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Acrylonitrile-butadiene-styrene (ABS) is a thermoplastic copolymer commonly used in the electronics, automotive, and construction industries. In the aquatic environment, the formation of microplastics from larger-sized plastic waste occurs naturally, induced by physical, chemical, and biological processes that promote the aging of these particles. Here, we investigated the interactions between the freshwater amphipod Hyalella azteca and ABS microplastics (10-20 μm) (pristine and after accelerated aging) over 7 days of exposure. At the end of the exposure period, we evaluated the ability of H. azteca to fragment the ABS particles, as well as the changes in its oxidative stress biomarkers (SOD, CAT, MDA, and GST) as the result of ABS exposure. H. azteca promoted a significant fragmentation of ABS particles. The ratio of this biofragmentation was more pronounced in pristine particles. Despite the absence of significant changes in the mortality of exposed organisms, alterations in the oxidative stress biomarkers were observed. The results demonstrate the ability of H. azteca to fragment pristine and aged ABS microplastics and, the consequent susceptibility of these organisms to the effects of microplastic exposure.

Peptides, due to their diverse and controllable properties, are used as both liquid and gas phase recognition elements for both biological and chemical targets. While it is well understood how binding of a peptide to a biomolecule can be converted into a sensing event, there is not the same mechanistic level of understanding with regard to how peptides modulate the selectivity of semiconductor/conductor-based gas sensors. Notably, a rational, mechanistic study has not yet been performed to correlate peptide properties to the sensor response for volatile organic compounds (VOCs) as a function of chemical properties. Here, we have designed a peptide that has (1) two amino acid residues that bind the sensor surface, (2) two flexible linkers (GG) that eliminate steric strain, and (3) a five amino-acid repeat that can bind the analyte of interest either by formation of a binding pocket (such as from peptides selected by phage display) or by forming a semiselective adsorption layer. The nine peptide sequences containing both a six amino acid constant sequence (WGGWGG) and a five amino acid variable sequence (XXXXX) were synthesized, and their impact on the selectivity and sensitivity of carbon nanotube (CNT) gas sensors was explored. The response of each sensor to the following VOCs with diverse chemical properties: isopropyl alcohol (polar protic), acetone (polar aprotic), isoprene (nonpolar, linear hydrocarbon), and toluene (nonpolar aromatic), was then recorded and analyzed. This study revealed multiple key factors that influence the response of peptides on CNTs to select VOCs. First, the stability of the CNT-peptide aqueous dispersion correlated to the aromaphilicity of the side chain, strongly suggesting that the side chains of peptides are interfacing with the CNT, and not the peptide backbone. Second, the sensing response profile cannot solely be explained by peptides adsorbing to the gas molecules with similar polarities/dielectrics and may instead be due to analyte displacement of the peptide side chain on the CNT surface as measured by changes in the peptide bond orientation using near-edge X-ray absorption fine structure spectroscopy (NEXAFS). These two observations create a new paradigm to explain how peptides confer selectivity to semiconductor-/conductor-based gas sensors and can provide insights into future design and implementation of peptide-coated solid state sensors for gas targets.

Carbon black (CB) as rubber reinforcement has raised environmental concerns regarding this traditional petroleum-based filler, which is less susceptible to biodegradability. Although it has great reinforcing properties, the production technique is no longer sustainable, and its cost increases regularly. For these reasons, it is wise to look for sustainable replacement materials. Microalgal biomass (MB) has demonstrated great potential for use as biodegradable nano fillers in rubber composites. Microalgal has a high biomass productivity compared to traditional crops. They can produce a large amount of biomass per unit of land area, making them highly efficient in terms of resource utilization. In the present research, microalgal biomass was blended with CB at different concentrations for preparing two different kinds of rubber composites: Nitrile rubber Acrylonitrile-butadiene rubber (NBR) and styrene-butadiene rubber (SBR) are two common synthetic rubbers. In this study, the researchers investigated using microalgal biomass as filler in rubber composites. They assessed the filler-matrix interaction by evaluating the processability, mechanical characteristics, Payne effect, and swelling properties of the MB/CB-filled composites and compared them to CB-filled composites. The results show that rubber composites incorporating dual fillers (microalgal biomass and carbon black) had faster cure times, increased torque, and improved mechanical properties. The results prove biomass helps to minimize bulk quantities of CB and may be used as a partial replacement while still improving the mechanical properties. According to the study, microalgal biomass can successfully replace up to 50% of the CB filler. This will reduce petroleum dependence and possibly costs, depending on current petroleum prices., Competing Interests: Declarations. Consent for publication: All the authors have read and approved the manuscript in all respects for publication. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Composites derived from plant fibers are promising reinforcing materials for engineering because of their renewable and easily available characteristics. In this study, a simple pretreatment method was developed to fabricate structurally intact bamboo cellulose scaffolds. Water-stable, flexible, impact-resistant, and high damping ratio bamboo-based rubber composites were synthesized using carboxylated styrene-butadiene latex-impregnated 3D bamboo scaffolds. The composites were prepared by "Ethanol dehydration-delignification-polymer redistribution" strategy. The bamboo cellulose aggregate state structure and multiple crosslinked networks in the composite systems endowed the composites with strong mechanical and damping properties. The prepared composites had a high tensile strength, 67 times that of pure rubber (101.58 MPa and 1.25 MPa), which is higher than that of reported polymer-based vibration-damping materials, and the hydrostability was also significantly improved. The composites exhibited the characteristic viscoelasticity of polymers, with a recovery angle of 132° after 1000 extreme 180° flexion tests. More importantly, composites maintain a higher effective damping factor (Tan δ = 0.5) at room temperature. These bamboo-based rubber composites with excellent comprehensive performances have great potential for engineering applications, particularly for vibration damping, lightweight design, and flexible materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Nanomaterials are increasingly being used in road engineering with the development of road construction technology. The smoke suppression performance of asphalt can be substantially improved using organic nano-montmorillonite (OMMT)/styrene-butadiene-styrene (SBS) block modifiers. Pyrolysis gas chromatography-mass spectrometry (PY-GC-MS), fluorescence microscopy (FM), thermogravimetric analysis (TG), and gel permeation chromatography (GPC) were used to explore the characteristics and microscopic mechanisms of flue gas emissions. The addition of OMMT effectively reduced the emissions of carbon dioxide and Volatile Organic Compounds (VOCs) in asphalt flue gas, as well as increased the SBS swelling degree in the asphalt matrix and the compatibility between the SBS and asphalt matrix. The stable interlayer structure formed via OMMT/SBS co-modification effectively inhibited the release of VOCs during the thermal decomposition of asphalt, being more environmentally friendly because of the reduction in emissions compared with traditional asphalt. The SBS, OMMT, and asphalt matrix is a physically modified mixture. The incorporation of OMMT increases the macromolecule content in the modified asphalt, showing that OMMT inhibited the decomposition of asphalt macromolecules into smaller molecules, thus reducing the release of VOCs. Including the appropriate macro and small molecules helps strengthen the ability of asphalt to resist permanent deformation at high temperatures, maintain its flexibility, and effectively prevent cracking at low temperatures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Rapid gas sensing with high sensitivity and selectivity is pivotal in advanced production, in smart living, and increasingly in medical health applications. This study presents a novel Pt@InNiO x nanoflake isoprene sensor that achieves an exceptionally low limit of detection (LOD) at 2 ppb, the lowest reported for isoprene sensors to date. Notably, it exhibits high selectivity and remarkable antihumidity capacity, thus meeting the stringent requirements for lung cancer screening. To unravel the sensing mechanism, we fabricate an operando DRIFTS-Raman cell coupled to online electrical measurements. It reveals that the ultrasensitive performance of Pt@InNiO x nanoflakes stems from the activated conjugated structure of isoprene by Pt nanoclusters and from the enhanced isoprene adsorption and electron interaction due to the nanoflake morphology. The p-n junction constructed by doping Ni maintains Fermi level equilibrium, shielding it from humidity interference. Practically, we integrate these ultrasensitive Pt@InNiO x nanoflakes into a miniaturized portable electronic device that successfully distinguishes lung cancer patients with expiratory isoprene below 40 ppb, from the healthy population with isoprene above 60 ppb, enabling an accurate diagnosis in clinics. Our work not only provides a breakthrough in low-cost, noninvasive cancer screening through breath analysis but also advances the rational design of cutting-edge gas sensing materials.

