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Some statistical copolymers of styrene and methyl vinyl ketone, prepared by free radical copolymerization, have been photolyzed in benzene solution using u.v. light of wavelength 300 or 350nm. It is confirmed by n.m.r. spectroscopy that the oligomeric products so obtained have unsaturated end-groups with structures resembling that of α-methyl styrene, as would be expected on the basis of a predominantly...
A water-insoluble dye was used to probe the particle nucleation loci in the semibatch emulsion polymerization of styrene (ST). Most of the dye molecules are present in the monomer droplets and some of them are solubilized in the monomer-swollen micelles. The extremely hydrophobic dye molecules cannot diffuse from the monomer droplets and micelles to the growing latex particles. Thus, determination...
A technique is described for the synthesis of polystyrene-block-poly(vinylidene fluoride)-block-polystyrene (St-VDF-St) triblock copolymers through a poly(vinylidene fluoride) macroinitiator. The bromine terminated poly(vinylidene fluoride), which was prepared by radical telomerization of vinylidene fluoride with 1,2-dibromotetrafluoroethane, initiated polymerization of styrene in presence of copper(I)...
Epoxystyrene (ethenylphenyloxirane) has been synthesised in a single-stage process by mono-epoxidation of divinylbenzene using magnesium monoperoxyphthalic acid. Copolymers of epoxystyrene and styrene were then synthesised by living free radical polymerisation and atom transfer radical polymerisation methods. In both cases the oxirane group of epoxystyrene was found to be stable under the conditions...
The atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate with differently substituted model and macroinitiators was performed, in order to evaluate qualitatively the structural features which affect the efficiency of the initiation step. It was found that substituents which stabilize radicals enhance the dissociation of the halogen atom and lead to high initiation efficiencies...
The effects of various reaction parameters on the styrene miniemulsion polymerizations stabilized by nonylphenol polyethoxylate with an average of 40 ethylene oxide units per molecule (NP-40) and dodecyl methacrylate (DMA) at 80 o C were investigated. These parameters include the concentrations of DMA ([DMA]), NP-40 ([NP-40]), sodium persulfate ([SPS]), and 2,2'-azobisisobutyronitrile ([AIBN])...
Macromonomer with styrenic polymerizable group was synthetized by anionic polymerization of ethylene oxide initiated by a mixture of potassium p- and m-vinylbenzyl alcoholate. The corresponding alcohol was prepared by modified two-step method described by Bamford et al. (Polymer 1973;14:330) using vinylbenzyl chloride as a starting material. Emulsion polymerization of styrene was carried out in the...
Styrene is frequently used as comonomer for unsaturated polyester (UP) resins. Variations in the styrene content in the polyester affect the resulting properties. Dynamic mechanical tests show the phase separation in the cured resin with an increase of styrene concentration. The dependence of the glass transition temperature of the UP resin on the styrene content is complex and reflects a balance...
The ceiling temperature constraint encountered in the homopolymerization of alphamethylstyrene, AMS, can be circumvented by copolymerization with acrylonitrile to prepare multicomponent random microstructures that offer higher heat resistance than SAN. The feasibility of a thermal initiation of free radical chain polymerization is evaluated by the study of the terpolymerization kinetics of AMS-AN-Styrene...
In this study, a relatively novel macromonomer having a relatively shorter chain length, poly(ethylene glycol) ethyl ether methacrylate (PEG-EEM) was used to increase the stability of styrene-water emulsion. The uniform latex particles in the range of 0.4-1.2μm were prepared by the emulsion copolymerization of styrene (S) and PEG-EEM. The copolymerizations were achieved by using potassium persulphate...
The polymerisation of styrene was studied using Cu(I)/Cu(II)-based atom transfer radical polymerisation catalysts in conjunction with a variety of N-alkyl-2-pyridinemethanimines as complex ligands. Increasing the length of alkyl chain on the ligand from propyl to octyl resulted in a catalyst complex with improved solubility in xylene, and enabled the production of polymers of narrower molecular weight...
Copolymers of tribromostyrene (TBS) with styrene (S) and methyl methacrylate (MMA) were synthesized. The miscibility regions for blends of STBS copolymers with the homopolymers polystyrene (PS), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), tetramethyl bisphenol A polycarbonate (TMPC), as well as blends of MMA–TBS copolymers with poly(methyl methacrylate) (PMMA) were determined. Blends of MMA–TBS...
Polymerization of styrene occurs at ambient temperature in the presence of H(OCH2CH2)nO−, K+, where n=1–5. The reaction rate and molecular weight of polymer can be controlled by the number of ether oxygen atoms in the initiator molecule. These dependencies are related to the presence of aggregates of alkoxide molecules and to the formation of associates of oligo(ethylene oxide) chains with potassium...
The copolymerization behaviour of 2-methylene-1,3-dioxepane (MDO) with styrene has been studied via pulsed-laser polymerization. The average propagation rate coefficients, 〈kp〉,were determined for a number of feed ratios of MDO ranging from 0 to 0.938 at both 30 and 40°C. Both the 〈kp〉 and the polymer composition data indicate a complete absence of copolymerization — contrary to a previously published...
The elemental distribution in latex particles during the ab-initio and seeded emulsion polymerization of styrene was studied by electron spectroscopy imaging, in an analytical transmission electron microscope. Surface anchoring effect, chain migration and the extent of burying of the sulfate groups from the initiator were investigated by comparing the distributions of the different elements.
Phase behavior of supercritical CO2/styrene/poly (ethylene terephthlate) (PET) system was determined at 35°C and different pressures. The concentration of styrene in the fluid phase ranged from 0 to 1.3mol/l. Styrene partitioned between the fluid phase and PET films, and significant amount of styrene was absorbed into PET matrix. When the styrene contained 0.3mol% initiator azobis (isobutyronitrile)...
The effects of a small amount of carboxylic monomers (AA and MAA) on the styrene miniemulsion polymerizations stabilized by SDS/DMA or SDS/SMA are studied. A mixed mode of particle nucleation (monomer droplet nucleation and homogeneous nucleation) is operative during polymerization. Formation of particle nuclei in the aqueous phase predominates in the SDS/SMA stabilized polymerization in the absence...
Polystyrene (PSt)/polytetrahydrofuran (PTHF) A2B2 miktoarm star copolymers were prepared by transformation of cationic ring-opening polymerization (CROP) to atom transfer radical polymerization (ATRP). The synthetic approach involves the synthesis of PTHF with two secondary bromine groups in the center of a macromolecular chain, (PTHF)2Br2, by the CROP of THF with the symmetric tetrafunctional initiator...
Batch emulsion polymerization of styrene initiated by an oil-soluble initiator and stabilized by non-ionic emulsifier (Tween 20) has been investigated. The rate of polymerization vs. conversion curve shows the two non-stationary rate intervals typical for the non-stationary-state polymerization. This behavior is a result of the continuous particle nucleation and the decrease of monomer concentration...
Reverse atom transfer radical polymerization (ATRP) of styrene initiated with tetraethylthiuram disulfide (TD)/cuprous bromide (CuBr)/2,2'-bipyridine (bpy) has been successfully carried out at 120 o C. The kinetic plot was first order in monomer. The measured number-average molecular weight was in good accordance with the theoretical one. Radical scavenger 1,1-diphenyl-2-picrylhydrazyl (DPPH)...
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