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Various excellent catalysts have been explored for the methanolysis of polycarbonate (PC), but it is still challenging to develop green and economical catalysts for solvent-free PC methanolysis to recover both bisphenol A (BPA) and dimethyl carbonate (DMC). Herein, green, efficient and solvent-free degradation of PC to BPA and DMC was achieved using urea as a cheap green catalyst. At 140 °C for 3 h, PC was completely degraded to BPA and DMC with yields of 93.4% and 74.7%, respectively. A possible catalytic degradation mechanism of PC was proposed by kinetic experiments and NMR, where urea, methanol and carbonate formed a six-membered ring in the reaction. It was found that the increase of urea concentration significantly reduced the activation energy, which was attributed to the fact that the increase of urea concentration made the six-membered ring easier to form and activated the carbonate bond. The degradation system can be reused directly up to 10 times and 100% degradation rate can be maintained. This work provides a simple, green and economical method for industrial PC recycling. [ABSTRACT FROM AUTHOR]

Endocrine disruptive compounds are natural or anthropogenic environmental micropollutants that alter the function of the endocrine system ultimately damaging the metabolism. Bisphenol A (BPA) is the most common of these pollutants and it is often used in epoxy coatings and polycarbonates as a plasticizer. Therefore, monitoring BPA levels in different environments is very important and challenging. In recent years, an increasing number of BPA detection methods have been proposed. This article presents a critical review of aptamer-based electrochemical, fluorescence-based, colorimetric, and several other BPA detection platforms published in the last decade. Furthermore, a statistical evaluation has been made using principle component analysis showing analytical performance parameters do not create very different clusters. Comparisons to other BPA detection methods are also presented so that the reader has an overall literature overview. [ABSTRACT FROM AUTHOR]

Synthesis of polycarbonates (PCs) from isosorbide (ISB) monomers has been recently investigated. However, compared to bisphenol A, PCs face challenges in commercialization because their high rigidity renders it difficult to increase their molecular weight, resulting in high brittleness. To address these limitations, a flexible co‐monomer, ethoxylated ISB (EI5), was mixed with ISB to produce ISB/EI5‐based PCs. The structures of the ISB/EI5‐based PCs were controlled by varying the ISB/EI5 ratio from 100/0 to 60/40 mol%. Films were fabricated, and their thermal, optical, and mechanical properties and degradability were investigated. With increasing EI5 content, the thermal processability of the ISB/EI5‐based PCs improved, and the produced films exhibited excellent visible light transmittance and UV‐blocking effects. The mechanical properties of the ISB/EI5‐based PCs indicated sufficient tensile strength (σ = 89.7–72.9 MPa), competitive to that of commercial PC, and the properties could be controlled by adjusting the ISB/EI5 ratio. The contact angle and hydrolysis behavior of the ISB/EI5‐based PC films indicated increased surface hydrophilicity and increased degradation rate with increasing EI5 content. In conclusion, the structural control of the ISB/EI5‐based PCs enhanced their moldability and degradability, suggesting their potential commercial utilization. [ABSTRACT FROM AUTHOR]

Plastics are versatile materials, offering lightweight, durable, and affordable solutions across various industries. However, their non‐degradable nature poses challenges by end of their life. This study presented an innovative carbonyl extraction method to utilize waste poly(bisphenol A carbonate) (PC) as reaction precursor to synthesis of activated furan as precursor for photoswitchable Stenhouse adducts. This innovative chemical strategy not only generated N,N'‐functionalized barbiturates but also provided an eco‐friendly and cost‐effective alternative to traditional synthesis methods. The method presented hereby not only promotes sustainability by repurposing waste polycarbonate as carbonyl equivalent under green conditions but also yielded reusable bisphenol A (BPA). Furthermore, the derived activated furans exhibited their functionality by forming colored donor‐acceptor Stenhouse adducts (DASAs) on aminated polymer surfaces. This work demonstrated a transition from a linear plastics economy toward a circular one, highlighting the potential of plastic waste as a resource for creating materials with improved properties. [ABSTRACT FROM AUTHOR]

The combination of the best properties of Polycarbonate (PC) and Acrylonitrile-butadiene-styrene (ABS) has resulted in the development of commercially available PC/ABS blends that have been found to be useful in many molding applications. PC has excellent mechanical and optical properties, but predominant use of bisphenol A in PC synthesis raises concerns regarding its potential environmental harm. In this study, we have studied the alternative for the PC/ABS blend by replacing PC with the bio-based PC and ABS with the Acrylonitrile-styrene-acrylate (ASA). A blend of bio-based PC and ASA was prepared by the melt blending techniques and investigated mechanical, thermal, and degradation (hydrolytic and soil burial degradation) properties. [ABSTRACT FROM AUTHOR]

Optically transparent polycarbonates (PCs) and Copoly(Imide-Carbonate)s (Co-PICs) were synthesized by the melt polycondenzation method. Rigid (imide) and flexible (-O- and –C(CH3)2−) moieties were incorporated in the structure of bisimide diol comonomer using 4-aminophenol and 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride). The structural properties of synthesized comonomers and polymers were confirmed by 1H, 13C-NMR and FT-IR spectra. Thermal properties of polycarbonates and copolycarbonates were examined using DSC and TG analysis. Thermal properties (glass transition T g and thermal decomposition (Td) temperature) of copolymers were enhanced without sacrificing properties of BPA-based PC (high transparency, ductility, and processability) by the incorporation of active functional bisimide diol comonomer (5–10 mole %) in the polycarbonate backbone. Different sets of PCs and Co-PICs thin film substrates were prepared by the solvent casting method and used to design frequency selective surface. The proposed flexible FSS offers shielding of 20 dB at 8.8 GHz. In addition, the FSS offers polarization independent operation with its symmetrical unit cell geometry. [ABSTRACT FROM AUTHOR]

