• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.998-1008
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• 1994

Copolyeters consisted of p-oxybenzoly, naphthalene isomer and dimethyldisiloxyl group in different comonomer sequences were synthesized by solution polycondensation and characterized. The naphthalene isomers used in this study were of the 1,4 1,5, 2,6 and 2,7 naphthylene units. The inherent viscosities of the polymers were between 0.27~0.42dl/g and all of the polymers, with the exception of the 2,7-ordered copolyester, showed enantiotropic nematic behavior. Annealing the copolyesters resulted in increasing molecular weights and degree of crystallinity of crystallizable compositions. Ordered copolyesters exhibit significant differences in thermal transitions, thermal stability, crystalline properties and liquid crystallinity when compared with the properties of the corresponding radom copolyesters.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.137-141
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• 2008

Copolymerization of ethylene and ${\alpha}$-olefin using $rac-Et[Ind]_2ZrCl_2/MAO$ catalyst embedded onto polysty-rene was examined. The embedded catalyst was prepared by polymerizing a small amount of styrene with $rac-Et[Ind]_2ZrCl_2$. The catalytic activities of the embedded catalyst were higher than those of the homogeneous catalystregardless of comonomer type and the characteristic of the active sites of the embedded catalyst was not affected duringthe embedding process. Based on the DSC and NMR analyses of the produced copolymers, it was thought that theembedded catalyst had similar or slightly better comonomer incorporation ability. Furthermore, the copolymers produced by the embedded catalyst had higher bulk densities and better particle morphology than those by the homogeneous catalyst.

• Journal of Fashion Business
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• v.11 no.5
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• pp.155-164
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• 2007

Viscose rayon has advantages such as vivid luster, good dyeability, low static electricity, good absorbance and good spinnability but also has flaws such as easy crease and decrease of physical properties when it gets wetting, and it requires dry cleaning. Therefore in order to synthesize the polymer to solve the problems of rayon while keeping the advantages of it, this study made the high specific gravity polyester for ultra drape property and high contraction polyester for rayon-like fiber having volume, soft and warm sense. The polyester with high specific gravity, 1.47 was made by adding 7 wt% of $BaSO_4$ as additive. High contraction polyester was made by copolymerization by using IPA 5 mole% to increase the amorphous region as comonomer and also using Newpol BPE-20(NPE) 1.5 wt% not to decrease the properties.

• Journal of Photoscience
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• v.9 no.1
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• pp.23-28
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• 2002

In order to obtain thermal-stable, low birefringent, and low optical loss waveguiding materials, we synthesized several fluorinated poly (maleimide-co-glycidylmethacrylate)s using a pentafluorophenylmaleimide (PEM) and two kinds of methacrylate derivatives as comonomers and glycidylmethacrylate as a crosslinker. One comonomer is a linear fluorinated methacrylate (HFBM) and another is a bulky norbornane-derived methacrylate (NMMA). These copolymers could be self-crosslinked by heating due to epoxy groups of glycidylmethacrylates. As a maleimide contents increased to 50 mol%, these copolymers showed high decomposition temperatures of above 300$^{\circ}C$. The refractive index could be precisely controlled by the variation of PFM/HFBA or PFM/NMMA feed ratio in the range of 1.410∼1.508 at 643 nm. The copolymers had very low birefringence in the range of 1∼5${\times}$10$\^$-4/.

• Proceedings of the Korean Fiber Society Conference
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• 1987.06b
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• pp.12-12
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• 1987

To improve the fibrillation phenomenon and processibili to of poly(p-phenyleneterephthalamide) (PPD-T) , a P/E copolyamide was prepared by introducing 4,4'-ethylene dianiline (EDA) into rigid chain backbone. The effects of semi-flexible segment on the liquid crystalline properties were investigated. The EDA, used as a comonomer, was prepared by catalylitic reduction of p,p'-dinitrophenyl , obtained by oxidative coupling of p,p'-dinitrotoluene. Various high molecular weight PIE copolyamides were prepared by low temperature solution polycondensation of terephthaloyl chloride (TPC) with various mixtures of p-phenylene diamine (PPD) and EOA. The PfE copolyamides were completely dissolved in 100% svlfuric acid, and the phase transition of P/E copolyamide-sulfuric acid systems was examined in teams of concentration and temperature. Over the chemical compositions, PIE=911, 812, and 713, solutions of anisotropic single phase were acquired. In particular, the two mixing ratios, 911 and 812, gave a good anisotropic spinning dope.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.371-377
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• 1973

The low temperature anionic copolymerization of p-tolylisocyanate ($M_1$) with n-hexylisocyanate ($M_2$) in DMF was carried out with NaCN. Copolymers were characterized by osmometry and I. R. spectrophotometry. Also copolymer composition was analyzed by spectral measurements. The behavior of this copolymerization system was the type of less ideal, that is the $M_2$ prefers to react exclusively with the same kind of species. The stress-strain behavior of the copolymer obtained from equimolar comonomer feed exhibited somewhat brittle or rigid character.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.440-444
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• 1998

