• Title/Summary/Keyword: Styrene dimer

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A Method for Analysis of Styrene Dimer and Trimer in Foods and Containers (식품 및 용기 중 스티렌 다이머 및 트리머의 분석법)

  • Sung, Jun-Hyun;Kwon, Ki-Sung;Lee, Kwang-Ho
    • Korean Journal of Food Science and Technology
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    • v.32 no.6
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    • pp.1234-1243
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    • 2000
  • A method for quantitative determination of styrene dimer and trimer, which are suspected as endocrine disruptors, in foods and containers was studied. For residual contents of styrene dimer and trimer in two-kinds of containers, which contained instant noodle and yogurt, sample pieces were completely dissolved in tetrahydrofuran. The polymer was precipitated with n-hexane, a portion of supernatant was concentrated for analysis. A sensitive method was also optimized for the quantification of styrene dimer and trimer in foods such as instant cup noodle and yogurt by using GC/MS. Limits of Detection were about 3.2-87.0 ppb for styrene dimers and trimers. The highest recovery was obtained by extraction with acetone/hexane(1:1), followed by florisil clean-up. The levels of styrene dimer and trimer migrated by food simulants were much higher in heptane.

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Isolation and Cultural Characteristics of Styrene Dimer [Endocrine Disrupter] Biodegrading Microorganism (Styrene dimer [환경호르몬 물질] 분해균주의 분리 및 배양특성)

  • ;;;Saido Katsuhiko
    • KSBB Journal
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    • v.19 no.4
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    • pp.315-320
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    • 2004
  • We examined the culture conditions and degrading characteristics of styrene dimer (endocrine disrupter) using microorganism. The isolated microbe were consisted of 3 kinds of strain. The strains were identified to Pseudomonas sp. and Klebsiella pneumoniae by API 20E kit, but one was not identified. Single strain was not grown on the C-medium containing styrene dimer. However the complex strain YH3 could grow and we confirmed it by the broth color and O.D$_{660nm}$ (optical density 660 nm). The optimal culture conditions of complex strain YH3 were 35$^{\circ}C$, 1,000 ppm (v/v) of styrene dimer and pH 7.0, respectively. In tolerance test against the organic solvents, the complex strain YH3 could grow above log P=3.1, and could degrade ethyl benzene and 2,4-D, one kind of herbicide. As a result of TLC (Thin Layer Chromatography) analysis, we confirmed that the metabolite of styrene dimer was created by YH3 after 5th day, but not at control samples.

The substitution of paper cup for the PSP noodle cup (컵라면 용기의 종이컵 대체)

  • Kim, Seong-Jin
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.5 no.2
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    • pp.59-62
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    • 1999
  • After reported that Styrene dimer and Styrene trimer was Endocrine Disrupter, if it was a fact or not, the sales of PSP noodle cup was rapidly decreased and social responsibilities of the substitution materials development was raised. Therefore we had studied many materials like paper, pulp mold, PP injection molding, PP lamination, etc as substitution materials and selected paper cup which was safe in many sides and easy to recycle. Mainly we had checked the shape, safety, stability and recycling possibility of paper cup and secured many data which could prove them.

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Novel Method for Polystyrene Reactions at Low Temperature

  • Katsuhiko Saido;Hiroyuki Taguchi;Yoichi Kodera;Yumiko Ishihara;Ryu, In-Jae;Chung, Seon-yong
    • Macromolecular Research
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    • v.11 no.2
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    • pp.87-91
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    • 2003
  • Thermal decomposition reactions of polystyrene using a new heating medium were carried out by a batch system at 190-280 $^{\circ}C$ to clarify the manner in which decomposition is initiated. Polystyrene obtained from a commercial source and low molecular weight compounds obtained from the thermal decomposition were analyzed by GC, GPC, IR, $^{13}$ C-NMR and GC-MS. The main chain underwent virtually no change by heat application. Polystyrene underwent decomposition below its molding temperature and the major decomposition products were 2,4,6-triphenyl-1-hexene (trimer), 2,4-diphenyl-1-butene(dimer) and styrene (monomer). Ethylbenzene, propylbenzene, naphthalene, benzaldehyde, biphenyl and 1,3-diphenylpropane were detected as minor products. This paper presents a new method for examining the decomposition of polystyrene at low temperature into volatile low molecular weight compounds.

A Study on Pyrolysis of Styrene Dimer Fraction (SDF) (스티렌 이량체 유분의 열분해 연구)

  • Pei, Hai-Song;Kang, Yong;Cho, Deug-Hee;Choi, Myong-Jae;Lee, Sang-Bong
    • Applied Chemistry for Engineering
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    • v.17 no.3
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    • pp.321-326
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    • 2006
  • Thermal degradation of styrene dimer fraction (SDF, main compound: 47 wt% of 1,3-diphenylpropane), 5~15% of total products produced during decomposition of waste expanded polystyrene (WEPS) was investigated. Reaction condition of $360^{\circ}C$, and 152 kPa to 202 kPa was an optimum for high pressure degradation. Under this operating condition, the yield of oil was 73.8% and the selectivities to Ben, Tol, EB, SM, and AMS were 0.4, 30.9, 15.0, 19.6, and 4.2%, respectively. Non-catalytic fixed bed continuous degradation was conducted at reaction temperatures of $510{\sim}610^{\circ}C$ and contact time ranges of 2~24 min, where the yield was increased by increasing of reaction temperature and contact time. A $Cr_2O_3$ catalyst showed the highest activity and SM yield among acid, base, and redox catalysts. The conversion of 74.6% and the yield of Ben, Tol, EB, SM, and AMS were 0.4, 21.6, 9.7, 17.9, and 3.5%, respectively at $560^{\circ}C$ and contact time of 24 min. It is thought that styrene is converted to EB and other secondary products throughout the formation of diradicals of styrene.

