Composite polymer particles containing bismuth vanadate particles for self-cleaning fabrics

The aim of this research was to prepare composite polymer particles containing bismuth vanadate (BiVO4) particles through microsuspension iodine transfer polymerization ( ms ITP) for fabric coating as a self-cleaning fabric. To reduce the aggregation of pristine BiVO4 particles during the fabric coating process, composite polymer particles containing the visible-light-driven photocatalyst as BiVO4 particles in self-cleaning fabric applications were investigated in the first time. First, BiVO4 particles were prepared via an aqueous chelating method where the stable precursor solutions of Bi3+ and V5+ with ethylenediaminetetraacetic acid ligand were obtained. After calcination at 500 °C, the BiVO4 particles were obtained. To disperse them well in an oil (monomer) phase in ms ITP, the BiVO4 surface was modified by oleic acid as o-BiVO4 to present a hydrophobic surface. The encapsulation efficiency of the o-BiVO4 (≥60%) in composite poly(methylmethacrylate-divinylbenzene) (P[MMA-DVB]/o-BIVO) particles was significantly higher than that (≈10%) of the pristine BiVO4 particles. Using polyethylene glycol 30 dipolyhydroxystearate (DPHS) as a porogen, porous P(MMA-DVB)/o-BiVO4 particles still maintaining their spherical shape were obtained with an 8% particle of DPHS. Furthermore, increasing the hydrophilic polymer shell by adding 2-hydroxyethyl methacrylate (HEMA) in the oil phase of ms ITP, the P(MMA-DVB-HEMA)/o-BiVO4 particles showed a much higher methylene blue (MB) degradation rate under visible light for 1 h (24 mg MB/g BiVO4 or 96% MB degradation) than that (13 mg MB/g BiVO4 or 52% MB degradation) of the pristine BiVO4. Moreover, the fabric coated with porous P(MMA-DVB-HEMA)/o-BiVO4 particles showed a satisfactory self-cleaning property.

Carboxylic acid modified pH-responsive composite polymer particles

pH-responsive polymers are attracting much interest from researchers because of their wide application potentials in areas like biosensor, bioseparator, bioreactor, biocatalysis, drug delivery, and water treatments. In this investigation a two-step process is evaluated to prepare carboxyl(–COOH) functional submicrometer-sized pH-responsive composite polymer particles. First, submicrometer-sized polystyrene (PS) particles are prepared by a modified conventional dispersion polymerization. In the second step, PS/poly(methacrylic acid-acrylamide-ethylene glycol dimethacrylate) [PS/P(MAA-AAm-EGDMA)] composite polymer particles are synthesized by seeded co-polymerization of methacrylic acid, acrylamide, and ethylene glycol dimethacrylate in the presence of PS seed particles. The size distributions and morphologies analyzed by electron micrographs suggested that seeded copolymerization smoothly occurred without formation of any secondary tiny copolymer particles. The surface composition and functionality are confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. The hydrodynamic diameter increased with the increase in pH values as part of the carboxyl groups are deprotonated, which favored the swelling of copolymer layer formed around the surface of PS particles. The adsorption of cationic and anionic surfactants at two different pH values showed that adsorption of cationic surfactant is favored at higher pH value whereas that of anionic surfactant is favored at lower pH value.

Fabrication of Epoxide Functional Hydrophobic Composite Polymer Particles by Suspension Polymerization and Subsequent Doping with Fe3O4 Nanoparticles

This investigation described a simple three-step process for the fabrication of micrometer-sized magnetic composite polymer particles. This composite polymer particle consisted of crosslinked hydrophobic poly(lauryl methacrylate-divinyl benzene) (P(LMA-DVB)) core, prepared by suspension polymerization. Then, P(LMA-DVB) copolymer core particles were coated with poly(glycidyl methacrylate) (PGMA) by seeded polymerization to introduce epoxide functionality. Finally, P(LMA-DVB)/PGMA composite particles were doped with iron oxide (Fe3O4) nanoparticles following in situ co-precipitation of Fe2+ and Fe3+ from their alkali aqueous solution. The presence of strained oxirane ring derived from PGMA segment present at the surface is expected to induce high affinity towards precipitated magnetic Fe3O4 nanoparticles. The compositional structure of P(LMA-DVB)/PGMA/Fe3O4 composite polymer particles was confirmed by Fourier Transform IR (FTIR), electron microscopy, thermogravimetry (TG), X-ray diffraction (XRD) and energy-dispersive X-ray (EDX).

Preparation of Highly Cross-linked Magnetic Polymer Composite Particles and Application in the Separation of Arsenic from Water

Iron oxide magnetic particles have become a promising research field in separation technology because of their easy separation by external magnetic field and can be applied for the removal of toxic metals from waste water. Highly cross-linked Fe3O4/P(S-DVB) particles were prepared in this research by suspension polymerization of styrene (S) and divinylbenzene (DVB) in presence of nanosized Fe3O4 particles. At first Fe3O4 nanoparticles were prepared by co-precipitation of Fe2+ and Fe3+ from their alkaline aqueous solution. To stabilize the magnetic particles, the surface of the particles was modified with oleic acid. The morphology and surface structure were characterized by Fourier Transform IR(FTIR), Transmission Electron Microscope (TEM), Scanning Electron Microscope(SEM), and light microscope.The adsorption behavior of As(III) on composite polymer particles was evaluated and a comparative study with reference copolymer particles revealed that composite polymer particles possessed better adsorption capacity.