• Polymer(Korea)
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• v.30 no.5
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• pp.432-436
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• 2006

The new dinuclear CGC (constrained geometry complexes) with indenyl and methyl sub-stituted indenyl and polymethylene bridge have been synthesized, and the copolymerization of ethylene and styrene has been studied in the presence of methylalumionoxane. The activity of 12-methylene and 9-methylene bridged dinuclear CGC were 4 times higher than that of 6-methylene bridged dinucleay CGC. This result might be understood by the implication that the steric effect rather than the electronic effect nay play a major role to direct the polymerization behavior of the dinuclear CGC. The dinuclear CGCs are very efficient to incorporate styrene in backbone. The styrene contents in the formed co-polymers ranged from 6 to 45 mol% according to the polymerization conditions. The melting temperature of copolymers disappeared at high content of styrene (about 11 mol%) There is no styrene-styrene diblock sequence in copolymers. This result Indicates that the dinuclear CGC are very effective to generate random copolymer of ethylene and styrene.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.159-160
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• 2006

We developed novel catalyst, PHENICS composed of the combination of a cyclopentadienyl group to perform a high catalytic activity and a bulky phenoxy group, which performs the production of high molecular weight polyolefin. The polymerization activity of PHENICS at high temperature is higher than well-known CGC catalyst. PHENICS showed the excellent ability of comonomer incorporation into polymer chain. The obtained copolymer had a high molecular weight. The PHENICS catalyst is also active to the copolymerization of ethylene and several vinyl comonomers such as styrene, norbornen, and conjugated dienes. We will discuss new cocatalysts for PHENICS to improve activity and the ability of molecular weight control.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.195-198
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• 2002

Poly(crown ether)s as a functional polymer materials have powerful and selective complexation properties with a large number of metal cations and have advantage of facility of their recovery and modification of their complexation properties in contrast to their monomeric analogues. Poly(crown ether)s having pendant macrocyclic groups can easily form 2:1-type crown ether ring-to-cation complexes with particular metal ions which are a little larger than the cavity of the crown ether ring. (omitted)

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.71-76
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• 2006

Porous polymer monolithic columns were prepared by the direct free radical copolymerization of methacrylic acid and ethylene glycol dimethacrylate within the confines of a chromatographic column in the presence of toluene-dodecanol as a porogenic solvent. The separation characteristics of the monolithic columns were tested by a homologous series of xanthine derivatives, theophylline and caffeine. The effects of the polymerization mixture composition and polymerization condition, mobile phase composition, flow rate and temperature on the retention times and separation efficiencies were investigated. The results showed that the selection of correct porogenic solvents and appropriate polymerization conditions are crucial for the preparation of the monolithic stationary phases. The separation efficiency was only extremely weakly dependent on flow rate and temperatures. Hydrogen-bonding interaction played an important role in the retention and separation. Compared with conventional particle columns, the monolithic column exhibited good stability, ease of regeneration, high separation efficiency and fast analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.221-226
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• 2008

Novel synthetic routes were proposed for hydroxy-terminated Poly(EO-co-THF) by Cationic ring-opening copolymerization of Tetrahydrofuran(THF) and Ethylene oxide(EO). It was carried out using Boron trfluoride tetrahydrofuranate($BF_3$ THF complex) as catalyst in the presence of 1,4-butandiol. The resultant products are well-defined linear polyetherpolyol. Polyurethane(TPU) were prepared using resultant polyetherpolyol with IPDI/N-100 as curing agent and TPB(Triphenylbismuth) /MA(Maleic anhydride) mixture as cure catalyst. Mechanical properties of TPU prepared from poly(EO-co-THF) polyol were investigated and compared with polyurethane using ATK HTPE.

• Macromolecular Research
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• v.11 no.4
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• pp.231-235
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• 2003

Phase behavior information is necessary for accomplishing homogeneous copolymerization to obtain high yield of copolymers and prevent a fouling problem. Cloud-point data to $160^{\circ}C$ and 1,450 bar are presented for five $C_6$ hydrocarbon solvents, normal hexane, 2,2-dimethyl butane, 2,3-dimethyl butane, 2-methyl pentane, and 3-methyl pentane, with poly(ethylene-co-53 mol% norbornene) ($PEN_{53}$). The pressure-concentration isotherms measured for $PEN_{53}$/n-hexane have maximums that range between 5 and 12 wt% $PEN_{53}$. The cloud-point curves for $PEN_{53}$ all have negative slopes that decrease in pressure with temperatures. The single-phase region of $PEN_{53}$ in n-hexane is larger than the regions in 2,2-dimethyl butane, 2,3-dimethyl butane, 2-methyl pentane, and 3-methyl pentane. The cloud-point curve of $PEN_{53}$ in 2,2-dimethyl butane is located at higher temperatures and pressures than the curve in 2,3-dimethyl butane due to the reduced dispersion interactions with and limited access of 2,2-dimethyl butane to the copolymer. Similar cloud-point behavior is observed for $PEN_{53}$ in 2-methyl pentane and 3-methyl pentane.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.417-421
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• 2005

