• Title, Summary, Keyword: soap-free emulsion polymerization

Search Result 14, Processing Time 0.035 seconds

Electrolyte Effect on the Particle Characteristics Prepared by Soap-Free Emulsion Polymerization

  • Han, Seung-Tak;Lee, Kang-Seok;Shim, Sang-Eun;Saikia, Prakash J.;Choe, Soon-Ja;Cheong, In-Woo
    • Macromolecular Research
    • /
    • v.15 no.5
    • /
    • pp.403-411
    • /
    • 2007
  • Monodisperse micron-sized polystyrene (PS) spheres were successfully obtained using a single stage soap-free emulsion method in aqueous media mixed with ethanol (co-solvent) containing NaCI as the electrolyte. The optimum conditions for preparing the monodisperse PS microspheres, using soap-free emulsion polymerization in a water/ethanol mixture with an electrolyte, were studied. The presence of the co-solvent and electrolyte controlled the particle dispersion stability during the polymerization. The microspheres formed using PS, with a weight-average diameter of $2.6{\mu}m$, coefficient of variation of 5.3% and zeta potential of -15.1 eV, were successfully obtained in the presence of 0.1 wt% NaCI, 10 wt% monomer, 0.1 wt% initiator and 95/5 (g/g) of a water/ethanol mixture reacted at $70^{\circ}C$ for 24 h.

Preparation of Ultra Fine Poly(methyl methacrylate) Microspheres in Methanol-enriched Aqueous Medium

  • Shim, Sang-Eun;Kim, Kijung;Sejin Oh;Soonja Choe
    • Macromolecular Research
    • /
    • v.12 no.2
    • /
    • pp.240-245
    • /
    • 2004
  • Monodisperse PMMA micro spheres are prepared by means of a simple soap-free emulsion polymerization in methanol-enriched aqueous medium in a single step process. The size and uniformity of the microspheres are dependent on the polymerization temperature. In a stable system, the uniformity is improved with the polymerization time. The most uniform and stable micro spheres are obtained under mild agitation speed of 100 rpm at 70$^{\circ}C$. The monodisperse PMMA microspheres in the size range of 1.4-2.0 $\mu\textrm{m}$ having less than 5% size variation are successfully achieved with varying concentrations of monomer and initiator. As the monomer and initiator concentrations increase, the larger micro spheres with enhanced uniformity are obtained. However, the decreased amount of water induces the polydisperse PMMA particles due to the generation of secondary particles.

The Effect of Various Hydrophilic Acrylic Comonomers on Soap-Free Emulsion Polymerization of Styrene-Butadiene Rubber (Styrene-Butadiene 무유화제 유화공중합에서의 아크릴계 친수성 공단량체의 영향)

  • Chung, Huey-Sil;Lee, Chang-Sung;Kim, Byung-Kyu;Shin, Young-Jo
    • Elastomers and Composites
    • /
    • v.28 no.4
    • /
    • pp.267-273
    • /
    • 1993
  • A number of hydrophilic acrylic comonomers were incorporated into styrene-butadiene soap-free emulsion polymerization. It was found that reaction rate decreased according to : AN>AA>MMA>EA>IA>AAM>MA>HEMA. It was also observed that reaction rate increased with decreasing H-bonding factor contribution to the solubility parameter of the hydrophilic comonoer. The SBR latexes were very monodisperse with the particle size distribution of $1.03{\times}1.12$. Since growth rate is proportional to polymerization time, the difference in conversion rates between various comonomers was resulted from the particle number density of SBR latexes for the various hydrophilic comonomers. It was also found that the colloidal stability of the latexes was excellent because no external emulsifier was incorporated.

  • PDF

A Study on Synthesis of Starch-acryl Pressure Sensitive Adhesive by Soap-free Emulsion Polymerization (무유화제 유화중합에 의한 전분-아크릴 점착제의 합성에 관한 연구)

  • Song, Su-Hyun;Kim, Young-Seok;Cho, Ur-Ryong
    • Elastomers and Composites
    • /
    • v.44 no.4
    • /
    • pp.429-435
    • /
    • 2009
  • The pressure sensitive adhesives (PSA) were synthesized by soap-free emulsion polymerization of acrylic monomers such as butyl acrylate, 2-ethyl hexyl acrylate, and acrylic acid in the presence of starch as a protective colloid and copolymer. The peel strength and holding power of PSA were increased with starch contents due to the enhancement of gel content, But the initial tackiness of PSA was decreased with starch contents. The contact angle analysis of PSA indicated that the wettability was increased with starch contents owing to the increase of polarity by hydroxy group in starch. In the pH measurement of emulsion with time for biodegradability, the starch in the PSA accelerated the lowering of pH due to the formation of organic acids followed by decomposition of starch.

Part 1 : Soap-Free Emulsion Copolymerization of Styrene with COPS-I (Part 1 : Styrene과 COPS-I의 무유화공중합)

  • Lee, KiChang;Choo, HunSeung;Ha, JeongMi
    • Journal of Adhesion and Interface
    • /
    • v.15 no.3
    • /
    • pp.93-99
    • /
    • 2014
  • Monodisperse poly[styrene-co-(COPS-I)] latices in the size range of 165~550nm were successfully prepared by soap-free emulsion polymerization with various polymerization conditions (Styrene, COPS-I, KPS, DVB concentrations and polymerization temperature). In general, the COPS-I and KPS, DVB concentrations and polymerization temperature were closely related to the polymerization rate and the number of particles, molecular weight, and zeta potential. The polymerization rate and zeta potential increased, but molecular weight decreased, with increasing in the number of particles.