In this study, the melt polycondensation reaction of 9,9'- bis(4-hydroxyphenyl)fluoride (BHPF) and diphenyl carbonate (DPC) was catalyzed using three ionic liquids (ILs) and a conventional alkali metal as catalysts. The optimal IL catalysts were determined to be [BMmim][BF4] ionic liquid catalysts, and the catalytic mechanism was investigated. Furthermore, the optimum process conditions were identified: the optimal amount of [BMmim][BF4] was 0.05 mol% based on DPC, the polycondensation temperature was set at 200°C for a duration of 3 h, followed by polymerization at 280°C for another 3 h. As a result, the Mn value of poly(9,9-bis(4-hydroxyphenyl) carbonate) (PFC) reached up to 41387 g/mol with a glass transition temperature band of approximately 254°C and Td-5% value of around 436°C. [ABSTRACT FROM AUTHOR]

Environmental damage caused by waste plastics and downstream chemical breakdown products is a modern crisis. Endocrine‐disrupting bisphenol A (BPA), found in breakdown products of poly(bisphenol A carbonate) (PC), is an especially pernicious example that interferes with the reproduction and development of a wide range of organisms, including humans. Herein we report a single‐stage thiocracking method to chemically upcycle polycarbonate using elemental sulfur, a waste product of fossil fuel refining. Importantly, this method disintegrates bisphenol A units into monoaryls, thus eliminating endocrine‐disrupting BPA from the material and from any potential downstream waste. Thiocracking of PC (10 wt%) with elemental sulfur (90 wt%) at 320 °C yields the highly crosslinked network SPC90. The composition, thermal, morphological, and mechanical properties of SPC90 were characterized by FT‐IR spectroscopy, TGA, DSC, elemental analysis, SEM/EDX, compressive strength tests, and flexural strength tests. The composite SPC90 (compressive strength = 12.8 MPa, flexural strength = 4.33 MPa) showed mechanical strengths exceeding those of commercial bricks and competitive with those of mineral cements. The approach discussed herein represents a method to chemically upcycle polycarbonate while deconstructing BPA units, and valorizing waste sulfur to yield structurally viable building materials that could replace less‐green legacy materials. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a common synthetic endocrine disruptor that can be utilized in the fabrication of materials such as polycarbonates and epoxy resins. Numerous studies have linked BPA to learning and memory problems, although the precise mechanism remains unknown. Gamma‐aminobutyric acid (GABA) is the most abundant inhibitory neurotransmitter in the vertebrate central nervous system, and it is intimately related to learning and memory. This study aims to evaluate whether altered cognitive behavior involves the GABA signaling pathway in male offspring of rats exposed to BPA during the prenatal and early postnatal periods. Pregnant rats were orally given BPA (0, 0.04, 0.4, and 4 mg/kg body weight (BW)/day) from the first day of pregnancy to the 21st day of breastfeeding. Three‐week‐old male rat offspring were selected for an open‐field experiment and a new object recognition experiment to evaluate the effect of BPA exposure on cognitive behavior. Furthermore, the role of GABA signaling markers in the cognition affected by BPA was investigated at the molecular level using western blotting and real‐time polymerase chain reaction (RT‐PCR). The research demonstrated that BPA exposure impacted the behavior and memory of male rat offspring and elevated the expression of glutamic acid decarboxylase 67 (GAD67), GABA type A receptors subunit (GABAARα1), and GABA vesicle transporter (VGAT) in the hippocampus while decreasing the expression levels of GABA transaminase (GABA‐T) and GABA transporter 1 (GAT‐1). These findings indicate that the alteration in the expression of GABA signaling molecules may be one of the molecular mechanisms by which perinatal exposure to BPA leads to decreased learning and memory in male rat offspring. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC) is a thermoplastic engineering plastic with excellent properties, and its excellent dielectric properties have broad application prospects in the field of electronics. In this paper, bisphenol Z (BPZ) and diphenyl carbonate (DPC) are used as raw materials to synthesize special polycarbonate (BPZ‐PC) by melt transesterification. The effects of catalyst type, catalyst dosage, molar ratio of raw materials, transesterification reaction time and vacuum degree, polycondensation reaction temperature and time on the molecular weight of the product are investigated, and the optimal reaction conditions are obtained. The chemical structure of the product is verified by FTIR, 1H‐NMR and 13C‐NMR spectra tests. The thermal properties, mechanical properties, optical properties and dielectric properties of BPZ‐PC are evaluated. Therefore, due to its excellent performance, BPZ‐PC, a high‐performance low‐dielectric polycarbonate, can be widely used in high‐frequency communication, microelectronics, and aerospace industries. [ABSTRACT FROM AUTHOR]

Diphenolic acid, or 4,4-bis(4-hydroxyphenyl)pentanoic acid, represents one of the potentially most interesting bio-products obtainable from the levulinic acid supply-chain. It represents a valuable candidate for the replacement of bisphenol A, which is strongly questioned for its toxicological issues. Diphenolic acid synthesis involves the condensation reaction between phenol and levulinic acid and requires the presence of a Brønsted acid as a catalyst. In this review, the state of the art related to the catalytic issues of its synthesis have been critically discussed, with particular attention to the heterogeneous systems, the reference benchmark being represented by the homogeneous acids. The main opportunities in the field of heterogeneous catalysis are deeply discussed, as well as the bottlenecks to be overcome to facilitate diphenolic acid production on an industrial scale. The regioselectivity of the reaction is a critical point because only the p,p′-isomer is of industrial interest; thus, several strategies aiming at the improvement of the selectivity towards this isomer are considered. The future potential of adopting alkyl levulinates, instead of levulinic acid, as starting materials for the synthesis of new classes of biopolymers, such as new epoxy and phenolic resins and polycarbonates, is also briefly considered. [ABSTRACT FROM AUTHOR]

