Polystyrene Composite Microspheres Research Articles

Preparation and microwave absorption properties of flexible composites containing Ag decorated polystyrene powders

Polystyrene (PS) microspheres have the advantages of good stability, corrosion resistance and low density, which have a broad application prospect. In this paper, PS composite microspheres with 20% silver plating content were prepared by chemical plating method and incorporated into polydimethylsiloxane (PDMS) flexible matrix to prepare Ag@PS/PDMS flexible wave-absorbing materials. The electromagnetic parameters were adjusted to optimize the dielectric and wave-absorbing properties by varying the additional amount of Ag@PS composite microspheres in Ag@PS/PDMS composites. The X-ray diffraction (XRD) results proved the successful preparation of Ag@PS composite microspheres. The SEM and EDS images indicated that the Ag particles were attached to the external surface of PS. The presence of Ag particles in the Ag@PS composite microspheres enhances their electrical conductivity and enables the formation of a conductive network. This, in turn, improves the composites’ dielectric constant. The optimal wave-absorbing capability of the composites was achieved when the Ag@PS composite microspheres were added at a weight percentage of 50%. When the sample attains a thickness of 1.8[Formula: see text]mm, a reflection loss of at least −39.8[Formula: see text]dB is attained at 10.4[Formula: see text]GHz, along with a bandwidth of 1.6[Formula: see text]GHz (9.1–10.7[Formula: see text]GHz) for the effective absorption bandwidth (EAB). The pressure-sensitive properties of the pliable composites were investigated as well. The optimal pressure-sensitive performance of Ag@PS/PDMS composites was achieved with a 60[Formula: see text]wt.% addition of Ag@PS composite microspheres. The resistance undergoes significant changes when subjected to pressure with a sensitivity of 9.7. The results indicate that the flexible composites’ wave-absorption and pressure-sensitivity properties can be modulated by adjusting the amount of Ag@PS composite microspheres added.

Preparation and Lubricating Properties of Polystyrene Composite Microspheres.

In order to improve the lubrication performance of polystyrene microspheres (PS) as solid lubricant in drilling fluids, elastic graphite-polystyrene composite microspheres (EGR/PS), montmorillonite-elastic graphite-polystyrene composite microspheres (OMMT/EGR/PS), and polytetrafluoroethylene-polystyrene composite microspheres (PTFE/PS) were prepared by suspension polymerization. OMMT/EGR/PS has a rough surface, while the surfaces of the other three composite microspheres are smooth. Among the four kinds of composite microspheres, the largest particle is OMMT/EGR/PS, and the average size is about 400 μm. The smallest particle is PTFE/PS, and the average size is about 49 μm. Compared with pure water, the friction coefficient of PS, EGR/PS, OMMT/EGR/PS and PTFE/PS reduced by 25%, 28%, 48%, and 62%, respectively. The wear tracks of EGR/PS, OMMT/EGR/PS and PTFE/PS are narrower and smoother than those of pure water. When the content of PTFE is 4.0 wt%, the friction coefficient and wear volume of PTFE/PS are 0.213 and 2.45 × 10-4 mm3-74% and 92.4% lower than that of pure water, respectively.

Highly loaded silver nanoparticle‐modified monodispersed polystyrene composite microspheres (PS/Ag) for rapid catalytic reduction of methylene blue

AbstractIn this research, monodispersed polystyrene (PS) microspheres were prepared by dispersion polymerization. PS microspheres decorated with silver nanoparticles (PS/Ag composite microspheres) were synthesized by a modified chemical plating method with water as the synthesis medium. The microspheres at each stage were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), UV–visible spectroscopy (UV–vis), field‐emission scanning electron microscopy (FESEM), and energy‐dispersive spectrometer (EDS). The reduction of methylene blue (MB) was carried out with PS/Ag composite microspheres as a catalyst and NaBH4 as a reducing agent. The results showed that the MB dye was reduced to colorless within 180 s. The reduction of the MB dye followed pseudo‐first‐order kinetics with an apparent rate constant (Kapp) value of 0.01425 s−1. Control experiments were also carried out by adding microspheres from each chemical plating pretreatment stage to the MB, without PS/Ag composite microspheres. The catalytic activity of the PS/Ag composite microspheres was high after five consecutive cycles of recovery, showing promising reusability. The catalytic activity of the prepared PS/Ag catalysts was superior to other catalysts for the reduction of MB.

