Styrene Oligomers Research Articles

Scaling relations for brittle fracture of entangled polystyrene melts and solutions in elongational flow

The criterion for brittle fracture of entangled polymer liquids [Wagner et al., J. Rheol. 62, 221–223 (2018)] is extended by including the effects of finite chain extensibility and polymer concentration. Crack initiation follows from rupture of primary C–C bonds, when the strain energy of entanglement segments reaches the energy of the covalent bond. Thermal fluctuations will concentrate the strain energy on one C–C bond of entanglement segments, leading to bond scission and rupture of polymer chains followed by crack initiation and fast crack growth. In start-up flows, entanglement segments characterized by long relaxation times, i.e., predominantly those in the middle of the polymer chain, will be the first to reach the critical strain energy and will fracture. Recent experimental data of Huang [Phys. Fluids 31, 083105 (2019)] of fracture of a monodisperse polystyrene melt and of several solutions of monodisperse polystyrenes dissolved in oligomeric styrene are in agreement with the scaling relations for critical Weissenberg number as well as Hencky strain and stress at fracture derived from this fracture criterion and the extended interchain pressure model [Narimissa, Huang, and Wagner, J. Rheol. 64, 95–110 (2020)].

Accumulation of styrene oligomers alters lipid membrane phase order and miscibility

Growth of plastic waste in the natural environment, and in particular in the oceans, has raised the accumulation of polystyrene and other polymeric species in eukyarotic cells to the level of a credible and systemic threat. Oligomers, the smallest products of polymer degradation or incomplete polymerization reactions, are the first species to leach out of macroscopic or nanoscopic plastic materials. However, the fundamental mechanisms of interaction between oligomers and polymers with the different cell components are yet to be elucidated. Simulations performed on lipid bilayers showed changes in membrane mechanical properties induced by polystyrene, but experimental results performed on cell membranes or on cell membrane models are still missing. We focus here on understanding how embedded styrene oligomers affect the phase behavior of model membranes using a combination of scattering, fluorescence, and calorimetric techniques. Our results show that styrene oligomers disrupt the phase behavior of lipid membranes, modifying the thermodynamics of the transition through a spatial modulation of lipid composition.

Sandy beaches as hotspots of bisphenol A

Bisphenol A (BPA) poses a serious environmental threat and health concern. This study presents the global monitoring of BPA on oceanic sandy beaches. According to monitoring results, many beach sands contain a harmful concentrations of BPA. Likewise, styrene oligomers (SOs), anthropogenic chemicals derived from polystyrene plastics, show similar concentrations as BPA. This study shows a strong, positive correlation between BPA and SOs. The results indicate that probably BPA-containing materials including micro- and nano-plastics can be an important source of BPA to the sand beaches. Therefore, BPA presents potential health risks to people spending considerable time on the beach.

Current contamination status of traditional and emerging persistent toxic substances in the sediments of Ulsan Bay, South Korea

Contamination status of traditional and emerging persistent toxic substances (PTSs) in sediments and their major sources were investigated in Ulsan Bay, Korea. A total of 47 PTSs, including 15 traditional PAHs, ten styrene oligomers (SOs), six alkylphenols (APs), and 16 emerging PAHs (E-PAHs) were analyzed. Concentrations of traditional PAHs, SOs, and APs ranged from 35 to 1300 ng g−1 dry weight (dw), 30 to 3800 ng g−1 dw, and 30 to 430 ng g−1 dw, respectively. For the last 20 years, PTSs contamination in the bay area has been improved. However, 12 E-PAHs were widely detected in sediments, with a maximum of 240 ng g−1 dw (for benzo[e]pyrene) at the creek site. These E-PAHs seemed to originate from surrounding activities, such as biomass combustion, mobile sources, and diesel combustion. Due to environmental concerns for E-PAHs, further research on the potential toxicity, distribution, and behavior of these compounds should be implemented.