Organic aerosols (OAs) may serve as ice-nucleating particles (INPs), impacting the formation and properties of cirrus clouds when their phase state and viscosity are in the semisolid to glassy range. However, there is a lack of direct parameterization between aerosol viscosity and their ice nucleation capabilities. In this study, we experimentally measured the ice nucleation rate of 2-methyltetrols (2-MT) aerosols, a key component of isoprene-epoxydiol-derived secondary organic aerosols (IEPOX-SOA), at different viscosities. These results demonstrate that the phase state has a significant impact on the ice nucleation abilities of OA under typical cirrus cloud conditions, with the ice nucleation rate increasing by 2 to 3 orders of magnitude when the phase state changes from liquid to semisolid. An innovative parametric model based on classical nucleation theory was developed to directly quantify the impact of viscosity on the heterogeneous nucleation rate. This model accurately represents our laboratory measurement and can be implemented into climate models due to its simple, equation-based form. Based on data collected from the ACRIDICON-CHUVA field campaign, our model predicts that the INP concentration from IEPOX-SOA can reach the magnitude of 1 to tens per liter in the cirrus cloud region impacted by the Amazon rainforest, consistent with recent field observations and estimations. This novel parameterization framework can also be applied in regional and global climate models to further improve representations of cirrus cloud formation and associated climate impacts.

3-Methylenebutane-1,2,4-triol and 3-methyltetrahydrofuran-2,4-diols, previously designated "C 5 -alkene triols", were recently confirmed as in-particle isomerization products of isoprene-derived β-IEPOX isomers that are formed upon acid-driven uptake and partition back into the gas phase. In chamber experiments, we have systematically explored their gas phase oxidation by hydroxyl radical ( • OH) as a potential source of secondary organic aerosol (SOA). • OH-initiated oxidation of both compounds in the presence of ammonium bisulfate aerosol resulted in substantial aerosol volume growth. Compositions of low-volatility products in both the gas and particulate phases were established by high-resolution mass spectrometry measurements. Under conditions mimicking the Southeast USA (50% relative humidity, bulk seed aerosol pH 1.4), we estimate the SOA yield from • OH-initiated oxidation of 3-methylenebutane-1,2,4-triol to be 93.1%, equating to 1.95 ± 0.81 Tg C Yr -1 , and from 3-methyltetrahydrofuran-2,4-diol oxidation to be 26.7%, equating to 1.76 ± 1.26 Tg C Yr -1 . Previously unreported isoprene-derived oxidation products, 2,3-dihydroxy-2-(hydroxymethyl)propanal, 1,3,4-trihydroxybutan-2-one, and four organosulfates have been confirmed in ambient SOA, and aid in understanding isoprene oxidation pathways in HO 2 • dominated environments as NO x levels continue to decline in the US. This work underlines the need for inclusion of partitioning of in-particle formed semivolatile products and their atmospheric oxidation pathways in atmospheric models.

Elucidating the mutual effects between the different volatile organic compounds (VOCs) is crucial for comprehending the formation mechanism of atmospheric secondary organic aerosols (SOA). Here, the mixed VOCs experiments of isoprene and Δ 3 -carene/β-caryophyllene were carried out in the presence of O 3 using an indoor smog chamber. The suppression effect of isoprene was recognized by the scanning mobility particle sizer spectrometer, online vacuum ultraviolet free electron laser (VUV-FEL) photoionization aerosol mass spectrometry, and quantum chemical calculations. The results indicate that the suppression effect of isoprene on the ozonolysis of Δ 3 -carene and β-caryophyllene shows fluctuating and monotonous trends, respectively. The carbon content of the precursor could be the main factor for regulating the strength of the suppression effect. Plausible structures and formation mechanisms of several new products generated from the single VOC precursor and VOC-cross-reaction are proposed, which enrich the category of VOC oxidation products. Meanwhile, a new dimerization mechanism of the RO 2 + R'O 2 reaction is suggested, which offers an intriguing perspective on the gas phase formation process of particle phase accretion products. The present findings provide valuable insights into clarifying the pivotal roles played by isoprene in the interplay between different VOCs and understanding of SOA formation mechanisms of VOC mixtures, especially nearby the emission origins., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2023. Published by Elsevier B.V.)

The study aimed to investigate the impact of low-intensity pulsed ultrasound (LIPUS) on human urinary-derived stem cells (hUSCs) viability within three-dimensional (3D) cell-laden gelatin methacryloyl (GelMA) scaffolds. hUSCs were integrated into GelMA bio-inks at concentrations ranging from 2.5% to 10% w/v and then bioprinted using a volumetic-based method. Subsequent exposure of these scaffolds to LIPUS under varying parameters or sham irradiation aimed at optimizing the LIPUS treatment. Assessment of hUSCs viability employed Cell Counting Kit-8 (CCK8), cell cycle analysis, and live&dead cell double staining assays. Additionally, Western blot analysis was conducted to determine protein expression levels. With 3D bio-printed cell-laden GelMA scaffolds successfully constructed, LIPUS promoted the proliferation of hUSCs. Optimal LIPUS conditions, as determined through CCK8 and live&dead cell double staining assays, was achieved at a frequency of 1.5 MHz, a spatial-average temporal-average intensity (ISATA) of 150 mW cm -2 , with an exposure duration of 10 min per session administered consecutively for two sessions. LIPUS facilitated the transition from G0/G1 phase to S and G2/M phases and enhanced the phosphorylation of ERK1/2 and PI3K-Akt. Inhibition of ERK1/2 (U0126) and PI3K (LY294002) significantly attenuated LIPUS-induced phosphorylation of ERK1/2 and PI3K-Akt respectively, both of which decreased the hUSC viability within 3D bio-printed GelMA scaffolds. Applying a LIPUS treatment at an ISATA of 150 mW cm -2 promotes the growth of hUSCs within 3D bio-printed GelMA scaffolds through modulating ERK1/2 and PI3K-Akt signaling pathways., (Creative Commons Attribution license.)

Hexachloro-1,3-butadiene (HCBD) has received increasing attention because of its adverse effects on human health. Although HCBD is regulated under the Stockholm Convention, it is still widely detected in the environment. However, detailed reports on the chemical mechanisms of HCBD reactions in the environment are lacking. This review comprehensively summarizes HCBD's unintentional industrial sources and formation mechanisms, and chemical reactions and transformations in different media (gas, water, and biological phases). Photochemical reactions in the atmosphere can degrade and transform HCBD and potentially form other toxic compounds, such as phosgene. Aerobic pyrolysis of HCBD can generate complex byproducts. Further research is essential to fully understand the environmental behavior of HCBD., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A series of donor-acceptor (D-π-A) substituted diphenylbutadienes exhibiting solvatochromic emission and a large Stokes shift (100-200 nm) were designed and synthesized for distinctive organelle labelling, enabling real-time monitoring of organelle behaviour such as lysosomal dynamics, mitophagy monitoring, and stress responses. The morpholine-substituted D-A-D diphenylbutadiene (M2) was employed to investigate selective imaging of lysosomes, the uptake of damaged mitochondria through mitophagy, and monitoring lysosomal viscosity or pH changes. Other diphenylbutadiene derivatives (M1, M3, M4) selectively accumulated in lipid droplets. All the synthesized derivatives demonstrated significant uptake in 5-day post-fertilization zebrafish larvae, with M2 showing maximum uptake in the enterocyte-containing heart and intestinal regions, which include the lysosomes., (© 2024 Wiley-VCH GmbH.)