A study on preparation of modified Graphene Oxide and flame retardancy of polystyrene composite microspheres

ABSTRACT In this paper, the ODOPM, a kind of 9, 10-dihydro-9-oxygen-heterooxy-10-phosphoro-10-oxygen (DOPO) derivative, was obtained by hydroxylation of DOPO. Further, a phosphorus nano-flame retardant (GO-ODOPM) was obtained by addition reaction with carboxylated Graphite Oxide (GO-COOH). And then Graphene Oxide/polystyrene (GO-ODOPM/PS) composite microspheres were obtained via suspension polymerization of styrene with GO-ODOPM. The decrease of the peak heat release rate (HRR) and total heat release rate (THR) for the GO-ODOPM/PS composite microspheres was obtained when the content of the additives was only 3.0 wt% is more than 36.2% and 33.6% compared with the pure PS microspheres, respectively. Thermogravimetric (TG), dynamic rheology and carbon residue analysis were used to study the flame-retardant mechanism of GO-ODOPM in PS microspheres. The results revealed that the addition of GO-ODOPM obviously reduced the fire hazard of polystyrene (PS) microspheres. Thus, this work provided a feasible method to design efficient flame retardants for enhancing fire safety of polymers.

Preparation of antistatic polystyrene superfine powder with polystyrene modified carbon nanotubes as antistatic agent

A facile approach for fabricating antistatic polystyrene (PS) microspheres used in 3D print had been carried out by introducing polystyrene onto the MWCNTs (MWCNTs@PS) surface. Firstly, poly (styrene-co-acryloyl chloride) (PS-co-APCl) was synthesized via free radical polymerization. Then azide-poly (styrene-co-acrylic acid) (PS-co-APAA) were prepared through the reaction between the acylchloride groups of PACl with the sodium azide. Subsequently, the azide groups of PS-co-APAA hich produced nitrene under high temperature, reacting with the sp2 carbon in MWCNTs. MWCNTs@PS thus obtained were characterized using FTIR, EDS, Raman, TAG and TEM, and used as antistatic agent in PS in-situ suspension polymerization. MWCNTs@PS/PS composite microspheres were characterized using TAG, SEM and TEM. Results revealed that PS was covalently bonded onto the surface of MWCNTs, which improved the compatibility with matrix. Thus, the antistatic performances were enhanced by a well-constructed electrostatic discharge channel in the polystyrene matrix. As a result, the surface resistance of the percolation threshold was 3.54 × 108 Ω when the loading of MWCNTs@PS was at 0.5 wt%.The average diameter of MWCNTs@PS/PS microspheres was about 54 μm and the morphology was also very smooth, which could be used in 3D print.

Synthesis of polypyrrole–polystyrene composite microspheres via pseudo-multicomponent heterophase polymerization and the potential application on Cr(vi) removal

Polypyrrole–polystyrene (PPy–PS) composite hollow microspheres with a dry-plum-like morphology were prepared via pseudo-multicomponent heterophase polymerization in an aqueous dispersion system.

Preparation of luminescent polystyrene microspheres via surface-modified route with rare earth (Eu3+ and Tb3+) complexes linked to 2,2′-bipyridine

Luminescent polystyrene microspheres were easily fabricated from poly (styrene-co-methacrylic acid) and aqueous RE(III) chloride solution (RE=Eu, Tb) in the presence of 2,2′-bipyridine as second ligand. The negative charges of carboxyl groups on the surface of microspheres coordinated with rare earth ions at first, such as complexes covalently linked to 2,2′-bipyridine, resulting in strong photoluminescence. Various methods, including transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and fluorescence spectrophotometer, were used to characterize the resultant polystyrene composite microspheres. This work highlights the idea that it is facile to synthesis luminescent microspheres by surface-modified method directly.