Analysis of Styrene Dimer and Trimer in Cup Noodle Containers (컵라면 용기중의 스티렌다이머와 트리머의 분석)

  • Lee, Kwang-Ho;Jang, Young-Mi;Kwak, In-Shin;Yoo, Seung-Seok;Kim, Ki-Myeong;Choi, Byung-Hee;Lee, Chul-Won
    • Korean Journal of Food Science and Technology
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    • v.31 no.4
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    • pp.931-937
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    • 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.

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The Continuous Pyrolysis of Waste Polystyrene using Wetted-Wall Type Reactor (Wetted-Wall Column 형 반응기를 이용한 폐 EPS 연속 열분해반응)

  • Han, Myung Sook;Han, Myung Wan;Yoon, Byung Tae;Kim, Seong Bo;Choi, Myoung Jae
    • Korean Chemical Engineering Research
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    • v.45 no.4
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    • pp.396-399
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    • 2007
  • Organic residue and carbonized solid producing from the thermal degradation gave a influence on oil conversion, formation of styrene and side products such as ${\alpha}-methyl$ styrene, ethyl benzene, dimer. Thus, new reaction system using wetted-wall type reactor was proposed and examined on influence of various parameters such as reaction temperature, feeding rate and removal velocity of formed vapor. Optimum condition were obtained from continuous thermal degradation using wetted-wall type reactor and styrene was continuously obtained as the yield up 65%.

Monitoring of Endocrine Disruptors (Bisphenol A and Styrene Oligomers) in the Streams of Cholla-namdo Province in South Korea (전라남도 지역의 하천수에 존재하는 내분비 장애물질(Bisphenol A와 Styrene oligomer)의 실태조사)

  • Park, Song-In;Chung, Seon-Yong;Kstsuhiko, Saido;Hideto, Sato;Na, Suk-Hyun
    • Journal of Korean Society on Water Environment
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    • v.28 no.5
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    • pp.669-675
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    • 2012
  • Recently, there have been active researches regarding endocrine-disrupting chemicals (EDCs). In this study, fifteen small freshwater streams in Cholla-namdo province, South Korea were investigated with respect to the concentration of the endocrine disruptors - Bisphenol A (BPA), styrene monomer (SM), styrene dimer (SD), and styrene trimer (ST) by gas chromatography-mass spectrometry (GC-MS). Measured concentration of the target compounds in the sampled water ranged from

Study for Reducement of Polymerization Time and Improvement of Stability in Manufacturing Carboxylated Styrene-butadiene Latex (카르복실화 스티렌-부타디엔 라텍스의 중합시간 단축과 안정성 개선을 위한 연구)

  • Cho, Ur-Ryong
    • Elastomers and Composites
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    • v.37 no.1
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    • pp.31-38
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    • 2002
  • Polymerization of carboxylated styrene-butadiene latex takes longer time than that of acrylic emulsion due to delocalization of radical in butadiene unit having conjugated double bond. A latex stability is the most important properties owing to use intact without separating polymer from base latex. For reducing polymerization time without decreasing any properties of latex, carbon tetra-chloride which has been used as the most popular chain transfer agent was replaced to combination of tert-dodecylmercaptane and ${\alpha}$-methylstyrene dimer. The replacement yielded reducement or 2 hr in polymerization time. In the increment step, charge amount of acrylic acid was limited to 0.3 part to restrain viscosity enhancement. Just after initial step, addition of 0.1 part acrylamide prevent polymer chain from diffusing between two region followed by giving hardness and final good adhesive force to latex particles.

Effect of Organic Residue on the Continuous Pyrolysis of Waste Polystyrene (연속식 폐 EPS 열분해 반응에 대한 잔류물의 영향)

  • Yoon, Byung Tae;Kim, Seong Bo;Lee, Sang Bong;Choi, Myoung Jae
    • Korean Chemical Engineering Research
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    • v.43 no.1
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    • pp.125-128
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    • 2005
  • Oil formation rate, composition of crude oil and formation of side products such as ${\alpha}-methyl$ styrene, ethyl benzene, benzene, toluene, dimer and trimer on thermal degradation of polystyrene were affected by various factors. Especially, formation of organic residue formed during reaction gave an important influence on formation of oil and composition of crude oil. Also, composition of formed crude oil showed a significant difference on reaction time. These results were caused by organic residue and carbonized solid formed during continuous reaction. Increase of residue and carbonized solid gave a decrease of yield of styrene and an increase of formation of ${\alpha}-methyl$ styrene, ethyl benzene, benzene, toluene. New reaction system was proposed for continuous operation at the thermal degradation of polystyrene.