• Polymer(Korea)
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• v.27 no.6
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• pp.528-535
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• 2003

The effects of surfactants, organic solvents, and functional monomers on the emulsion polymerization of perfluoroalkyleoylacryaltes and n-alkylacrylates were investigated. In particular, the dependence of the surface properties, contact angle and water repellency on the crystal melting temperature (T$\_$m/) of the fluorocopolymer and the variation of polymer latex particle sizes was investigated. Using WAXD experiments and synthesizing different types of fluorocopolymers which have fallowing fluoroacrylaytes [CH$_2$=CHCO$_2$CH,$_2$(CF$_2$CF$_2$) nH] (n = 4, 5 or 6), the relationship between the molecular packing structure of pendent side groups of fluorocopolymers and the surface properties was also investigated. We observed that the structure of primary carbon atoms of pendent side groups of fluorocopolymers plays key role in determining the surface properties.s.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.597-601
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• 2013

In this study, we present simple microfluidic approach for the synthesis of monodisperse microcapsules by using droplet-based system. We generate double emulsion through single step in the microfluidic device having single junction while conventional approaches are limited in surface treatment for the generation of double emulsion. First, we have injected disperse fluid containing FC-77 oil and photocurable ethoxylated trimethylolpropane triacrylate (ETPTA) and water containing 3 wt% poly(vinyl alcohol) (PVA) as continuous phase into microfluidic device. Under the condition, we easily generate double emulsion with high monodispersity by using flow focusing. The double emulsion droplets are transformed into microcapsules under the UV irradiation via photopolymerization. In addition, we control thickness of double emulsion's shell by controlling flow rate of ETPTA. We also show that the size of double emulsions can be controlled by manipulation of flow rate of continuous phase. Furthermore, we synthesize microcapsules encapsulating various materials for the application of drug delivery systems.

• Polymer(Korea)
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• v.29 no.5
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• pp.433-439
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• 2005

The copolymers were prepared by the emulsion copolymerization of fluoroalky lacrylate-stearylacrylate-m-isopropenyl-${\alpha},\;{\alpha}'$-dimethylbenzyl isocyanate (TMI) in order to obtain water repellent polymers. The respective copolymerization rates of the three monomers considerably depended upon the use of the nonionic emulsifier and the nonionic-cationic mixed emusifier, and the optimum conditions were obtained. The particle sizes of the copolymers were in the range of 105 to 222nm. The particle sizes of the copolymers prepared by the use of the mixed emulsifiers were smaller than those of the copolymers prepared by the use of the nonionic emulsifier. The reactions of both TMI-N-methyl acetamide and TMI-cellobiose did not take place. However, the reaction of TMI-n-butylamine occurred. The water contact angles before and after washing three times for nylon and poly(ethylene terephthalate) (PET) fabrics coated with the copolymer prepared by the use of mixed emulsifier were about $139^{\circ}\;and\;133^{\circ}$ Therefore, the copolymer showed good durable repellency for nylon and PET.

• Polymer(Korea)
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• v.30 no.4
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• pp.332-337
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• 2006

Monodisperse polymer particles were prepared via one-step seeded polymerization using PMMA seed particles and HDDA (or EGDMA) as crosslinking monomer. For the study, the effects of 1) the ratio of the absorbed monomer or monomer mixture to the seed polymer particles (swelling ratio), 2) the ratio of EGDMA in absorbed monomer mixture, 3) the dosage of initiator, and 4) electro less Ni plating on the variation of mechanical properties of monodisperse polymer particles, such as recovery rate, K-values, breaking strength and breaking displacement, were investigated by using MCT (micro compression test). It was observed that monomer swelling ratio influenced only breaking strength, but EGDMA ratio in monomer mixture, dosage of initiator and electroless Ni plating affected both K-values and breaking strength.

• Polymer(Korea)
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• v.28 no.5
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• pp.404-411
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• 2004

The microcapsules containing triphenyl phosphate (TPP), a flame retardant, were prepared by phase-inversion emulsification technique using the epoxy resin (Novolac type) with excellent physical properties and network structure. This microencapsulation process was adopted for the protection of TPP evaporation and wetting of polymer composite during the polymer blend processing. The TPP, epoxy resin and mixed surfactants were emulsified to oil in water (O/W) by the phase inversion technology and then conducted on the crosslinking of epoxy resin by in-situ polymerization. The capsule size and size distribution of TPP capsules was controlled by mixed surfactant ratio, concentration and TPP contents, The formation and thermal property of TPP capsules were measured by differential scanning calorimetry and thermogravimetric analysis. The morphology and size of TPP capsules were also investigated by scanning and transmission electron microscopies. As the surfactant concentration increased, the TPP capsules were more spherical and mono-dispersed at the same weight ratio of mixed surfactants (F127: SDBS).

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.673-678
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• 1997

Associative acrylic thickeners were prepared by emulsion copolymerization using nonionic vinyl surfactant esters as an associative macromonomer and their rheological properties were investigated. The thickening efficiency was shown to depend on the chain length of therminal hydrophobe and degree of ethoxylation of VSE. increasing the content of VSE enhanced the efficiency of the resulting polymers as a thickener. It was attributed to the intermolecular association of terminal hydrophobes of associative thickener in aqueous solution. The chain transfer agent caused to reduce the molecular weight of associative thickener, resulted in decrease of thickening efficiency.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.536-542
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• 1996

Water-based acrylic sizing agent(GSW-7000) was prepared by emulsion copolymerization for sizing polyester yarns. Ammonium salt version of the acrylic sizing agent offered greater abrasion resistance to weaving forces and water resistance for water jet loom. GSW-7000 exhibited proper viscosity for sizing, high penetration ability and excellent adhesion to polyester yarn. It was possible to reduce the size pick-up to 70~80% of ordinary solvent-based sizing agent due to excellent adhesive strength of GSW-7000.

• Journal of the Korean Applied Science and Technology
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• v.12 no.1
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• pp.93-99
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• 1995

As the surfactants that were used in micellar reaction, emulsion polymerization and phase-transfer reaction etc. have the problems, the cleavable surfactant that was converted to inactive compound after such as the reaction was synthesized to above 90% yield. And this surfactant and intermediates were separated through thin layer chromatography and column chromatatography and their molecular structures were confirmed from IR. $^{1}H$-NMR and elementary analysis spectra. And its surface-active properties and acid hydrolysis will be serialized in II.

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

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.393-400
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• 1996

The conducting polymer composites were prepared by imbibing the porous particle with an $FeCl_3$ oxidant solution, drying the imbibed porous particle, and imbibing again with pyrrole solution for polymerization to take place in the pore. The conductivity of the porous composite particles, was higher than that of nonporous particles. Also, the conductivity of composite was increased with increasing specific surface area and pore specific volume of the host porous particles since the degree of formation of conducting polymer in the pore increased.