Construction of a top-loading adiabatic calorimeter equipped with a refrigerator

A top-loading type adiabatic calorimeter equipped with a refrigerator, which functions in the temperature range of 20–300 K, is developed. Since the refrigerator is built in, measurements can be conducted without replenishing liquid nitrogen or liquid helium; this, in addition to the top-loading type calorimeter features, reduces the time required to set the sample by 10 min. The heat capacity of benzoic acid, used as a standard sample for heat capacity measurement, is measured to evaluate the device performance. The heat capacity measurement imprecisions were ±0.8 % at 20–50 K, ± 0.3 % at 50–130 K, and ±0.2 % at above 130 K. The inaccuracies of the heat capacity from the benzoic acid measurement results were ±1.1 % at 20–100 K and ±0.9 % at 100–300 K. These performance results are the same for any traditional adiabatic calorimeter considering the heat capacity ratio between the sample and the cell. Using this device, the molecular-weight dependence of the heat capacity of the styrene oligomer in the solid state is measured and the effect of the end groups on the heat capacity is investigated. It is suggested that the influence of the end group on the heat capacity disappeared rapidly as the molecular weight increased.

Low Temperature Decomposition of Polystyrene

Styrene oligomers (SOs), of styrene (styrene monomer, SM), 1,3-diphenylpropane (styrene dimer, SD1), 2,4-diphenyl-1-butene (styrene dimer, SD2) and 2,4,6-triphenyl-1-hexene (styrene trimer, ST), had been detected in the natural environments far from industrial area. To confirm SOs formation through thermal decomposition of polystyrene (PS) wastes in the nature, purified polystyrene (SO-free PS) has been shown to decompose at 30 to 150 °C. The SO ratio of SM:SD:ST was about 1:1:5 with ST as the main product. Mass spectrometry with selected ion monitoring was used for the quantitative analysis of the trace amounts of SOs. The rate of PS decomposition was obtained as k(year−1)=5.177 exp(−5029/T(K)) based on the amount of ST. Decomposition kinetics indicated that not only does drifting lump PS break up into micro/nano pieces in the ocean, but that it also subsequently undergoes degradation into basic structure units SO. According to the simulation at 30 °C, the amounts of SOs in the ocean will be over 400 MT in 2050.

Trophic transfer of persistent toxic substances through a coastal food web in Ulsan Bay, South Korea: Application of compound-specific isotope analysis of nitrogen in amino acids

Trophic magnification factor (TMF) of persistent toxic substances (PTSs: Hg, PCBs, PAHs, and styrene oligomers (SOs)) in a coastal food web (12 fish and four invertebrates) was determined in Ulsan Bay, South Korea. The nitrogen stable isotope ratios (δ15N) of amino acids [δ15NGlu−Phe based on glutamic acid (δ15NGlu) and phenylalanine (δ15NPhe)] were used to estimate the trophic position (TPGlu−Phe) of organisms. The TPGlu−Phe of organisms ranged from 1.64 to 3.69, which was lower than TP estimated by δ15N of bulk particulate organic matter (TPBulk: 2.46–4.21). Mercury and CB 138, 153, 187, and 180 were biomagnified through the whole food web (TMF > 1), while other PTSs, such as PAHs and SOs were not (biodilution of SOs firstly reported). In particular, the trophic transfer of PTSs was pronounced in the resident fish (e.g., rock bream, sea perch, Korean rockfish). Of note, CB 99, 101, 118, and 183 were additionally found to be biomagnifying PTSs in these species. Thus, fish residency appears to represent an important factor in determining the TMF of PTSs in the coastal environment. Overall, δ15NGlu−Phe provided accurate TPs of organisms and could be applied to determine the trophic transfer of PTSs in coastal food webs.

Environmental Distribution of Styrene Oligomers (SOs) Coupled with Their Source Characteristics: Tracing the Origin of SOs in the Environment

Despite growing concerns regarding plastic additives, their environmental fate coupled with leaching from source materials are not well known. Styrene oligomers (SOs), which are unintended additives in expanded polystyrene (EPS), are estrogenic micropollutants. Here, we identified the effects of their potential sources (i.e., EPS buoy and its leachate) and environmental dilution on SO distribution within coastal sediments. SO content in fresh EPS particles was 0.1% (w/w), dominated by 2,4,6-triphenyl-hexene (ST-1), while 2,4-diphenyl-1-butene (SD-2) accounted for most of the SOs in EPS leachate, indicating its faster leachability. In lake and offshore environments, the SO composition profiles from their terrestrial inputs and inner sites were similar to those of EPS leachate; meanwhile, the exponentially decreasing SO concentration and increasing styrene trimers (STs) fraction with distance from the inner to outer sites were evident. These profiles indicated continuous SO leaching from their potential sources in the inland, followed by a change in SOs due to environmental dilution. SOs in beach sediment implied the presence of micro-sized EPS particles. We suggest the ST-1 to SD-2 ratio as an index to differentiate among freshly leached SOs (∼0.02), environmentally diluted SOs after leaching (∼0.1), SOs in fresh EPS (∼1.2), and SOs in aged EPS (> 2).

