• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.121-125
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• 2007

Siloxane monomer and oligomer were introduced to n-butyl acrylate and methyl methacrylate copolymer for improvement of water resistance and tactile sensation of acryl-type emulsion. Terpolymerimerization of n-butylacrylate, methyl methacrylate and siloxane monomer or oligomer was carried out in aqueous solution. The glass transition temperature (Tg) of terpolymer decreased with increasing siloxane monomer, however, the Tg of terpolymer increased with increasing siloxane oligomer due to the crosslinking of acrylated end group. The adhesion property and surface energy of the obtained terpolymer decreased with introducing siloxane monomer or oligomer in terpolymer. Decrement of tack and surface energy means the enhancement of water resistance and tactile sensation of the emulsion.

• Polymer(Korea)
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• v.38 no.5
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• pp.620-625
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• 2014

The effect of polyvinyl alcohol/polyamide-epichlorohydrin (PVA/PAE) complex strengthening additive on dry and wet strength and surface properties of paper was investigated. The enhancements of dry and wet strength and dimensional stability were found when PVA/PAE was applied as a complex strengthening additive compared with the cases of applying individual PVA or PAE. This was understood as physical crosslinking between PVA and PAE in the PVA/PAE complex strength additive. This complex strengthening additive also lowered surface roughness and increased sizing. As a result, PVA/PAE complex strengthening additive provided the distinctive gain dot in printed papers.

• Polymer(Korea)
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• v.34 no.6
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• pp.574-578
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• 2010

In this study, the caprolactone modified hydroxy acrylates (CHAs) were synthesized by ring-opening reaction of caprolactone and 2-hydroxyethyl acrylate (2-HEA) as initiator. Also, the caprolactone modified urethane acrylate (UA) oligomers were synthesized by condensation reaction of previously synthesized CHAs, 2-hydroxyethyl acrylate (2-HEA) and hexamethylene diisocyanate trimer (HDT). Using the hydroxy number of CHAs, the molecular weights of the CHAs were calculated easily and their molecular weight was similar to the theoretical molecular weight of them. The viscosity of UA oligomers decreased as increasing a content of CHA in the UA oligomer. Cure films were prepared from UA oligomer, reactive diluents, and UV initiator to investigate their physical properties. The thermal stability and color difference on high temperature for the cured film were improved as increasing the crosslinking density. Their surface hardness was also increased as increasing crosslinking density of the cured films, but their elongation at break was decreased.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.305-311
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• 2019

The acrylic copolymer was designed and prepared for soft lens with high content. The copolymers were prepared using 2-hydroxyethyl methacrylate(HEMA) as a monomer and ethylene glycol dimethacrylate(EGDMA), glycerol dimethacrylate(GD), or glycerol 1,3-diglycerolate diacrylate (GDD) as a cross linking agent. The water content for high water content lens was 46%, which was higher compared to general purpose of 36%. The contact angle decreased from 38.6 to 34.4, which appears hydrophilic surface. The tensile strength decreased from 0.1 Mpato 0.08, then again to 0.05 as hydrophilic properties of cross linking agents increased. No phase separation was observed in the cross section of lens using scanning electron microscope. The real-time infrared technique was used in photo-polymerization. The initial polymerization rate increased from 0.6 to 0.9, depending on crosslinking agent.

• Elastomers and Composites
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• v.54 no.1
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• pp.54-60
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• 2019

The rapid development of the automobile industry is an important factor that led to the dramatic development of synthetic rubber. The tread part of tire that comes in direct contact with the road surface is related to the service life of the tire. Rubber compounds used in tire treads are often blended with SBR (styrene-butadiene rubber) and BR (butadiene rubber) to satisfy physical property requirements. However, when two or more kinds of rubber are blended, phase separation and silica dispersion problems may occur due to non-uniform mixing of the rubber. Therefore, in this study, we synthesized an SBR copolymer with the same composition as that of a typical SBR/BR blend compound by controlling butadiene content during ESBR (emulsion styrene-butadiene rubber) synthesis. Subsequently, silica filled compounds were manufactured using the synthesized ESBR, and their mechanical properties, dynamic viscoelasticity, and crosslinking density were compared with those of the SBR/BR blended compound. When the content of butadiene was increased in the silica filled compound, the cure rate accelerated due to an increased number of allylic positions, which typically exhibit higher reactivity. However, the T-2 compound with increased butadiene content by synthesis less likely to show an increase in crosslink density due to poor silica dispersion. In addition, the T-3 compound containing high cis BR content showed high crosslink density due to its monosulfide crosslinking structure. Because of the phase separation, SBR/BR blend compounds were easily broken and showed similar $M_{100%}$ and $M_{300%}$ values as those of other compounds despite their high crosslink density. However, the developed blend showed excellent abrasion resistance due to the high cis-1,4 butadiene content and low rolling resistance due to the high crosslink density.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2665-2668
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• 2014

