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Molecularly Imprinted and Ion Imprinted Polymers for Selective Recognition and Sensing of Organics and Ions
Published in Asit Baran Samui, Smart Polymers, 2022
Pankaj E. Hande, Asit Baran Samui
Several preparation methods have been reported for the development of MIPs/IIPs, such as bulk polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, and precipitation polymerization. In bulk polymerization, the initiator, a template-monomer, and a cross-linker are added together in one phase where the initiator is completely soluble in the template-monomer and cross-linker. Suspension polymerization is a heterogeneous radical polymerization where the template, monomer, cross-linker, and initiator are soluble in each other and mixed together by high-speed mechanical stirring in a liquid phase such as water to get polymeric beads. In emulsion polymerization, the template, monomer, and cross-linker are polymerized using an oil-in-water emulsion in the presence of a surfactant where the initiator is water-soluble. Precipitation polymerization is the type of radical polymerization where the template, monomer, cross-linker, and initiator are dissolved in a solvent but during the process of reaction (polymerization), precipitation takes place.
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Published in Joseph C. Salamone, Polymeric Materials Encyclopedia, 2020
Precipitation polymerization may be defined as a polymerization that starts as a homogeneous solution of monomer and initiator in a solvent that is a precipitant for the polymer formed. In certain cases, such as vinyl chloride or acrylonitrile, the monomer itself is a precipitant for its own polymer so that precipitation polymerization can take place in bulk. Precipitation polymerization is distinct from the closely related dispersion polymerization process in that no steric or electrostatic stabilizers are present, and there is therefore the potential to produce polymers uncontaminated by any residual stabilizer or surfactant.
Ionic Chain-Reaction and Complex Coordination Polymerization (Addition Polymerization)
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Precipitation polymerization, also called slurry polymerization, is a variety of solution polymerization where the monomer is soluble but the polymer precipitates as a fine flock. The formation of olefin polymers via coordination polymerization occurs by a slurry process. Here, the catalyst is prepared and polymerization is carried out under pressure and at low temperatures, generally less than 100°C. The polymer forms viscous slurries. Care is taken so that the polymer does not cake up on the sides and stirrer.
Microwave-assisted synthesis of magnetic Pb(II)-imprinted-poly(schiff base-co-MAA) for selective recognition and extraction of Pb(II) from industrial wastewater
Published in Journal of Dispersion Science and Technology, 2023
Junde Xing, Na Li, Yukun Liang, Fang Zhu
In recent years, microwave-assisted (MA), as an auxiliary method,[23] has attracted more attention. Microwave-assisted can make the reactants directly absorb microwave.[24,25] It can also affect the thermal reaction by changing the activation energy, so that it can be heated quickly and evenly.[26,27] The main merit of microwave-assisted approach is to synthesize expected materials simply and effectively, which makes the imprinted polymers more stable and uniform. Liang et al.[28] prepared a 4-nitrophenol molecularly imprinted sorbent by surface imprinting technology under microwave irradiation. The adsorption capacity could reach 134.23 mg·g−1. Mustafai et al.[29] prepared a As(III)-imprinted sorbent by precipitation polymerization under microwave irradiation. The time consumed by traditional method was about 10 times that of microwave. The detection limit and quantitative limit of arsenic ions were 1.0 and 3.3 μg·L−1, respectively. Xu et al.[30] proposed a microwave-assisted method to prepare molecularly imprinted polymer fibers in batches. The detection limits and the relative recoveries of bisphenol A were 2.0 ng·mL−1 and 82.5% ∼103.8%, respectively.
Swelling of composite microgels with soft cores and thermo-responsive shells
Published in Mechanics of Advanced Materials and Structures, 2022
Aleksey D. Drozdov, Jesper deClaville Christiansen
Structure of polymer networks and distribution of chains in core-shell microgels were investigated experimentally in Refs. [72–76], to mention a few. These studies reveal that the inhomogeneity in distribution of polymer chains observed in the actual (swollen) state of a composite microgel is induced by two factors: (i) conditions of precipitation polymerization for a shell growing on a soft core particle, and (ii) the so-called “corset-effect” [77, 78] caused by interactions between the core and the shell with different mechanical and swelling properties. Bearing in mind that the influence of the former factor requires further clarification (observations show, e.g., that batch and continuous precipitation polymerization methods under identical conditions result in different network structures of microgels [79]), we disregard its effect in the present study (a simple way to account for the non-uniformity of the reference state was suggested in Ref. [52]) and focus on the analysis of inhomogeneities driven by core-shell interactions in microgels.
Expanded graphene oxide-supported molecularly imprinted polymer nanoparticles based on polystyrene for dibenzothiophene removal
Published in Journal of Sulfur Chemistry, 2019
Mohammad Saleh Vosoughi, Mahshid Fallah-Darrehchi, Payam Zahedi
The first step through the MIP synthesis is the formation of a complex between template and functional monomer. Five different molar ratios of template to monomer [DBT: styrene (mmol)] were selected as follows: 1:2 (MIP2), 1:4 (MIP4), 1:6 (MIP6), 1:8 (MIP8), and 1:10 (MIP10). In this line, the amounts of the other components were kept constant including EGO/MPS ratio of 0.1 g/mL, and EGDMA of 16 mmol. The predetermined amounts of DBT were added to 25 mL of acetonitrile in separate within glass bottles, and sonicated in order to reach well-dispersed solutions containing the template, and porogenic solvent in an ice-water bath. After 6–8 h, predetermined amounts of EGDMA, AIBN, and MPS-functionalized EGO were added to the mixture. For initializing the polymerization process, first the atmosphere of polymerization medium was replaced with nitrogen gas completely for all bottles. Then they were inserted in an oil bath at the temperature of 65°C for 48 h. The precipitation polymerization of styrene monomer was completed, and the final solutions were centrifuged at the speed of 8000 rpm for 10 min. The deposited polymers were dried in a vacuum chamber at the temperature of 30°C overnight.