A photonic crystal fiber (PCF) sensor for detecting harmful chemicals such as di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), and bisphenol S (BPS) in polycarbonate plastics has been proposed using fused silica as the substrate, consisting of a decagonal core hole and 2 layers of circular cladding air holes arranged in a hexagonal pattern, and numerically analysed using COMSOL Multiphysics with the Finite Element Method. The PCF sensor was evaluated for the effective area, nonlinear coefficient, chromatic dispersion, V-parameter, power fraction, relative sensitivity, and confinement loss from the visible to infrared wavelength range. The results show relative sensitivities of 99.14%, 99.93%, and 99.95% for DEHP, BPA, and BPS, respectively, at an optimum wavelength of 0.4 µm, with confinement losses ranging from 10−21 to 10−17 dB/m for all the test analytes. The design was also shown to be robust against variations in cladding air hole layers and global dimensions, making it a promising candidate for practical sensing applications in the plastic production industry. Furthermore, the sensor's ability to achieve low confinement losses, low chromatic dispersion, and a high nonlinear coefficient demonstrates its suitability for a range of other applications including optical communication, supercontinuum generation, and light illumination. [ABSTRACT FROM AUTHOR]

The effects of gamma radiation on the AC electrical properties of highly cross-linked epoxy resin/bisphenol A-based polycarbonate samples have been investigated as a function of concentrations of bisphenol A-based polycarbonate, frequency, and temperature. The composite samples contained different bisphenol A-based polycarbonate concentrations of 0, 4, 8, 10, and 15 by wt%. The gamma irradiation process was performed at different gamma doses of 0, 100, 300, and 500 Gy. The AC electrical properties of the tested samples were studied before and after gamma irradiation within a frequency range of 200 kHz to 1 MHz. The results show that after irradiation, a consistent decrease in complex impedance values ( Z ∗ ) was observed, indicating an increase in conductivity due to radiation-induced scission of the composite structure. Dielectric properties, including the dielectric constant ( ε r ) and dielectric loss ( ε i ), exhibited an increase with higher doses and higher polycarbonate concentrations, signifying the formation of defect sites and charge carrier trapping. AC electrical conductivity ( σ a c ) displayed a notable rise post irradiation, with temperatures ranging from 30 °C to 110 °C, and higher radiation doses and higher temperatures led to increased conductivity. The activation energy (   E a ) decreased as the radiation dose increased, reflecting structural modifications induced by radiation. [ABSTRACT FROM AUTHOR]

Bisphenol-A (BPA) is a toxic chemical largely produced and used in polycarbonate plastics worldwide. Majoon Suranjan (MS), a polyherbal formulation, is used as an anti-inflammatory medicine against rheumatoid arthritis. The present study aimed to evaluate BPA-induced toxicity and its possible amelioration by MS. To test our hypothesis, we performed gas chromatography-mass spectrometry (GC-MS) analysis, DNA interaction studies, genotoxicity tests, oxidative stress parameters, and histopathological examinations. GC-MS profiling of MS revealed the presence of various anti-oxidant compounds. DNA interaction studies showed that both chemicals intercalate between DNA base pairs. Next, we observed BPA-induced genotoxicity and oxidative damage. The observed effects might be due to BPA-induced reactive oxygen species production. Further, BPA changed the anti-oxidant enzyme activities, increased the malondialdehyde, alanine aminotransferase, alkaline phosphatase, and total bilirubin levels, and caused gross damage to the liver and kidney. Interestingly, these effects were significantly reversed by MS. In conclusion, MS shows protective effects against BPA-induced toxicity and could be a potential alternative medicine against BPA toxicity, especially in third-world countries where BPA uses are not strictly regulated. Bisphenol-A (BPA) induces multiple toxic effects. BPA induces genotoxicity, oxidative and tissue damage. Majoon Suranjan (MS) ameliorates the BPA induced toxic effects. GC-MS profiling show various active anti-oxidant compounds in MS. MS is anti-genotoxic, anti-oxidant, and hepato-renal protective [ABSTRACT FROM AUTHOR]

First, three basic lithium imidazolium salt catalysts were prepared by reacting imidazole, benzimidazole, and 2,2′-biimidazole with lithium hydroxide. Second, these catalysts were evaluated and examined for their chemical compositions, crystal structures, and thermal stability. Then, to study the effects of temperature, pressure, reaction time, and catalyst dosage on the catalytic performance, these three prepared catalysts were used to catalyze the transesterification reaction and polycondensation reaction between diphenyl carbonate (DPC) and bisphenol A (BPA) to synthesize polycarbonate (PC). Finally, revealed the catalytic mechanism. The results showed that the prepared three lithium imidazolium salts had better catalytic performance than traditional catalysts such as LiOH, C8H18OSn, and conventional alkaline ionic liquid [BMIM] OH. Among them, lithium imidazolium (MZ-Li) demonstrated the best catalytic performance. When the molar ratio of raw materials n (DPC)/n (BPA) = 1.06: 1, catalyst consumption was 0.25% of the total mass of the raw materials (1.51 × 10−2 mol/mol reactant), the reaction temperature at the transesterification reaction stage was 165 °C, reaction pressure 3 kPa, reaction time 40 min, the reaction temperature at the polycondensation reaction stage was 265 °C, reaction pressure 500 Pa, reaction time 2.5 h, the conversion of BPA could reach 99.37%, the yield of PC was 97.44%, and the viscosity-average molecular weight was 19,031. The catalyst has a simple preparation process, low-cost, and catalytic activity. The synthesized PC had a controllable molecular weight and a narrow distribution, and it was a catalyst with great industrial application prospects. [ABSTRACT FROM AUTHOR]

Bioderived polycarbonate (ISB-PC) was synthesized via transesterification and polycondensation of isosorbide (ISB) and diphenyl carbonate (DPC) using lithium acetoacetone as a catalyst. The resulting ISB-PC exhibited high glass transition temperatures similar to bisphenol A polycarbonate (BPA-PC) and was thermally stable up to 350 ℃. The incorporation of isosorbitol into the polymer chain imparted an improved mechanical property of ISB-PC, such as a higher bending and tensile modulus and higher elongation at break. ISB-PC can be readily cast into transparent films with a tensile strength of 73.3 MPa and a tensile modulus of 534 MPa. ISB-PC displayed high UV transmittance and possessed blue fluorescence under UV irradiation. At the same time, ISB-PC also has strong anti-yellowing ability. [ABSTRACT FROM AUTHOR]

