• Macromolecular Research
• /
• v.16 no.4
• /
• pp.293-302
• /
• 2008

In our previous publication, the problem of particle deformation and coagulation at the nucleation stage in the presence of cross-linker was intensely studied by seeded batch dispersion polymerization of methyl methacrylate (MMA). In the present work, highly cross-linked, monodisperse PMMA particles were prepared under various reaction conditions by seeded semi-continuous process. Monodisperse, $6.5{\mu}m$-diameter PMMA particles containing up to 8 wt% of DVB or EGDMA were successfully made by seeded semi-continuous process and multi-semi-continuous addition process, respectively. Therefore, this study shows that seeded semi-continuous process is more effective and efficient to prepare highly cross-linked, monodisperse particles than non-seeded and seeded batch processes.

• Macromolecular Research
• /
• v.15 no.3
• /
• pp.244-255
• /
• 2007

Nucleation is the most sensitive stage in the preparation of highly cross-linked, monodisperse microspheres by dispersion polymerization, since the addition of a small amount of cross-linker results in particle deformation and coagulation. To overcome these problems, $5\;{\mu}m$ poly(methyl methacrylate) seed particles prepared by dispersion polymerization were used in the preparation of mono disperse, cross-linked PMMA particles containing up to 7 wt% divinylbenzene by seeded batch dispersion polymerization. Spherical particles with a narrow size distribution containing up to 8 wt% of EGDMA were prepared by seeded multi-batch dispersion polymerization processes. These particles were identified by scanning electron microscopy and DSC.

• Journal of the Korean Applied Science and Technology
• /
• v.21 no.4
• /
• pp.370-379
• /
• 2004

Highly crosslinked micron-size monodispersed PMMA/PDVB and PS/PDVB particles were prepared using seeded multi-stage emulsion polymerization. PMMA and PS seed particles were synthesized by seeded multi-stage emulsion polymerization and soap-free emulsion polymerization. Then PMMA/PDVB and PS/PDVB particles were obtained using semi-batch type emulsion polymerized using divinyl benzene as a cross-linkable monomer in the presence of seed particles. PMMA particles with size of ca. 730 nm and polydispersity of 1.03 were successfully prepared in this experiment. PS particles with size of ca. 1.5 ${\mu}m$ and polydispersity of 1.01 were prepared in this experiment. Highly crosslinked PS/PDVB particles with size of ca. 1.3 ${\mu}m$ and polydispersity of 1.00 were obtained.

• Elastomers and Composites
• /
• v.46 no.1
• /
• pp.60-69
• /
• 2011

The various types of PBA/PMMA composite latexes were prepared by $2.1\;{\mu}m$ PBA seeded batch and seeded semi-continuous dispersion polymerization. The morphology of the PBA/PMMA composite latexes by seeded batch process was found to be closely dependant on the weight ratios of methanol/water in polymerization medium and of PBA seed/MMA at the second stage. In general, egg, snowman, confetti, peanut-like nonspherical composite latex particles were formed with increasing amount of water and MMA as a result of the occurrence of the phase separation between PBA seed and PMMA. The morphology of the PBA/PMMA composite latexes by seeded semi-continuous process was controlled by the addition time of MMA, especially, spherical shaped core(PBA)/shell(PMMA) composite latex particles were prepared under the monomer-starved condition at the second stage.

• Polymer(Korea)
• /
• v.30 no.1
• /
• pp.50-55
• /
• 2006

When the monodisperse polystyrene(PS)/HDDA polymer particles were synthesized via one-step polymerization using polystyrene seed particles by dispersion polymerization, the effects of 1) the molecular weight of seed polymer particles, 2) the ratio of the absorbed HDDA to the seed polymer particles (swelling ratio) and 3) seeded polymerization rate on the surface morphology of PS/HDDA polymer particles were investigated. It was observed that the creation of the crater shaped defect on the surface of PS/HDDA polymer particles was irrespective of the molecular weight of seed polymer ant swelling ratio. But its surface morphology could be controlled by the change of the seeded polymerization rate.

