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Fishbone-derived carbon sulfonate, modified through incipient wetness impregnation with titanium tetraisopropoxide and iron nitrate salts, displays catalytic activity in the oxidation of styrene with hydrogen peroxide (H2O2) as an oxidant. This was done to develop a cost-effective, non-toxic, and environmentally friendly bimetallic oxide catalyst, incorporating titanium and iron oxides on mesoporous-derived carbon fishbone to enhance styrene conversion and benzaldehyde selectivity in styrene oxidation using aqueous H2O2. The catalyst, featuring a combination of titanium and iron oxides on the surface of the fishbone-derived carbon sulfonate, demonstrates higher catalytic activity than single oxide catalysts, such as titanium or iron oxides alone. Factors influencing the catalyst's performance are investigated by using FTIR, XRD, XRF, SEM, and BET surface area. The results reveal that the presence of both titanium and iron oxides on the surface of the fishbone-derived carbon sulfonate and the catalyst's surface area creates a synergistic effect, the primary factors affecting its catalytic activity in styrene oxidation using H2O2 as an oxidant.

A precautionary specific migration limit of 40 µg/kg for styrene from food contact materials is currently under evaluation in Europe. In the ongoing discussion about applicable methods to demonstrate compliance, testing with food instead of simulants or total transfer calculations has been proposed. In this study, the residual styrene levels in high-impact polystyrene (HIPS) blended with general-purpose polystyrene (GPPS) were determined at several levels of the processing chain of yoghurt pots (from pellets to sheets, then to pots). The styrene migration from extruded sheets and thermoformed pots was analyzed in food simulants at 10 days/20 °C and 40 °C, as well as in yoghurt after storage at 8 °C after 50 days. The obtained results show that the residual styrene content in the PS materials correlates with migration. However, the migration of styrene was far below the total transfer assumption. Styrene migration from the sheets into food simulants and into yoghurt exceeded that migrating from the pots. Styrene migration into food simulants in 20% ethanol at 10 days/20 °C and 40 °C and, more clearly, in 50% ethanol at 10 days/40 °C, was higher than that into yoghurt tested on the best-before date. Styrene migration from PS pots into yoghurt after storage at 8 °C for 50 days reached up to 15 µg/kg (applying the EU cube model), which would be conservatively covered by testing the PS pots with 20% ethanol at 10 days/20 °C.

To fill a research gap on firefighter exposures and breast cancer risk, and guide exposure reduction, we aimed to identify firefighter occupational exposures linked to breast cancer. We conducted a systematic search and review to identify firefighter chemical exposures and then identified the subset that was associated with breast cancer. To do this, we compared the firefighter exposures with chemicals that have been shown to increase breast cancer risk in epidemiological studies or increase mammary gland tumors in experimental toxicology studies. For each exposure, we assigned a strength of evidence for the association with firefighter occupation and for the association with breast cancer risk. We identified twelve chemicals or chemical groups that were both linked to breast cancer and were firefighter occupational exposures, including polycyclic aromatic hydrocarbons, volatile aromatics, per- and polyfluoroalkyl substances, persistent organohalogens, and halogenated organophosphate flame retardants. Many of these were found at elevated levels in firefighting environments and were statistically significantly higher in firefighters after firefighting or when compared to the general population. Common exposure sources included combustion byproducts, diesel fuel and exhaust, firefighting foams, and flame retardants. Our findings highlight breast-cancer-related chemical exposures in the firefighting profession to guide equitable worker’s compensation policies and exposure reduction.

High molar mass copolymers with a tapered interface are mechanically tough materials with an accessible order-to-disorder transition temperature and hence processability. We report the first ordering kinetics for a tapered tetrablock copolymer in comparison to a conventional diblock copolymer made sequentially. We show that tapered copolymers belong to the Brazovskii "universality class," where fluctuations play a dominant role. Consequently, the order-to-disorder transition has a very weak, fluctuation-induced first-order character. The ordering kinetics of the lamellar phase from the supercooled disordered melt revealed several distinct differences associated with the range of metastability (increased), the timescales (bimodal), and the exact mechanism of ordering. The results are discussed in terms of the reduced interaction parameter and the introduction of structural defects within the lamellar grains. [ABSTRACT FROM AUTHOR]

We are interested in converting second generation feedstocks into styrene, a valuable chemical compound, using the solvent-tolerant Pseudomonas putida DOT-T1E as a chassis. Styrene biosynthesis takes place from L-phenylalanine in two steps: firstly, L-phenylalanine is converted into trans-cinnamic acid (tCA) by PAL enzymes and secondly, a decarboxylase yields styrene. This study focuses on designing and synthesizing a functional trans-cinnamic acid decarboxylase in Pseudomonas putida. To achieve this, we utilized the "wholesale" method, involving deriving two consensus sequences from multi-alignments of homologous yeast ferulate decarboxylase FDC1 sequences with > 60% and > 50% identity, respectively. These consensus sequences were used to design Pseudomonas codon-optimized genes named psc1 and psd1 and assays were conducted to test the activity in P. putida. Our results show that the PSC1 enzyme effectively decarboxylates tCA into styrene, whilst the PSD1 enzyme does not. The optimal conditions for the PSC1 enzyme, including pH and temperature were determined. The L-phenylalanine DOT-T1E derivative Pseudomonas putida CM12-5 that overproduces L-phenylalanine was used as the host for expression of pal/psc1 genes to efficiently convert L-phenylalanine into tCA, and the aromatic carboxylic acid into styrene. The highest styrene production was achieved when the pal and psc1 genes were co-expressed as an operon in P. putida CM12-5. This construction yielded styrene production exceeding 220 mg L−1. This study serves as a successful demonstration of our strategy to tailor functional enzymes for novel host organisms, thereby broadening their metabolic capabilities. This breakthrough opens the doors to the synthesis of aromatic hydrocarbons using Pseudomonas putida as a versatile biofactory. Highlights: This study focuses on the conversion of sugars into styrene, a valuable chemical compound, using as a host the solvent-tolerant Pseudomonas putida DOT-T1E as a chassis. The biosynthesis of styrene involves a two-step process, starting with the conversion of L-phenylalanine into trans-cinnamic acid (tCA) through PAL enzymes, followed by decarboxylation to yield styrene. A synthetic trans-cinnamic acid decarboxylase was designed using a novel 'wholesale' approach that involved the derivation of consensus sequences from homologous yeast FDC1 genes with > 60% identity, leading to the design of a functional Pseudomonas codon-optimized protein named PSC1. Assays demonstrated successful decarboxylation of tCA into styrene by the PSC1 enzyme. Optimal conditions for PSC1 enzyme activity in vivo were determined, including pH and temperature. Highest styrene biosynthesis efficiency was achieved by co-expressing the pal and psc1 genes as an operon in P. putida CM12-5, a P. putida DOT-T1E derivative that produces L-phenylalanine, showcasing the significance of coordinated expression for improved chemical production. The utilization of the solvent-tolerant Pseudomonas putida chassis as a biofactory for styrene production highlights the potential of microbial engineering for sustainable and environmentally-friendly chemical synthesis. [ABSTRACT FROM AUTHOR]