The chemical depolymerisation of poly(bisphenol A carbonate) (BPA-PC) was studied using α-hydroxyketones as nucleophiles to give bisphenol A as the original monomer and the corresponding vinylene carbonates as co-products. The optimisation revealed that 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) is an efficient organocatalyst to perform this reaction under mild conditions (25 °C in 2-MeTHF). The success of TBD was attributed to the fact that it can both activate α-hydroxyketones and BPA-PC, through hydrogen bonding. The substrate scope was then investigated with a range of α-hydroxyketones to give vinylene carbonates (symmetrical and unsymmetrical, aromatic, heteroaromatic and alkyl) with moderate to high yields (30–97%, 13 examples). Scale-up experiments were also conducted to highlight the synthetic utility of this method. Finally, it was demonstrated that vinylene carbonates can be produced from waste polycarbonate contained in compact disks (CDs) and other BPA-PC containing materials, thus providing a safe and economical access to these species. [ABSTRACT FROM AUTHOR]

A validation study was performed on the modified analytical method for the migration solution of heptane, 20％ ethanol and 4％ acetic acid for the determination of bisphenol A migrating from polycarbonate food apparatuses, containers, and packaging. The analytes for the method were bisphenol A, phenol and p-tert-butylphenol. The repeatability, within-laboratory reproducibility and trueness of the method was estimated in the range of 0.2–1.8％, 0.4–2.6％ and 95–102％ respectively. These results showed that the method is useful as an analytical method for the migration solution of heptane, 20％ ethanol and 4％ acetic acid. Furthermore, the applicability of the determination methods with a fluorescence detector was verified. As a result of the validation study, the repeatability, within-laboratory reproducibility and trueness of the method was estimated in the range of 0.1–2.9％, 0.2–3.1％ and 94–101％ respectively. It was confirmed that the measurement with a fluorescence detector is also available. [ABSTRACT FROM AUTHOR]

The paper studies thermal characteristics of new polycarbonates obtained using the bisphenol A-free technology. Thermal tests of polycarbonates were carried out in a wide temperature range using the DSC (diffrential scanning calorimetry) and TG (thermogravimetry) analyses. The DSC data confirmed that all materials are homogeneous whereas the endothermic peaks are responsible for melting. Additionally, the analysis of the released gases was made by means of the infrared spectroscopic analysis. Our research proved that the new polycarbonates are relatively heat resistant. In the range of the thermal destruction of the studied materials there can be considered, two types of degradation reactions. The first step around 200 °C and the second one around 300 °C. Gel permeation chromatography were performed to determined molar masses of polymers. XRD analysis showed that the obtained polycarbonates showed a partially crystalline structure. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a major component of polycarbonate plastics and epoxy resins. While many studies have investigated the effect BPA exposure has upon changes in gut microbial communities, the influence of gut microbiota on an organism's ability to metabolize BPA remains comparatively unexplored. To remedy this, in this study, Sprague Dawley rats were intermittently (i.e., at a 7-day interval) or continuously dosed with 500 μg BPA/kg bw/day for 28 days, via oral gavage. In the rats which underwent the 7-day interval BPA exposure, neither their metabolism of BPA nor their gut microbiota structure changed greatly with dosing time. In contrast, following continuous BPA exposure, the relative level of Firmicutes and Proteobacteria in the rats' guts significantly increased, and the alpha diversity of the rats' gut bacteria was greatly reduced. Meanwhile, the mean proportion of BPA sulfate to total BPA in rat blood was gradually decreased from 30 (on day 1) to 7.4% (by day 28). After 28 days of continuous exposure, the mean proportion of BPA glucuronide to total BPA in the rats' urine elevated from 70 to 81%, and in the rats' feces the mean proportion of BPA gradually decreased from 83 to 65%. Under continuous BPA exposure, the abundances of 27, 25, and 24 gut microbial genera were significantly correlated with the proportion of BPA or its metabolites in the rats' blood, urine, and feces, respectively. Overall, this study principally aimed to demonstrate that continuous BPA exposure disrupted the rats' gut microbiota communities, which in turn altered the rats' metabolism of BPA. These findings contribute to the better understanding of the metabolism of BPA in humans. [ABSTRACT FROM AUTHOR]

The responses of the impact strength and structure of bisphenol A polycarbonate (PC) to aging in a 5 wt% aqueous solution of NaCl were studied in detail. The results of the Izod notched impact test showed that the impact strength decreased from 71.1 kJ/m2 to 17.5 kJ/m2 after an aging time of only 1 day in the aqueous solution of NaCl. The surface appearance of the aged PC observed by polarizing optical microscopy indicated that a large number of microvoids formed, and the size and number of these microvoids increased substantially with an increase in the aging time. The glass transition temperature, measured by differential scanning calorimetry, underwent a slight decrease after aging in the NaCl solution. In addition, no crystallization could be inferred from the heating curves. Thermal gravimetric analysis showed that the thermal decomposition temperature moved to a lower temperature, and the changes of the NaCl solution pH values indicated that hydrolysis was the dominant mechanism of degradation during aging in the aqueous solution of NaCl. Furthermore, the presence of NaCl accelerated the hydrolysis during the early stages of aging. A ductile-brittle transition caused by aging was inferred from observations of fracture surfaces using scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The rheological properties and processability at injection molding were studied for bisphenol-A polycarbonate (PC) that was modified by low-density polyethylene (LDPE) having a low shear viscosity. The LDPE addition significantly decreased the steady-state shear viscosity, especially in the high shear rate region. The decrease did not originate from slippage on the die wall but due to interfacial slippage between the PC and dispersed LDPE droplets that deformed to the flow direction to a great extent. As a result of the viscosity decrease, injection pressure largely decreased from 150 to 110 MPa with the addition only 5 wt.% of LDPE. The enhanced flowability also reduced the warpage of the molded product significantly, demonstrating that the processability at injection molding was improved by the addition of LDPE. [ABSTRACT FROM AUTHOR]

