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A simple and straightforward addition or defluorination of α-(trifluoromethyl)styrenes with 2-nitroimino-imidazolidine (2a), 2-(nitromethylene)imidazolidine (2b), 2-cyanoimino-thiazolidine (2c), and (E)-1-methyl-2-nitroguanidine (2d), in a controlled manner, was developed. The hydroamination of α-(trifluoromethyl)styrenes with 2a, 2b, 2c, and 2d was completed in the presence of DBN at room temperature within 0.5–6 h, affording structurally diverse β-trifluoromethyl-β-arylethyl analogues of neonicotinoids in moderate to good yields. The γ,γ-difluoro-β-arylallyl analogues of neonicotinoids were also successfully synthesized via defluorination of α-(trifluoromethyl)styrenes, with 2a and 2c using NaH as base at an elevated temperature together with a prolonged reaction time of 12 h. The method features simple reaction setup, mild reaction conditions, broad substrate scope, high functional group compatibility, and easy scalability.

Styrene remains a major hazard in fiberglass-reinforced plastic (FRP) manufacturing. The current 10 ppm 8-h TLV-TWA is half the former limit, and the movement by several European states toward comparable or lower OELs highlights the need for fresh exposure–response data. In this study, eighty-five Korean FRP workers were monitored cross-sectionally. Full-shift breathing-zone styrene was measured by GC-FID; post-shift urine was analysed for mandelic acid (MA) and phenyl-glyoxylic acid (PGA), and dermal uptake was estimated with fluorescent tracers. Neuro-irritative symptoms were assessed by questionnaire and clinically verified in a subset. The results showed that median styrene levels were 18.65 ppm (spray-up), 12.42 ppm (hand lay-up) and 6.37 ppm (closed-mold). Urinary MA and PGA correlated with air levels (r = 0.78, 0.77). Dermal styrene load showed a moderate correlation with urinary MA (r = 0.42, p < 0.001). Symptom prevalence rose from 19% to 71% across exposure quartiles (adjusted OR = 5.6). A biomarker-based model using urinary mandelic acid (MA) with covariates (age, ventilation) showed strong apparent discrimination (AUC = 0.93). We propose 0.38 mg/g creatinine (MA) as a candidate operational (“early-warning”) threshold, pending external validation. In conclusion, integrated air, biological and dermal metrics reveal dose-dependent acute effects at or below 10 ppm. In this cross-sectional analysis, higher styrene exposure was associated with increased acute symptoms at or below ~10 ppm; these associations warrant confirmation in longitudinal studies with repeated biomonitoring. We present 0.38 mg/g creatinine (MA) as a candidate operational (“early-warning”)threshold to flag workers for closer evaluation; external validation is needed, and engineering controls remain the primary means of risk reduction.

2-Phenylethanol (2-PE) is an important flavor ingredient and is widely applied in the fields of food, cosmetics, and pharmaceuticals. Despite that Saccharomyces cerevisiae has the ability to naturally synthesize 2-PE via the Ehrlich pathway, de novo synthesis of 2-PE in high titer still remains a huge challenge. In this study, a non-native styrene degradation pathway was introduced into S. cerevisiae, which represents the first time to demonstrate the functional expression of “styrene-derived” 2-PE synthesis in yeast. Using a host strain engineered with L-phenylalanine (L-Phe) overproduction, the heterologous 2-PE pathway coupled with endogenous Ehrlich pathway produced 233 mg/L 2-PE under shake flasks. Additionally, we further engineered the permease transporters to improve the intracellular L-Phe availability, and further improved the 2-PE titer to 680 mg/L. Taken together, our work represents one of the pioneering reports to explore “styrene-derived” pathway in S. cerevisiae. The synthetic yeast described here might be used as a platform for the future development of next-generation high-yielding 2-PE yeast strains.Key Points• A styrene-derived pathway was established in yeast for 2-phenylethanol productions; membrane-associated styrene oxide isomerase was functional in yeast.• Transporter engineering to improve the L-phenylalanine importation with enhanced 2-phenylethanol productions.