• Journal of Adhesion and Interface
• /
• v.10 no.4
• /
• pp.174-181
• /
• 2009

The viscosity for hi-solid pressure sensitive adhesive to improve water soluble low viscosity pressure sensitive adhesive polymerized using seeded polymerization. While seed binder polymerizing it produces an optimum polymerization condition, and acrylic acid and seed binder concentration changed were measurement of viscosity variation and adhesive power at the substrate (SUS420J) as flowing results. In adhesive polymerization, seed binder concentration 7 wt%/monomer was recovered 60% of solid content, 2,100 cps of low viscosity and clear adhesive film. When acrylic acid content was 4 wt%/monomer, it was turned excellent adhesive power and holding power.

• Applied Chemistry for Engineering
• /
• v.10 no.6
• /
• pp.889-894
• /
• 1999

Preparation of micron size polymer particles which have desired morphology, size, and structure by emulsion polymerization is very difficult due to coagulation of latex particles and formation of second generation particles. But there are attractive merits such as preparation of structural and functional polymer particles in seeded emulsion polymerization. Seeded emulsion polymerization of n-butyl acrylate(BA) was carried out to investigate the effects of stirring rate, reaction temperature, concentration of initiator, emulsifier, and cross-linking agent on the particle size and size distribution. By the combination of suitable reaction conditions, we succeeded in preparing $0.14{\sim}3.67{\mu}m$ diameter of poly(n-butyl acrylate)(PBA) particles using sequential seeded emulsion polymerization.

• Macromolecular Research
• /
• v.17 no.4
• /
• pp.250-258
• /
• 2009

One-step seeded polymerization was used to prepare $7{\sim}10{\mu}m$ of crosslinked monodisperse spheres with four crosslinking agents using $4.68{\mu}m$ poly(methyl methacrylate)(PMMA) seed particles in aqueous-alcoholic media in the absence of the swelling process. The crosslinking agents used were ethylene glycol dimethacrylate(EGDMA), allyl methacrylate(AMA), 1,6-hexanediol diacrylate(HDDA) and trimethylolpropane trimethacrylate(TMPTMA). The effects of the type and concentration of the crosslinking agents on the swelling, pore size, thermal property of the networks and morphology of the particles were studied. The chemical structures and concentrations of the crosslinking agents affected both the swelling ratio and the porosity of the networks. In addition, the chemistry of the reactive vinyl group and chain length of the crosslinking agents affected the stability of the monodisperse particles of the ultimate morphology.

• Journal of the Korean Applied Science and Technology
• /
• v.19 no.2
• /
• pp.131-136
• /
• 2002

As model waterborne acrylic coatings, mono-dispersed poly(butyl acrylate-methyl methacrylate) copolymer latexes of random copolymer and core/shell type graft copolymer were prepared by seeded multi-staged emulsion polymerization with particle size of $180{\sim}200$ nm using semi-batch type process. Sodium lauryl sulfate and potassium persulfate were used as an emulsifier and an initiator, respectively. The effect of particle texture including core/shell phase ratio, glass transition temperature and crosslinking density, and film forming temperature on the film formation and final properties of film was investigated using SEM, AFM, and UV in this study. The film formation behavior of model latex was traced simultaneously by the weight loss measurement and by the change of tensile properties and UV transmittance during the entire course of film formation. It was found that the increased glass transition temperature and higher crosslinking degree of latex resulted in the delay of the onset of coalescence of particles by interdiffusion during film forming process. This can be explained qualitatively in terms of diffusion rate of polymer chains. However, the change of weight loss during film formation was insensitive to discern each film forming stages-I, II and III.

• Journal of the Korean Applied Science and Technology
• /
• v.21 no.1
• /
• pp.69-75
• /
• 2004

In this study, various model composite latexes were synthesized using n-butyl acrylate and methyl methacrylate as comonomers by seeded multi-staged emulsion polymerization. Monodispersed model composite latex particles with size of 190 nm and polydispersity index of 1.05, which have various morphology including random copolymer particle, soft-core/hard-shell particle, hard-core/soft shell particle, and gradient-type copolymer particle, homopolymers particles were prepared. The designed morphology of model composite particles were confirmed.