Preparation, structure and morphology of polymer supports

Sherrington, David C.

doi:10.1039/a803757d

Cited by 530 publications

(483 citation statements)

References 32 publications

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“…After that, the copolymer beads were filtered and washed with dilute HCl solution and sufficient quantity of hot water and extracted with acetone, dried at 150°C and sieved. Then, they were washed first with acetone and finally with pure methanol (Ghaderi et al 2006;Sherrington 1998). …”

Section: Synthesis Of Polystyrene Divinylbenzene Copolymer Beadsmentioning

confidence: 99%

Cation exchange resin nanocomposites based on multi-walled carbon nanotubes

et al. 2012

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Carbon nanotubes (CNTs) are of great interest due to their potential applications in different fields such as water treatment and desalination. The increasing exploitation of multi-walled carbon nanotubes (MWCNTs) into many industrial processes has raised considerable concerns for environmental applications. The interactions of soluble salt with MWNCTs influence in the total salt content in saline water. In this work, we synthesized two cation exchange resins nano composites from polystyrene divinylbenzene copolymer (PSDVB) and pristine MWNCTs. The prepared compounds were characterized using infra red spectroscopy, thermal stability, X-ray diffraction, and electro scan microscope. Also, the ion capacities of prepared cation exchange resins were determined by titration. Based on the experimental results, it was found that the thermal stability of prepared nanocomposites in the presence of MWNCTs increased up to 617°C. The X-ray of PSDVB and its sulfonated form exhibits amorphous pattern texture structure, whereas the nano composite exhibits amorphous structure with indication peak at 20°and 26°for the PSDVB and MWCNTs, respectively. The ion-exchange capacity increased from 225.6 meq/100 g to 466 mg/100 g for sulfonated PSDVB and sulfonated PSDVB MWNCTs-pristine, respectively.

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Section: Synthesis Of Polystyrene Divinylbenzene Copolymer Beadsmentioning

confidence: 99%

Cation exchange resin nanocomposites based on multi-walled carbon nanotubes

et al. 2012

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“…Thus, the length of the topological loops defined by super-crosslinks defines the pore sizes and heterogeneity in the bulk material while the rigidity prevents the polymeric network collapse. Obviously, this is related with the utilization of highly cross-linked P(S-DVB) resins as catalyst, [13][14][15][16][17][18][19] since the rigid pores defined by super-crosslinks ensure high surface areas. Accordingly, the existence of super-crosslinks affects the distribution of the sulfonic groups (see below) and facilitates the swelling and the accessibility to the active sites.…”

Section: Structural Propertiesmentioning

confidence: 99%

“…11,12 In addition, the utilization of P(S-DVB) resins as catalyst in a number of industrial processes is also quite important, as they offer potentially much higher capacity for the supported functionality than the conventional inorganic carriers. [13][14][15][16][17][18][19] Thus, many key large-scale chemical processes have been established employing sulfonic acid resins as catalyst. These include the manufacture of bisphenol A, isopropyl alcohol, alkylated phenols, branched ethers (petrol organic 'anti-knocks') such as methyl tert-butyl ether (MTBE), and a variety of alkyl esters including important (meth)acrylate esters.…”

Section: Introductionmentioning

confidence: 99%

Atomistic simulations of the structure of highly crosslinked sulfonated poly(styrene-co-divinylbenzene) ion exchange resins

et al. 2015

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The microscopic structure of highly crosslinked sulfonated poly(styrene-codivinylbenze) resins have been modeled by generating atomistic microstructures using stochastic-like algorithms that are , subsequently, relaxed using molecular dynamics.Two different generation algorithms have been tested. Relaxation of the microstructures generated by the first algorithm, which is based on a homogeneous construction of the resin, leads to a significant overestimation of the experimental density as well as to an unsatisfactory description of the porosity. In contrast, the generation approach that combines algorithms for the heterogeneous growing and branching of the chains enables the formation of crosslinks with different topologies. In particular, the intrinsic heterogeneity observed in these resins is well reproduced when topological loops, which are defined by two or more crosslinks closing a cycle, are present in their microscopic description. Thus, the apparent density, porosity and pore volume estimated using microstructures with these topological loops, called super-crosslinks, are in very good agreement with experimental measures. Although the backbone dihedral angle distribution of the generated and relaxed models is not influenced by the topology, the number and type of crosslinks affect the medium-and long-range atomic disposition of the backbone atoms and the distribution of the sulfonic groups. Analysis of the distribution of the local density indicates that super-crosslinks are responsible of the heterogeneous homogenization observed during the MD relaxation. Finally, - stacking interactions between aromatic phenyl groups have been analyzed, those in which the two rings adopt a T-shaped disposition being considerably more abundant than those with the rings co-facially oriented, independently of the resin topology.3