Oxidative alkene cleavage of a series of (hetero)aryl alkyl styrenes in aqueous medium has been developed using either 9‐mesityl‐10‐methylacridinium perchlorate ([AcrMes]ClO4) and sodium anthraquinone‐2‐sulfonate (SAS) as photosensitizers under blue LED irradiation. Reaction conditions were studied to find a suitable media for the development of a linear cascade after subsequent stereoselective reduction of the corresponding ketone intermediate. The use of cesium carbonate provided an adequate pH to the reaction medium for the alcohol dehydrogenase action. [AcrMes]ClO4 was found to be the best photocatalyst, allowing the development of concurrent or sequential cascades depending on the ability of the photosensitizer to oxidize back the chiral alcohol to the ketone. Overall, the photobiocatalytic approach has allowed the synthesis of a wide number of alcohol compounds, the formation of (S)‐ or (R)‐enantiomers being attained with excellent stereoselectivity and moderate to good yields. [ABSTRACT FROM AUTHOR]

This work describes the palladium(II)‐catalyzed regioselective C8‐H olefination of 1‐naphthamides. Interestingly, naphthamide fused lactam 2,3‐dihydro‐1H‐benzo[de]isoquinolin‐1‐one derivatives were also synthesized in the case of a particular class of napthamides. This protocol was found well compatible with a diverse range of acrylates and styrenes leading to product formation in good yields along with a wide functional group tolerance. The developed strategy was further applied to the synthesis of different drug derivatives. [ABSTRACT FROM AUTHOR]

The palladium-catalyzed oxidative C3-alkenylation of anthranils (2,1-benzisoxazoles) with various styrenes has been successfully achieved. The C3-alkenylated anthranils were subsequently utilized in a [4+2]-cycloaddition with in situ generated α,β-unsaturated ketones leading to the synthesis of a diverse range of olefin-containing quinolines. Notably, this reaction exclusively yielded mono-alkenylated products with E-selectivity. The optimized catalytic conditions were compatible with a wide variety of substituted olefins and anthranils, forming various C3-alkenylated anthranils with good yields. To showcase the application of the present methodology, the C3-alkenylated anthranils have been employed as synthons to access a wide range of substituted quinolines. [ABSTRACT FROM AUTHOR]

Conventional photocatalytic CO2 reduction is usually combined with the oxidation of H2O or sacrificial agents, which faces problems such as low catalytic activity and inefficient atom economy. In this work, a photocatalytic CO2 reduction and selective styrene oxidation synergetic system is developed with an NH4Cl-modified g-C3N4/BiOBr composite photocatalyst. The interfacial heterostructure promotes the formation of surface amino groups and oxygen vacancies, which facilitates the adsorption and chemical reduction of CO2. The heterostructure also improves the separation of photogenerated electron–hole pairs and enhances the photocatalytic activity. The simultaneous consumption of electrons and holes is beneficial for both CO2 reduction and styrene oxidation processes. Meanwhile, the oxygen atoms removed during CO2 reduction are utilized efficiently for styrene oxidation in this synergistic system, and thus the atom economy is improved significantly. The generation rates of CO, CH4, benzaldehyde and styrene oxide are 802, 8, 684 and 139 μmol g−1 h−1, respectively. This study provides a novel strategy for designing a green photocatalytic CO2 reduction system. [ABSTRACT FROM AUTHOR]

Increasing industrialization and rapid change in market demand has led to aggressive competition impacting both business and environmental sustainability globally. In view of the new legislations, regulations and restrictions on the usage of hazardous materials, it becomes mandatory to use eco-friendly materials. In the present work, various petroleum-based and different modified vegetable oils are characterised for chemical and analytical properties. Styrene butadiene rubber (SBR) is extended with these oils at laboratory scale through emulsion polymerisation technique. Totally four number of petroleum-based oils like distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), residual aromatic extract (RAE) and naphthenic type oil and two number of modified vegetable oils, NO_2 and NO_6, are evaluated. All oils have shown compatibility with SBR latex which is confirmed by checking solvent extractables as well as oil leaching checking by visual inspection of oil extended rubber samples. These raw rubber samples are characterised for raw rubber properties as well as in ASTM-based rubber compound recipe to check their processing behaviour. Compounds prepared with both vegetable oil-based styrene butadiene rubber have shown comparable or slightly better processing properties as compared to compounds prepared with petroleum oil-based rubbers. Experimental compounds are also showing comparable carbon black dispersion and better polymer–filler interaction which may be due to the presence of various surface functional groups in vegetable oils. Microscopic pictures also confirm the comparable carbon black dispersion for all the samples. [ABSTRACT FROM AUTHOR]

A sustainable system for the carbocarboxylation of olefins with redox-active esters and CO2via visible-light-induced photoredox catalysis has been developed using metal-free boron carbonitride (BCN) as the photocatalyst. The scheme introduces versatile alkyl groups (including primary, secondary, and tertiary) and CO2 into the C–C double bond in a fully regioselective manner to produce valuable carboxylic derivatives with excellent yields. [ABSTRACT FROM AUTHOR]

A sustainable system for the carbocarboxylation of olefins with redox-active esters and CO2via visible-light-induced photoredox catalysis has been developed using metal-free boron carbonitride (BCN) as the photocatalyst. The scheme introduces versatile alkyl groups (including primary, secondary, and tertiary) and CO2 into the C–C double bond in a fully regioselective manner to produce valuable carboxylic derivatives with excellent yields. [ABSTRACT FROM AUTHOR]

