• Environmental Engineering Research
• /
• v.11 no.5
• /
• pp.266-276
• /
• 2006

Commonly, the flocculant is dissolved in process or recycle water in industrial plant which has many ionic materials. Therefore, the polymer degradation in aqueous solution by chemical, mechanical or bacteriological may occur, sometimes rapidly. Even if the same flocculant is dissolved, the flocculation characteristics and the properties of dissolving polymer varied with the kind of dissolving water. In this study, we try to estimate the interaction between flocculants and ionic materials in dissolving water using self inversing emulsion polymer; polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride flocculants which have varying molecular weights and structures at a several conditions. The polymeric flocculant is dissolved in artificial dissolving water with Potassium Chloride (PC), Calcium Chloride anhydrous (CC), Potassium Hydroxide (PH), Sodium Chloride (SC), Sodium Bromate (SB) and Iron (II) Sulfate Heptahydrate (IS) as ionic sources. Experimental results indicate that the cationic and anionic ions in dissolving water induce the hydrolysis, degradation of cationic functional group and uncoiling of polymeric flocculants, therefore, the flocculation efficiency decreased by undesired polymer. According that result, it is important to estimate not only its structures and physical properties but also the qualities of dissolving water to optimize the efficiency.

• Journal of the Korean Applied Science and Technology
• /
• v.19 no.4
• /
• pp.265-272
• /
• 2002

$CaCO_{3}$ absorbed sodium lauryl sulfate (SLS) surfactant was prepared, Core-shell polymers of inorganic/organic pair, which have both core and shell component, were synthesized by sequential emulsion polymerization using styrene(St) as a shell monomer and potasium persulfate (KPS) as an initiator, We found that when $CaCO_{3}$; core prepared by adding 2,0 wt% SLS, $CaCO_{3}$ core/PSt shell polymerization was carried out on the surface of $CaCO_{3}$ particle without forming the new PSt particle during St shell polymerization in the inorganic/organic core-shell polymer preparation, The structure of core-shell polymer were investigated by measuring the degree of decomposition of $CaCO_{3}$ using HCl solution, thermal decomposition of polymer composite using thermogravimetric analyzer and morphology by scanning electron microscope.

• Elastomers and Composites
• /
• v.35 no.4
• /
• pp.281-287
• /
• 2000

Waterborne polyurethane(PU) microgel dispersions were synthesized with different mole ratio of polytetramethylene glycol(PTMG) to dimethylol propionic acid(DMPA). Particle size distribution, thermal and mechanical properties of the PU microgels were investigated. Particle size of the microgels was distributed in the range of $98{\sim}$680{\mu}m$ and decreased with increasing the mole ratio of DMPA and 1,2,6-hexanetriol. Glass transition temperature and melting temperature of the microgels were in the range of $-79.7 {\sim}-78.1^{\circ}C$, $22{\sim}24^{\circ}C$ respectively. Tensile strength and elongation of the PU microgel films were maximum in the case of 60/40 mole ratio of PTMG/DMPA.

• Applied Chemistry for Engineering
• /
• v.10 no.4
• /
• pp.523-530
• /
• 1999

Acrylic pressure-sensitive adhesive has been made utilizing organic solvents, but nowadays it is made by solvent-free system due to environmental problems. In this study, emulsion polymerization were carried out at $40^{\circ}C$ with methacrylic acid(MAA), n-butyl acrylate(n-BA) and 2-ethylhexyl acrylate(2-EHA) as monomers in the presence of anionic(sodium dodecyl sulfate, SDS) and nonionic(ethylene oxide types) surfactant mixtures. The overall conversion of the polymerization reaction in a mixed surfactant system was found to be higher than that in a single surfactant system. Emulsion stability in mixed or anionic surfactant systems was found to be over 12 week, which was better than that in nonionic surfactant system. Emulsion particle size decreased as surfactant content increased. The Tg and molecular weight of emulsion polymer were inependent of the type, the amount and the mixing ratio of surfactant. Based on the results of stability and peel strength, the optimum nonionic surfactant ratio in total 4 g of surfactant mixture systems is found to be 40~60% by weight where the nonionic surfactant has 50 ethylene oxide groups and 16~18 carbon atoms in hydrophobic alkyl chain.

• Journal of the Korean Applied Science and Technology
• /
• v.26 no.1
• /
• pp.74-79
• /
• 2009

The inorganic-organic composite particles with core-shell structure were polymerized by using styrene and potassium persulfate (KPS) as a shell monomer and an initiator, respectively. We studied the effect of surfactants on the core-shell structure of silicone dioxide/styrene composite particles polymerized in the presence of sodium dodecyl sulfate(SDS), polyoxyethylene alkylether sulfate (EU-S133D), and at none surfactant condition. We found that $SiO_2$ core / polystyrene(PS) shell structure was formed when polymerization of styrene was conducted on the surface of $SiO_2$ particles, and the concentration SDS and EU-Sl33D was $8.34{\times}10^{-2}mole/L$. The core-shell structure was confirmed by measuring the thermal decomposition of the polymer composite using thermogravimetric analyzer (TGA), and the morphology of the composite particles was characterized by transmission electron microscope (TEM).