This work aimed to investigate the effects of aging on the microstructures and rheological properties of modified asphalt with a GO/SBS composite, since the styrene–butadiene–styrene block copolymer is potentially compatible with graphene oxide (GO). The GO/SBS composites, which were used as a kind of modifier, were prepared via the solution-blending method. GO/SBS composites with varying GO contents were employed to prepare the GO/SBS-compound-modified asphalt (GO/SBS-MA). Then, the GO/SBS-MA underwent PAV (pressure aging vessel) or UV (ultraviolet) aging tests to simulate different aging circumstances. The microstructures of the asphalt binders were studied using FTIR (Fourier-transform infrared spectroscopy) and AFM (atomic force microscope) tests. Moreover, DSR (dynamic shear rheometer) and BBR (bending beam rheometer) experiments were carried out to investigate the rheological properties of the GO/SBS-MA. The results showed that the addition of GO improved the high-temperature stability of the asphalt binder while slightly impairing its performance at low temperatures. GO restrained the formation of carbonyl and sulfoxide groups as well as the breakdown of C=C bonds in the polybutadiene (PB) segment, promoting the anti-aging performance of GO/SBS-MA. Furthermore, the interactions between the GO/SBS and the asphalt binder resulted in the formation of needle-like aggregates, enhancing the stability of the asphalt binder. The asphalt binders with a higher content of graphene oxide (GO) exhibited not only a better high-temperature performance, but also a better aging resistance. It was concluded that the macroscopic properties and microstructures were significantly affected by GO, and a moderate increase in the amount of GO could contribute to a better aging resistance for GO/SBS-MA.

Amorphous nanomaterials with long-range disordered structures could possess distinct properties and promising applications, especially in catalysis, as compared with their conventional crystalline counterparts. It is imperative to achieve the controlled preparation of amorphous noble metal-based nanomaterials for the exploration of their phase-dependent applications. Here, we report a facile wet-chemical reduction strategy to synthesize various amorphous multimetallic Pd-based nanomaterials, including PdRu, PdRh, and PdRuRh. The phase-dependent catalytic performances of distinct Pd-based nanomaterials towards diverse catalytic applications have been demonstrated. Specifically, the usage of PdRu nanocatalysts with amorphous and crystalline face-centered cubic (fcc) phases can efficiently switch the ring-opening route of styrene oxide to obtain different products with high selectivity through alcoholysis reaction and hydrogenation reaction, respectively. Moreover, when used as an electrocatalyst for hydrogen evolution reaction (HER), the synthesized amorphous PdRh nanocatalyst exhibits low overpotential and high turnover frequency values, outperforming its crystalline fcc counterpart and most of the reported Pd-based HER electrocatalysts.

The study focuses on improving the viscosity property of asphalt material by adding a polymeric material which is styrene butadiene styrene a grade of T6302 in different weight percentages with changing the temperature and mixing time. The bitumen was mixed with the polymer by a mixer and by weight ratios of the additive (2, 3, 4, 5 and 6) % at different temperatures (170, 175, 180, 185 and 190) °C and the mixing time (30, 45, 60, 75 and 90) rpm. Taguchi method used to design of the experiments and investigated the best values of these three parameters that effective on viscosity of produced asphalt. Through the tests conducted on the mixture after the mixing process, there was a significant development and improvement in the viscosity of bitumen, which indicates the effect of additives, temperature and mixing process on the quality of the bitumen produced. The obtained results indicated best viscosity for produced bitumen is 2.55 Pa. sec under the following conditions: weight ratio 4-5%, 175 °C and mixing speed 75 minutes.

When temperatures drop to significantly low levels, road pavements are subjected to thermally-induced stresses, resulting in the appearance of thermal cracking, among other distresses. In these situations, polymers can be used as asphalt binder modifiers to improve certain asphalt binder properties, such as elastic recovery, cohesion, and ductility. Polymers also minimize some of the problems of asphalt mixtures, such as thermal and fatigue cracking and permanent deformation. This work’s objective was to study the behavior of asphalt mixtures at low temperatures, mainly when using modified binders. Thus, three binders were selected and tested: a standard 50/70 penetration grade bitumen and two polymer-modified binders (PMB), obtained by adding, respectively, 2.5% and 5.0% of styrene–butadiene–styrene (SBS) in the 50/70 pen grade bitumen. Then, the PMBs were incorporated into stone mastic asphalt mixtures (namely SMA 11), which were subjected to low-temperature mechanical tests based on the most recent European Standards. The asphalt binders and mixtures evaluated in this work were tested for thermal cracking resistance, creep, elastic recovery, cohesive strength, and ductility strength. Overall, it is concluded that the studied asphalt mixtures with PMB, with just 2.5% SBS, performed adequately at low temperatures down to −20 °C.