Summary: Polycarbonate (PC) is a polymer containing Bisphenol A (BPA) monomers in its structure. It is frequently used in manufacturing consumer goods such as food storage containers, reusable water bottles, infant feeding bottles, microwave containers and microwaveable cups. Under varying pH and temperature conditions, additives used in the plastic manufacture can leach in trace levels into the food in contact and negatively affect human health over time. Therefore, quantitative determination of BPA in food can be of great significance. The present study analysed the migration of BPA in coffee from different qualities of polycarbonate microwaveable cups under the influence of microwave heating by reversed‐phase ultra‐high‐performance liquid chromatography (UHPLC). The amount of BPA detected in samples ranged from undetected to 391.105 ± 0.05 μg kg−1. Results obtained indicate that BPA migration is minimal in good‐quality polycarbonate cups. Poor‐quality cups are accelerated time‐dependent; increased contact duration between polycarbonate and hot contact medium leads to more significant BPA migration. Furthermore, the BPA leaching process is enhanced during microwave heating due to high temperatures reached in a short time. [ABSTRACT FROM AUTHOR]

A bisphenol monomer bearing pendant propargyloxy group viz, 1, 1-bis (4-hydoxyphenyl)-1-(4′-propargyloxyphenyl) ethane (BPP) was synthesized starting from commercially available 1, 1, 1-tris (4-hydroxyphenyl) ethane (THPE) by mono O-propargylation reaction using propargyl bromide. A new series of pendant propargyloxy-functionalized aromatic (co)polycarbonates was synthesized by low-temperature solution polycondensation of BPP or different molar ratios of BPP and bisphenol-A with triphosgene in dichloromethane in the presence of triethylamine. The formation of reasonably high molecular weight (co)polycarbonates was confirmed by inherent viscosity (0.52–0.83 dL/g) and gel permeation chromatography (Mn 37,000–69,800 g/mol, polystyrene standards) measurements. 13C NMR spectral studies supported formation of random copolycarbonates in copolymerization of BPP and BPA with triphosgene. The 10% weight loss temperature (T10) values of (co)polycarbonates, determined by thermogravimetric analysis under nitrogen atmosphere, were in the range 427–438 °C indicating their good thermal stability. The glass transition temperature (Tg) values of (co)polycarbonates were observed in the range 147–152 °C. The crosslinking ability of (co)polycarbonates involving pendant propargyloxy groups leading to formation of networked structure was evaluated via non-isothermal curing studies by DSC. As a proof-of-concept, the post-modification of a representative polycarbonate bearing pendant propargyloxy groups with 1-octane thiol as a model compound via thiol-yne click reaction was briefly studied. [ABSTRACT FROM AUTHOR]

Cellulose-based matrices are expected to be ideal enzyme carriers due to their sustainability and biocompatibility. However, the linkages between immobilized enzymes and celluloses often suffer from low-density and non-biodegradability, leading to inefficient loading of enzymes as well as persistent generation of solid wastes after reuse. In the present study, cellulose-based functional materials with degradable polycarbonates brushes have been successfully synthesized as enzyme carriers via ring-opening polymerization of 5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one (MAC) following with ally epoxidation of MAC units. After covalent bonding with laccase, the resulting HPC-PMAC-Laccase could assemble in aqueous solution to form spherical nanoparticles with an enzyme immobilization efficiency of 88%. The immobilized laccase showed more tolerance towards pH and high temperature compared with free laccase. Moreover, the immobilized laccase demonstrated effective removal efficiency of bisphenol A and reached 83% in 3 h. After repeated usage for 8 times, the HPC-PMAC-Laccase still maintained relatively high enzyme activity. Especially, the polycarbonates brushes in the enzyme carriers could be totally hydrolyzed in 12 h to achieve its degradable property. Cellulose-based functional polycarbonates as degradable enzyme carriers. [ABSTRACT FROM AUTHOR]

Standard limits for harmful chemicals in consumer goods are important for consumer safety and the development of relevant industries. This paper proposes a method for determining content limits of chemicals in consumer goods by extending the "as low as reasonably practicable" (ALARP) principle by adding the impact of price and cost changes. While giving due consideration to the price and cost factors of consumer goods, this method derives such limits by measuring "acceptable consumer risk level" on the demand side and "industrial tolerance to chemical limits" on the supply side to obtain the ALARP area. Through a combination of functional relations between different factors and chemical limits, including consumer welfare, producer welfare, and external cost, a general chemical limit decision model can be created for the determination of the general limits of chemicals. This research provides a new methodology for studying decisions on chemical limits by considering consumer and industry affordability. In the final part of this paper, the feasibility and effectiveness of the proposed method are verified based on data of Bisphenol A used in the production of polycarbonate (PC) toys; the data were obtained from enterprise surveys and consumer questionnaires. Through our method, in this paper, a more suitable determination of harmful chemical substances can be obtained. [ABSTRACT FROM AUTHOR]

This study investigated the release of a known endocrine disruptor—bisphenol A (BPA), in drinking water and carbonated drinks stored in polycarbonate bottles and exposed to sunlight with a view of assessing the health risk involved in their consumption. BPA in the samples was extracted using solid-phase extraction method and determined with high performance liquid chromatography equipped with ultra-violet detector. Results showed that there were significant increase (p < 0.05) in BPA concentration of bottled water and carbonated drink exposed at 1, 3, 7 and 21 days. Also, there were enrichment of BPA levels ranging 31–868% in the bottled water and 17–920% carbonated drinks from 1 to 60 days when compared with the control. However, BPA migrating rate decreases with increase in exposure duration and later remains fairly constant as exposure duration progresses. The chronic daily intake of BPA in carbonated drinks and bottled water were low. The health risk index of BPA in polycarbonate bottled carbonated drinks and water was less than one in both adult and child and thus, there may be no probable adverse health effect on consumers of such products. However, caution should be taken as BPA is also released from other food packaging materials. [ABSTRACT FROM AUTHOR]

