• Korean Journal of Food Science and Technology
• /
• v.32 no.6
• /
• pp.1234-1243
• /
• 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.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.5 no.2
• /
• pp.59-62
• /
• 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.

• Macromolecular Research
• /
• v.11 no.2
• /
• pp.87-91
• /
• 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.

• KSBB Journal
• /
• v.19 no.4
• /
• pp.315-320
• /
• 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.

• 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 Korean Society on Water Environment
• /
• v.28 no.5
• /
• pp.669-675
• /
• 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

• Korean Chemical Engineering Research
• /
• v.43 no.1
• /
• pp.125-128
• /
• 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.

• Applied Chemistry for Engineering
• /
• v.28 no.1
• /
• pp.23-28
• /
• 2017

Pyrolysis characteristics of waste plastic films were investigated by using a thermogravimetric analysis and pyrolyzer-gas chromatography/mass spectrometry. Thermogravimetric analysis results revealed that the pyrolysis of waste plastic films can be divided into two distinct reactions; (1) the decomposition reaction of starch at between 200 and $370^{\circ}C$ and (2) that of other plastic polymers such as PS, PP, PE at between 370 and $510^{\circ}C$. The kinetic analysis results obtained by using the revised Ozawa method indicated that the apparent activation energy of the pyrolysis reaction of waste plastic films was also changed dramatically according to the different decomposition reactions of two major waste plastic film components. Py-GC/MS results also revealed that the typical pyrolyzates of each polymer in waste plastic films were levoglucosan (starch), terephthalic acid (PET), styrene monomer, dimer, and trimer (PS), methylated alkenes (PP), and triplet peaks (PE) composed of alkadiene/alkene/alkane. The phthalate, used as a polymer additive, was also detected on the pyrogram of waste plastic films mixture.

• Korean Chemical Engineering Research
• /
• v.46 no.3
• /
• pp.535-539
• /
• 2008

Conversion to oil, yield of styrene and formation of side products such as ${\alpha}-methyl$ styrene, ethyl benzene, benzene, toluene, dimer and trimer were affected by residue formed during thermal degradation. Also, control of reaction temperature had a difficulty at the first stage. Thus, new reaction system using wetted-wall type reactor was proposed and examined on various parameters such as reaction temperature, feeding rate and removal velocity of formed vapor. Optimun condition was obtained from continuous thermal degradation using wetted-wall type reactor and reaction kinetic study was carried out at new type reactor.