Batch, in situ seeded and stepwise dosing monomer, and normal seeded soap‐free emulsion polymerizations (SFEP) of styrene were carried out by using the oil‐soluble 2,2′‐azobis(isobutyronitrile) as initiator. Gel permeation chromatography (GPC) and scanning electron microscopy were employed to characterize the experimental results. Typical auto‐accelerative effect in the bulk free‐radical polymerization was also observed in the macro‐kinetics of batch SFEP at 60 and 65°C. Flat‐roof GPC curves appeared at the post‐auto‐acceleration. In addition, Mn¯ in particles exhibited a positive relationship with the size of particles. The bigger size the larger Mn¯. In the in situ seeded polymerization, the flat‐roof GPC curves of seed turned into the asymmetric Gaussian type exhibiting the great increase of the fraction of larger Mn¯ with the sequential addition of styrene. In addition, the number of seeds was kept constant throughout the polymerization. It indicated that the free radicals were generated and confined in the growing particles. In the normal seeded polymerization, Mn¯ showed a strong dependence on the average assigned amount of St per seed particle. The more monomers per seed particle the larger Mn¯ was gained. Based on these results, it was postulated that the free radicals were living due to the gel effect occurring in particles, namely that the free radicals were segregated by the dry polymer chains. The kinetics model was also given based on the microdroplets theory. [ABSTRACT FROM AUTHOR]

The mixed metal oxide nanostructures (Fe-Mn-Si-O) and Fe-Mn-Si-O/Multi walled carbon nanotubes (Fe-Mn-Si-O/MWCNT) were synthesized by a hydrothermal approach. The prepared samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Fe-Mn-Si-O has efficient removal of methylene blue (MB) and rhodamine b (RhB) from aqueous solution and both prepared compounds have an effective catalytic property in styrene oxidation reaction. In the process of exploring the adsorption conditions, the isotherms were found to be well fitted by Langmuir and Freundlich models. Moreover, the thermodynamic of RhB and MB adsorption was also studied. To investigate the adsorption mechanism, it was found that the adsorption kinetics of MB and RhB onto the Fe-Mn-Si-O surface was best described by the pseudo second-order model. In the next step, the catalytic behavior of Fe-Mn-Si-O and Fe-Mn-Si-O/MWCNT were studied in the styrene oxidation reaction, which yielded only benzaldehyde. Highlights: Novel Fe-Mn-Si-O and Fe-Mn-Si-O/MWCNT were prepared by hydrothermal method. Fe-Mn-Si-O and Fe-Mn-Si-O/MWCNT were applied as catalyst in the styrene oxidation reaction The adsorption of MB and RhB was studied on the Fe-Mn-Si-O. Fe-Mn-Si-O and Fe-Mn-Si-O/MWCNT showed excellent behavior in catalytic reactions. [ABSTRACT FROM AUTHOR]

Various petroleum based mineral oils like Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Residual Aromatic Extract (RAE) and Naphthenic oils are used for extension of emulsion polymerized Styrene Butadiene Rubber (E-SBR). Vegetable oils are alternate to these petroleum oil from sustainability point of view as vegetable oils have no Polycyclic Aromatic (PCA) content. They improve abrasion resistance leads to less rubber particulates spread in the environment and reduce rolling resistance leads to lower fuel consumption. However, introduction of few vegetable oils leads to slow down the cure reaction due to high unsaturation to saturation ratio. Presence of high fatty acid content in vegetable oils help in better rubber-filler interaction. In the present research, vegetable origin oils as such without any modification (Decas, Palmolein, Groundnut, Soybean, Mustard and Coconut) extended Styrene Butadiene Rubber (OE-SBR) were characterized in standard American Society for Testing and Materials (ASTM) compound recipe for various processing, different vulcanizate and other performance properties. Curative's dosages were adjusted in the recipe of vegetable oil extended SBR's to achieve the 300% modulus value like naphthenic oil. Vegetable oil extended Emulsion Styrene Butadiene Rubber (E-SBR) grades (Prepared with Palmolein and Coconut oils) were showing comparable rheometric and stress-strain properties, high reinforcement index (around 5%), better rubber-filler interaction parameter (around 12%), better abrasion resistance (around 23%) and comparable tanδ value @0°, 30° and 60°C as compared to naphthenic oil extended SBR based compound. [ABSTRACT FROM AUTHOR]

Risk assessment of human health hazards has traditionally relied on experiments that use animal models. Although exposure studies in rats and mice are a major basis for determining risk in many cases, observations made in animals do not always reflect health hazards in humans due to differences in biology. In this critical review, we use the mode-of-action (MOA) human relevance framework to assess the likelihood that bronchiolar lung tumors observed in mice chronically exposed to styrene represent a plausible tumor risk in humans. Using available datasets, we analyze the weight-of-evidence 1) that styrene-induced tumors in mice occur through a MOA based on metabolism of styrene by Cyp2F2; and 2) whether the hypothesized key event relationships are likely to occur in humans. This assessment describes how the five modified Hill causality considerations support that a Cyp2F2-dependent MOA causing lung tumors is active in mice, but only results in tumorigenicity in susceptible strains. Comparison of the key event relationships assessed in the mouse was compared to an analogous MOA hypothesis staged in the human lung. While some biological concordance was recognized between key events in mice and humans, the MOA as hypothesized in the mouse appears unlikely in humans due to quantitative differences in the metabolic capacity of the airways and qualitative uncertainties in the toxicological and prognostic concordance of pre-neoplastic and neoplastic lesions arising in either species. This analysis serves as a rigorous demonstration of the framework's utility in increasing transparency and consistency in evidence-based assessment of MOA hypotheses in toxicological models and determining relevance to human health. [ABSTRACT FROM AUTHOR]

Flexible antennas are placed near or on the human body without having an adverse effect on it. Therefore, they must be comfortable, flexible and not contribute to discomfort. At the same time, they must have a small value of the tangent of the angle of dielectric loss (tan δε), a minimum absorption of electromagnetic power, the ability to withstand mechanical loads and have a small change in the complex dielectric permittivity in a wide frequency range. The aim of the study is to verify the possibilities of using spinel pigments as fillers in styrene-butadiene rubber composites applicable as substrates and insulating layers in flexible portable antennas for wireless communications. It was found that the filler used has characteristics that ensure good performance of the antenna, combined with an aesthetic appearance. The optimal concentration of the spinel pigment, which determines the best operational characteristics of the antenna, has been established. [ABSTRACT FROM AUTHOR]

Styrene polymerization is a strong exothermic reaction, where the reactants, initiators and diluents are flammable and explosive substances. Once the reaction is out of control, it is extremely easy to cause fire and explosion accidents. In order to analyze the thermal hazards of styrene polymerization reactions, the thermal behaviors of reactions at different reaction conditions are investigated in this paper. Differential scanning calorimeter (DSC) and adiabatic rate calorimeter (ARC) were used to study thermal behavior of styrene polymerization reactions initiated by dual initiators (azodiisobutyronitrile/tert-butyl peroxybenzoate) with different ratios. Reaction calorimetric experiments were performed via reaction calorimeter (RC1e) to analyze the process hazard and calculate thermal hazard parameters. Subsequently, the thermal decomposition properties of the polymerization products were studied by simultaneous thermal analyzer (TGA–DSC). Moreover, the apparent activation energy (Ea) during product decomposition was calculated by Starink and Friedman methods. The results show that the presence of initiators increases the risk of thermal runaway of the reaction. The thermal hazard of styrene polymerization can be reduced due to the addition of ethylbenzene. The most serious consequences of thermal runaway were caused at an early stage. It can be concluded that the reaction of the system containing AIBN initiator reacts at a lower temperature, while the reaction of the system with TBPB is relatively lagged. This study is valuable for the selection of initiator in the polymerization reaction process. [ABSTRACT FROM AUTHOR]