In this paper, the structure and properties of transparent films composed of bisphenol-A polycarbonate (PC) and a commercially available copolyester, poly(1,4-cyclohexanedimethanol-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol-co-terephthalate) (CPE), were studied. Both PC and CPE films are known to be transparent with good mechanical toughness. It was found that PC/CPE (50/50) showed miscibility in both the molten and solid states, indicating that there is a high possibility for the blend system to be miscible in the whole blend ratios. Because of the miscibility, the blend films showed no light scattering originating from phase separation. The mechanical properties of the films, such as Young's modulus, yield stress, and strain at break, were determined by the blend ratio, and the glass transition temperature increased with the PC content, which corresponded well with the values predicted by the Fox equation. These results demonstrate that the thermal and mechanical properties of the films can only be controlled by the blend ratio. Since these transparent films showed excellent mechanical toughness irrespective of the blend ratios, they can be employed in various applications. [ABSTRACT FROM AUTHOR]

Mixed plastic waste‐streams are a main obstacle to a more extensive implementation of polymer recycling. Separating mixed‐plastic waste streams demands time and effort at collection or in the recycling plant, while many products consist of multiple polymers that cannot be readily separated. Chemical recycling could provide the key to overcome this issue by targeting specific chemical bonds, enabling selective depolymerization of a single polymer class in a mixture. This work explores the depolymerization of polycarbonate (PC) and polyethylene terephthalate (PET) in separate and in mixed streams. Selective depolymerization of mixed streams composed of PET and PC and one‐step separation of their constituent monomers are carried out with outstanding energy efficiency through an inexpensive KOH‐in‐methanol hydrolysis (KMH) process developed for instantaneous PET hydrolysis. The activation energies for depolymerization of PC and PET pellets are 68.6 and 131.4 kJ mol−1, respectively. Randomly mixed streams are fully depolymerized within 2 min at 120 °C using 30 mL of depolymerization solution per gram of polymer. The separation of bisphenol A and terephthalic acid is demonstrated in a one‐step separation process, yielding 98 and 97 % purity without any secondary reactions detected. Simultaneous depolymerization and selective one‐step separation of monomers are also demonstrated for a PET/PC polymer blend prepared by solution casting, showing that this process also works for intimately mixed PET/PC mixtures. [ABSTRACT FROM AUTHOR]

Objective: Polyethylene terephthalate (PET) and polycarbonate (PC) bottles have been used widely in the last years for the consumption of water and the increased use of these chemicals has raised many concerns regarding their adverse effects on health. Phthalates and bisphenol A (BPA) are the main endocrine disrupting chemicals (EDCs) that can migrate from these plastics into potable water. Materials and Methods: The concentrations of phthalate and BPA were measured in water samples that were stored in PET and PC bottles at different storage conditions. The method of ELISA was used for the determination of phthalate and BPA levels. A standard curve is obtained from the standards prepared at known concentrations of phthalate, BPA, according to their absorbance at 450 nm. The BPA levels of the samples were obtained through the calculation of the absorbance values acquired using the standard curve. Results: Different storage and heating processes applied on the samples significantly increased the levels of BPA and phthalate. One year of storage led to a statistically significant increase in phthalate levels when compared to the control group. Both BPA and phthalate levels detected in the water samples were higher than the control group depending on the storage conditions including exposure to high temperatures, sunlight and outdoor conditions. Conclusion: Our results indicate the necessity to establish the environmental conditions that must be ensured during the production, transportation and storage processes of the bottles, on a legal basis with legal regulations. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) have become promising candidate to replace common liquid electrolyte due to highly improved security. However, the practical use of SPEs is still restricted by their decomposition and breakage at the electrode interfacial layer especially at high voltage. Herein, a new cationic covalent organic framework (COF) is designed and synthesized as a reinforced skeleton to resist the constant oxidative decomposition of solid polycarbonate electrolyte, which can stabilize cathode electrolyte interphase layer to develop long‐term cycle solid lithium metal battery. The ultralow HOMO energy (−12.55 eV according to density functional theory (DFT) calculations), reflecting its oxidation resistance at positive potential, would be responsible for the high decomposition voltage of 5.2 V versus Li+/Li of solid polycarbonate electrolyte. Furthermore, the smooth surface of interfacial layer and inhibited decomposition reaction at cathode side is confirmed in solid LiCoO2 cell, which realizes high initial capacity up to 160.3 mAh g−1 at 0.1 C and greatly improved stability in 4.5 V class solid polymer lithium metal battery with high capacity retention over 200 cycles. This new type of high‐voltage resistant solid polymer electrolyte promotes the realization of high‐voltage cathode materials and higher energy density lithium metal battery. [ABSTRACT FROM AUTHOR]

Bisphenols are a family of chemicals commonly used to produce polycarbonate plastics and epoxy resins. Exposure to bisphenol A (BPA) is associated with a variety of adverse effects; thus, many alternatives to BPA, such as bisphenol AF (BPAF) and bisphenol S (BPS), are now emerging in consumer products. We have determined the effects of 3 bisphenols on endochondral ossification and the transcriptome in a murine limb bud culture system. Embryonic forelimbs were cultured in the presence of vehicle, BPA, BPAF, or BPS. BPA (⁠ ≥ 10 μM), BPAF (⁠ ≥ 1 μM), and BPS (⁠ ≥ 50 μM) reduced the differentiation of hypertrophic chondrocytes and osteoblasts. Chondrogenesis was suppressed by exposure to ≥ 50 μM BPA, ≥ 5 μM BPAF, or 100 μM BPS and osteogenesis was almost completely arrested at 100 μM BPA or 10 μM BPAF. RNA sequencing analyses revealed that the total number of differentially expressed genes increased with time and the concentration tested. BPA exposure differentially regulated 635 genes, BPAF affected 554 genes, whereas BPS affected 95 genes. Although the genes that were differentially expressed overlapped extensively, each bisphenol also induced chemical-specific alterations in gene expression. BPA- and BPAF-treated limbs exhibited a downregulation of Rho-specific guanine nucleotide dissociation inhibitor (RhoGDI) signaling genes. Exposure to BPA and BPS resulted in the upregulation of key genes involved in cholesterol biosynthesis, whereas exposure to BPAF induced an upregulation of genes involved in bone formation and in the p53 signaling pathway. These data suggest that BPAF may be more detrimental to endochondral ossification than BPA, whereas BPS is of comparable toxicity to BPA. [ABSTRACT FROM AUTHOR]