Isoprene epoxydiol (IEPOX) is an important reactive gas-phase intermediate produced by the photooxidation of isoprene under low NO x conditions, playing a key role in the formation of secondary organic aerosols (SOA). Previous studies have mostly focused on the liquid-phase reactions of IEPOX within aerosols; however, interfacial heterogeneous chemical reactions are equally important in SOA formation. This study systematically explores the reaction mechanisms of IEPOX at the acidic aerosol interface and in the bulk phase using classical molecular dynamics (MD) and ab initio molecular dynamics simulations (AIMD). The study found that the free energy of IEPOX at the aerosol interface significantly decreases, indicating that interfacial heterogeneous chemical reactions are indispensable for the formation of IEPOX-derived SOA. The research reveals the formation pathways of 2-methyltetrols (2-MTO) and 1,3,4-trihydroxy-3-methylbutan-2-yl sulfates (2-MTOOS), finding that the protonation of the epoxy O atom and the cleavage of the C-O bond are the rate-controlling steps, while the nucleophilic addition is a spontaneous process. Through multiple sets of simulations, it was observed that the formation frequency of 2-MTO at the acidic aerosol interface and in the bulk phase reached 53.8%, significantly higher than the 30.8% of 2-MTOOS, which is consistent with field observation data. Additionally, through metadynamics (MTD) simulations, it was suggested that IEPOX could undergoes acid-catalyzed ring-opening reactions at the interface, potentially followed by the transfer of H atoms from primary alcohols into the aerosol, leading to the possible formation of the intermediate product 3-methylbut-3-ene-1,2,4-triol (one of the proposed structures of C 5 -alkene triols). These findings provide new insights into the formation mechanism of IEPOX-derived SOA and offer a scientific basis for future studies on their physicochemical properties and atmospheric fate., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

One of the challenges in the plastic industry is the cost and time spent on the characterization of different grades of polymers. Compressed sensing is a data reconstruction method that combines linear algebra with optimization schemes to retrieve a signal from a limited set of measurements of that signal. Using a data set of signal examples, a tailored basis can be constructed, allowing for the optimization of the measurements that should be conducted to provide the highest and most robust signal reconstruction accuracy. In this work, compressed sensing was used to predict the values of numerous properties based on measurements for a small subset of those properties. A data set of 21 fully characterized acrylonitrile-butadiene-styrene samples was used to construct a tailored basis to determine the minimal subset of properties to measure to achieve high reconstruction accuracy for the remaining nonmeasured properties. The analysis showed that using only six measured properties, an average reconstruction error of less than 5% can be achieved. In addition, by increasing the number of measured properties to nine, an average error of less than 3% was achieved. Compressed sensing enables experts in academia and industry to substantially reduce the number of properties that must be measured to fully and accurately characterize plastics, ultimately saving both costs and time. In future work, the method should be expanded to optimize not only individual properties but also entire tests used to simultaneously measure multiple properties. Furthermore, this approach can also be applied to recycled materials, of which the properties are more difficult to predict.

The thermodynamic incompatibility between the soft and hard segments of thermoplastic polyurethane (TPU) results in a microphase-separated behavior and excellent mechanical properties. However, the effect of the chain extender on the degree of microphase separation (DMS) and the resultant mechanical properties of TPU have not been well studied because of the complex interactions between the soft and hard segments. Herein, hydroxyl-terminated polybutadiene-based TPUs(HTPB-TPUs) without hydrogen bonding between the soft and hard segments are synthesized using hydroxyl-terminated polybutadiene, toluene diisocyanate, and four different chain extenders, and the effect of the chain extender structure on DMS is analyzed experimentally using a combination of analytical techniques. Furthermore, the solubility parameters of the soft and hard segments, glass transition temperatures, and hydrogen-bond density of the HTPB-TPUs, are computed using all-atom molecular dynamics simulations. The results clearly reveal that the chain extender significantly affects the DMS and thus the mechanical properties of HTPB-TPUs. This study paves the way for studying the relationship between the structure and properties of TPU., (© 2024 Wiley‐VCH GmbH.)

1,3-Butadiene (BD) is a carcinogenic air pollutant. N-acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine (MHBMA3 or 4HBeMA), an urinary BD metabolite with unspecified configuration, is considered the most sensitive BD biomarker and has been used in routine biomonitoring since 2012. However, two issues remain unaddressed: why its concentrations are unusually high relative to other urinary BD biomarkers and why some authors reported no detection of the biomarker whereas other authors readily quantitated it. To address the issues, we synthesized and structurally characterized the authentic trans- and cis-isomers of MHBMA3 (designated NE and NZ, respectively), developed an isotope-dilution LC-MS/MS method for their quantification, and examined 67 urine samples from barbecue restaurant personnel (n = 47) and hotel administrative staff (n = 20). The restaurant personnel were exposed to barbecue fumes, which contain relatively high concentrations of BD. The results showed that NE and NZ had highly similar NMR spectra, and were difficult to be well separated chromatographically. The NMR data showed that the MHBMA3 isomer investigated in most previous studies was NE. We did not detect NE and NZ in any samples; however, an interfering peak with varying heights was observed in most samples. Notably, under the chromatographic conditions used in the literature, the peak exhibited indistinguishable retention time from that of NE. Thus, it is highly likely that the interfering peak has been mis-identified as NE in previous studies, providing a reasonable explanation for the high MHBMA3 concentration in urine. The contradiction in the presence of MHBMA3 in urine was also caused by the mis-identification, because the researchers who reported the absence of MHBMA3 were actually detecting NZ. Thus, we clarified the confusion on MHBMA3 in previous studies through correctly identifying the two MHBMA3 isomers. The presence of NE and NZ in human urine warrants further investigations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Developing an electronic skin (e-skin) is becoming popular due to its capability to mimic human skin's ability to detect various stimuli. Mostly, such skins are tactile-based sensors. However, the exploration of nontactile-based sensing capability in the e-skin is still in a nascent stage. Herein, we report an approach toward developing electrical hysteresis- and cross-interference-free nontactile e-skin using liquid polyisoprene with an ultralow concentration of multiwalled carbon nanotubes (ϕ = 0.006 volume fraction) by leveraging the stencil printing technique. The impact of cross-linking the samples was studied. Uncross-linked samples demonstrated higher electrical conductivity than the cross-linked samples. A coarse-grained phenomenological model with molecular dynamics simulation was utilized to investigate filler network formation and percolation that dictate the conductivity of uncross-linked and cross-linked samples. Simulation studies supported the fidelity of the experimental findings. The uncross-linked e-skin demonstrated a higher temperature sensitivity (-1.103%/°C) than the cross-linked e-skin (-0.320%/°C) in the thermal conduction mode. Despite the superior sensitivity of the uncross-linked e-skin, the cross-linked systems demonstrated superior cyclic stability (35 thermal cycles), ensuring reliable sensor readings over extended usage. Judicious choice of encapsulant warranted the cross-linked e-skin sensor to nullify the impact of moisture on signal output, thereby providing cross-interference-free results. The optimized e-skin sample retained a similar thermal sensitivity even when used in the nontactile mode. From the application purview, the utility of the developed sensor was tested successfully for nontactile sensing of human body temperature. Additionally, the sensor was utilized to determine the respiratory profile by integrating the developed sensor into a wearable mask. This study advances nontactile e-skin-based sensing technology and opens new avenues for creating wearable and IoT devices for healthcare and human-machine interactions.

