, were estimated by using the values of V ϕ ,2 and K ϕ ,2 of CB and EA in styrene at infinite dilution. The excess and deviation functions were fitted to Redlich and Kister type polynomial equation. Moreover, theoretical predictions of refractive index of the two binary mixtures are made on the basis of empirical and semiemperical relations by using the experimental values of the pure components. The results provide information on the molecules in the pure liquids as well as in the binary mixtures.

Covalent attachment of microbial lipase onto microporous styrene–divinylbenzene copolymer by means of polyglutaraldehyde

A novel method for immobilization of Thermomyces lanuginosus lipase onto polyglutaraldehyde–activated poly(styrene–divinylbenzene) (STY–DVB), which is a hydrophobic microporous support has been successfully developed. The copolymer was prepared by the polymerization of the continuous phase of a high internal phase emulsion (polyHIPE). The concentrated emulsion consists of a mixture of styrene and divinylbenzene containing a suitable surfactant and an initiator as the continuous phase and water as the dispersed phase. Lipase from T. lanuginosus was immobilized covalently with 85% yield on the internal surface of the hydrophobic microporous poly(styrene–divinylbenzene) copolymer and used as a biocatalyst for the transesterification reaction. The immobilized enzyme has been fully active 30 days in storage and retained the activity during the 15 repeated batch reactions. The properties of free and immobilized lipase were studied. The effects of protein concentration, pH, temperature, and time on the immobilization, activity, and stability of the immobilized lipase were also studied. The newly synthesized microporous poly(styrene–divinylbenzene) copolymer constitutes excellent support for lipase. It given rise to high immobilization yield, retains enzymatic activity for 30 days, stable in structure and allows for the immobilization of large amount of protein (11.4 mg/g support). Since immobilization is simple yet effective, the newly immobilized lipase could be used in several application including oil hydrolysis, production of modified oils, biodiesel synthesis, and removal of fatty acids from oils.

Preparation of a carbon monolith with bimodal perfusion pores

We have initiated a method for the synthesis of a carbon monolith with trimodal porous structure of macro/macro/mesopores by nano-casting and phase separation. In this method, a silica monolith was employed as the hard template. A mixture of styrene and divinylbenzene, in the presence of initiator and porogenic reagent (dodecanol), was filled into the void of the silica monolith template. After the subsequent polymerization, carbonization and removal of the silica template, a carbon monolith with bimodal perfusion pores was successfully prepared. The primary perfusion pores were resulted from the dissolution of the silica template and the secondary perfusion pores were originated from the phase separation in the polymerization. In addition to macropores, mesopores also existed in the skeletons of the carbon monolith. Such structure of the carbon monolith has been characterized by scanning electron microscopy, mercury porosimetry and nitrogen sorption.

Synthesis and characterization of novel swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays

AbstractThe oligomeric poly(styrene‐acrylamide‐vinylbenzylchloride) (P(St‐AM‐VBC)) quaternary ammonium salts have been prepared from the reactions of trimethylamine with the corresponding P(St‐AM‐VBC)s, which were synthesized by free‐radical polymerization of a mixture of styrene, acrylamide, and vinylbenzylchloride. Then the swelling tunable oligomeric poly(styrene‐co‐acrylamide) modified clays have been prepared through cation exchange of the sodium ions in the clay with the corresponding P(St‐AM‐VBC) quaternary ammonium salts. The P(St‐AM‐VBC) and its modified clays have been characterized by infrared spectra (IR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), proton nuclear magnetic resonance (1H NMR), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The solvent‐swelling capacity of poly(styrene‐co‐acrylamide) modified clays have also been tested, and the experimental results have indicated that these clays are novel swelling tunable organic clays. XRD and TEM studies have shown that these novel swelling tunable clays are well‐intercalated or exfoliated. Furthermore, TGA analysis shows that these polymerically modified clays have high thermal stability for nanocomposites by melt blending. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Toluene and P-Xylene Mixture Exerts Antagonistic Effect on Lipid Peroxidation in vitro