This review aims to cover the topic of polycarbonate synthesis via ring-opening polymerization (ROP) of cyclic carbonates. We report a wide variety of ROP-initiating systems along with their detailed mechanisms. We focus on the challenges of preparing the polymers; the precise control of the properties of the materials, including molecular weight; the compositions of the copolymers and their structural characteristics. There is no one approach that works for all scales in cyclic carbonates ROP. A green process to produce polycarbonates is a luring challenge in terms of CO2 utilization and the targeted domains for application. The main resolution seems to be the use of controlled incorporation of functional/reactive groups into polymer chains that can tailor the physicochemical and biological properties of the polymer matrices, producing what appears to be an unlimited field of applications. Glycerol carbonate (GC) is prepared from renewable glycerol and considered as a CO2 fixation agent resulting in GC compound. This family of five-membered cyclic carbonates has attracted the attention of researchers as potential monomers for the synthesis of polycarbonates (PCs). This cyclic carbonate group presents a strong alternative to Bisphenol A (BPA), which is used mainly as a monomer for the production of polycarbonate and a precursor of epoxy resins. As of December 2016, BPA is listed as a substance of very high concern (SVHC) under the REACH regulation. In 2006, Mouloungui et al. reported the synthesis and oligomerization of GCs. The importance of GCs goes beyond their carbonate ring and their physical properties (high boiling point, high flash point, low volatility, high electrical conductivity) because they also contain a hydroxyl group. The latter offers the possibility of producing oligo and/or polycarbonate compounds that have hydroxyl groups that can potentially lead to different reaction mechanisms and the production of new classes of polycarbonates with a wide range of applications. [ABSTRACT FROM AUTHOR]

Bisphenol A polycarbonate (BPA‐PC) is an important engineering plastic with unique properties. However, it has some inherent flaws like chemical resistance toward greases and oils. Hence, to improve the chemical resistance the effect of small amounts of polybutylene terephthalate (PBT) functionalized with allyl glycidyl epoxy (AGE) were evaluated. Low amounts of PBT and AGE provided a transparent blend composition with an allyl functionality. Detailed structural analysis by 1H‐NMR showed the addition reaction of AGE‐epoxy with acid end group of PBT, followed by an expected substitution reaction of the modified PBT with BPA‐PC. This unique blend composition exhibited Tg of 131°C and melting temperature (Tm) of 221°C by differential scanning calorimetry (DSC). Further, the microscopy study of blend revealed the stable morphology of PBT domain distributed into PC matrix indicating chemical compatibilization. The mechanical property evaluation of the blend demonstrated an improved flow, an increase in modulus, tensile strength, and higher elongation at break. Thus, a chemical compatible transparent blend of BPA‐PC and PBT with allyl group functionalization has been achieved and first evaluations show slight improvement of chemical resistance toward Banana Boat Sun cream over the BPA‐PC homopolymer. [ABSTRACT FROM AUTHOR]

ZnII‐complexes bearing half‐salan ligands were exploited in the mild and selective chemical upcycling of various commercial polyesters and polycarbonates. Remarkably, we report the first example of discrete metal‐mediated poly(bisphenol A carbonate) (BPA‐PC) methanolysis being appreciably active at room temperature. Indeed, Zn(2)2 and Zn(2)Et achieved complete BPA‐PC consumption within 12–18 mins in 2‐Me‐THF, noting high bisphenol A (BPA) yields (SBPA=85–91 %) within 2–4 h. Further kinetic analysis found such catalysts to possess kapp values of 0.28±0.040 and 0.47±0.049 min−1 respectively at 4 wt%, the highest reported to date. A completely circular upcycling approach to plastic waste was demonstrated through the production of several renewable poly(ester‐amide)s (PEAs), based on a terephthalamide monomer derived from bottle‐grade poly(ethylene terephthalate) (PET), which exhibited excellent thermal properties. [ABSTRACT FROM AUTHOR]

Full circle: ZnII-complexes bearing half-salan ligands facilitate the mild and selective degradation of various commercial polyesters and polycarbonates into value-added products (green solvents and chemical building blocks). We report the first example of discrete metal-mediated poly (bisphenol A carbonate) methanolysis being appreciably active at room temperature, whilst the production of several renewable poly (ester-amides)s demonstrates a completely circular PET waste upcycling approach. ZnII-complexes bearing half-salan ligands were exploited in the mild and selective chemical upcycling of various commercial polyesters and polycarbonates. Remarkably, we report the first example of discrete metal-mediated poly (bisphenol A carbonate) (BPA-PC) methanolysis being appreciably active at room temperature. Indeed, Zn (2)2 and Zn (2)Et achieved complete BPA-PC consumption within 12–18 min in 2-Me-THF, noting high bisphenol A (BPA) yields (SBPA = 85–91%) within 2–4 h. Further kinetic analysis found such catalysts to possess kapp values of 0.28 ± 0.040 and 0.47 ± 0.049 min−1, respectively, at 4 wt%, the highest reported to date. A completely circular upcycling approach to plastic waste was demonstrated through the production of several renewable poly (ester-amide)s (PEAs), based on a terephthalamide monomer derived from bottle-grade poly (ethylene terephthalate) (PET), which exhibited excellent thermal properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • The methanolysis process presented in this work can operate at high polycarbonate loading (47 wt%) to obtain ≥ 95 % BPA yield with a low environmental impact factor. • Two distinct depolymerization pathways were observed during methanolysis at low temperatures (125 °C – 150 °C) and high temperatures (175 °C). • The optimized process was used to recover BPA from end-of-life PC and PC/ABS blends with high isolated BPA yield (>93 %). • The easiness and low environmental impact of the process will be the driving force towards upscaling and industrialization. Poly(bisphenol A carbonate) (PC) is an essential polymer from fossil sources. Currently, PC lacks any economically viable recycling strategy, which leads to a loss of valuable resources, and the accumulation of PC in the environment can have a negative impact on human health due to the leaching of toxic Bisphenol A (BPA). BPA recovery from PC wastes is a prerequisite to meet the demand for sustainable resource utilization and address environmental concerns. Hence, this work demonstrates the efficient BPA recovery from PC wastes via methanolysis at high PC loading (47 wt%) in the presence of a low amount of sodium hydroxide (NaOH, ≤0.05 wt%) at moderate temperatures (125 °C – 175 °C). Selected conditions prevented unwanted decomposition of BPA and ensured a mild alkaline product requiring simple purification steps to recover BPA. The environmental impact factor (ξ) of these processes was shown to be quite low compared to the ones represented in the literature. When these processes were used to recover BPA from real wastes: 93 ± 1.5 % of pure BPA was recovered from end-of-life PC roof panels (EOL-PC) after 30 min at 175 °C with 0.004 wt% of NaOH. On the other hand, direct recovery of BPA from the EOL-PC/acrylonitrile butadiene styrene (EOL-PC/ABS) blend was hindered by additive contamination and proceeded at a slower reaction rate due to the presence of ABS. However, subjecting EOL-PC/ABS to a decolorization-depolymerization method ensured ∼94 ± 2.5 % BPA yield. [ABSTRACT FROM AUTHOR]