Asymmetric three‐component, 1,2‐aminoxy‐trifluoromethylation of styrenes with N‐hydroxy‐1,3‐benz/naphthoxazine‐2,4‐diones (i. e. N‐OH‐(B/Np)OxzOn) catalysed by chiral vanadyl complexes derived from N‐salicylidene‐L‐t‐leucinate were explored. Among 14 different solvents and 13 different catalysts screened, the best reaction scenarios were in 2‐propanol with 3‐(2,5‐dimethyl)phenyl‐5‐bromo (DMP), or 3‐t‐butyl‐5‐bromo substituted catalysts that led to the corresponding complementary (R)‐ and (S)‐products with potential biological activities in 45–91% yields and up to 85 and 75% ee, respectively. Further optimisation with the DMP catalyst led to the best combination of 3‐halo/3,5‐dihalo‐styrenes with 6‐/7‐Br−N−OH‐(B/Np)OxzOn as the trapping agents. The corresponding eight different products were isolated in 52–75% yields with ees in a range of 88–93% (R). Based on Density Functional Theory (DFT) calculations with conformational searches, the origin of enantiocontrol and the working mechanism were proposed by resorting to a bidentate‐chelation between the amide or carbamate C=O group and N−OH group in the trapping agent to the vanadyl center followed by asymmetric benzylic radical trapping in an SH2 fashion. Subsequent Fragment Molecular Orbital (FMO)/Pair Interaction Energy Decomposition Analysis (PIEDA) calculations with the DMP catalyst were carried out to rationalize the extent of asymmetric induction. One representative product derived from p‐methyl‐styrene and NpOxzOn was hydrolyzed in basic MeOH with decarboxylation to unmask its carbamate moiety. The resulting chiral (R)‐N‐benzoxy‐3‐hydroxy‐2‐naphthamide was subjected to aerobic, oxidative homo‐coupling catalysed by the DMP catalyst in CCl4. The corresponding 2,2‐binaphthol product was isolated in 90% (brsm) yield with nearly complete diastereo‐control at the created (M)‐axial chirality, allowing for sequential, bi‐functional asymmetric cross‐coupling applications. [ABSTRACT FROM AUTHOR]

The replacement of palladium catalysts for Wacker‐type oxidation of olefins into ketones by first‐row transition metals is a relevant approach for searching more sustainable protocols. Besides highly sophisticated iron catalysts, all the other first‐row transition metal complexes have only led to poor activities and selectivities. Herein, we show that the cobalt‐tetraphenylporphyrin complex is a competent catalyst for the aerobic oxidation of styrenes into ketones with silanes as the hydrogen sources. Remarkably, under room temperature and air atmosphere, the reactions were exceedingly fast (up to 10 minutes) with a low catalyst loading (1 mol %) while keeping an excellent chemo‐ and Markovnikov‐selectivity (up to 99 % of ketone). Unprecedently high TOF (864 h−1) and TON (5,800) were reached for the oxidation of aromatic olefins under these benign conditions. Mechanistic studies suggest a reaction mechanism similar to the Mukaiyama‐type hydration of olefins with a change in the last fundamental step, which controls the chemoselectivity, thanks to a unique hydrogen bonding network between the ethanol solvent and the cobalt peroxo intermediate. [ABSTRACT FROM AUTHOR]

The circular economy (CE) is widely known for its emphasis on reducing waste and maximizing the use of resources by reusing, recycling, and repurposing materials to create a sustainable and efficient system. The CE is based on 3R—reuse, reduce, and recycle. The aim of this article is to use styrene butadiene rubber dust (SBR) in building material, constituting secondary waste in the production of SBR, which is currently disposed of as landfill. SBR is partly intended to replace the natural raw material sand. The purpose of the final material is to use it for its light weight, insulating properties, or ability to absorb vibrations and sounds. Various shares of SBR dust in mortars were tested. Some of the mortars used SBR thermal pre-treatment at temperatures of 200, 275, and 350 °C. The strength and SEM results are presented. The best pre-treatment for SBR dust is thermal treatment at 275 °C. The maximum usage of rubber dust with thermal treatment is 60% as a sand substitute. The novel finding of this study is the possibility to use more than 30% rubber dust (as a substitute for sand) thanks to pre-treatment, whereby 30% is a common maximum ratio in mortars. [ABSTRACT FROM AUTHOR]

In light of the current economic, environmental and geopolitical challenges related to securing and diversifying energy sources, wind energy has taken a great deal of attention as a sustainable technology for the production of clean energy. However, waste wind turbine blades (WTBs) present a significant environmental challenge that requires an effective recycling solution, especially fiberglass-reinforced polyester resin composite which accounts for a large part of WTBs with high toxicity. Within this context, this research aims to recover styrene compound from WTBs (fiberglass/polyester resin) using pyrolysis process. Pyrolysis experiments were carried out using a thermogravimetry (TG) on WTBs and their components, including resin and fiber. The formation of pyrolysis vapors is observed using TG-FTIR and GC/Ms measurements. The pyrolysis kinetics of each configuration was studied under different heating rates (5–30 °C min−1) using various linear and nonlinear isoconversional modeling techniques. Also, the thermal degradation phases of WTBs were mathematically simulated using the DAEM and IPR models. In addition, the thermodynamic coefficients (enthalpy, Gibbs free energy, and entropy) were determined. TG analysis revealed that the main decomposition reaction site for WTBs was between 350–490 °C, while the TG-FTIR results showed that (carbonyl (C = O)) was the main functional group in the released pyrolysis vapor. Whereas the GC/MS analysis showed that the released vapor was very rich in styrene compound up to 62% and the maximum recovery rate was obtained at 30 °C min−1 with an increase of 27% compared to that obtained at 5 °C min−1. Regarding kinetic analysis, the results showed that the average activation energies were 182 kJ mol−1 (KAS), 228 kJ mol−1 (FWO), 224 kJ mol−1 (Friedman), and 160 kJ mol−1 (Vyazovkin and Cai) with R2 > 0.94. Based on these results, pyrolysis treatment can be used to extract styrene from WTBs with high recovery performance. [ABSTRACT FROM AUTHOR]