Previous research on a group of workers occupationally exposed to styrene, ethylene glycol, toluene, p-xylene and their mixture showed elevated levels of the main products of lipid peroxidation: malondialdehyde and 4-hydroxynonenal (MDA+,4-HNE) in plasma [1]. Moreover, an earlier in vitro study indicated a synergistic interaction between styrene and ethylene glycol on lipid peroxidation [2]. Therefore, it seemed interesting to investigate the effect of combined exposure to toluene and p-xylene on lipid peroxidation and define the type of the interaction. An in vitro model of human placenta mitochondria was used in the study. The concentration of TBARS (thiobarbituric active reagent species) was measured by spectrophotometry, and of hydroxyl radical (.OH) by assessment of deoxyribose degradation. It was investigated whether the administration of coenzyme Q10 (CoQ10) could have a protective function (if given before solvent exposure) or a reparatory function (if given after exposure) in solvent-induced oxidative stress. Exposure to p-xylene at concentrations ranging from 5.3 to 265 microg/ml produced an increase in TBARS concentration. The results showed that p-xylene had a stronger influence on lipid peroxidation than toluene. The mixture of toluene and p-xylene induced an antagonistic effect on lipid peroxidation, measured as TBARS concentration. The mechanism connected with .OH generation was found to play an important role in the oxidative damage to lipids resulting from p-xylene exposure. Administration of coenzyme Q10 at the doses of 3.0 and 12.0 microg/ml successfully decreased the TBARS level that was elevated after solvent exposure. In contrast to the synergistic effect that the mixture of styrene and ethylene glycol had on lipid peroxidation (previous study), an antagonism between toluene and p-xylene could be observed. The coenzyme Q10 can be considered a protective agent against lipid peroxidation.

Intermolecular Interactions in Binary Liquid Mixtures of Styrene with m-, o-, or p-xylene

The densities (ρ), ultrasonic speeds (ν), and refractive indices ( n) of binary mixtures of styrene (STY) with m-, o-, or p-xylene, including those of their pure liquids, were measured over the entire composition range at the temperatures 298.15, 303.15, 308.15, and 313.15 K. The excess volumes ( V E), deviations in isentropic compressibilities (Δk s), acoustic impedances (ΔZ), and refractive indices (Δ n) were calculated from the experimental data. Partial molar volumes ( V 0 ϕ,2) and partial molar isentropic compressibilities ( K 0 ϕ,2) of xylenes in styrene have also been calculated. The derived functions, namely, V E, Δk s, ΔZ, Δn, V 0 ϕ,2, and K 0 ϕ,2 were used to have a better understanding of the intermolecular interactions occurring between the component molecules of the present liquid mixtures. The variations of these parameters suggest that the interactions between styrene and o-, m-, or p-xylene molecules follow the sequences: p-xylene> o-xylene> m-xylene. Apart from using density data for the calculation of VE, excess molar volumes were also estimated using refractive index data. Furthermore, several refractive index mixing rules have been used to estimate the refractive indices of the studied liquid mixtures theoretically. Overall, the computed and measured data were interpreted in terms of interactions between the mixing components.

Surface Chemical Analysis of Plasma‐Deposited Copolymer Films Prepared from Feed Gas Mixtures of Ethylene or Styrene with Allylamine

AbstractPlasma deposited ethylene/allylamine and styrene/allylamine copolymer films were prepared and analyzed using XPS, NEXAFS and ToF‐SIMS. The relative partial flow rate of the each monomer was used as the variable deposition parameter, while the other deposition parameters were kept constant at optimized values for the retention of functional groups. The effect of the variation in the relative partial flow rates of co‐monomers on various chemical aspects of the films like unsaturation, nitrogen retention and branching was investigated revealing several non‐linear correlations. This observation is taken as an indication for chemical copolymerization processes during film deposition. An attempt is made to compare these non‐linear correlations with approaches which have been developed for classic radical copolymerization processes. The aging behavior of these plasma copolymer films was also studied; the results indicated a stabilization against oxidation in comparison to the aging of allylamine plasma homopolymers.magnified image

Influence of epoxy resin on the morphological and rheological properties of PBT/ABS blends compatibilized by ASMA