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“…When the dispersed phase consists only of monomer(s), crosslinker and polymerisation initiator, the produced particles are hard glassy transparent beads with very low surface area in the dry state of less than 10 m 2 g -1 (Sherrington, 1998). These polymeric particles swell in a thermodynamically good solvent and create a porous internal structure which is temporarily and disappears when the swollen particles are re-dispersed in a bad solvent.…”

Section: A Permanently Porous Particles Prepared Using Porogenic Solmentioning

confidence: 99%

“…In this process, polymer chains are initially fully soluble in the dispersed phase, but at a certain polymer concentration phase separation occurs and the reaction mixture separates into a polymer-rich phase and a porogen-rich phase (Figure 16a). Removal of the porogen from phase-separated particles yields porous beads whose total pore volume depends on the amount of porogen added in the dispersed phase (Sherrington, 1998). The point at which phase separation occurs depends on the nature of porogen, its compatibility with the polymer network and the concentration at which it is used.…”

Section: A Permanently Porous Particles Prepared Using Porogenic Solmentioning

confidence: 99%

Structured microparticles with tailored properties produced by membrane emulsification

Vladisavljević

2015

Advances in Colloid and Interface Science

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This paper provides an overview of membrane emulsification routes for fabrication of structured microparticles with tailored properties for specific applications. Direct (bottom-up) and premix (top-down) membrane emulsification processes are discussed including operational, formulation and membrane factors that control the droplet size and droplet generation regimes. A special emphasis was put on different methods of controlled shear generation on membrane surface, such as cross flow on the membrane surface, swirl flow, forward and backward flow pulsations in the continuous phase and membrane oscillations and rotations. Droplets produced by membrane emulsification can be used for synthesis of particles with versatile morphology (solid and hollow, matrix and core/shell, spherical and non-spherical, porous and coherent, composite and homogeneous), which can be surface functionalised and coated or loaded with macromolecules, nanoparticles, quantum dots, drugs, phase change materials and high molecular weight gases to achieve controlled/targeted drug release and impart special optical, chemical, electrical, acoustic, thermal and magnetic properties. The template emulsions including metal-in-oil, solid-in-oil-in-water, oil-in-oil, multilayer, and Pickering emulsions can be produced with high encapsulation efficiency of encapsulated materials and narrow size distribution and transformed into structured particles using a variety of different processes, such as polymerisation (suspension, mini-emulsion, interfacial and in-situ), ionic gelation, chemical crosslinking, melt solidification, internal phase separation, layer-by-layer electrostatic deposition, particle self-assembly, complex coacervation, spray drying, sol-gel processing, and molecular imprinting. Particles fabricated from droplets produced by membrane emulsification include nanoclusters, colloidosomes, carbon aerogel particles, nanoshells, polymeric (molecularly imprinted, hypercrosslinked, Janus and core/shell) particles, solder metal powders and inorganic particles. Membrane 2 emulsification devices operate under constant temperature due to low shear rates on the membrane surface, which range from (1−10) × 10 3 s −1 in a direct process to (1−10) × 10 4 s −1 in a premix process.Keywords: Membrane Emulsification; Polymeric microsphere; Microgel; Janus Particle; Core/Shell Particle, Colloidosome. Membrane emulsificationMembrane emulsification (ME) involves preparation of emulsions by pressing a pure dispersed phase or pre-emulsified mixture of the dispersed and continuous phase through a microporous membrane under controlled injection rate and shear conditions. In direct membrane emulsification (DME), one liquid (a dispersed phase) is injected through a microporous membrane into another immiscible liquid (the continuous phase) (Nakashima et al., 1991;, which leads to the formation of droplets at the membrane/continuous phase interface ( Figure 1a). In premix membrane emulsification (PME) (Figure 1b), a pre-emulsion is pressed through the membrane (...

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Preparation, structure and morphology of polymer supports

Cited by 530 publications

References 32 publications

Cation exchange resin nanocomposites based on multi-walled carbon nanotubes

Cation exchange resin nanocomposites based on multi-walled carbon nanotubes

Atomistic simulations of the structure of highly crosslinked sulfonated poly(styrene-co-divinylbenzene) ion exchange resins

Structured microparticles with tailored properties produced by membrane emulsification

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