The removal and detection of toxic analytes, including monomers and plasticizers, is important for both health and the environment. Potential absorbents and/or sensing materials are successfully made from polyaniline (PANI) and PANI doped with 10 wt.% of aluminum oxide (PANI‐Al2O3) and titanium dioxide (PANI‐TiO2). The amount of metal oxide incorporated into the surface layers of the polymer and the total amount incorporated are confirmed by energy dispersive X‐rays (EDX) and microwave plasma‐ atomic emission spectroscopy (MP‐AES), respectively. All three materials are evaluated as potential sensing materials and/or absorbents for styrene, monobutyl phthalate (MBP), and dibutyl phthalate (DBP) at 100 ppm in aqueous solutions. It is found that incorporating TiO2 into PANI improved both the sensitivity and selectivity to styrene, making PANI‐TiO2 a good absorbent and potential sensing material for styrene. Additionally, incorporating Al2O3 into PANI improved the sorption to MBP, but reduced the selectivity. As a proof‐of‐concept, the responses of the polymeric nanocomposites are combined and analyzed using principal component analysis (PCA) as such an algorithm. The output reveals good separation of the responses to each analyte, thereby demonstrating how sensing materials with poorer selectivity can be used together to overcome limitations in selectivity. [ABSTRACT FROM AUTHOR]

The utilization of waste biomass is a significant issue for sustainable development. Oil contamination has been recognized as one of the major threats to the aquatic ecosystem. Aiming to the remediation of the oil spill accidents, an apple-pomace-based and styrene-modified oil absorbent, denoted as SMAP, was synthesized by graft copolymerization via active hydroxyl group on cellulose anhydroglucose unit (AGU) of apple pomace using styrene as the monomer, ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as homogeneous reaction medium, benzoyl peroxide (BPO) as initiator, and N, N-dimethylformamide (DMF) as cosolvent at 80 ℃ with the reaction time 3 h. The FTIR and CP/MAS 13C NMR spectra of SMAP and AP (apple pomace) showed that styrene was successfully grafted onto AP, the surface wettability by contact angle measurement revealed the hydrophobicity of SMAP was greatly enhanced, and thermogravimetric analysis showed the thermal stability of SMAP was improved. SMAP showed superior oil absorbency, floatability, and reusability to AP. The maximum sorption capacities of SMAP for model oils of toluene and chloroform were 10.5 g·g−1 and 15.6 g·g−1, respectively, which were higher than those of AP (3.1 g·g−1 and 7.5 g·g−1). The sorption kinetics showed that the sorption of toluene and chloroform by AP and SMAP followed the pseudo-second-order kinetics. The ionic liquid AmimCl could be recovered by chromatography column and vacuum distillation and showed better reusability. This work provides a facile way for fabricating cellulosic materials that might be used for the remediation of oil spill accidents. [ABSTRACT FROM AUTHOR]

Herein we report the first synthesis of tetrahydrocarbazole embedded styrene atropisomers via the reaction between 1‐(aryl‐ethynyl)‐naphthalen‐2‐ol and 2,3,4,9‐tetrahydro‐1H‐carbazole. The reaction proceeds through in situ vinylidene ortho‐quinone methide (VQM) intermediate formation. The styrene derivatives were obtained in good to high yields with high diastereoselectivities with a catalytic amount of PTSA. A catalytic asymmetric version is also reported. [ABSTRACT FROM AUTHOR]

High impact polystyrene (HIPS) is a two-phase polymeric material that consists of a free polystyrene (PS) matrix and rubber particles. HIPS occupies a substantial portion of plastic waste. Even though HIPS waste could potentially be employed as an efficient feedstock for the recovery of the styrene monomer via pyrolysis, several challenges must be overcome first, like the low styrene yield (<50%) and the generation of char due to the presence of rubber. To tackle these challenges, a green fractionation process using ethyl acetate (EtOAc) as an efficient solvent to separate rubber from the free PS matrix in HIPS is envisioned, which is carried out under mild conditions. The subsequent pyrolysis of the fractionated sample at 300 °C led to a 20% increase in styrene selectivity compared to the pyrolysis of untreated HIPS. Moreover, the revalorization of the rubber particles was accomplished by ethenolysis metathesis, in which after 4 h at 100 °C, polybutadiene was split to produce 1,5-hexadiene as a major product (60% yield) and isolated PS, which was further thermally degraded, achieving a styrene selectivity of 70%. [ABSTRACT FROM AUTHOR]

Transition‐mental‐free multi‐component hydroxysulfenylation of styrenes with NH4SCN and water to from β‐hydroxysulfides is established. The reaction mechanism proceeded via a domino reaction after a radical addition to 2‐phenylimidazo[1,2‐a]pyridines. This approach features a wide substrate scope and functional group compatibility, providing 34 compounds in acceptable yields. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs), a type of non-protein-coding and small RNAs, are encouraging molecular biomarkers for prior diagnosis of the certain diseases. Here, an electrochemical sensor based on iron oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate (Fe3O4/PEDOT:PSS) hybrid coated glassy carbon electrode (GCE) is reported to determine microRNA-21 (miRNA-21) as a biosensing platform based on hybridization event. The biosensor was characterized by cyclic voltammetry (CV) measurements. The Fe3O4/PEDOT:PSS demonstrated good sensing performance, including a wide detection range (0.1 pM-1 µM) and a low detection limit (0.023 pM) for potential medical applications. [ABSTRACT FROM AUTHOR]

Photoinduced direct α‐alkylation reactions of ketones with arylalkenes using an organophotocatalyst and a Brønsted base were developed. It was found that the choice of both Brønsted base and photocatalyst was crucial, and in the presence of catalytic amounts of 2,4,6‐tris(diphenylamino)‐3,5‐difluorobenzonitrile (3DPA2FBN) and LiOtBu, the desired reactions of ketones with styrene analogues proceeded smoothly under blue‐LED light irradiation to afford the products in moderate to high yields. This method constitutes an atom‐economical alkylation process for α‐functionalization of both cyclic and acyclic ketones. [ABSTRACT FROM AUTHOR]

The crosslink density of rubber compounds has a great effect on the properties of the final product. For this reason, a suitable characterization method is required to understand and optimize the final performance of rubber materials. Four different experimental techniques were used to determine the crosslink density of silica-filled styrene butadiene rubber composites: equilibrium swelling experiments, stress–strain measurements using the Mooney–Rivlin theory, freezing point depression temperature tests and Temperature Scanning Stress Relaxation (TSSR) measurements. The evaluation of these different techniques shows that the results obtained follow a similar trend for all four methods. The results from the Mooney-Rivlin and TSSR measurements correlate the best. These two techniques are the least affected by the presence of fillers and are the less time-consuming ones. Furthermore, they also show the best correlation with the mechanical properties of the studied compounds. [ABSTRACT FROM AUTHOR]