Microplastics represent a novel category of environmental pollutants, and understanding their interactions with typical xenobiotics is crucial. In this study, we investigated the impact of ionic liquids (ILs) containing herbicidal anions, namely glyphosate [Glyph] and 2,4-dichlorophenoxyacetate [2,4-D], and the surfactant cation - dodecyltrimethylammonium [C 12 TMA] on acrylonitrile butadiene styrene (ABS) microplastics. The aim of the study was to assess the sorption capacity of microplastics that were present in both untreated and aged form using standard and modified Fenton methods. In addition, impact on toxicity and stress adaptation of the model soil bacterium Pseudomonas putida KT2440 was measured. Upon ageing, ABS microplastics underwent a fivefold increase in BET surface area and total pore volume (from 0.001 to 0.004 cm 3 /g) which lead to a dramatic increase in adsorption of the cations on ABS microplastics from 40 to 45% for virgin ABS to 75-80% for aged ABS. Toxicity was mainly attributed to hydrophobic cations in ILs (EC 50 ∼ 60-65 mg/dm 3 ), which was also mitigated by sorption on ABS. Furthermore, both cations and anions behaved similarly across different ILs, corresponding chlorides, and substrates used in the ILs synthesis. These findings highlight microplastics potential as hazardous sorbents, contributing to the accumulation of xenobiotics in the environment., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

For the need of direct contact with the skin, electronic skins (E-skins) should not only fulfill electric functions, but also ensure comfort during wearing, including permeability, waterproofness, and easy removal. Herein, the study has developed a self-adhesive, detach-on-demand, breathable, and waterproof E-skin (PDSC) for motion sensing and wearable comfort by electrospinning styrene-isoprene block copolymer rubber with carbon black nanosheets as the sensing layer and liner copolymers of N, N-dimethylacrylamide, n-octadecyl acrylate and lauryl methacrylate as the adhesive layer. The high elasticity and microfiber network structure endow the PDSC with good sensitivity and high linearity for strain sensing. The hydrophobic and crystallizable adhesive layer ensures robust, waterproof, and detaching-on-demand skin adhesion. Meanwhile, the fiber structure enables the PDSC good air and water permeability. The integration of electric and wearable functions endows the PDSC with great potential for motion sensing during human activities as both the sensing and wearable performances., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

The poor interfacial compatibility of natural fiber-reinforced polymer composites has become a major challenge in the development of industry-standard high-performance composites. To solve this problem, this study constructs a novel rigid-flexible balanced molecular crosslinked network transition interface in composites. The interface improves the interfacial compatibility of the composites by balancing the stiffness and strength of the fibers and the matrix， effectively improving the properties of the composites. The flexural strength and flexural modulus of the composites were enhanced by 38 % and 44 %, respectively. Water absorption decreased by 30 %. The initial and maximum thermal degradation temperatures increased by 20 °C and 16 °C, respectively. The maximum storage modulus increased by 316 %. Furthermore, the impact toughness was elevated by 41 %, attributed to the crosslinked network's efficacy in absorbing and dissipating externally applied energy. This innovative approach introduces a new theory of interfacial reinforcement compatibility, advancing the development of high-performance and sustainable biocomposites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Synthesis of monomer-recyclable polyesters solely from CO 2 and bulk olefins holds great potential in significantly reducing CO 2 emissions and addressing the issue of plastic pollution. Due to the kinetic disadvantage of direct copolymerization of CO 2 and bulk olefins compared to homopolymerization of bulk olefins, considerable research attention has been devoted to synthesis of polyester via the ring-opening polymerization (ROP) of a six-membered disubstituted lactone intermediate, 1,2-ethylidene-6-vinyl-tetrahydro-2H-pyran-2-one (𝜹-L), obtained from telomerization of CO 2 and 1,3-butadiene. However, the conjugate olefin on the six-membered ring of 𝜹-L leads to serious Michael addition side reactions. Thus, the selective ROP of 𝜹-L, which can precisely control the repeating unit for the production of polyesters potentially amenable to efficient monomer recycling, remains an unresolved challenge. Herein, the first example of selective ROP of 𝜹-L is reported using a combination of organobase and N,N'-Bis[3,5-bis(trifluoromethyl)phenyl]urea as the catalytic system. Systematic modifications of the substituent of the urea show that the presence of electron-deficient 3,5-bis(trifluoromethyl)-phenyl groups is the key to the extraordinary selectivity of ring opening over Michael addition. Efficient monomer recovery of oligo(𝜹-L) is also achieved under mild catalytic conditions., (© 2024 Wiley‐VCH GmbH.)

Coordinative chain transfer polymerization (CCTP) of ethylene and its copolymerization with 1,3-butadiene is conducted in toluene at 80 °C using a combination of {(Me 2 Si(C 13 H 8 ) 2 )Nd(μ-BH 4 )[(μ-BH 4 )Li(THF)]} 2 (1) metal complex and various organomagnesium compounds used as chain transfer agents including n-butyl-n-octyl-magnesium (BOMAG), n-butyl-mesityl-magnesium (n-BuMgMes), n-butyl-magnesium chloride (n-BuMgCl), n-pentyl-magnesium bromide (n-C 5 H 11 MgBr), pentanediyl-1,5-di(magnesium bromide) (PDMB) and isobutyl-magnesium chloride (i-BuMgCl). Kinetics and performance in terms of control of the (co)polymerization are comparatively discussed particularly considering the presence of ether and the nature of the organomagnesium compounds employed. Taking advantage of the well-known reactivity between nitrile and molecular organomagnesium compounds, the functionalization of the chains is further carried out by deactivation of the polymerization medium with benzonitrile or methoxybenzonitrile compounds leading to ketone ω-functionalized chains. The success of the functionalizations is extended to coupling strategies using dinitrile reagents and to the functionalization of high molar mass ethylene butadiene rubber (EBR)., (© 2024 Wiley‐VCH GmbH.)

Isoprene is the most relevant volatile organic compound emitted during the biosynthesis of metabolism processes. The oxidation of isoprene by a hydroxy radical (OH) is one of the main consumption schemes that generate six isomers of isoprene hydroxy hydroperoxide radicals (ISOPOOs). In this study, the rate constants of ISOPOOs + sulphur dioxide (SO 2 ) reactions that eventually generate sulphur trioxide (SO 3 ), the precursor of sulphate aerosol (SO 4 2- (p)), are determined using microcanonical kinetic theories coupled with molecular structures and energies estimated by quantum chemical calculations. The results show that the reaction rates range from 10 -27 to 10 -20 cm 3 molecule -1 s -1 , depending on the atmospheric temperature and structure of the six ISOPOO isomers. The effect of SO 3 formation from SO 2 oxidation by ISOPOOs on the atmosphere is evaluated by a global chemical transport model, along with the rate constants obtained from microcanonical kinetic theories. The results show that SO 3 formation is enhanced in regions with high SO 2 or low nitrogen oxide (NO), such as China, the Middle East, and Amazon rainforests. However, the production rates of SO 3 formation by ISOPOOs + SO 2 reactions are eight orders of magnitude lower than that from the OH + SO 2 reaction. This is indicative of SO 4 2- (p) formation from the direct oxidation of SO 2 by ISOPOOs, which is almost negligible in the atmosphere. The results of this study entail a detailed analysis of SO 3 formation from gas-phase reactions of isoprene-derived products.

The abstract provides an overview of a study focused on analyzing diverse strategies to achieve sustainable utilization of synthetic polymers through effective waste management. The escalating global consumption of synthetic polymers has precipitated a concerning increase in plastic waste and environmental degradation. To address this challenge, novel materials with specified application goals, such as engineered plastic, have been developed and are intended for recycling and reuse. Despite the reuse and recycling, when plastic gets disposed into the environment, the degradation properties of plastics render a direct disposal hazard, posing a significant environmental threat. To mitigate these issues, the concept of replacing specific monomers of engineered synthetic plastics with bio-alternatives or blending them with other polymers to enhance sustainability and environmental compatibility has emerged. In this study, Acrylonitrile Butadiene Styrene (ABS) plastic is the focal material, and three distinct investigations were conducted. First, replacing ABS plastic's butadiene monomer with natural rubber was explored for its properties and environmental impact. Second, ABS plastic was blended with virgin, recycled, and bio-alternatives of PET (polyethylene terephthalate) and PVC (polyvinyl chloride) polymers. Lastly, recycled ABS blended with recycled PET and PVC was analyzed for mechanical properties. Comparative assessments of these blends were made based on mechanical properties, carbon emissions, and cost-effectiveness. The study determined that the r-ABS/r-PVC (recycled) blend exhibited the most favorable characteristics for practical application., (© 2024 Wiley Periodicals LLC.)

