Search results for "Styrene"
showing 10 items of 561 documents
Enhanced styrene removal in a two-phase partitioning bioreactor operated as a biotrickling filter: Towards full-scale applications
2017
Abstract Styrene vapor abatement was investigated in a two-phase partitioning bioreactor operated as a biotrickling filter (TPPB-BTF). The removal performance of the TPPB-BTF was simultaneously compared with a conventional BTF, which served as a control. Industrial-grade silicone oil was used as the non-aqueous phase in the TPPB-BTF due to its high affinity for styrene. Both bioreactors were operated at styrene inlet concentrations ranging from 55 to 323 mg C m −3 and empty bed residence times (EBRT) of 15–30 s, corresponding to pollutant loading rates of 13–77 g C m −3 h −1 . Both bioreactors exhibited styrene removal efficiencies (REs) higher than 90% at an EBRT of 30 s. Nevertheless, th…
Ionomers in solution: 1. Viscometric and chromatographic studies in cononsolvent and cosolvent mixtures
1997
Abstract The viscosity and elution behaviour of polystyrene sulfonate ionomers with varying ionic content has been studied in the pure solvents chloroform (CHL), tetrahydrofuran (THF), dioxan (DIO), ethyl acetate (EA) and dimethylformamide (DMF) as well as in their cononsolvent mixtures CHL/THF (50:50), DIO/CHL (75:25) and in the cosolvent mixture EA/DMF (50:50). In the pure solvents with low dielectric constant the reduced viscosities of ionomers are lower at low concentrations and higher at moderate ones than the respective viscosities of the polystyrene precursor. These results can be explained by formation of intramolecular and intermolecular associations. Moreover, differences in visco…
Reversed-phase high-performance liquid chromatography of proteins and polypeptides on polystyrene-coated silica supports
1990
Abstract A new type of hydrolytically stable reversed-phase packing material prepared by multi-point covalent binding of polystyrene chains onto the surface of porous silica was examined in the high-performance liquid chromatography of proteins and polypeptides. Whereas wide-pore material was shown to give a rapid and efficient resolution of proteins, packings with smaller pores provided better selectivities for peptides.
Influence of oscillating main flow on separation efficiency in asymmetrical flow field-flow fractionation.
2021
The steadily rising interest in the investigation of interactions between nanomaterials and biological media has also led to an increasing interest in asymmetrical flow field-flow fractionation (AF-FFF). The biggest strength of AF-FFF is the possibility to alter the flow profiles to suit a specific separation problem. In this paper, the influence of an oscillating main flow on the separation efficiency of AF-FFF is investigated. Such oscillations can e.g. be caused by the main pump To investigate the influence of such flow conditions on the separation efficiency in AF-FFF systematically, different oscillation profiles were applied and their influence on the elution profile and the retention…
Modelling the influence of nanoparticles in the phase behaviour of an epoxy/polystyrene mixture
2007
Abstract The cloud point temperatures of four series of epoxy/polystyrene blends have been experimentally determined as a function of polymer mass and system composition. The phase diagrams show an UCST behaviour, increasing incompatibility as the molar mass increases. The Flory–Huggins theory with a concentration-dependent interaction parameter has been developed to study the compatibility of two polymers in presence of spherical nanoparticles. This theory has been first compared with the experimental cloud point curve in absence of nanoparticles, and secondly it has been used to predict the thermodynamic behaviour in presence of different volume fraction of nanoparticles. Nanoparticles co…
Enhanced structural correlations accelerate diffusion in charge-stabilized colloidal suspensions
1999
Theoretical calculations for colloidal charge-stabilized and hard sphere suspensions show that hydrodynamic interactions yield a qualitatively different particle concentration dependence of the short-time self-diffusion coefficient. The effect, however, is numerically small and hardly accessible by conventional light scattering experiments. Applying multiple-scattering decorrelation equipment and a careful data analysis we show that the theoretical prediction for charged particles is in agreement with our experimental results from aqueous polystyrene latex suspensions.
Reptation and constraint release
1991
Abstract The reptation and constraint release models are discussed by considering three recent experimental examples: (1) the diffusion of hydrogenated polybutadiene in matrices of molecular weights raning between 1 ⩽ Mw / Me ⩽ 253; (2) the diffusion of polystyrene (PS) chains in matrices of star branched PS; (3) the diffusion of very long PS chains in chemically cross-linked PS-networks. It is concluded that the reptation and constraint release models are applicable, but ‘constraint release’ should be understood in a wider sense allowing for non-reptative removal of barriers to lateral chain motion. The analysis of the third example proves that lateral modes of motion have a negligible inf…
Evolution of the “knitting pattern” morphology in ABC triblock copolymers
1996
A new morphology of ternary ABC triblock copolymers is presented which results from the asymmetric interaction between a centre block (poly(ethylene-co-butene)) to different end blocks (polystyrene and poly(methyl methacrylate)). This morphology with the appearance of a “knitting pattern” can be described as an intermediate of a morphology of A, B and C lamellae and a morphology of A and C lamellae with B cylinders at the A/C interface.
Enantio- and Diastereocontrol in Intermolecular Cyclopropanation Reaction of Styrene Catalyzed by Dirhodium(II) Complexes with Bulky ortho-Metalated …
2006
Enantiomerically pure dirhodium(II) complexes with ortho-metalated para-substituted aryl phosphines have been shown to lead to an enantio- and diastereoselective cyclopropanation of styrene with ethyl diazoacetate. Enantioselectivities up to 91% and diastereoselectivities up to 90% are observed for ethyl cis-2-phenylcyclopropanecarboxylate. High enantio- and diastereoselectivities are observed for the synthesis of ethyl cis-2-phenylcyclopropanecarboxylate using water as solvent. Additionally, a (+)-nonlinear effect, (+)-NLE, has been observed and studied in the asymmetric catalytic reaction developed in n-pentane.
Bimetallic complexes with ruthenium and tantalocene moieties: Synthesis and use in a catalytic cyclopropanation reaction
2006
Abstract The reaction of the tantalocene dichloride monophosphines ( 1 – 2 ) with the binuclear complex [( p -cymene)RuCl 2 ] 2 gives the heterobimetallic compounds ( p -cymene)[(η 5 -C 5 H 5 )(μ-η 5 :η 1 -C 5 H 4 (CH 2 ) 2 PR 2 )TaCl 2 ]RuCl 2 ( 3 – 4 ). The air oxidation of these bimetallic species 3 – 4 , leads to the cationic hydroxo tantalum ruthenium derivatives 5 – 6 . The last ones are easily deprotonated by a base to afford the oxo analogues 7 – 8 . A preliminary assessment in catalytic cyclopropanation of styrene with tantalum ruthenium bimetallic complexes 3 – 8 as precatalysts revealed a cooperative effect with a subtle role of the early metal fragment.