• Elastomers and Composites
• /
• v.55 no.4
• /
• pp.263-269
• /
• 2020

Novel flexible terpolymers with a reactive moiety were synthesized by coordination polymerization with a metallocene catalyst and a cocatalyst system. C2-symmetric rac-Et(Ind)2ZrCl2 and tri-iso-butylaluminum/dimethylanilinium tetrakis (pentafluorophenyl) borate were employed as the catalyst and cocatalyst, respectively. We synthesized reactive terpolymers consisting of ethylene, a high α-olefin content (1-hexene, 1-octene, 1-decene, and 1-dodecene), and divinylbenzene. The structure and composition of the terpolymers were characterized by 1H-nuclear magnetic resonance analysis. The catalytic activity, polymer yield, molecular weight, and molecular weight distribution were measured as functions of the chain length and high content of α-olefins. Furthermore, the thermal properties and crystallinity of the terpolymers were determined by differential scanning calorimetry and wide-angle X-ray scattering.

• Journal of the Korean Chemical Society
• /
• v.43 no.1
• /
• pp.74-84
• /
• 1999

Most of the reactions involving benzotriazoles as a synthetic auxiliary have been explained by ionic mechanisms, whereas benzotriazole-mediated radical reactions have received little attention. The reaction of 1-[(aryl)(phenylseleno)methyl]benzotriazole with $Bu_3$SnH in the presence of AIBN in benzene at reflux gave 2-aminodiphenyl selenide (16-29%), 2-aminobiphenyl (9-15%), diphenyl diselenide (30-93%), 1-(arylmethyl) benzotriazole (9-39%) and tributyltin-phenyl selenide (10-36%), whereas the compounds were treated with excess molar amount of $Bu_3$SnH in the absence of AIBN to afford N-(arylmethyl)anilines (44-66%) along with diphenyl diselenide (53-100%), benzotriazole (27-35%) and 1-(arylmethyl)benzotriazole (16-33%). Similarly, treatment of 6-aryl-6-(benzotriazol-1-yl)-1-hexenyl phenyl selenides with $Bu_3$SnH in the presence of AIBN gave 6-aryl-6-phenylamino-1-hexene (9-31%) and 1-aryl-1-oxo-5-pentene (15-44%). A mechanism for the formation of the products is proposed.

• Analytical Science and Technology
• /
• v.27 no.2
• /
• pp.100-107
• /
• 2014

Plastic has been widely used in modern artworks' materials due to its merits of process ability and mass production. In the country, value of plastic artifact is increasing but the field of plastic study is limited to industrial purpose. In this study, Identification methods of plastic were performed by SPME-GC/MS and pyrolysis-GC/MS using trace of samples. As a result of identification using SPME-GC/MS, aromatic compounds were identified from polyvinyl chloride. And alkane compounds were identified from polyethylene, and polypropylene. Aromatic compounds were identified from polystyrene, and diethylene glycol appeared in polyurethane based on polyester was identified from polyurethane. As a result of identification using pyrolysis- GC/MS, aliphatic alkenes compounds and phthalate(DEHP) were identified from polyvinyl chloride. Aliphatic alkenes compounds and phthalate(DIBP) were detected from polyethylene. 1-hexene, etc., were detected from polypropylene, aromatic compounds were identified from polystyrene, and methylene diphenyl diisocyanate which is polyurethane basic material was confirmed from polyurethane. This study suggested that non-destructive SPME and pyrolysis-GC/MS are useful to identify compounds particularly polystyrene and polyurethane. These two analytical methods were expected to be applied for identification of unidentified plastic artworks before conservation treatment.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.931-937
• /
• 1999