AbstractPolybutylene terephthalate (PBT)/acrylonitrile–butadiene–styrene (ABS) copolymer blends compatibilized by a mixture of styrene–acrylonitrile–maleic anhydride (ASMA) copolymers and epoxy resin (EP) were prepared through melt reactive extrusion. The morphological, rheological, and mechanical properties of these blends were studied. The epoxy functional groups of EP can react with anhydride groups of ASMA and the PBT terminal groups (OH and COOH) simultaneously, leading to the formation of ASMA–EP–PBT graft copolymers. Because of the effective compatibilization of these copolymers at the interface, finer dispersed phase morphologies were obtained. Compared with PBT/ABS/ASMA blends, the addition of EP induced a more stable molten phase structure, with increases of storage moduli, loss moduli, and dynamic viscosities. Results indicated that 1.5 wt% of the EP in the blends was most suited for the compatibilization. Impact properties of these blends were also investigated. POLYM. ENG. SCI., 47:1943–1950, 2007. © 2007 Society of Plastics Engineers

SAN-b-P4VP Block Copolymer Synthesis by Chain Extension from RAFT-Functional Poly(4-vinylpyridine) in Solution and in Emulsion

Reversible addition fragmentation chain transfer (RAFT)-mediated polymerization was successfully applied for the synthesis of poly(4-vinylpyridine) (P4VP) polymers of predetermined molar mass and of low polydispersity index. These RAFT end-functionalized polymers were then used as macro-RAFT agents and further chain extended with an azeotropic mixture of styrene (STY) and acrylonitrile (AN) (63 mol % STY). Initially, these chain extension experiments were carried out in solution. In that case, the formation of the P4VP-b-SAN block copolymers clearly demonstrated the large fraction of chain end functionality in these RAFT-functional P4VP polymers. Proof of the formation of low molar mass P4VP-b-SAN block copolymer was obtained by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. Gradient polymer elution chromatographic (GPEC) analysis confirmed successful formation of P4VP-b-SAN block copolymers. Block copolymer synthesis in emulsion was also investigated. The polymerization mediated by a RAFT-functional P4VP, macro-RAFT agent, was carried out as a semicontinuous process. The complete transformation of the P4VP starting block into P4VP-b-SAN block copolymer points to an efficient control of the polymerization in emulsion. This procedure leads to the formation of a colloidally stable latex. The results of GPEC analysis confirmed the successful block copolymer latex formation.

Surface Chemical Analysis of Plasma‐Deposited Copolymer Films Prepared from Feed Gas Mixtures of Ethylene or Styrene with Allyl Alcohol

AbstractPlasma deposited styrene/allyl alcohol and ethylene/allyl alcohol copolymer films were prepared and characterized using XPS, NEXAFS and ToF‐SIMS. The relative partial flow rates of the co‐monomers are used as deposition process parameters to vary and all other process parameters were constrained to conditions optimized for retention of functional groups. By doing this it is possible to control certain chemical properties of the copolymer films such as unsaturation, oxygen and hydroxyl group relative surface contents. The aging behavior of the plasma copolymer films on air was studied, too. Non‐linear variations of relative oxygen contents, contents of COR species and contents of carbonyl species are obtained vs. variation of feed gas composition for both monomer combinations. The chemical character of the plasma copolymer films varies between the limits given by the respective plasma homopolymers. The observed non‐linear correlations are discussed in terms of approaches developed for classic radical copolymerization. The aging behavior of the different plasma copolymers films depends on the feed gas composition. Principally these aging phenomena known from plasma polymer aging studies of that respective monomer which dominates the character of the plasma copolymer are observed.magnified image

Carbon nanotube/polystyrene composite electrode for microchip electrophoretic determination of rutin and quercetin in Flos Sophorae Immaturus

In this report, carbon nanotube/polystyrene (CNT/PS) composite electrodes have been fabricated as sensitive amperometric detectors of microchip capillary electrophoresis (CE) for the determination of rutin and quercetin in Flos Sophorae Immaturus. The composite electrode was fabricated on the basis of the in situ polymerization of a mixture of CNT and styrene in the microchannel of a piece of fused silica capillary under heat. The surface morphologies of the composite in the electrodes were observed by using a scanning electron microscope. The performance of this unique system has been demonstrated by separating and detecting rutin and quercetin. The new CNT-based CE detector offered significantly lower detection potentials, yielded substantially enhanced signal-to-noise characteristics, and exhibited resistance to surface fouling and hence enhanced stability. It demonstrated long-term stability and reproducibility with a relative standard deviation of less than 5% for the peak current ( n = 20) and should also find a wide range of applications in conventional CE, flowing injection analysis, and other microfluidic analysis systems.

