Redoxgraft polymerization of vinylic monomers on ozone-activated poly(styrene-divinylbenzene) microspheres of narrow size distribution

Abstract

Uniform micrometer-sized polystyrene/poly(styrene-divinylbenzene) composite particles were produced by a single-step swelling of polystyrene template microspheres with styrene, divinylbenzene and benzoyl peroxide, followed by polymerization of the monomers within the swollen particles at 70 1C. Uniform crosslinked poly(styrene-divinylbenzene) microspheres of high surface area were then produced by dissolution of the polystyrene template part of the former composite particles. Hydroperoxide-conjugated microspheres were produced by ozonolysis of the crosslinked poly(styrene-divinylbenzene) particles. Redox graft polymerization of acrylonitrile and chloromethylstyrene on the hydroperoxide-conjugated particles was then accomplished. The influence of various polymerization parameters on the grafting yield was elucidated. Uniform polyaldehyde microspheres were produced from the former particles in two ways: (1) LiAlH 4 reduction of the nitrile groups of the polyacrylonitrile-grafted particles, followed by reaction of the formed primary amino groups with glutaraldehyde; (2) Sommelet reaction on the polychloromethylstyrene-grafted particles. Trypsin was then covalently bound to the polyaldehyde-grafted microspheres. A comparison between the enzymatic activity of the conjugated and free trypsin was accomplished.

Au-Coated Polystyrene Nanoparticles with High-Aspect-Ratio Nanocorrugations via Surface-Carboxylation-Shielded Anisotropic Etching for Significant SERS Signal Enhancement

“…The above findings can be further verified by the HRXPS chemical shift spectra of C 1s in Figure to reveal the transformation of chemical structures before and after oxygen plasma treatment. In Figure a, the XPS spectrum presents that nontreated PSBs merely contain C–C groups (284.5 eV), C–H groups (284.1 eV), and π–π* shakeup satellites of the benzene ring (291.6 eV), in agreement with the chemical structure of polystyrene. , Nevertheless, after oxygen plasma treatment, C–O groups (286.2 eV), CO groups (287.6 eV), and O–CO groups (289.0 eV), appear in the XPS spectrum in Figure b, representing alcohol/ether, carbonyl, and carboxyl/ester groups, respectively. , This result provides further evidence that the nanostructures formed are highly related to the carboxyl groups on the surface. To oxidize polystyrene or other polymers to form carbonyl and carboxyl surface groups, the use of either UV, ozone, oxygen plasma, or acidic solution has also been reported in previous studies; ,, however, the treatment of polystyrene with argon plasma can only etch the surface without functionalization of the polymer, in concurrence with our finding.…”

“…In Figure 2a, the XPS spectrum presents that nontreated PSBs merely contain CÀC groups (284.5 eV), CÀH groups (284.1 eV), and πÀπ* shakeup satellites of the benzene ring (291.6 eV), in agreement with the chemical structure of polystyrene. 48,50 Nevertheless, after oxygen plasma treatment, CÀO groups (286.2 eV), CdO groups (287.6 eV), and OÀ CdO groups (289.0 eV), appear in the XPS spectrum in Figure 2b, representing alcohol/ether, carbonyl, and carboxyl/ester groups, respectively. 48,50 This result provides further evidence that the nanostructures formed are highly related to the carboxyl groups on the surface.…”

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

“…Since emulsion prepared seeds are generally in the submicron range, they are suitable for obtaining particles up to 10 µm in diameter after the suspension polymerization stage [68][69]. On the other hand, dispersion polymerized seeds can be in the range of 1-20 µm, thus 10-200 µm particles can be obtained in the suspension polymerization stage [70][71][72][73][74][75][76][77][78][79]. Note that a volume enlargement of 10 6 times would be needed for a 1 µm seed to be swollen by the new monomer(s) to 100 µm.…”

“…A slope instead of a plateau for the second zone of the curves indicates low mechanical strength [13,293]. In addition, combination of TGA and DSC is also proposed as a method of mechanical strength measurement [72][73]. These methods are suitable for particles of any shape, size and size distribution.…”

Synthesis and characterization of magnetic and non-magnetic core–shell polyepoxide micrometer-sized particles of narrow size distribution

“…Furthermore, uniform particles of a diameter larger than 5 μm usually cannot be prepared by dispersion polymerization. These limitations have been overcome by several swelling methods of micrometer-sized PS particles with appropriate hydrophobic monomers and initiators, e.g., multi-step swelling, dynamic swelling [30,31] and a single-step swelling [32][33][34][35], followed by polymerization of the monomers within the swollen particles. Functionalization of these particles was performed by polymerization, via surface produced oligoradicals, of appropriate hydrophilic monomers, e.g., acrylic acid sodium salt, dissolved in the aqueous continuous phase.…”