Styrene dimers and trimers from polystyrene cup noodle containers were analyzed by GC and GC/MS extracted with various simulants. For the quantitation of styrene dimers and trimers, 1,3-diphenylpropane (DP) and benzyln-butyl phthalate (BBP) were chosen as the standards. The results showed that the average of the styrene dimers in the containers was 603 ppm, and that of trimers was 5731 ppm. Four styrene dimers, including 1,2-diphenyl-cyclobutane, were identified as well as seven trimers such as 2,4,6-triphenyl-l-hexene. The migration of the styrene dimers and trimers, from the cup noodle containers of polystyrene into foods, was conducted using simulants including boiling water as well as soybean oil and n-heptane. In addition to, the analysis of each migrated styrene was also performed filled with boiling water into noodle and soup after certain time (5, 10, 20, 30 min). The results showed that the migration of styrene dimers and trimers from cup noodle containers was not detected in the case of using boiled water or soybean oil as a simulant, while styrene dimers and trimers were detected 1.18 ppm and 14.21 ppm, respectively, when heptane was adopted as a simulant. In the case of filling with boiled water into noodle and soup, both styrenes were not detected at 5 min and 10 min, however, some samples standing for 20 min released styrene dimers and trimers as much as 0.009 ppm, and 0.019 ppm for 30 min.

• Journal of the Korean Chemical Society
• /
• v.38 no.4
• /
• pp.295-301
• /
• 1994

The Ru(Ⅲ), Ni(Ⅱ), Cu(Ⅱ), and Pd(Ⅱ) complexes of N$_4$-polydentate ligands(meso-Me$_6$-[14]-ane, rac-Me$_6$-[14]-ane, and cyclam) have been prepared and their catalytic activity and selectivity in the oxidation of olefins in the presence of oxidant such as NaOCl, H$_2$O$_2$, t-BuOOH, and PhIO studied. The oxidations of cyclohexene, 1-hexene, cyclooctene, 1-octene, and styrene as substrates have been investigated gas chromatographically. The Ru(Ⅲ)-N$_4$ complexes showed high selectivity for epoxide in the catalyzed oxidation of olefins with NaOCl. The catalytic activities of Ru(Ⅲ)-N$_4$ complexes were discussed in terms of the flexibility of N$_4$-polydentate ligands, the Ru(Ⅲ)-Cl bond interaction and the steric effect of oxidants. The oxidation of 1-octene using PhIO as oxidant was carried out to verify. The Pd(Ⅱ) complex turned out to be more active catalyst than the Ni(Ⅱ) complexes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.6
• /
• pp.958-964
• /
• 2002

To select the irradiation-induced marker components from volatile flavor compounds in irradiated chicken, and complement the extraction problems of liquid continuous extraction (LLCE) method, the volatile compounds of irradiated (0,1,3,5 and 10 kGy) chicken were analyzed by Purge and Trap (P&T) and gas chromatography/mass spectrometry (GC/MS) methods. A total of 119 compounds were detected in irradiated chicken, and these compounds were composed mainly of 7 aldehydes,22 ketones,8 alcohols,30 esters,36 hydrocarbons,8 aromatic compounds and 8 miscellaneous compounds. Among these, only 21 compounds were detected in both LLCE and P&T methods, and the 98 other were detected in omly P&T method. Among volatile compounds detected in irradiated chicken, only 3 compounds such as hexene (r=0.96, p<0.01), propanol (r=0.93, p<0.05) and 1,3-bis(1,1-dimethylethyl) benzene (r=0.96, p<0.05) were newly selected as marker compounds in irradiated chicken by P&T method, which showed significant and high positive correlation coefficient in the change of relative concentration according to the increment of irradiation dosage.