Living anionic polymerization of 2‐vinyldibenzothiophene: Homopolymer and block copolymers with styrene

Abstract2‐Vinyldibenzothiophene (2VDBT) was synthesized from the 2‐bromodibenzothiophene previously prepared. Then, anionic polymerization of 2‐vinyldibenzothiophene and its copolymerization with styrene were carried out under nitrogen atmosphere in benzene at 30 °C using n‐butyllithium as initiator. The anionic polymerization of 2VDBT showed a living character, since it fulfilled the criterion for the linearity of the plot of ln([M]0[M]) with time, together with the requirement that Mn must vary linearly with conversion. Narrow molecular weight distribution (MwMn < 1.1) and predictable molecular weight were obtained for homopolymerization of poly(2VDBT), taking into account the overestimation of experimental Mn(GPC) due to the possible higher hydrodynamic volume arising from the bulky dibenzothiophenyl group of poly(2VDBT) in comparison to the phenyl group of polystyrene. Also, sequential copolymerization by addition of 2VDBT and styrene yielded block copolymers showing narrow polydispersity (MwMn <1.08). The anionic polymerization of mixtures of 2VDBT and styrene was carried out and their relative reactivity ratios were estimated by applying both the Kélen–Tüdös and the Joshi–Joshi methods. The former yielded values of r2VDBT = 1.11 ± 0.77 and rSt = 0.49 ± 0.10, whereas the latter gave the values r2VDBT = 1.05 ± 0.05 and rSt = 0.50 ± 0.10 for the reactivity ratios. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1993–2003, 2007

Penicillin-bound polyacrylate nanoparticles: Restoring the activity of β-lactam antibiotics against MRSA

This report describes the preparation of antibacterially active emulsified polyacrylate nanoparticles in which a penicillin antibiotic is covalently conjugated onto the polymeric framework. These nanoparticles were prepared in water by emulsion polymerization of an acrylated penicillin analogue pre-dissolved in a 7:3 (w:w) mixture of butyl acrylate and styrene in the presence of sodium dodecyl sulfate (surfactant) and potassium persulfate (radical initiator). Dynamic light scattering analysis and atomic force microscopy images show that the emulsions contain nanoparticles of approximately 40 nm in diameter. The nanoparticles have equipotent in vitro antibacterial properties against methicillin-susceptible and methicillin-resistant forms of Staphylococcus aureus and indefinite stability toward β-lactamase.

Synthesis of polymer particles possessing radical initiating sites on the surface by emulsion copolymerization and construction of core–shell structures by a photoinduced atom transfer radical polymerization approach

AbstractThe crosslinked polystyrene particles possessing photofunctional N,N‐diethyldithiocarbamate groups on their surface were prepared by free‐radical emulsion copolymerization of a mixture of styrene, divinylbenzene and 4‐vinylbenzyl N,N‐diethyldithiocarbamate with redox system as an initiator under UV irradiation. In this copolymerization, the inimer 4‐vinylbenzyl N,N‐diethyldithiocarbamate acted the formation of hyperbranched structures by living radical photopolymerization. The particle sizes (number‐average particle diameter = 214–523 nm) were controlled by varying the feed amount of surfactant and size distributions were relatively narrow. Subsequently, core–shell particles were synthesized by photoinduced atom transfer radical polymerization approach of methyl methacrylate initiated by photofunctional polystyrene particles as a macroinitiator. Such core–shell particles were stabilized sterically by grafted chains in organic solvents. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1771–1777, 2007

SBS/Pani · DBSA mixture plasticized with DOP and NCLS – Effect of the plasticizers on the probability density of volume resistivity measurements

Plasticized mixtures of styrene–butadiene–styrene block copolymer (SBS) and Polyaniline (Pani) were prepared in a Haake internal mixer. Two different plasticizers were used: dioctyl phthalate (DOP) and cashew nut shell liquid (CNSL). Pani and plasticizers were characterized by FTIR and the resistive behavior of plasticized mixtures was investigated along the electrification time. It is shown that obtained experimental data are subject to deterministic dynamic fluctuations that cannot be described by single normal probability distribution functions (PDF) along the time. The PDF analysis shows that obtained PDFs must be described as sums of at least three distinct Gaussian distributions with different areas. It is also shown that the Gaussian component with larger area may provide better representation of the measured volume resistivity values.