Multiple Bioassays and Targeted and Nontargeted Analyses to Characterize Potential Toxicological Effects Associated with Sediments of Masan Bay: Focusing on AhR-Mediated Potency.

An enhanced, multiple lines of evidence approach was applied to assess potential toxicological effects associated with polluted sediments. Two in vitro bioassays (H4IIE-luc and Vibrio fischeri) and three in vivo bioassays (microalgae: Isochrysis galbana and Phaeodactylum tricornutum; zebrafish embryo: Danio rerio) were applied. To identify causative chemicals in samples, targeted analyses (polycyclic aromatic hydrocarbons (PAHs), styrene oligomers (SOs), and alkylphenols) and nontargeted full-scan screening analyses (FSA; GC- and LC-QTOFMS) were performed. First, great AhR-mediated potencies were observed in midpolar and polar fractions of sediment extracts, but known and previously characterized AhR agonists, including PAHs and SOs could not fully explain the total potencies of samples. Enoxolone was identified as a novel AhR agonist in a highly potent sediment fraction by use of FSA. Enoxolone has a relative potency of 0.13 compared to benzo[a]pyrene (1.0) in the H4IIE-luc bioassay. Nonylphenols associated with membrane damage that influenced the viability of the microalgae were also observed. Finally, inhibitions of bioluminescence of V. fischeri and lethality of D. rerio embryos were strongly related to nonpolar compounds. Overall, the present work addressed assay- and end point-specific variations and sensitivities for potential toxicities of mixture samples, warranting a significant utility of the "multiple lines of evidence" approach in ecological risk assessment.

Additive-Triggered Chain Transfer to a Solvent in Coordination Polymerization

Low-molecular-weight polystyrene (LMPS) is the precursor of a brominated styrene oligomer that is used for small, precise, thin electrical components and an environmentally benign flame-retardant m...

Large-scale monitoring and ecological risk assessment of persistent toxic substances in riverine, estuarine, and coastal sediments of the Yellow and Bohai seas

The Yellow and Bohai seas comprise one of the most rapidly developing regions in the world, but efforts to assess coastal pollution by persistent toxic substances (PTSs) on wide spatial scale are lacking. The present study aimed to (1) measure the concentrations of PTSs, such as polycyclic aromatic hydrocarbons (PAHs), alkylphenols (APs), and styrene oligomers (SOs) via large-scale sediment monitoring (total of 125 locations), (2) assess potential ecological risk of PTSs in sediments to coastal ecosystems, (3) estimate various sources and fresh inputs of PTSs, (4) determine distribution patterns of PTSs by human activities and land-use type, and (5) address decadal (2008–2018) changes in distributions of PTSs. The high concentrations of PAHs [> 7000 ng g−1 dry weight (dw)] in sediments were detected in Nantong in the Yellow Sea of China (YSC) and Huludao and Qinhuangdao in the Bohai Sea (BS), whereas lesser concentrations (< 200 ng g−1 dw) were detected in the Yellow Sea of Korea (YSK). We found relatively high concentrations of sedimentary APs and SOs in Nantong, Huludao, and Qinhuangdao from the YSC and BS regions, but corresponding concentrations were generally below < 100 ng g−1 dw in other locations. Concentrations of PAHs at 38 locations (30% of YSC and BS) posed a potential risk to aquatic ecosystems, whereas relatively low risk concentrations occurred in all locations of YSK. The main source of PAHs (concentrated in YSC and BS) were by-products of diesel and gasoline combustion (42% of total concentration), whereas biomass combustion (24%) dominated in YSK. Fresh inputs of PTSs indicated that the generation and use of PTSs continue across all regions and locations. Among PTSs, concentrations of PAHs were significantly associated with location (p < 0.05) relative to land-use within a given region, whereas concentrations of APs and SOs showed no significant relationships (p > 0.05) among or within regions. Over time, concentrations of PAHs have generally declined, but sediment contamination has increased at some locations in China, with sources shifting from a mixture of PAHs types to those linked to diesel and gasoline combustion. Additional studies are needed on the fate and potential ecological risk posed by certain PTSs in hotspots. This is one of the first efforts providing backgrounds on PTS pollution in the large marine ecosystem of the Yellow and Bohai seas.