• Journal of Adhesion and Interface
• /
• v.3 no.2
• /
• pp.45-52
• /
• 2002

기존의 점착제 합성방법에서 탈피하여 용액형 점착제(Solution)의 장점과 입자형 점착제(Emulsion)의 장점을 동시에 보유한 NAD (Non-Aqueous Dispersion Polymer)를 합성하였다. NAD는 메탄올 분위기에서 6개월 이상의 분산 안정성을 유지하였다. NAD는 용액에서 입자형 고분자의 형태를 이루고 있음을 도공 공정에서 확인하였다. 또한 기존의 아크릴 점착제의 장점과 고무계점착제의 장점을 결합한 고분자량의 점착제, GP (Graft Polymer)를 합성하였다. GP는 자체가 매우 높은 분자량을 보유하여 가교제의 첨가 없이도 우수한 물성을 나타내었다. GP는 일반적으로 고 분자량의 고분자에서 나타나는 Weissenberg effect 현상을 나타내었다. 이들의 점착제로 응용시 각각의 물성을 비교하여 나타내었다.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.85-85
• /
• 2006

The micellization behavior and the metal-nanoparticle formation in PDEAEMA-b-PHEGMA double hydrophilic block copolymers are investigated. The hydrophobic PDEAEMA block is pH-sensitive: at low pH it can be protonated and it becomes hydrophilic, leading to molecular solubility, whereas at higher pH micelles are formed; the behavior is studied by DLS, NMR and AFM. In these micellar nanoreactors, metal nanorystals nucleate and grow upon reduction with sizes in the range of a few nm's as observed by TEM and XRD. Similarly, metal nanocrystals can be formed within pH-sensitive microgels (${\sim}250nm$ in diameter), synthesized by emulsion copolymerization of DEAEMA, which also exhibit reversible swelling properties in water by adjusting the pH.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.40 no.5
• /
• pp.20-26
• /
• 2008

Behavior of micro stickies was analyzed using model micro stickies prepared with PVAc emulsion adhesive. Flocculation of micro stickies increased with temperature. Acidic state also induced greater flocculation of micro stickies since they became more unstable under these conditions. Flocculation of micro stickies increased as calcium ion concentration increased. But the presence of calcium carbonates made micro stickies dispersed indicating that calcium carbonates cause two different effects on the behavior of micro stickies. Talc increased flocculation of micro stickies because of its hydrophobic nature. Cationic polymer increased flocculation of micro stickies. Especially cationic starch has far greater effect in flocculating sticky particles by forming bridging flocculations.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.101-101
• /
• 2006

We have studied the micellisation of poly(n-butyl acrylate)-block-poly(acrylic acid) and poly(n-butyl acrylate)-graft-poly(acrylic acid) in aqueous solution. The size and structure of the formed micelles was elucidated by scattering and imaging techniques. The micelle structure depends on pH, composition, and topology: graft copolymers form much smaller micelles that block copolymers of similar composition. We have also synthesized block copolymers of acrylic acid and N-isopropylacrylamide (NIPAAm) or N,N-diethylacrylamide (DEAAm). Due to the LCST of polyNIPAAm and polyDEAAm, these block copolymers spontaneously form micelles upon heating and they form inverse micelles upon decreasing pH below 4. If the LCST block is much longer than the PAA one, this presents a very convenient way to prepare crew-cut micelles. The polymers have been successfully used as stabilizers in emulsion polymerization. They also have been conjugated to streptavidin. The conjugates reversibly form mesoscopic particles on heating.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.6
• /
• pp.53-60
• /
• 2019

The purpose of this study is to evaluate the degree of improvement in strengths by mixing blast-furnace slag and fly ash in polymer cement mortar(PCM). The test specimens are prepared with EVA polymer dispersion, two types of Admixtures (blast-furnace slag and fly ash), five kinds of polymer-cement ratios (0, 5, 10, 15 and 20%), and six kinds of admixtures (0, 3, 5, 10, 15 and 20%). Plain cement mortar is also made for comparison. From the test results, the flowing of PCM is greatly improved with the mixing of the admixtures, and strengths of PCM compared to ordinary cement mortar are also improved due to a decrease in water cement ratio. In addition, the strength characteristics of PCM by admixtures are greatly improved in flexural strength with fly ash compared to other strengths. It is apparent that the optimum mix proportions with polymer-cement ratio of 10% or more, admixture contents 5 to 10% of flay ash for flexural strength improvement of EVA-cement mortar are recommended in this study.