3D printers have been the focus of many researchers in recent years. Many thin-walled structures can be produced using 3D printers. One of the thin wall structures that can be made with 3D printers is the core of sandwich panels. In this research, cores with rectangular cross section have been made using Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA) filaments. These cores were reinforced using aluminum and composite face sheets and subjected to a three-point bending test. Glass fibers with a density of 200 g/m2 were used to make composite shells. The results showed that the addition of aluminum and composite face sheets, although increasing the flexural strength, greatly reduces the flexibility of the core. [ABSTRACT FROM AUTHOR]

To ensure the safety of construction and operation of the tunnel near the goaf. Based on dynamic numerical analysis, three-dimensional finite difference numerical simulation software was developed by FISH programming. Then, on basis of the construction of practical engineering, the safety distance and energy evolution mechanism in an underlying mining goaf area of deep tunnel are studied. The results show that according to the different safe distance in an underlying mining goaf area of deep tunnel, the tunnel structure is divided into danger zone, influence zone and safe zone. The relationship between the cumulative horizontal energy and stress ratio can be divided into three stages: acceleration, average stability, and deceleration. The energy evolution of the three stages can also better reflect the damage and failure mechanism inside the surrounding rock mass. The measured field curve shows that when the safety distance is 12 m, the goaf has limited influence on the stability of the tunnel, and the construction in an underlying mining goaf area of deep tunnel is stable overall and meets the safety requirements. The best safe distance between the tunnel and goaf is about one time of the tunnel span. [ABSTRACT FROM AUTHOR]

Genotoxicity of styrene monomer was evaluated in male Fischer 344 rats using the alkaline comet assay for DNA damage, micronucleus assay for cytogenetic damage and the Pig‐a assay for gene mutations. In a dose range finding (DRF) study, styrene was administered by oral gavage in corn oil for 28 consecutive days at 0, 100, 500, and 1000 mg/kg/day. The bioavailability of styrene was confirmed in the DRF by measuring its plasma levels at approximately 7‐ or 15‐min following dosing. The 1000 mg/kg/day group exceeded the maximum tolerated dose based on body weight and organ weight changes and signs of central nervous system depression. Based on these findings, doses of 0, 100, 250, and 500 mg/kg/day (for 28 or 29 days) were selected for the genotoxicity assays. Animals were sacrificed 3–4 h after treatment on Day 28 or 29 for assessing various genotoxicity endpoints. Pig‐a mutant frequencies and micronucleus frequencies were determined in peripheral blood erythrocytes. The comet assay was conducted in the glandular stomach, duodenum, liver, lung, and kidney. These studies were conducted in accordance with the relevant OECD test guidelines. Oral administration of styrene did not lead to genotoxicity in any of the investigated endpoints. The adequacy of the experimental conditions was assured by including animals treated by oral gavage with the positive control chemicals ethyl nitrosourea and ethyl methane sulfonate. Results from these studies supplement to the growing body of evidence suggesting the lack of in vivo genotoxic potential for styrene. [ABSTRACT FROM AUTHOR]

In the present research work, multiphase catalytic pyrolysis (in-situ catalytic cracking) of waste expanded polystyrene (WEPS) has been carried out using calcium carbonate (CaCO3) as a solid base catalyst. The multiphase catalytic pyrolysis of WEPS has been conducted at different temperatures ranging from 400°C to 700°C at a heating rate of 15 °C/min and feed to catalyst ratio of 20:1. The thermal pyrolysis of WEPS has produced a maximum liquid yield of 94.37 wt.% at a reaction temperature of 650oC and heating rate of 15 °C/min. Whereas, the maximum liquid yield of 85.99 wt.% is obtained at a reaction temperature of 550°C and heating rate of 15 °C/min for the multiphase catalytic pyrolysis. The GC-FID analysis confirm that the thermal pyrolysis oil is mainly composed of benzene (0.62 wt.%), toluene (10.21 wt.%), ethylbenzene (0.55 wt.%) and styrene (84.74 wt.%). Whereas, the pyrolysis oil obtained from multiphase catalytic pyrolysis using CaCO3 catalyst contains very high styrene content of 93.24 wt.% along with a very low amount of fuel range hydrocarbons benzene (0.25 wt.%), toluene (2.09 wt.%) and ethyl benzene (0.52 wt.%). Thus, the present study clearly indicates that the basic catalyst CaCO3 shows the high selectivity towards the styrene monomer. [ABSTRACT FROM AUTHOR]

Copyright of Erzincan University Journal of Science & Technology is the property of Erzincan Binali Yildirim Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iraq Journal of Market Research & Consumer Protection / Al-Mağallaẗ al-ʿIrāqiyyaẗ li-Buḥūṯ al-Sūq wa-Ḥimāyaẗ al-Mustahlik is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Comprehensive Summary: Here, we report a cobalt‐catalyzed sequential dehydrogenative Heck silylation/hydroamination of styrenes with hydrosilane and diazo compound to access 1‐amino‐2‐silyl compounds with excellent regioselectivity. This difunctionalization reaction could undergo smoothly using 1 mol% catalyst loading with good functional group tolerance. Not only di‐ and tri‐substituted hydrosilanes, but also alkoxysilane is suitable, which does explore the scope of the family of 1‐amino‐2‐silyl compounds. The ligand relay phenomenon between neutral tridentate NNN ligand and anionic NNN ligand is observed for the first time via absorption spectral analysis in this one‐pot, two‐step transformations. The primary mechanism has been proposed based on the control experiments. [ABSTRACT FROM AUTHOR]