Aptamers are oligonucleotides or peptide molecules that are able to bind to their specific target molecules with high affinity via molecular recognition. In this study, we present development of aptamer-based precipitation assays (or simply aptamoprecipitation) for His-tagged proteins and thrombin to compare their purification efficiency with other conventional affinity precipitation methods. A crosslinking method was employed to immobilize thiol-functionalized aptamers onto the surface of polystyrene resins, enabling them to specifically bind to His-tag and to thrombin, respectively. The resulting aptamer-functionalized resins were successfully applied via a one-step experiment to purification of His-tagged proteins from complex E. coli and to thrombin extraction, exhibiting superior or at least comparable purification results to the conventional immobilized metal affinity precipitation or immunoprecipitation.

• Macromolecular Research
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• v.17 no.5
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• pp.339-345
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• 2009

The core/shell type structure of the highly crosslinked poly(glycidylmetharylate-co-divinylbenzene) microspheres prepared in the precipitation polymerization in acetonitrile was thoroughly verified by means of swelling, $^1H$ NMR, XPS, TEM and TGA measurements. In the XPS measurement, the higher the GMA content, the higher the oxygen content was observed, implying that the higher content of GMA is observed in the particle surface. The further verification of the core/shell structure of the poly(GMA-co-DVB) particles was carried out using $^1H$ NMR and TEM techniques, resulting in the poly(GMA-co-DVB) particles with the GMA rich-phase and DVB rich-phase. In overall, the poly(GMA-co-DVB) microspheres consist of a highly crosslinked DVB rich-phase in the core and slightly or non-crosslinked GMA rich-phase in the shell part due to the different reaction ratios between two monomers and self-crosslinking density of DVB.

• Korean Journal of Agricultural Science
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• v.38 no.3
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• pp.459-464
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• 2011

A simplified model for the colloidal calcium phosphate (CCP) nanocluster was developed from an active role of phosphate in the precipitation of casein (CN)/Ca mixtures and the composition of casein micelles (CM). The possible shape of the CCP nanocluster was selected as a tetrahedron, and we estimated that 4 CN molecules were involved in crosslinking a single CCP nanocluster. Similar values were obtained for the number of CN molecules involved in stabilizing the nanocluster when the number of CNs attached onto each nanocluster surface was deduced from the composition of CM. If one phosphoserine cluster consisted of 3 phosphoserine residues, the theoretical molecular weight and volume for the nanocluster were estimated to be 4,898 g/mol and 2.88 $nm^3$, respectively. It was also shown that the position of Ca present in our model were reasonably located to accommodate the serine phosphate in CN molecule.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.198-201
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• 1994

Stability improvement of fragile LB films was attempted by polyion complexation of monolayers at the air-water interface and crosslinking of the resulting LB films. The spreading polymers were synthesized by radical copolymerization of monoalkyl itaconate with oligoethyleneglycol methyl vinylether, and poly(allylamine) was employed as the subphase polymer. Formation and characteristic of the monolayers were comfirmed by surface pressure-area($\pi$-A) isotherms. The two different polymers formed polyion-complexed monolayer through the formation of carboxylate/ammonium salt at the air-water interface. Y-type deposition occurred on solid substrates, and the transfer ratio was over 0.7. Pores (diameter, 0.1$\mu\textrm{m}$) of a membrane filter could be covered by polyion-complexed 6 layers. Interactions of the polymers with metal ions were investigated of the air-water interface and in the LB films. The structure change and macroscope morphology of the LB films were confirmed by FT-lR and SEM, respective1y.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.3
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• pp.414-422
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• 1999

The purpose of this study is to develop multifunctional fabric that was improved antimicrobial activity and reduction rate of gas by treatment of mixture that was blended chito colla ad crosslinking material for Nylon. Antimicrobial activity was proved 99% reduction rat of gas in case of treated was icreased. The surface of treated fiber noted harshness and irregularity. Whiteness of treated on the baking condition was decreased as time and temperature was increased. Air permeability and moisure regain of treated equally was maintained. Water absorption and static voltage of treated were increased. KOSHI and T.H.V. of treated was increased than that of untreated B/W of treated was improved that, that of untreated and 2HB/B. W/T of treated were reduced.