Bright, transparent, and light-emitting films using fluorescent QDs–polystyrene composite microspheres

In this paper, we have developed a simple method to prepare transparent composite fluorescent films by using poly(acrylic acid) co-polymer as a matrix and QDs–polystyrene fluorescent microspheres as light-emitting materials. The strategies include encapsulating fluorescent hydrophobic QDs into polystyrene microspheres with a miniemulsion polymerization process and fabricating composite fluorescent films with a coating method. The obtained light-emitting films were transparent under visible region and showed bright red, green, and blue lights under the irradiation of UV light. The PL intensity of the composite films shows linear increase when the concentration of QDs–polystyrene microspheres is increased within a certain range. Moreover, a white light-emitting film can be obtained by combination of red, green, and blue QDs–polystyrene microspheres with a correct proportion.

Preparation and characterization of porous titanium dioxide sulfonated polystyrene composite microspheres with amphiphilicity

Porous particles with amphiphilicity were prepared by a nonpolymeric pore-formation process with the sulfonation of polystyrene microspheres. Nano titanium dioxide (TiO2) particles were then grafted onto the surface via a sol–gel method to finally form the composite particles. The effects of the mass ratio of ethanol (EtOH) to water, temperature, and solubility parameter on the pore-formation process is discussed in detail. The morphology, porous structure, and wetting properties of the particles were studied by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and contact angle measurement. The results show that porous sulfonated polystyrene (SP) microspheres could be fabricated at 60°C with a 1 : 1 mass ratio of EtOH–water and a solubility parameter of 29.69 MPa1/2. The TiO2 particles were determined to be grafted onto the SP microspheres by physical-bond interaction on the basis of FTIR analysis. The contact angles for both water (aqueous-phase) and various organic solvent (oil-phase) droplets with different polarities on the surface of compressed tablets of TiO2–SP powder were all lower than 30°; this indicated excellent amphiphilicity in the composite particles. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Facile preparation and characterization of luminescent polystyrene composite microspheres

Luminescent microspheres [poly(St-co-VBA)–Tb] were easily fabricated from poly(St-co-VBA) and aqueous Tb(III) chloride solution in the presence of triethylamine. The negative charges on the surface of microspheres coordinated with Tb3+, resulting in strong photoluminescence. Such terbium compounds were firmly stabilized in the microspheres. Various methods, including TGA, TEM, SEM-EDS, ICP-MS, EPR, SEM, FT-IR, fluorescence spectrophotometry and laser scanning confocal fluorescence microscopy, were used to characterize the resultant polystyrene composite microspheres.

Preparation of carbon nanotube/chitosan/gold nanoparticle composite microspheres

The electrostatic layer-by-layer (LbL) assembly of acid-modified multi-walled carbon nanotubes (MWNTs) and biopolymer chitosan (CHIT) is realized on planar substrates and polystyrene (PS) microsphere templates, respectively. The successful stepwise growing process of the composite films on planar substrates is investigated and confirmed by scanning electron microscopy and UV–vis spectroscopy. The transfer of the LbL assembly of MWNTs and CHIT to spherical PS microspheres leads to novel (MWNT/CHIT)PS core-shell structure, on which the gold nanoparticles (GNPs) are deposited to fabricate GNP(MWNT/CHIT)PS composite microspheres. The glass carbon electrodes modified with such (MWNT/CHIT)PS or GNP(MWNT/CHIT)PS composites exhibit satisfactory electrocatalytic activities for biomolecule dopamine.

Anionic surfactant for silica-coated polystyrene composite microspheres prepared with miniemulsion polymerization

Raspberry-like composite microspheres with polystyrene (PS) cores and silica shell were prepared through miniemulsion polymerization by using the anionic sodium dodecyl sulfate (SDS) as a surfactant and 1-vinylimidazole (1-VID) as an auxiliary monomer. The strong acid–base interaction between acidic hydroxyl groups of silica surfaces and basic amino groups of 1-VID promote the formation of long-term stable PS/SiO2 nanocomposite microspheres. Transmission electron microscopy TEM studies indicated that the acid–base interaction between silica nanoparticles and auxiliary monomer was strong enough for the formation of colloidally stable composite microspheres, which have raspberry-like morphology. Influences of several synthetic parameters, such as initial silica amount, the amount of auxiliary monomer 1-VID, and SDS concentration on the polymerization stability, diameters, and morphology of the composite microspheres were studied. A tentative mechanism of the formation of nanocomposite particles was proposed.