Composite synthesis from carbon nanotubes and styrene oligomers, the functionalization and magnetic field effect in their properties

The nanostructure materials are a prefer option to the high-growth technological changes. The remarkable nanotubes and other carbon nanostructure properties have been theoretically and experimentally tested. These nanostructures can be used as reinforcement materials in composites; the research main challenge is the dispersion of these carbon materials in different matrices caused by cluster formations produced by the intermolecular forces. The aim of this research was the synthesis and characterization of a composite material from carbon nanotubes and styrene oligomers with hydroxyl end groups; and the analysis of their dispersion and mechanical and electrical properties. Pristine and functionalized carbon nanotubes and polystyrene with hydroxyl end groups were synthesized; furthermore, magnetic field was applied to the composites to promote dispersion of carbon nanotubes. The materials were characterized by scanning electron microscopy, FTIR and Raman spectroscopy. The Raman spectroscopy has demonstrated interaction between carbon nanostructures and polymers; this changes their mechanical and electrical properties. The composites formed with functionalized carbon nanotubes (1.6 wt%) have the highest hardness value (91.16 HV), five times over the pristine polymer. As carbon nanostructure concentration increases, the composite acquires conductivity and the electron transport is promoted. The values obtained in the composites qualify them as electromagnetic interference shields, those demand materials with higher electrical conductivity than conventional polystyrene.

Long-term trends of persistent toxic substances and potential toxicities in sediments along the west coast of South Korea

For decades, in response to industrialization and urbanization, environmental qualities of estuarine and coastal areas of the west coast of Korea have been deteriorating. Long-term changes in concentrations of persistent toxic substances (PTSs) in sediments, including PAHs, styrene oligomers, nonylphenols, and metals and their potential toxicities via AhR- and ER-mediated potencies, and bioluminescent bacterial inhibition, were investigated. Long-term monitoring in five estuarine and coastal areas (2010–2018; 10 sites) showed that concentrations of PAHs and nonylphenols in sediments have declined while concentrations of some metals, Cd, Cr, and Hg have increased. Similarly, AhR-mediated potencies in sediments have declined, but inhibitions of bioluminescent bacteria have increased. Concentrations of sedimentary PAHs and AhR-mediated potencies were significantly (p < 0.01) and positively correlated. Sources of PAHs from combustion have been gradually declining while inputs from vehicle exhaust by-products have been increasing. Overall, this study brought our attention a balanced regulation in chemical-specific manner.

Evolution Profiles of Styrene Oligomers Observed by Thermal Desorption/Pyrolysis-Direct Analysis in Real Time (DART)-Mass Spectrometry

Evolution Profiles of Styrene Oligomers Observed by Thermal Desorption/Pyrolysis-Direct Analysis in Real Time (DART)-Mass Spectrometry

Elongational rheology of polystyrene melts and solutions: Concentration dependence of the interchain tube pressure effect