Viscoelastic behavior can be beneficial in enhancing the unprecedented dynamics of polymer metamaterials or, in contrast, negatively impacting their wave control mechanisms. It is, therefore, crucial to properly characterize the viscoelastic properties of a polymer metamaterial at its working frequencies to understand viscoelastic effects. However, the viscoelasticity of polymers is a complex phenomenon, and the data on storage and loss moduli at ultrasonic frequencies are extremely limited, especially for additively manufactured polymers. This work presents a protocol to experimentally characterize the viscoelastic properties of additively manufactured polymers and to use them in the numerical analysis of polymer metamaterials. Specifically, the protocol includes the description of the manufacturing process, experimental procedures to measure the thermal, viscoelastic, and mechanical properties of additively manufactured polymers, and an approach to use these properties in finite-element simulations of the metamaterial dynamics. The numerical results are validated in ultrasonic transmission tests. To exemplify the protocol, the analysis is focused on acrylonitrile butadiene styrene (ABS) and aims at characterizing the dynamic behavior of a simple metamaterial made from it by using fused deposition modeling (FDM) three-dimensional (3D) printing. The proposed protocol will be helpful for many researchers to estimate viscous losses in 3D-printed polymer elastic metamaterials that will improve the understanding of material-property relations for viscoelastic metamaterials and eventually stimulate the use of 3D-printed polymer metamaterial parts in various applications.

The blend of butadiene and acrylonitrile copolymer (NBR) with natural poly-cis-isoprene (NR) shows increased resistance to swelling in solvents in comparison to the individual components. In aerospace, NBR rubber is used as thermal protection for rockets and shall not contain other polymers, even in low contents, otherwise, it can affect the protection performance and rocket safety by causing detachment of the elastomer/propellant interface; therefore, this investigation presents methodologies to determine the NR/NBR contents. This study explores different analytical techniques, such as Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy, in the mid-infrared (MIR) by reflection and in the near-infrared by reflectance (NIRA) modes, Furthermore, quantification strategies by univariate, bivariate and multivariate (chemometric) models are evaluated and compared. A proposed methodology, based on multivariate Raman microscopy with partial least squares regression (PLS), showed high linearity (R2 > 0.99) and low error (< 0.82 %). The validation of FT-MIR data for the CH3, which presented lower error (1.3%) than vinylidene band (6%), showed that both methodologies (reflection and NIRA reflectance) can be used for the quantification of NR in NR/NBR. These results constitute a contribution to the state of the art in researching industrial and aerospace elastomeric applications.

Eucommia ulmoides rubber (EUR) is a high-quality natural rubber resource, which can be extracted from different organs of the Eucommia ulmoides tree. In this study, EUR was isolated from the leaves, barks, and pericarps, and the structural characteristics and physicochemical properties of EUR were systematically determined. The accumulation and distribution of EUR in different tissues were assessed through in situ observations combined with cellular and subcellular scales. The preliminary analyses indicated that the variations in the physicochemical properties of EUR across different tissues were associated with its accumulation microstructure. Further analyses by SEM and TEM showed that the initial cell differentiation and fusion resulted in the formation of tubular structures without any nucleus. A limited number of rubber particles were generated within the cytoplasm, concurrent with aggregation and fusion. Eventually, rubber particles filled the entire cytoplasm, and organelles disappeared to form highly aggregated filamentous structures. In addition, the number and area of EUR-containing cells were closely related to the organization sizes of barks and leaves. This study provided valuable insights into Eucommia ulmoides histology and the rubber industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A versatile and robust end-group derivatization approach using oximes has been developed for the detection of oxidative degradation of synthetic polyisoprenes and polybutadiene. This method demonstrates broad applicability, effectively monitoring degradation across a wide molecular weight range through ultraviolet (UV)-detection coupled to gel permeation chromatography. Importantly, it enables the effective monitoring of degradation via derivatization-induced UV-maximum shifts, even in the presence of an excess of undegraded polyene, overcoming limitations previously reported with refractive index detectors. Notably, this oxime-based derivatization methodology is used in enzymatic degradation experiments of synthetic polyisoprenes characterized by a cis: trans ratio with the rubber oxygenase Lcp K30 . It reveals substantial UV absorption in derivatized enzymatic degradation products of polyisoprene with molecular weights exceeding 1000 g mol -1 - an unprecedented revelation for this enzyme's activity on such synthetic polyisoprenes. This innovative approach holds promise as a valuable tool for advancing research into the degradation of synthetic polyisoprenes and polybutadiene, particularly under conditions of low organocatalytic or enzymatic degradation activity. With its broad applicability and capacity to reveal previously hidden degradation processes, it represents a noteworthy contribution to sustainable polymer chemistry., (© 2024 The Authors. Macromolecular Rapid Communications published by Wiley‐VCH GmbH.)

Latex clearing proteins (Lcps) catalyze the oxidative cleavage of the C = C bonds in cis-1,4-polyisoprene (natural rubber), producing oligomeric compounds that can be repurposed to other materials. The active catalytic site of Lcps is buried inside the protein structure, thus raising the question of how the large hydrophobic rubber chains can access the catalytic center. To improve our understanding of hydrophobic polymeric substrate binding to Lcps and subsequent catalysis, we investigated the interaction of a substrate model containing ten carbon-carbon double bonds with the structurally characterized LcpK30, using multiple computational tools. Prediction of the putative tunnels and cavities in the LcpK30 structure, using CAVER-Pymol plugin 3.0.3, fpocket and Molecular Dynamic (MD) simulations provided valuable insights on how substrate enters from the surface to the buried active site. Two dominant tunnels were discovered that provided feasible routes for substrate binding, and the presence of two hydrophobic pockets was predicted near the heme cofactor. The larger of these pockets is likely to accommodate the substrate and to determine the size distribution of the oligomers. Protein-ligand docking was carried out using GOLD software to predict the conformations and interactions of the substrate within the protein active site. Deeper insight into the protein-substrate interactions, including close-contacts, binding energies and potential cleavage sites in the cis-1,4-polyisoprene, were obtained from MD simulations. Our findings provide further justification that the protein-substrate complexation in LcpK30 is mainly driven by the hydrophobic interactions accompanied by mutual conformational changes of both molecules. Two potential binding modes were identified, with the substrate in either extended or folded conformations. Whilst binding in the extended conformation was most favorable, the folded conformation suggested a preference for cleavage of a central double bond, leading to a preference for oligomers with 5 to 6 C = C bonds. The results provide insight into further enzyme engineering studies to improve catalytic activity and diversify the substrate and product scope of Lcps., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Abu Hassan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The chemistry of conjugated nitrodienes is becoming increasingly popular. These molecules are successfully applied in cycloaddition to synthesize six-membered rings in Diels-Alder reactions. Nitrodienes can be also applied to obtain bis-compounds in [3+2] cycloaddition. Moreover, the presence of a nitro group in the structure provides a possibility of further modification of the products. The simplest symmetrical representative of conjugated nitrodienes is (1 E ,3 E )-1,4-dinitro-1,3-butadiene. Although the first mentions of the compound date back to the early 1950s, the compound has not yet been examined thoroughly enough. Therefore, in this article, a comprehensive study of (1 E ,3 E )-1,4-dinitro-1,3-butadiene has been described. For this purpose, an experimental study including the synthesis process as well as an evaluation of the spectral characteristics has been conducted. So as to better understand the properties of this compound, a computational study of reactivity indices based on MEDT and also an assessment of pharmacokinetics and biological activity according to ADME and PASS methodologies have been made. On this basis, some future application trends of (1 E ,3 E )-1,4-dinitro-1,3-butadiene have been proposed.