Competitive adsorption of fibrinogen and albumin onto polymer microspheres having hydrophilic/hydrophobic heterogeneous surface structures

The competitive adsorption of bovine fibrinogen (BFb) and bovine serum albumin onto polymer microspheres from the mixture solution was examined under various protein-to-microsphere ratios using various homopolymer microspheres and poly(2-hydroxyethyl methacrylate)/polystyrene composite microspheres having heterogeneous surface structures consisting of both hydrophilic and hydrophobic parts. They were produced by emulsifier-free (seeded) emulsion polymerizations. The selective adsorption of BFb was not observed for the homopolymer microspheres, but observed for the composite polymer microspheres having optimum compositions.

Preferential adsorption of bovine fibrinogen dimer onto polymer microspheres having heterogeneous surfaces consisting of hydrophobic and hydrophilic parts

AbstractThe adsorption onto polymer microspheres of bovine fibrinogen (BFb) containing both dimeric and monomeric species was examined using various homopolymer, copolymer, and poly(2‐hydroxyethyl methacrylate)/polystyrene composite microspheres which were produced by the emulsifier‐free (seeded) emulsion polymerization technique. The preferential adsorption of the BFb dimer was clearly observed in an optimum region of the surface hydrophilicities of the polymer microspheres. The preferential adsorption of the BFb dimer onto the composite polymer microspheres having heterogeneous surfaces with both hydrophilic and hydrophobic parts was more remarkable than that onto the homopolymer and copolymer microspheres having homogeneous surfaces. The behavior is discussed in comparison with those for bovine serum albumin and human γ‐globulin.

Preferential adsorption of bovine serum albumin dimer onto polymer microspheres having a heterogeneous surface consisting of hydrophobic and hydrophilic parts

The adsorption behaviors of bovine serum albumin (BSA) containing both dimeric and monomeric species onto polymer microspheres were examined using various homopolymers and poly(2-hydroxyethyl methacrylate)/polystyrene composite microspheres which were produced by the emulsifier-free (seeded) emulsion polymerization technique. The preferential adsorption of the BSA dimer was clearly observed in an optimum region of the surface hydrophilicities of the polymer microspheres. The preferential adsorption of the BSA dimer onto the composite polymer microspheres having heterogeneous surfaces consisting of hydrophilic and hydrophobic parts was more marked than those onto the homopolymer and copolymer microspheres having homogeneous surfaces.

Covalent immobilization of trypsin onto poly(2-hydroxyethyl methacrylate)/polystyrene composite microspheres by cyanogen bromide method and its enzymatic activity

Covalent immobilization of trypsin onto poly(2-hydroxyethyl methacrylate)/ polystyrene composite microspheres, produced by emulsifier-free seeded emulsion polymerization technique, was carried out using the cyanogen bromide method under various conditions. The highest enzymatic activities of the trypsin immobilized in this study against N-α-benzoyl-L-arginine ethyl ester and N-α-benzoyl-L-arginine-p-nitroanilide, as low-molecular substrates and casein as a high-molecular substrate, were high, as corresponding to 80%, 85% and 50% of those of free trypsin, respectively.

Adsorption of trypsin onto poly(2‐hydroxyethyl methacrylate)/polystyrene composite microspheres and its enzymatic activity

AbstractPoly(2‐hydroxyethyl methacrylate)/polystyrene (PHEMA/PS) composite microspheres were produced by emulsifier‐free seeded emulsion polymerization for styrene in the presence of PHEMA seed particles. Effects of the surface characteristics of the PHEMA/PS composite microspheres on the adsorption immobilization of trypsin and on its enzymatic activity were discussed. Above 5 mol% of HEMA content, trypsin molecules adsorbed had high activity, 65–100% of the activity of free trypsin. The excellence of the composite microspheres as a carrier for trypsin seems to be closely related with the surface heterogeneity consisting of both hydrophilic and hydrophobic parts.