The elongational viscosity data of Bach et al. [Macromolecules 36, 5174–5179 (2003)] and Huang et al. [ACS Macro Lett. 2, 741–744 (2013); Macromolecules 48, 4158–4163 (2015); Macromolecules 46, 5026–5035 (2013)] on monodisperse polystyrene melts and concentrated polystyrene solutions in oligomeric styrene represent a unique benchmark for improving the tube model of Doi and Edwards with respect to its predictive capabilities of nonlinear viscoelasticity and especially chain stretch. By relaxing one of the basic assumptions of the original tube model of Doi and Edwards [J. Chem. Soc., Faraday Trans. 2 Mol. Chem. Phys. 74, 1802–1817 (1978); J. Chem. Soc., Faraday Trans. 2 Mol. Chem. Phys. 74, 1818–1832 (1978)], i.e., the assumption of a constant tube diameter, and assuming that chain stretch is inversely proportional to a deformation-dependent tube diameter, the extended interchain pressure (EIP) theory [Wagner and Rolon-Garrido, AIP Conf. Proc. 1152, 16–31 (2009); Wagner and Rolon-Garrido, Korea Aust. Rheol. J. 21, 203–211 (2009)] allowed a parameter-free modeling of the elongational viscosity of monodisperse polystyrene melts. Here, we demonstrate that when the dependence of the interchain pressure effect on polymer concentration and molar mass of the oligomeric solvent is considered, the EIP model agrees with experimental evidence that at low Weissenberg numbers W i R = e ˙ τ R < 1 melts and solutions show extension thinning behaviors, while at W i R ≅ 1 solutions switch to extensional thickening or show a more or less constant steady-state elongational viscosity and melts continue with extension thinning behavior with a scaling of η E ∝ W i R − 0.5. We explain quantitatively the effects of molar mass of solvent and of polymer concentration on the elongational viscosity in the investigated concentration range from 10% to 100% (melt), based solely on the linear-viscoelastic characterization. For polystyrene dissolved in oligomeric styrene with molar mass larger than a quarter of the entanglement molar mass of the melt, M o s ≥ M e m / 4 = 3.3 kg / mol, we predict a universal relation for the steady-state elongational stress at W i R ≫ 1, which is independent of polymer concentration and molar mass of the solvent, while the stretch potential of polystyrene dissolved in oligomeric styrene with M o s < 3.3 kg / mol increases with decreasing molar mass of solvent and decreasing polymer concentration in agreement with available experimental evidence.The elongational viscosity data of Bach et al. [Macromolecules 36, 5174–5179 (2003)] and Huang et al. [ACS Macro Lett. 2, 741–744 (2013); Macromolecules 48, 4158–4163 (2015); Macromolecules 46, 5026–5035 (2013)] on monodisperse polystyrene melts and concentrated polystyrene solutions in oligomeric styrene represent a unique benchmark for improving the tube model of Doi and Edwards with respect to its predictive capabilities of nonlinear viscoelasticity and especially chain stretch. By relaxing one of the basic assumptions of the original tube model of Doi and Edwards [J. Chem. Soc., Faraday Trans. 2 Mol. Chem. Phys. 74, 1802–1817 (1978); J. Chem. Soc., Faraday Trans. 2 Mol. Chem. Phys. 74, 1818–1832 (1978)], i.e., the assumption of a constant tube diameter, and assuming that chain stretch is inversely proportional to a deformation-dependent tube diameter, the extended interchain pressure (EIP) theory [Wagner and Rolon-Garrido, AIP Conf. Proc. 1152, 16–31 (2009); Wagner and Rolon-Garrido, Korea Aust. Rheol...

Major AhR-active chemicals in sediments of Lake Sihwa, South Korea: Application of effect-directed analysis combined with full-scan screening analysis

This study utilized effect-directed analysis (EDA) combined with full-scan screening analysis (FSA) to identify aryl hydrocarbon receptor (AhR)-active compounds in sediments of inland creeks flowing into Lake Sihwa, South Korea. The specific objectives were to (i) investigate the major AhR-active fractions of organic extracts of sediments by using H4IIE-luc in vitro bioassay (4 h and 72 h exposures), (ii) quantify known AhR agonists, such as polycyclic aromatic hydrocarbons (PAHs) and styrene oligomers (SOs), (iii) identify unknown AhR agonists by use of gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOFMS), and (iv) determine contributions of AhR agonists to total potencies measured by use of the bioassay. FSA was conducted on fractions F2.6 and F2.7 (aromatics with log Kow 5–7) in extracts of sediment from Siheung Creek (industrial area). Those fractions exhibited significant AhR-mediated potency as well as relatively great concentrations of PAHs and SOs. FSA detected 461 and 449 compounds in F2.6 and F2.7, respectively. Of these, five tentative candidates of AhR agonist were selected based on NIST library matching, aromatic structures and numbers of rings, and available standards. Benz[b]anthracene, 11H-benzo[a]fluorene, and 4,5-methanochrysene exhibited significant AhR-mediated potency in the H4IIE-luc bioassay, and relative potencies of these compounds were determined. Potency balance analysis demonstrated that these three newly identified AhR agonists explained 1.1% to 67% of total induced AhR-mediated potencies of samples, which were particularly great for industrial sediments. Follow-up studies on sources and ecotoxicological effects of these compounds in coastal environments would be required.