Given the rise in both usage and disposal of dangerous electronics, there is a catastrophic rise in assemblage of electronic waste (e-waste). E-waste including various plastic resins are among the most frequently discarded materials in electronic gadgets. In current digital era, managing e-waste has become universal concern. From the viewpoint of persisting lacuna of e-waste managing methods, the current study is designed to fabricate an eco-friendly e-waste treatment with native soil bacteria employing an enrichment culture method. In the presence of e-waste, indigenous soil microbes were stimulated to degrade e-waste. Microbial cultures were isolated using enrichment medium containing acrylonitrile-butadiene styrene (ABS) as the primary carbon source. Priestia aryabhattai MGP1 was found to be the most dominant e-polymer degrading bacterial isolate, as it was reported to degrade ABS plastic in disposed-off television casings. Furthermore, to increase degradation potential of MGP1, Response Surface Methodology (RSM) was adopted which resulted in optimized conditions (pH 7, shaking-speed 120 rpm, and temperature 30 °C), for maximum degradation (18.88%) after 2 months. The structural changes induced by microbial treatment were demonstrated by comparing the findings of Field emission scanning electron microscopy (FESEM) images and Fourier Transform Infrared (FTIR) spectra confirming the disappearance of ≡ C─H peaks along with C-H, C=C and C ≡N bond destabilization following degradation. Energy-dispersive X-ray (EDX) analyzers of the native and decomposed e-polymer samples revealed a considerable loss in elemental weight % of oxygen by 8.4% and silica by 0.5%. Magnesium, aluminium and chlorine which were previously present in the untreated sample, were also removed after treatment by the bacterial action. When seeds of Vigna radiata were screened using treated soil in the presence of both e-waste and the chosen potent bacterial strain, it was also discovered that there was reduced toxicity in terms of improved germination and growth metrics as a phytotoxicity criterion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Human exposure to known carcinogen 1,3-butadiene (BD) is common due to its high concentrations in automobile exhaust, cigarette smoke, and forest fires, as well as its widespread use in the polymer industry. The adverse health effects of BD are mediated by epoxide metabolites such as 3,4-epoxy-1-butene (EB), which reacts with DNA to form 1-hydroxyl-3-buten-1-yl adducts on DNA nucleobases. EB-derived mercapturic acids (1- and 2-( N -acetyl-l-cysteine- S -yl)-1-hydroxybut-3-ene (MHBMA) and N -acetyl- S -(3,4-dihydroxybutyl)-l-cysteine (DHBMA)) and urinary N7-(1-hydroxyl-3-buten-1-yl) guanine DNA adducts (EB-GII) have been used as biomarkers of BD exposure and cancer risk in smokers and occupationally exposed workers. However, low but significant levels of MHBMA, DHBMA, and EB-GII have been reported in unexposed cultured cells, animals, and humans, suggesting that these metabolites and adducts may form endogenously and complicate risk assessment of butadiene exposure. In the present work, stable isotope labeling in combination with high-resolution mass spectrometry was employed to accurately quantify endogenous and exogenous butadiene metabolites and DNA adducts in vivo. Laboratory rats were exposed to 0.3, 0.5, or 3 ppm of BD- d 6 by inhalation, and the amounts of endogenous ( d 0 ) and exogenous ( d 6 ) DNA adducts and metabolites were quantified in tissues and urine by isotope dilution capillary liquid chromatography/high resolution electrospray ionization tandem mass spectrometry (capLC-ESI-HRMS/MS). Our results reveal that EB-GII adducts and MHBMA originate exclusively from exogenous exposure to BD, while substantial amounts of DHBMA are formed endogenously. Urinary EB-GII concentrations were associated with genomic EB-GII levels in tissues of the same animals. Our findings confirm that EB-GII and MHBMA are specific biomarkers of exposure to BD, while endogenous DHBMA predominates at sub-ppm exposures to BD.

Isoprene (2-methyl-1,3-butadiene) is emitted to the atmosphere each year in sufficient quantities to rival methane (>500 Tg C yr -1 ), primarily due to emission by trees and other plants. Chemical reactions of isoprene with other atmospheric compounds, such as hydroxyl radicals and inorganic nitrogen species (NO x ), have implications for global warming and local air quality, respectively. For many years, it has been estimated that soil-dwelling bacteria consume a significant amount of isoprene (~20 Tg C yr -1 ), but the mechanisms underlying the biological sink for isoprene have been poorly understood. Studies have indicated or confirmed the ability of diverse bacterial genera to degrade isoprene, whether by the canonical iso-type isoprene degradation pathway or through other less well-characterized mechanisms. Here, we review current knowledge of isoprene metabolism and highlight key areas for further research. In particular, examples of isoprene-degraders that do not utilize the isoprene monooxygenase have been identified in recent years. This has fascinating implications both for the mechanism of isoprene uptake by bacteria, and also for the ecology of isoprene-degraders in the environments., (© 2022 The Authors. Environmental Microbiology published by Applied Microbiology International and John Wiley & Sons Ltd.)

Hydroxyl-terminated polybutadiene (HTPB)-based piezoelectric polymer (m-HTPB) is prepared for the first time by functionalized branch chain modification strategy. In the presence of HTPB with >98.8% cis-1,4 content, the C=C bond partly breaks down, and functionalized acetylferrocene groups are introduced to the cis-1,4 polybutadiene branch chain, retaining the high cis-1,4 content of HTPB. The whole process is conducted under mild conditions, without complicated manipulations. The microstructure and molecular weight of m-HTPB are characterized by Fourier-transform infrared (FTIR) spectra, 1 H or 13 C nuclear magnetic resonance spectrum (NMR), and gel permeation chromatography (GPC). The thermal properties of HTPB and m-HTPB are determined by differential scanning calorimetry (DSC). Electrochemical investigations reveal that m-HTPB exhibits higher conductance compared with HTPB. The m-HTPB flexible piezoelectric polymer is further used for in situ and real-time pressure monitoring. This simple and effective strategy provides a promising polymeric material for flexible piezoelectric sensors.

Dichloro(2,2'-bipyridine)copper was synthesized by reacting copper dichloride with bypyridine, and its behavior, in combination with methylaluminoxane (MAO), in the polymerization of butadiene, isoprene, 2,3-dimethyl-1,3 butadiene, and 3-methyl-1,3-pentadiene was examined. The purpose of this study is to find catalytic systems that are more sustainable than those currently used for the polymerization of butadiene and isoprene (e.g., Co and Ni), but that are comparable in terms of catalytic activity and selectivity. Predominantly, syndiotactic 1,2 polybutadiene, crystalline syndiotactic 3,4 polyisoprene, crystalline syndiotactic 1,2 poly(3-methyl-1,3-pentadiene), and crystalline cis -1,4 poly(2,3-dimethyl-1,3-butadiene) were obtained in a manner similar to that observed with the analogous iron complex. As far as we know, the investigated catalytic system represents the first example of a copper-based catalyst in the field of stereospecific polymerization. Given the great availability of copper, its extremely low toxicity (and therefore high sustainability), and the similarity of its behavior to that of iron, the result obtained seems to us of considerable interest and worthy of further investigation.

Iodide-bound ruthenium-JOSIPHOS complexes catalyze the redox-neutral C-C coupling of primary alcohols with methylallene (1,2-butadiene) or 1,3-butadiene to form products of anti-crotylation with good to excellent levels of diastereo- and enantioselectivity. Distinct from other methods, direct crotylation of primary alcohols in the presence of unprotected secondary alcohols is possible, enabling generation of spirastrellolide B (C9-C15) and leucascandrolide A (C9-C15) substructures in significantly fewer steps than previously possible., (© 2022 Wiley-VCH GmbH.)