Preparation and Physical Properties of Poly(Styrene/Acrylate) Core-Shell Latex Particles (Poly(Styrene/Acrylate) Core-Shell 라텍스 입자의 제조와 물성에 관한 연구)

  • Lee, Kyoung-Goo;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
    • /
    • v.20 no.1
    • /
    • pp.27-32
    • /
    • 2003
  • The core-shell latex particles were prepared by sequential emulsion polymerization of alkyl methacrylate and styrene(ST) by using an water-soluble initiator(APS) after preparing monomer pre-emulsion in the presence of an anionic surfactant(SDBS). In organic/organic core-shell polymerization, the pre-emulsion method, which minimized required quantity of sulfactant, has been used to increase the conversion rate and the stability of core-shell latex particles as well as to reduce the formation of secondary particle that cause problems of soap-free emulsion during shell polymerization. We used several methods to observe the core-shell structure. The core-shell structure was studied by measuring pH change during hydrolysis by NaOH, glass transition temperature($T_g$) by differential scanning calorimeter(DSC), morphology of latex by transmission electron microscope(TEM) and change of particle size and distribution by a particle analyzer.

Preparation of Micron-size Monodispersed PMMA/PDVB and PS/PDVB Particles by Multi-staged Seeded Emulsion Polymerization (다단계 유화중합을 이용한 마이크론 크기의 PMMA/PDVB 및 PS/PDVB 단분산 입자의 제조)

  • Choi, Bong-Cheol;Um, Ki-Beom;Byun, Ja-Hoon;Park, Hong-Soo;Wu, Jong-Pyo;Baik, Baik
    • 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.

Synthesis and Characterization of Thermo Sensitive Poly(styrene-co-N-isopropylacrylamide) Microgels (열 감응성 Poly(styrene-co-N-isopropylacrylamide) 마이크로겔의 합성 및 특성)

  • Cho, Suk Hyeong;Kim, Kong Soo;Jung, Tea Uk
    • Applied Chemistry for Engineering
    • /
    • v.16 no.3
    • /
    • pp.397-402
    • /
    • 2005
  • Core-shell Poly(styrene-co-N-isopropylacrylamide) (poly(St-co-NIPAm) was prepared by soap-free emulsion polymerization of styrene (St) and N-isopropylacrylamide (NIPAm) in aqueous solution with potassium persulfate (KPS) as an initiator. The effects of St/NIPAm ratio, concentrations of monomer and crosslinker were studied. Also, Thermo sensitivity of microgels prepared was investigated. Particle size of microgels increased with increasing mol ratio of NIPAm to styrene. Transmittance of the microgel dispersion decreased rapidly when heated above a low critical solution temperature (near $32{\sim}34^{\circ}C$, cloud point). Swelling ratio of the microgel increased with increasing of the concentration of monomer (NIPAm) and decreased proportional to the concentration of crosslinker.

Synthesis and Characterization of Poly(urethane-ethyl acrylate) Hybrid Emulsion (폴리(우레탄-에틸 아크릴레이트) 혼성 에멀젼의 합성과 물성 비교 연구)

  • Cheong, In Woo;Lee, Jong Kil;Kim, Jung Hyun
    • Applied Chemistry for Engineering
    • /
    • v.16 no.1
    • /
    • pp.86-92
    • /
    • 2005
  • Poly(urethaneethyl acrylate) hybrid emulsions were synthesized to improve their thermomechanical and solvent resistance properties. In the synthesis, dimethylol propionic acid was used to impart hydrophilicity to the hybrid polymers, and ethyl acrylate monomer was added to the polyurethane prepolymer after neutralization with triethylamine. After dispersion of the neutralized prepolymer, chain extension was carried out with ethylene diamine. Consequently, poly(urethaneethyl acrylate) hybrid emulsion was prepared via soap free emulsion polymerization of ethyl acrylate with reduction-oxidation initiator couple of t-butyl hydroperoxide/sodium bisulfite at $50^{\circ}C$. Tehsile strength, 100% modulus, elongation, and solvent-resistance properties of the hybrid emulsion were measured and compared with those of polyurethane homopolymer, poly(ethyl acrylate) homopolymer, and simple blended samples.

Soap-Free Emulsion Polymerization of Styrene/Butadiene/Acrylonitrile System (Styrene/Butadiene/Acrylonitrile계 무유화제 유화중합)

  • Chung, Huey-Sil;Shin, Young-Jo
    • Applied Chemistry for Engineering
    • /
    • v.4 no.2
    • /
    • pp.284-290
    • /
    • 1993
  • The soap-free emulsion polymerization was carried out for Styrene/Butadiene system with Acrylonitrile as hydrophilic comonomer and KPS as initiator. Under the condition of below 50% conversion, the dependence of Rp on $[AN]^n$ and $[KPS]^n$ was found to be n=1.617-1.050 and n=0.83-0.96 for [AN] and [KPS], respectively. The effect of $[AN]^n$ and $[KPS]^n$ on particle number density (Np) was determined to be n=1.533 and n=0.733, respectively. The highest conversion was obtained under the conditions of pH=5 and ratio of total monomer (g) to water (g)=0.5. The mechanical properties of SBR obtained in this experiment were shown to be inferior to commercial SBR in terms of tensile strength, 300% modulus and elongation. It was found that cure rate of SBR prepared in this experiment was faster than that of commercial SBR.

  • PDF