In the present study, stress sensitivity of modified binders in the multiple stress creep and recovery (MSCR) test and its relationship with rutting resistance of the asphalt mixtures are investigated. For this purpose, different groups of styrene butadiene styrene (SBS), polyphosphoric acid (PPA) and SBS + PPA modified binders were produced; in each of which, the binders have the same continuous high temperature performance gradings (PGs) and linear viscoelastic (LVE) properties. The MSCR tests were performed at 40°C, 55°C, and at the PG temperatures of the modified binders to consider a wide range of high pavement temperatures. To depict the stress sensitivity, stress levels of 12.8, 25.6, and 40 kPa were added to the MSCR standard procedure and the non-recoverable compliance (Jnr) and percent recovery (R) parameters were obtained at all the stress levels applied. To study the rutting resistance of asphalt mixtures prepared with the same asphalt binders, the flow number (FN) and |E*| parameters were determined at 40°C and 55°C, through the dynamic creep and dynamic modulus performance tests, respectively. Results of the MSCR test show that at the temperature range considered, the standard stresses are not sufficient to enter the modified binders into nonlinear region, thus higher stress levels should be applied to assess the nonlinearity and address the true rutting potential. Results of the mixtures performance tests show great correlations with the results of the MSCR of the modified binders at the nonlinear stress levels, especially with the Jnr parameter, regardless of the test temperatures. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Here, we report a cobalt‐catalyzed sequential dehydrogenative Heck silylation/hydroamination of styrenes with hydrosilane and diazo compound to access 1‐amino‐2‐silyl compounds with excellent regioselectivity. This difunctionalization reaction could undergo smoothly using 1 mol% catalyst loading with good functional group tolerance. Not only di‐ and tri‐substituted hydrosilanes, but also alkoxysilane is suitable, which does explore the scope of the family of 1‐amino‐2‐silyl compounds. The ligand relay phenomenon between neutral tridentate NNN ligand and anionic NNN ligand is observed for the first time via absorption spectral analysis in this one‐pot, two‐step transformations. The primary mechanism has been proposed based on the control experiments. [ABSTRACT FROM AUTHOR]

Die Kenntnis der Struktur katalytisch aktiver Spezies/Phasen und die Bereitstellung von Methoden zu ihrer gezielten Herstellung sind zwei Voraussetzungen für die Entwicklung von Katalysatoren mit der gewünschten Performance. Hierin stellen wir eine einfache Methode zur präzisen Herstellung von Träger‐/Vollkatalysatoren vor. Diese Methode nutzt die Eigenschaft von Metalloxiden, bei Behandlung in wässrigen Ammoniaklösungen lösbar zu sein und gleichzeitig ausgefällt werden zu können. Bei Anwendung dieser Methode auf einen herkömmlichen VOx−Al2O3‐Katalysator wurde die Konzentration koordinativ ungesättigter Al‐Zentren einfach durch Änderung des pH‐Werts der Lösung eingestellt. Diese Stellen beeinflussen die Stärke der V−O−Al‐Bindungen isolierter VOx‐Spezies und damit deren Reduzierbarkeit. Diese Methode ist auch zur Steuerung der Reduzierbarkeit von Vollkatalysatoren anwendbar, wie am Beispiel eines CeO2−ZrO2−Al2O3‐Systems gezeigt wurde. Die Einsetzbarkeit der entwickelten Katalysatoren wurde in der oxidativen Dehydrierung von Ethylbenzol zu Styrol mit CO2 und in der nichtoxidativen Propandehydrierung zu Propen bestätigt. Unser Ansatz lässt sich auf die Herstellung beliebiger Metalloxidkatalysatoren, die in einer Ammoniaklösung löslich sind, ausweiten. [ABSTRACT FROM AUTHOR]

In this study, a screen-printed electrode (SPE) for nitrite (NO2 -) sensing was fabricated through an inkjet printing technique using a commercial printer machine and preparing an ink composite solution containing graphene oxide (GO) and poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) as conductive materials. The optimum ink materials for SPE fabrication comprised GO and PEDOT:PSS with binders that resemble the viscosity of commercial ink. The surface topography of the fabricated SPE, which was characterized using scanning electron microscopy and atomic force microscopy, showed a smoother surface compared to the commercial screen-printed carbon electrode, with conductive ink materials deposited primarily from GO/PEDOT:PSS composites. This NO2 - sensor exhibited a linear response at the concentration range of 50-1000 µM, with limit of detection and limit of quantification as 25 and 50 µM, respectively. In addition, the stability, reproducibility, and selectivity of this sensor presented acceptable values in the analytical range. Furthermore, the performance of this sensor was compared with that of a spectrophotometry technique using synthetic water samples, and the results revealed its good analytical recovery at a confidence interval of 95%. Thus, our sensor based on SPE-modified GO/PEDOT:PSS, fabricated via the inkjet printing technique, can be potentially applied in monitoring NO2 - concentration in real samples. [ABSTRACT FROM AUTHOR]

The properties of amphiphilic triblock copolymer particles, which consist of a hydrophobic polystyrene (PS) core and a thermo-sensitive double hydrophilic block copolymer shell made of polyacrylic acid (PAA) and poly-N-isopropylacrylamide (PNIPAM) sequences, differ significantly depending on the sequence of the hydrophilic blocks from the core to the shell—either PS-PNIPAM-PAA or PS-PAA-PNIPAM. These triblock copolymer particles were prepared via reversible addition-fragmentation chain transfer polymerization (RAFT) following the PISA approach, using the corresponding double hydrophilic block copolymer macro-RAFT agents. The macro-RAFT agents (MRA) were synthesized through sequential polymerization of the corresponding monomers, using 4-cyano-4-(propylsulfonyl thiocarbonyl) sulfonyl pentanoic acid as the RAFT agent. These two different MRAs result in remarkable differences in the course of styrene emulsion polymerization (EP). Furthermore, the two types of polystyrene latexes behave differently in two key aspects: firstly, in terms of particle size and latex stability, which depend on both temperature and ionic strength, and secondly, in their capacity to disperse laponite disks within the particle shell when present during styrene emulsion polymerization. [ABSTRACT FROM AUTHOR]

A regioselective and trans-diastereoselective method for the preparation of 2-aryl-2,3-dihydro-1H-benzo[f]chromenes based on 2-naphthol Mannich bases as precursors of 1,2-naphthoquinone 1-methides and highly polarized β-(N,N-dimethylamino)styrene was developed. The resulting cycloadducts were transformed into cyclic acetals and hemiacetals as well as introduced into the Cope reaction leading to 2-aryl-1H-benzo[f]chromenes. [ABSTRACT FROM AUTHOR]