This paper reports a computational study on the specific 1,4-cis polymerization of butadiene catalyzed by the cationic gadolinium metallocene [(C 5 Me 5 ) 2 Gd][B(C 6 F 5 ) 4 ] combined with excess amount of Al( i Bu) 3 . Because this reaction system has no initial Gd-alkyl bond, a mechanism with conventional coordinative chain transfer polymerization (CCTP) is not feasible. Density functional theory (DFT) analyses indicate a novel mechanism in which the cationic Gd plays a crucial role by assisting butadiene insertion into one of the Al-C bond of Al( i Bu) 3 . The proposed butadiene polymerization mechanism can account for the specific 1,4-cis selectivity of this catalyst system., (© 2022 Wiley-VCH GmbH.)

Many heterocyclic compounds can be synthetized using diaza-1,3-butadienes (DADs) as key structural precursors. Isolated and in situ diaza-1,3-butadienes, produced from their respective precursors (typically imines and hydrazones) under a variety of conditions, can both react with a wide range of substrates in many kinds of reactions. Most of these reactions discussed here include nucleophilic additions, Michael-type reactions, cycloadditions, Diels-Alder, inverse electron demand Diels-Alder, and aza-Diels-Alder reactions. This review focuses on the reports during the last 10 years employing 1,2-diaza-, 1,3-diaza-, 2,3-diaza-, and 1,4-diaza-1,3-butadienes as intermediates to synthesize heterocycles such as indole, pyrazole, 1,2,3-triazole, imidazoline, pyrimidinone, pyrazoline, -lactam, and imidazolidine, among others. Fused heterocycles, such as quinazoline, isoquinoline, and dihydroquinoxaline derivatives, are also included in the review.

EPA designated 1,3-butadiene (BD) as a high priority chemical in December 2019 and is presently performing an evaluation under the Toxic Substances Control Act (TSCA). EPA's cancer dose-response assessment for BD was published in 2002 and was primarily based on a study on workers exposed to BD in the North American synthetic Styrene-Butadiene Rubber (SBR) Industry developed by the University of Alabama at Birmingham (UAB). EPA relied upon a Poisson regression of leukemia mortality data from this cohort (hereinafter referred to as the SBR study) to estimate the cancer potency of BD. At the time, the SBR cohort included more than 15,000 male workers that were followed up through 1991. The SBR cohort has undergone multiple updates over the past two decades. Most recently, Sathiakumar et al. (2021a, b) published an update, with 18 more years of follow up in addition to approximately 5,000 female workers and updated exposure concentration estimates. Recent EPA assessments (e.g., for ethylene oxide, USEPA 2016) based on epidemiological studies use Cox proportional hazards models because they offer better control of the effect of age in cancer development and are less restrictive than Poisson regression models. Here, we develop exposure-response models using standard Cox proportional hazards regression. We explore the relationship between six endpoints (all leukemia, lymphoid leukemia, myeloid leukemia, multiple myeloma, non-Hodgkin's lymphoma, and bladder cancer) and exposures to BD using the most recent exposure metrics and the most recent update of the SBR study. After adjusting for statistically significant covariates, an upper 95% confidence level on the cancer potency based on leukemia derived herein is 0.000086 per ppm, which is approximately 1,000-fold less than EPA's (2002) estimate of 0.08 per ppm and about 10-fold less than TCEQ's (2008) estimate of 0.0011 per ppm., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Christopher Kirman reports financial support was provided by American Chemistry Council. Christopher Kirman reports a relationship with American Chemistry Council that includes: consulting or advisory., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

The covalent cross-linking is an essential prerequisite for achieving the unique entropic elasticity of rubber products; however, the formation of a 3D cross-linked network and permanent cross-links makes thermosetting rubbers difficult to be recycled, causing serious environmental pollution at the end of their life. Herein, a facile, green, and promising strategy to introduce the exchangeable and cleavable acetal bonds into the chemically cross-linked networks of diene-typed rubbers is reported. For the first time, the hydroxyl-functionalized styrene-butadiene rubber (ESBR-HEMA) is prepared by introducing 2-hydroxyethyl methacrylate (HEMA) during the emulsion polymerization of styrene-butadiene rubber (ESBR). Then, based on hydroxyl-vinyl ether addition reactions, divinyl ether (DVE) could serve as a cross-linking agent to facilely and effectively cross-link hydroxyl-functionalized rubbers without additional additives, producing exchangeable and hydrolyzable acetal linkages. What's more, the acetal-containing cross-linked network in ESBR-HEMA vulcanizates could rearrange their topologies at elevated temperatures, endowing them with malleable and thermal reprocessing abilities. Moreover, the hydrolyzable acetal bonds could be selectively cleaved into hydroxyl and aldehyde groups in acidic conditions, resulting in a closed-loop chemical recycling of the ESBR-HEMA rubber. Hence, this work provides a facile and green cross-linking strategy for hydroxyl-functionalized rubbers to address the inherent problems brought from the covalent cross-linking of rubbers., (© 2022 Wiley-VCH GmbH.)

1,3-butadiene is a known human carcinogen and a chemical to which humans are exposed occupationally and through environmental pollution. Inhalation risk assessment of 1,3-butadiene was completed several decades ago before data on molecular biomarkers of exposure and effect have been reported from both human studies of workers and experimental studies in mice. To improve risk assessment of 1,3-butadiene, the quantitative characterization of uncertainty in estimations of inter-individual variability in cancer-related effects is needed. For this, we ought to take advantage of the availability of the data on 1,3-butadiene hemoglobin adducts, well established biomarkers of the internal dose of the reactive epoxides, from several large-scale human studies and from a study in a Collaborative Cross mouse population. We found that in humans, toxicokinetic uncertainty factor for 99th percentile of the population ranged from 3.27 to 7.9, depending on the hemoglobin adduct. For mice, these values ranged from less than 2 to 7.51, depending on the dose and the adduct. Quantitative estimated from this study can be used to reduce uncertainties in the parameter estimates used in the models to derive the inhalation unit risk, as well as to address possible differences in variability in 1,3-butadiene metabolism that may be dose-related., (Copyright © 2022 Elsevier Inc. All rights reserved.)

In this short communication we characterize the emission of volatile organic compounds (VOCs) from fused filament fabrication (FFF) 3D printing using four polymer materials, namely polyethylene terephthalate glycol-modified (PETG), acrylonitrile styrene acrylate (ASA), Nylon, and acrylonitrile butadiene styrene (ABS). Detailed emission profiles are obtained during thermal degradation of the polymers as a function of temperature and also in real-time during 3D printing. Direct quantitative measurement was performed using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Qualitative determination of the volatiles emitted from the printed elements at various temperatures was accomplished using gas chromatography-mass spectrometry (GC-MS). The emission rates of VOCs differ significantly between the different polymer filaments, with the emission from Nylon and PETG more than an order of magnitude lower than that of ABS.

Vibration and noise are ubiquitous in social life, which severely damage machinery and adversely affect human health. Thus, the development of materials with high-damping performance is of great importance. Rubbers are typically used as damping materials because of their unique viscoelasticity. However, they do not satisfy the requirements of different applications with various working conditions. In this study, the advantages of the high loss factor of styrene butadiene rubber (SBR) are combined with the strong designability of polyurethane. Hydroxyl-terminated solution-polymerized styrene butadiene rubbers (HTSSBRs) with different structures are prepared using anionic polymerization. HTSSBRs are then used as the soft segment during the synthesis of temperature-tunable high-damping performance polyurethanes (HTSSBR-polyurethanes (PUs)). The prepared HTSSBR-PUs with different structures exhibit excellent loss performance, a maximum loss factor (tan δ max ) of above 1.60, and an effective damping performance over a wide temperature range compared to traditional SBR and polyurethane. Therefore, this work offers an effective method for the design of damping materials with adjustable properties., (© 2022 Wiley-VCH GmbH.)