Novel two synthetic technics using cationic ring-opening copolymerization of tetrahydrofuran (THF) and ethylene oxide (EO), or just polymerized EO on Poly-THF, could lead to random hydroxyl-terminated poly(EO-ran-THF) or tri-block PEG-PTHF-PEC, respectively. These reactions were carried out using $BF_3O(C_2H_5)_2$ as catalyst, 1,4-butanediol or PTHF as diol initiator. Copolymer structures were controlled by monomer feed ratio, or initial PTHF and EO monomer added amount. The molecular weight of polymer was merely dependant on the ratio of [monomer]/[diol], but not on catalyst. Well-defined random and block hydroxyl-terminated copolyether was found to be as the prepolymer for the propellant binder from the experiment to polyurethane with them.

• Polymer(Korea)
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• v.24 no.6
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• pp.751-756
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• 2000

The copolymerization of ethylene (E) and cycloolefin (CO) was carried out with rac-Et(Ind)$_2$ZrC $l_2$ and MMAO cocatalyst system to examine the effect of CO structure on catalytic behaviors and properties of copolymer (COC). Various cycloolefins such as norbornene (N), 5-phenyl-2-norbornene (PN) and 5-vinyl-2-norbornene (VN) were used as comonomers. With increasing [CO]/[E] feed ratio, the catalytic activity decreased while the glass transition temperature of copolymer increased. With analysis of the structure of E/VN copolymer by FT-IR and $^{l3}$C-NMR, it was found that the cyclic C=C bond of VN comonomer is selectively polymerized and the vinyl C=C bond remains unreacted. The resulting vinyl C=C bond attached into copolymer provided the functionalization moiety using glycidyl methacrylate.e.

• Elastomers and Composites
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• v.24 no.2
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• pp.110-121
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• 1989

The radical initiated graft copolymerization of acrylonitrile(AN) and 4-chlorostyrene(4-Clst) onto ethylene-propylene-diene terpolymer(EPDM) rubber was investigated under various conditions. Graft copolymer(AU-EPDM-4-Clst) was isolated b: selective solvent extraction and identified by using IR spectroscopy. The percent grafting is determined as a function of solvent, reaction time, and monomer mole ratio. Percent grafting decreased in the order of tetrahydrofuran(THF)>THF/ethyl acetate(EA)(1 : 1)>cyclohexane/EA(1 : 1)>n-hexane/EA(1 : 1). Grafting increased continuously with increasing the reaction time up to 40 hr, beyond which the grafting levelled off. It was observed that percent grafting increased as increasing [4-Clst]/[AN] mole ratio, but decreased when [4-Clst]/[AN] mole ratio was higher than 1.60. The light resistance of graft copolymer(AN-EPDM-4-Clst) was better than that of ABS.

• Korean Journal of Materials Research
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• v.33 no.1
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• pp.1-7
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• 2023

The physical and antibacterial properties of ophthalmic lenses fabricated by copolymerization with hydrogel monomers using two types of graphene were measured, and their usability as contact lens materials was analyzed. For polymerization, silicone monomers, including SID-OH, 3-(methacryloxy)propyl tris(trimethylsiloxy)silane, and decamethylcyclopentasiloxane, were used, and N,N-dimethylacetamide, ethylene glycol dimethacrylate as a crosslinking agent, and azobisisobutyronitrile as an initiator were added. Also, graphene oxide nanoparticle (GON) and graphene nanoplate (GNP) were used as an additive, and the physical properties of the lenses fabricated after copolymerization were evaluated. The fabricated lenses satisfied the basic physical properties of general hydrogel contact lenses and showed the characteristics of lenses with high water content, and the disadvantage of very weak durability, due to low tensile strength. However, it was confirmed that the tensile strength and antibacterial properties were greatly improved by adding GON and GNP. With GON, the oxygen permeability and refractive index of the fabricated lenses were slightly improved. Therefore, it was determined that the graphene materials used in this study can be used in various ways as a contact lens material.