• Elastomers and Composites
• /
• v.48 no.1
• /
• pp.10-17
• /
• 2013

Polyolefin-g-poly(t-butylstyrene) as one of the high-temperature polyolefin-based thermoplastic elastomers was synthesized by the graft-from anionic living polymerization from the styrene moieties of the linear poly(ethylene-ter-1-hexene-ter-divinylbenzene) as a soft block to form the hard end blocks, poly(t-butylstyrene). The chemistry of the anionic graft-from polymerization involved complete lithiation of the pendant styrene unit of the soft polyolefin elastomer with sec-BuLi/TMEDA followed by the subsequent graft anionic polymerization of 4-tert-butylstyrene with Mn=10,000~30,000 g/mol. The graft-from living anionic polymerization were very effective and the grafting size increased proportionally with increasing monomer concentration and the reaction times. The synthetic methodology for the multi-hydroxyl chain-end modified polyolefin-g-poly(t-butylstyrene) was proposed by using the thiol-ene click reaction between 2-mercaptoethanol and the polyolefin-g-[poly(t-butylstyrene)-b-high vinyl polyisoprene], which was obtained from the subsequent living block copolymerization using polyolefin-g-Poly(t-butylstyrene) with isoprene. The result indicated that this process produced a new well-defined functionalized graft-type polyolefin-based TPE with high $T_g$ hard block(> $145^{\circ}C$).

• Journal of Adhesion and Interface
• /
• v.2 no.2
• /
• pp.1-10
• /
• 2001

Silica for Epoxy Molding Compound (EMC) was coated via plasma-polymerization with RF plasma (13.56 MHz) as a function of treatment time, power and pressure. 1,3-diaminopropane, allylamine, pyrrole, 1,2-epoxy-5-hexene, allylmercaptan or allylalcohol were utilized for plasma polymerization coating and adhesion of coated silica was evaluated by measuring flexural strength. CTE and water absorption of EMC were also measured, and fracture surface of flexural specimen was analyzed by SEM in order to elucidate the failure mode. The plasma polymer coated silica was analyzed by FT-IR and reactivity of plasma polymer coating with epoxy resin was evaluated with DSC in order to investigate the adhesion mechanism. The EMC prepared from the silica coated with 1,3-diaminopropane or allylamine exhibited high flexural strength, low CTE, and low water absorption compared with the control sample, and also exhibited 100% cohesive failure mode. These results can be attributed to the chemical reaction between the functional groups in the plasma polymer coating and epoxy resin, and also consistent with the results from FT-IR and DSC analysis.

• Journal of Environmental Science International
• /
• v.23 no.9
• /
• pp.1593-1600
• /
• 2014

Adsorption and desorption characteristics of the representative 10 kinds components consisting of gasoline vapor on activated carbon were investigated at the temperature range of $-30^{\circ}C{\sim}25^{\circ}C$. The breakthrough curves of each vapors obtained by the Thomas model were well described the breakthrough experimental results of this study. The breakthrough times of each vapors were correlated with the molecular weight, density, and vapor pressure. The breakthrough times had greater correlation with boiling point than molecular weight and density. The slope of the breakthrough curve was a proportional relationship with the rate constant (k) of Thomas model expression. The higher the slope of the breakthrough curve, the rate constant was larger. The biggest slope vapor had the smallest adsorption capacity ($q_e$). Adsorption and desorption characteristics of mixed vapor similar to the gasoline vapor were studied at room temperature ($25^{\circ}C$). The mixed vapor consisting of 9 components; group A (pentane, hexene, hexane), group B (benzene, toluene), group C (octane, ethylbenzene, xylene, nonane) was examined. Group A was not nearly adsorbed because of substitution by group C, and the desorption capacity of group A was smaller than group C. The adsorbed substances were confirmed to be Group C.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.5
• /
• pp.634-638
• /
• 2004

Titanium silicalite-1 (TS-1) molecular sieve was produced by microwave heating of amorphous titanium-containing solid precursors after impregnation with aqueous TPAOH solution. $SiO_2-TiO_2$ xerogel, sub-micron sized $SiO_2-TiO_2$ prepared by thermal plasma process, and Ti-containing mesoporous silica, Ti-HMS, were tested as the solid phase substrates. Highly crystalline product was obtained within 30 min. after microwave irradiation with yields over 90% using $SiO_2-TiO_2$ xerogel, which showed essentially identical physicochemical properties to TS-1 prepared by conventional hydrothermal method. Excellent catalytic activity was also obtained for 1-hexene epoxidation using $H_2O_2.\;SiO_2-TiO_2$ particles prepared by thermal plasma and Ti-HMS were found inferior as a substrate for TS-1, probably due to difficulties in wetting the surface uniformly with TPAOH.