Styrene-acrylonitrile-copolymer (SAN) and acrylonitrile-butadiene-styrene-copolymer (ABS) are gaining in importance as food contact materials. Oligomers and other non-intentionally added substances can migrate into foodstuffs. Five SAN and four ABS samples from the German market and manufacturers were extracted and the extractable oligomers were characterised by high performance liquid chromatography-mass spectrometry/ultraviolet detection/chemiluminescence nitrogen detection/fluorescence detection and gas chromatography-mass spectrometry. Trimers, formed from acrylonitrile and styrene units, were determined to be the dominating group of extractable oligomers in SAN and ABS in concentrations of about 4900-15800 mg/kg material. Furthermore, styrene-acrylonitrile dimers, styrene oligomers, styrene monomer and ethylbenzene were identified in the sample extracts. Migration testing with three consecutive migrations for multiple use articles was performed for two SAN articles. Migration of trimers into water, 3% acetic acid, 10% and 20% ethanol under hot-fill conditions (70°C, 2 h) was not detectable above 9 µg/dm 2 , while 50% ethanol acting as a food simulant for milk (124 µg/dm 2 trimers during the third migration) was shown to overestimate the actual migration into milk (< 11 µg/dm 2 trimers at 70°C, 2 h). 2-Amino-3-methyl-1-naphthalenecarbonitrile (AMNC), an oligomer degradation product and a primary aromatic amine, was detected in all material sample extracts (0.3-17.1 mg/kg material) and was released into food simulants in low amounts (< 0.014 µg/dm 2 during the third migration into 50% ethanol at 70°C, 2 h).

We designed and synthesized high χ-low N -maltoheptaose-(triazolium + /N(SO 2 CF 3 ) 2 - )-polyisoprene-(triazolium + /N(SO 2 CF 3 ) 2 - )-maltoheptaose ABA triblock elastomers featuring triazolium + /N(SO 2 CF 3 ) 2 - (TFSI - ) counteranion ionic interfaces separating their constituting polymeric sub-blocks. Spin-coated and solvent-vapor-annealed (SVA) MH 1.2k -(T + /TFSI - )-PI 4.3k -(T + /TFSI - )-MH 1.2k thin films demonstrate interface-induced charge cohesion through ca. 1 nm "thick" ionic nanochannels which facilitate the self-assembly of a perpendicularly aligned lamellar structure. Atomic force microscopy (AFM) and (grazing-incidence) small-angle X-ray scattering ((GI)SAXS) characterizations of MH 1.2k -(T + /TFSI - )-PI 4.3k -(T + /TFSI - )-MH 1.2k and pristine triBCP analogous thin films revealed sub-10 nm block copolymer (BCP) self-assembly and unidirectionally aligned nanostructures developed over several μm 2 areas. Solvated TFSI - counterions enhance the oligosaccharide sub-block packing during SVA. The overall BCP phase behavior was mapped through SAXS characterizations comparing di- vs triblock polymeric architectures, a middle PI sub-block with two different molecular masses, and TFSI - or I - counteranion effects. This work highlights the benefits of inducing single-point electrostatic interactions within chemical structures of block copolymers to master the long-range self-assembly of prescribed morphologies.

Lactate and isoprene are two common monomers for the industrial production of polyesters and synthetic rubbers. The present study tested the co-production of D-lactate and isoprene by engineered Escherichia coli in microaerobic conditions. The deletion of alcohol dehydrogenase ( adhE ) and acetate kinase ( ackA ) genes, along with the supplementation with betaine, improved the co-production of lactate and isoprene from the substrates of glucose and mevalonate. In fed-batch studies, microaerobic fermentation significantly improved the isoprene concentration in fermentation outlet gas (average 0.021 g/L), compared with fermentation under aerobic conditions (average 0.0009 g/L). The final production of D-lactate and isoprene can reach 44.0 g/L and 3.2 g/L, respectively, through fed-batch microaerobic fermentation. Our study demonstrated a dual-phase production strategy in the co-production of isoprene (gas phase) and lactate (liquid phase). The increased concentration of gas-phase isoprene could benefit the downstream process and decrease the production cost to collect and purify the bio-isoprene from the fermentation outlet gas. The proposed microaerobic process can potentially be applied in the production of other volatile bioproducts to benefit the downstream purification process.

Lignin-based flame retardants represent great promising next-generation flame retardants due to their sustainability, unique aromatic structure, and high charring capability. However, their applications are still limited by the compatibility, processability, and efficiency of flame retardancy. Here, a green functional lignin-based nanofiller (lignin-diethylenetriamine/red phosphorus nanoparticles, Lignin-N-P NPs) was prepared by the chemical modification and co-precipitation. After blending with the commercial acrylonitrile butadiene styrene copolymers (ABS), the physical, chemical, and flame retardant properties of the blends reveal that Lignin-N-P NPs/ABS blend has acceptable processability, mechanical properties, and significantly improved thermal stability and fire performance. Its values of peak heat release rate and total heat released per unit area were significantly dropped 67.8% and 77.5%, respectively. This study will initiate a new design for not only flame retardants but also lignin-based materials., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Internal conversion (IC) between the two lowest singlet excited states, 1 1 B u + and 2 1 A g - , of s- trans -butadiene and s- trans -hexatriene is investigated using a series of single- and multi- reference wave function and density functional theory (DFT) methodologies. Three independent types of the equation-of-motion coupled-cluster (EOMCC) theory capable of providing an accurate and balanced description of one- as well as two-electron transitions, abbreviated as δ-CR-EOMCC(2,3), DIP-EOMCC(4h2p){ N o }, and DEA-EOMCC(4p2h){ N u } or DEA-EOMCC(3p1h,4p2h){ N u }, consistently predict that the 1 1 B u + /2 1 A g - crossing in both molecules occurs along the bond length alternation coordinate. However, the analogous 1 1 B u + and 2 1 A g - potentials obtained with some multireference approaches, such as CASSCF and MRCIS(D), as well as with the linear-response formulation of time-dependent DFT (TDDFT), do not cross. Hence, caution needs to be exercised when studying the low-lying singlet excited states of polyenes with conventional multiconfigurational methods and TDDFT. The multistate many-body perturbation theory methods, such as XMCQDPT2, do correctly reproduce the curve crossing. Among the simplest and least expensive computational methodologies, the DFT approaches that incorporate the contributions of doubly excited configurations, abbreviated as MRSF (mixed reference spin-flip) TDDFT and SSR(4,4), accurately reproduce our best EOMCC results. This is highly promising for nonadiabatic molecular dynamics simulations in larger systems.

The identification of ILRs in fire investigations has attracted great attention for decades, and background at fire scenes caused complex interference on ILR identification by contributing characteristic compounds. Aiming at exploring the correlation between the interference extent to gasoline identification and chemical composition/structure, two polystyrene-butadiene rubbers (SBr) with typical styrene contents involving alkylbenzene in molecules were selected particularly. The free burning residues in the presence and absence of gasoline were collected and analyzed via gas chromatography-mass spectrometry. It is striking that SBr with typical styrene content caused the most remarkable interference to gasoline identification as far as reported since it is even impossible to be distinguished from gasoline through chromatography profiles. Additionally, the molecular structure together with the chemical composition influences the interference extent as well. To trace the source of the remarkable interference from SBr, polystyrene, polybutadiene, as well as one polystyrene-butadiene-styrene block copolymer, were picked particularly due to their specific chemical relations. The results of target compounds analysis on the corresponding combustion residues revealed that the remarkable interference of SBrs originated from the combination of 'styrene' and 'butadiene' by contributing different target compounds. The results provide further support for the proposal of the correlation of the interferents chemical compositions with the interference extent. Furthermore, this study provides important references for fire debris analysis by predicting the interference of different substrates on the basis of their chemical composition., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interests regarding the publication of this article., (Copyright © 2021. Published by Elsevier B.V.)

The first examples of rhodium-catalyzed carbonyl addition via hydrogen autotransfer are described, as illustrated in tandem butadiene-mediated carbonyl addition-redox isomerizations that directly convert primary alcohols to isobutyl ketones. Related reductive coupling-redox isomerizations of aldehyde reactants mediated by sodium formate also are reported. A double-labeling crossover experiment reveals that the rhodium alkoxide obtained upon carbonyl addition enacts redox isomerization without dissociation of rhodium at any intervening stage.