The development of fifth‐generation technology has resulted in increased demand for materials with low dielectric losses and superior thermal and mechanical properties. However, ensuring the widespread use of such materials by investigating their aging mechanisms and operating lifetimes remains challenging. In this study, a glass‐fiber (GF)‐reinforced acrylate‐styrene‐acrylonitrile/polycarbonate (ASA/GF/PC) composite is designed and comprehensively investigated its aging behavior, mechanism, and service lifetime under long‐term hygrothermal conditions. Based on the general Peck model, the composite maintains a high level of quality for over 10 years, including under harsh conditions of 40 °C and 80% relative humidity. The aging mechanism is primarily ascribed to cracking between the GF fibers and matrix, the breaking of chemical bonds, the generation of new cross‐linked domains, and physical aging. These findings provide valuable insights into the long‐term utilization of ASA/GF/PC composites in harsh environments. A kind of glass fiber (GF) reinforced acrylate‐styrene‐acrylonitrile/polycarbonate (ASA/GF/PC) composite and comprehensively investigated its aging behavior, mechanism, and service lifetime under long‐term hygrothermal conditions. Assisted by the general Peck model, the composite maintains a high level of quality for over 10 years, even under harsh conditions of 40 °C and 80% relative humidity.

Dry modified Styrene–Butadiene–Styrene is an innovative asphalt modification method applied at the mixture level, offering many advantages in environmental-friendliness, efficiency, and convenience. However, its engineering application lacks comprehensive theoretical support. To address this gap and provide practical guidance for the production process of dry modified Styrene–Butadiene–Styrene asphalt mixtures, this study evaluates systematically the mixing conditions and investigates the microscopic mechanisms and performance impacts of dry modified Styrene–Butadiene–Styrene concerning modifier dosage, mixing temperature, mixing duration, and storage time. The research includes multiple scales: molecular simulations to analyze microscopic interactions, fluorescence microscopy and Fourier-transform infrared spectroscopy for mesoscopic observations, and asphalt mixture performance tests for macroscopic evaluations. Molecular dynamics simulation results indicate that when the dosage of dry modified SBS increases from 4 to 6%, the diffusivity improves by 20% and the interface strength increases by 32%. Microscopic tests results show that the optimal diffusion effect of SBS can be achieved when the mixing time of the mixture is 90 s. Macroscopic experiments provide the best preparation scheme for dry modified SBS: SBS dosage of 6%, mixing temperature of 180–185 °C, mixing time of 90 s, and storage time of 30 min. Under these conditions, the pavement performance of the dry modified SBS mixture can achieve optimal results.

Bitumen exhibits viscoelastic properties, showcasing both viscous and elastic behaviors, which are characterized by the phase angle and dynamic modulus. Issues like early fatigue fractures, rutting, and permanent deformations in bituminous asphalt pavements arise due to moisture susceptibility, high-temperature deformation, low-temperature cracking, and overloading. These distresses result in potholes, alligator cracks, and specific deformations that lead to early pavement failure, increasing rehabilitation and maintenance costs. To address these issues, this study examines the dynamic modulus and phase angle behavior of Styrene Butadiene Styrene (SBS) modified and unmodified asphalt mixtures. SBS was incorporated in various proportions, ranging from 2 to 7% by the weight of bitumen. The asphalt mixture performance tester (AMPT) was utilized to measure the dynamic modulus at temperatures of 4.4, 21.1, 37.8, and 54.4 °C, and frequencies of 0.1, 0.5, 1, 5, 10, and 25 Hz. The study found significant correlations between dynamic modulus, temperature, loading frequency, and SBS content. Additionally, Multi Expression Programming (MEPX) and regression modeling were employed to estimate the dynamic modulus of SBS-modified HMA. Results indicated that increasing SBS content up to 7% decreased penetration and ductility values by up to 46% and 56%, respectively, while raising the softening point by 63% due to increased stiffness. The blend with 6% SBS by weight of bitumen exhibited superior performance compared to other mixtures. Phase angle initially increased with rising temperature, peaking at 37.8 °C at lower frequencies, and continued to increase at higher frequencies. Isothermal and isochronal plots showed that the 0% SBS mix had a higher phase angle due to increased bitumen content. Overall, the HMA mix with 6% SBS provided the best outcomes.