Study On The Preparation Of Functional Composite Superfine Particles

With 2,2' -azobis-2(amidineopropane) dihydrochloride (V5o) and ammonium persulphate (APS) being used as initiator, the cationic and anionic nanoparticles polystyrene (PS) latex were synthesized via emulsion polymerization respectively. Then by means of heterocoagulation and encapsulatin, on controlled condition the superfine powders of CaCO3 and TiO2 were coated with different nonaparticles Ps. The composite particles with core/shell structure were prepared by heating the composite particles above the glass transition temperature of PS. As predicted theoretically, the PS polymer spreaded over the surface of the titania particles to form composite particles with core-shell structure. The influence of pH value and non-ion surfactant in heterocoagulation was discussed. The property of the coated particles was characterized by SEM, and Zeta potential, particle size distribution of the particles before and after encapsulation was obtained by laser particle size analyzer.The mechanical modifying equipment was used to prepare compounded micro-spheres from PMMA particles and PS particles with metal particles and TiO2 nano-particles. The SEM was used to observe the images of particles and X-ray photoelectron spectroscopy (XPS) is used to obtain surface spectrum. Herein the TiO2 nano-particles can be dispersed on larger polymer particles and their surface morphology is different by using different polymer particles. Compare with the LG string method , encapsulated particles treated by dry impact method were well dispersed, processing time was shorter. The effect of size distribution of core particle was also discussed in dry impact method. SEM. particle size andZeta potential were used to characterize the properties of the composite particles.The polystyrene particles with 2.8 micrometer mean diameter were prepared by dispersion polymerization and hollow porous micro-sphere were prepared by extraction after seeding emulsion polymerization. Particles with multi-hollow structure were obtained and characterized by SEM, additionally the mechanism and factor about formation of porous structure were also discussed.To prepare the biodegradable nano-particles, reversed-phase micro-emulsion and ionotropic gelation methods were used. Two kinds of chitosan nano-particles were obtained and characterized by SEM, TEM. The nano-particles' size distribution and specifical surface were determined. BSA is used as a model macromolecule drug and the in-vitro release rate of BSA from chitosan nano-particles are sustained. The experiment results show that chitosan nano-particles prepared could be used as carrier for the delivery of drugs. In the presence of magnetite nano-particles prepared in our experiment, chitosan particles warpped the magnetite nano-particles. The magnetic biodegradable drug carrier can be obtained by this method.