Newly Identified AhR-Active Compounds in the Sediments of an Industrial Area Using Effect-Directed Analysis

Effect-directed analysis was used to identify previously unidentified aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area of Ulsan Bay, Korea. The specific objectives were to (i) investigate potent fractions of sediment extracts using the H4IIE-luc bioassay, (ii) determine the concentrations of known AhR agonists (polycyclic aromatic hydrocarbons (PAHs) and styrene oligomers (SOs)), (iii) identify previously unreported AhR agonists in fractions by use of GC-QTOFMS, and (iv) evaluate contributions of individual compounds to overall AhR-mediated potencies, found primarily in fractions containing aromatics with log Kow 5-8. Greater concentrations of PAHs and SOs were also found in those fractions. On the basis of GC-QTOFMS and GC-MSD analyses, 16 candidates for AhR agonists were identified in extracts of sediments. Of these, seven compounds, including 1-methylchrysene, benzo[j]fluoranthene, 3-methylchrysene, 5-methylbenz[a]anthracene, 11H-benzo[b]fluorene, benzo[b]naphtho[2,3-d]furan, and benzo[b]naphtho[2,1-d]thiophene, exhibited significant AhR activity. Relative potency values of newly identified AhR agonists were found to be greater than or comparable to that of benzo[a]pyrene (BaP). The potency balance analysis showed that newly identified AhR agonists explained 0.07-16% of bioassay-derived BaP-EQs. These chemicals were widely distributed in industrial sediments; thus, it is of immediate importance to conduct studies on sources and potential effects of those chemicals.

On the universality in the extensional rheology of monodisperse polymer melts and oligomer dilutions thereof

The startup and steady extensional viscosities were measured on two narrow molar mass distributed (NMMD) poly(methyl methacrylates) (PMMA) diluted in 57% 2.1 kg/mole oligomer methyl methacrylates. The oligomer is short enough to be random configured and un-entangled though it is still a Kuhn chain. The weight-based average molecular weights of the PMMAs are 86 kg/mole and 270 kg/mole with polydispersites of 1.08 and 1.09 respectively. The extensional viscosities were in theoretical agreement with a constant ‘interchain pressure’ model, representing the maximal level of strain hardening in a Kuhn fluid. This has been observed for similar (styrene) oligomer diluted NMMD polystyrenes before, when the styrene oligomers were Kuhn chains. The original ‘interchain pressure’ model by Marrucci and Ianniruberto (Macromolecules 37(10):3934–3942, 2004), represents the minimal level of strain hardening in a Kuhn fluid. It has been shown previously to predict the extensional viscosities of NMMD polystyrene melts, and it is also in agreement with the extensional viscosities of the 86 kg/mole NMMD PMMA melt as well.

Study on the Quantitative Analysis of Styrene Oligomers Originated from Styrene-based Plastic Polymer Materials

Study on the Quantitative Analysis of Styrene Oligomers Originated from Styrene-based Plastic Polymer Materials

Physicochemical properties of styrene oligomers in the environment

Currently, styrene oligomers (SOs) are persistent contaminants that are present in the environment globally. SOs are artificial substances originating from styrene-based polymer materials, mainly including PS plastic, resin, and rubber. However, the behavior of SOs in the environment is not well-understood yet due to the scarcity of experimental data. The objective of this study was to use in-silico tool to estimate key physicochemical properties of these SOs. The US EPA EPI suite program was used to predict SOs' physicochemical properties including solubility, vapor pressure, LogKow, Henry's constant, LogKoc, and fugacity-based multimedia mass balance. Although styrene monomer (SM) and SOs have structural similarity, the physicochemical properties of SOs are significantly different from those of SM, a precursor of SOs. In particular, it is estimated that as much as the heavy molecular weight, most SOs persist for comparable periods of time in a sandy environment. Although there is uncertainty, this preliminary in-silico study provides a sufficient reason to assure an experimental study to better determine properties of SOs.