[Display omitted] In the last 20 years, it has been demonstrated that oppositely charged polyelectrolyte-surfactant (PE-S) mixtures are prone to forming kinetically arrested non-equilibrium aggregates, which are present in the prepared mixtures from rather low surfactant-to-polymer-repeat-unit ratios. Practically, this means that the PE-S mixtures used for the structural investigations of the formed PE-S complexes are typically a mixture of the primary PE-S complexes and large non-equilibrium aggregates of close to charge-neutral complexes. In this work, we present a unique approach that allows the preparation of PE-S mixtures in the equilibrium one-phase region (surfactant binding β , is typically below 80%) without forming non-equilibrium aggregates. We used this method to prepare equilibrium, non-aggregated complexes of sodium poly(styrene sulfonate) (NaPSS, M w = 17 kDa) and dodecyltrimethylammonium bromide (DTAB) (β = 10 – 70%) both in water and in an inert electrolyte (100 mM NaCl). The evolution of the complex structure was monitored by small-angle X-ray scattering (SAXS) as a function of increasing surfactant binding (β), and the measured scattering data were fitted by suitable structural models on an absolute scale where concentrations, compositions, and scattering contrasts calculated from molecular properties are used as restraints. We could show that at low binding (β < 30%), the system is a mixture of bare polyelectrolyte coils and NaPSS-DTAB complexes containing a closed surfactant associates of low aggregation number wrapped by the polyelectrolyte chain. Once all polymer chains are occupied by a micelle-like surfactant aggregate, the aggregation number increases linearly with increasing surfactant chemical potential. Using the structural insight provided by the SAXS measurements, we could fit the experimental binding isotherm data with a physically coherent, simple thermodynamic model. Finally, we also compared the stoichiometric NaPSS-DTAB precipitate's structure with the equilibrium complexes' structure. [ABSTRACT FROM AUTHOR]

A novel double shelled titanium dioxide@mesoporous organosilica nanotubes as an amphiphilic photoactive nanoreactor for photocatalytic oxidation of styrene under green conditions. [Display omitted] In this work, we have proposed a strategy to fabricate double-shell nanotubes as amphiphilic photoactive nanoreactors (HTTBPC) through the ordered hybridization of mesoporous organosilicon (PMO) and titanium dioxide (TiO 2) nanotubes. Unlike the previous rough composite, the heterogeneous structure established between cobalt-porphyrin functionalized PMO and conventional TiO 2 has a staggered matching band gap, which makes it have excellent light harvesting and high carrier separation ability. This is still unexplored. Interestingly, the prepared photocatalysts exhibited superior activity (99%) and benzaldehyde selectivity (94%) in the oxidation of styrene in water at room temperature, which was 3.8 and 2.8 times higher than that of TiO 2 nanotubes and PMO functionalized with cobalt porphyrin, respectively. It was demonstrated that the strong interaction between cobalt porphyrin PMO and TiO 2 improved the separation of photogenerated carriers and the amphiphilic properties of mesoporous organosilica boosted the adsorption of substrate molecules in water, contributing to the significantly enhanced photocatalytic activity. This work provides a design of high-performance photocatalysts for alkene oxidation under green conditions. [ABSTRACT FROM AUTHOR]

The synthesis of poly(styrene sulfonate) with hydrolysable ester groups in the main chain is reported. The material is obtained by free radical copolymerization of either styrene sulfonate sodium salt (SSNa) or styrene sulfonate alkyl esters (SSA) with the cyclic ketene acetal 2‐methylen‐1,3,6‐trioxocane (MTC). As for other systems made from cyclic ketene acetals, the reactions are difficult to control and give copolymers with high polydispersity index. MTC homopolymer is obtained as a side product in both cases. Thermal cleavage of the alkyl protective groups of the poly(styrene sulfonate alkyl esters) to obtain the target polystyrene sulfonate anions remains incomplete. Thus, direct synthesis of the polyanion from SSNa and MTC is the more efficient process, especially since the poly(SSNa‐co‐MTC) copolymer can be easily separated from MTC homopolymer. 1H‐NMR analytics indicates MTC repeat unit contents of 2–11%, depending on the initial SSNa to MTC ratio. The MTC ester groups of the copolymers are hydrolyzed in aqueous conditions, with and without enzyme, and a marked decrease in the molar mass is observed after hydrolysis. This confirms that these copolymers have the designed intended break points in the main chain, and could become a part of fully degradable electroactive polymer systems. [ABSTRACT FROM AUTHOR]

Using basic polyether as substrate, styrene (ST) and acrylonitrile (AN) as copolymers, the effects of the mass ratio of styrene to acrylonitrile (m (ST) :m (AN) ) on the properties of polymer polyols (POP) and soft polyurethanes (PU) foam were investigated by semi-continuous polymerization. The results show that, when m (ST) :m (AN) is about 2.0, the synthesized POP has high solid content, low viscosity and low VOC content, and the POP particles have good roundness, uniformity, filtration performance and size distribution. Therefore, the soft PU foam produced with the POP has the highest tensile strength, elongation at break and tearing strength, and relatively high falling ball rebound rate and indentation hardness. With the decrease of m (ST) :m (AN), the graft rate of POP increase, and the corresponding viscosity, filtration time and filtration time also increase. Considering the solid content, viscosity, residual monomer content and filtering efficiency of POP and the mechanics performance of soft PU foam, suitable m (ST) :m (AN) is 2.0-2.5. The research results could provide good guidance to improve the properties of POP and soft PU foam. [ABSTRACT FROM AUTHOR]

Accidental chemical spills can result in styrene-contaminated soil. Styrene negatively affects human health and the environment. The objective of this study was to remediate styrene-contaminated soil using a combination of activated carbon-based nanoscale zero-valent iron (nZVI-AC) and phytoremediation by sunn hemp (Crotalaria juncea), zinnia (Zinnia violacea Cav.) and marigolds (Tagetes erecta L.). The results showed that all three plant types could potentially increase the removal efficiency of styrene-contaminated soil. At 28 days, all three plants showed complete removal of styrene from the soil with 1 g/kg of nZVI-AC, activated carbon-based nZVI synthesized by tea leaves (Camellia sinensis) (T-nZVI-AC), or activated carbon-based nZVI synthesized by red Thai holy basil (Ocimum tenuiflorum L.) (B-nZVI-AC). However, styrene removal efficiencies of sunn hemp, zinnia, and marigold without carbon-based nZVI were 30%, 67%, and 56%, respectively. Statistical analysis (ANOVA) revealed that the removal efficiencies differed significantly from those of phytoremediation alone. With the same removal efficiency (100%), the biomass of sunn hemp in nano-phytoremediation treatments differed by approximately 55%, whereas the biomass of zinnia differed by >67%, compared with that of the control experiment. For marigold, the difference in biomass was only 30%. Styrene was adsorbed on surface of soil and AC and then further oxidized under air-water-nZVI environment, while phytovolatilization played an important role in transporting the remaining styrene from the contaminated soil to the air. Marigold was used as an alternative plant for the nano-phytoremediation of styrene-contaminated soil because of its sturdy nature, high biomass, tolerance to toxic effects, and ease of cultivation. Remediation of one cubic meter of styrene-contaminated soil by a combination of carbon-based nanoscale zero-valent iron and phytoremediation by marigolds emitted 0.0027 kgCO2/m3.