Poly(phenylene sulfide-co-phenylene sulfide sulfone), PPS/PPSS copolymers were synthesized from p-dichlobenzene(DCB), p-dibromobenzene(DBB), p-diiodobenzene(DIB), 4-chlorophenyl sulfone(CPS) and sodium sulfide as comonomers under high temperature and pressure utilizing N-methyl-2-pyrrolidinone(NMP) as solvent. The yield of PPS/PPSS copolymer shoed maximum at $190^{\circ}C$ with [DBB]/[CPS] and [DIB]/[CPS] comonomer pair, while [DCB]/[CPS] pair exhibited maximum yield at $230^{\circ}C$. The change of yield is in the order of I>Br>Cl as leaving groups were in accordance with nucleophilic aromatic substitution reaction mechanism suggested for the synthesis of PPS type polymers. The molecular weight of PPS/PPSS copolymer was the highest($M_w=8,330g/mol$) with [DBB]/[CPS] comonomers in which [CPS] was 10 mole%. The PPS/PPSS copolymer made with 10 mole% of [CPS] showed about $15^{\circ}C$ higher $T_g$ and $15^{\circ}C$ lower $T_m$ than those of PPS homopolymer, which may be useful from the processing and thermal property point of view. The PPS/PPSS copolymer with 30 mole% of CPS or above did not exhibit Tm. The PPS/PPSS copolymer obtained with comonomer feed ratio of [DBB]/[CPS] = 95/5 mole% under $240^{\circ}C$ showed even higher molecular weight($M_w=10,300g/mole$) than PPS homopolymer made under similar reaction condition, retaining high crystallinity and thermal stability.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.267-276
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• 2020

Poly(epichlorohydrin) copolyol series (PECH copolyols) were synthesized via cationic ring-opening copolymerization (ROCP) of oxirane-based monomers and effects of reaction temperature, solvent type, and initiator were studied. As a comonomer, two types of alkylene oxides were used, and polymerization conditions were conducted both with diethylene glycol (DEG) as an initiator in methylene chloride (MC) solvent and tripropylene glycol (TPG) in toluene solvent. In order to induce the active monomer (AM) mechanism in the ring-opening copolymerization reaction, the monomer was injected by an incremental monomer addition (IMA) method using a syringe pump, and the polymerization was performed at -5 ℃. PECH copolyol, a synthesized ephichorohydrin (ECH)-based copolyol, was converted to glycidyl azide-based energy-containing copolyol (GAP copolyol) by azadizing the ECH unit through a substitution reaction. It was confirmed that the synthesized azide copolyol had little effects on changes of the solvent and the initiator. Also, the molecular weight increased 500 after the azide reaction, thereby the GAP copolyol was polymerized as designed. As the content of the comonomer increased, both the T_g and viscosity tended to decrease due to the influence of the alkyl chain length. It is possible to fundamentally prevent CH₃N₃ amount produced in the azide reaction process, and it is expected that a large-scale process could be achievable.

• Polymer(Korea)
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• v.25 no.2
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• pp.186-198
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• 2001

pH/Thermal sensitive copolymers with the various acidic comonomer compositions composed of N-isopropylacrylamide (NIPAAm) with acrylic acid (AAc), 2-acrylamido glycolic acid (AAmGAc), and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) were synthesized by free radial polymerization. In this study, to characterize the effect of different acidic comonomer composition and pH on the lower critical solution temperature (LCST) behaviors of their copolymers. phase transition experiments were performed with a thermo-optical analyzer (TOA). The phase transition temperature (T$^{p}$ ) of aqueous poly(NIPAAm-co-AAc) solution was lowered with increasing the ionization of the acid group in AAc, that is, the ionized state induced the electrostatic repulsion of ionized groups. In contrast, when AAmGAc was introduced into PNIPAAm, T$^{p}$ was little changed at pH 1-3, whereas climbed up significantly from pH 1 to pH 3. In the range of pH 6-10, Tp was lower than that of pH 3-5. This result was considered to be \"Ionic Screen Effect\" and this effect had been also observed in the case of poly(NIPAAm-co-AMPS).-co-AMPS).

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.526-530
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• 2014

Polystyrene-poly(etheramic acid) core-shell particles were prepared by dispersion polymerization of styrene using poly(etheramic acid) obtained by the reaction of 2,2'-bis[4-(3,4-dicarboxyphenoxy) phenyl]propane dianhydride and 3,5-diamniobenzoic acid as a stabilizer. 4-Vinylbenzyltrimethylammonium chloride was used as a comonomer to increase the binding efficiency of poly(etheramic acid). When the ethanol-water mixture (7 : 3) was used as a reaction medium, particles were stabilized well and the size distribution of particles was fairly narrow. The particle size increased with the amount of styrene. The particles polymerized in the dimethylformamide-water mixture had a broad size range. Polystyrene-poly(etheramic acid) core-shell particles were transformed to polystyrene-polyetherimide core-shell particles by the chemical imidization of shells.