Polycarbonate is an attractive transparent plastic with high mechanical/thermal properties. A family of copolycarbonates of bisphenol-A (BPA), 9, 9-bis (4-hydroxyphenyl) fluorene (BHPF), and diphenyl carbonate (DPC) were prepared by a transesterification polymerization. The weight-average molecular weight of the polycarbonates ranges from 65,000 to 107,000 g/mol; the copolycarbonates showed T g and T d − 5 % from 63-70°C and 100-105°C higher than the control, respectively. Meanwhile, the processing properties of polycarbonate remain unchanged. These properties endow the polymers with potential for use as high-temperature resistance materials. [ABSTRACT FROM AUTHOR]

In an attempt to perform polycarbonate chemical recycling in a more sustainable way, we took into consideration the combined use of ultrasound irradiation and task specific ionic liquids. Towards this aim, the methanolysis of polycarbonate, into dimethylcarbonate and bisphenol A, was carried out in the presence of cholinium-based ionic liquids featuring anions derived from amino acids and other eco-friendly species. The target process was optimized in terms of both energy and material amounts as well as in terms of the nature of the catalysts used. The proposed protocol allowed high conversion and yields of bisphenol A to be obtained, under milder conditions compared to the ones so far reported in the literature, perfectly fulfilling green chemistry principles. The best performing catalyst can be reused without significant loss in performance and the methodology can be successfully applied to post-consumer polycarbonate samples. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a versatile petrochemical used in the preparation of high volume polymers including polycarbonates and epoxy resins. Unfortunately, BPA is also an endocrine disrupter and has been banned from use in various consumer products by several regulatory agencies. To address this issue, our group evaluated the estrogenic activity of nine bio-based tris/bisphenols derived from resveratrol (1 and 2), anethole (3, 4), eugenol (5), carvacrol (6), and creosol (7–9). Compounds 5–9 were determined to be non-estrogenic, while compound 3 exhibited a response at a lower concentration than BPA, and compounds 1, 2, and 4 exhibited responses similar to BPA. Polycarbonates of the bio-based bisphenols (PC3–PC9) were then synthesized via interfacial polymerization and characterized by SEC, MALDI-MS, DSC, TGA, and UV-VIS spectroscopy. The bio-based polycarbonates exhibited Mn values up to 14 600 Da (SEC) and had a wide range of glass transition temperatures (Tg) with values up to 156 °C (∼25 °C higher than BPA with a similar molecular weight) depending on the monomer structure. The bio-based polycarbonates had high thermal stabilities with Td5% values up to 383 °C under a nitrogen atmosphere. The non-estrogenic properties of 5–9 coupled with the good thermal properties of the derivative polycarbonates suggests that these materials are sustainable, lower toxicity alternatives for BPA-based polycarbonates. [ABSTRACT FROM AUTHOR]

In this work, Makrofol DE 1–1 films were treated with O2 plasma for different treatment times ranging from 60 to 120 min at applied power 3.5 W and working pressure 0.4 Torr. The induced changes in Makrofol surface properties after plasma treatment were examined with Atomic Force Microscope (AFM), Scanning Electron Microscope (SEM), Photoluminescence (PL) spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy techniques. The changes in the wettability property and surface free energy (SFE) of the plasma treated Makrofol polymer samples have been investigated by measuring the water and glycerol contact angles. Moreover, the induced changes in the dielectric Parameters and AC conductivity of plasma treated Makrofol samples were studied at a wide range of frequencies at room temperature. AFM analysis revealed that the average surface roughness (Ra) of Makrofol samples was increased after plasma treatment. Also SEM images clearly indicated that more enhanced surface roughness can be obtained with increasing treatment time. A noticeable increase in the intensity of PL emission spectra with increasing plasma treatment time was observed. This increase could be attributed to the increase in surface roughness and surface area of Makrofol samples after plasma treatment. The measurements of contact angle showed an enhancement in the wettability property and surface free energy of Makrofol samples after plasma treatment time. The analysis of the results of UV–Vis spectra revealed that the absorbance, Urbach energy (EU), the refractive index (n), the extinction coefficient (k) and number of carbon per length (N) were increased while the transmission and optical energy band gap of Makrofol samples were decreased with increasing plasma treatment time. AC conductivity, dielectric constant and dielectric loss of Makrofol samples have been increased by increasing plasma treatment time. [ABSTRACT FROM AUTHOR]

High molar mass polycarbonate is synthesized via a solution transcarbonation of bis(methyl salicyl) carbonate and bisphenol‐A at temperatures between 60 and 160 °C without the removal of the condensate, allowing the incorporation of thermosensitive monomers into polycarbonate. Kinetic and equilibrium studies show that the polymerization is 20–30 times faster at 120 °C compared to 60 °C, whereas the equilibrium Mw increases from 11 × 103 g mol−1 at 120 °C to 16 × 103 g mol−1 at 60 °C. This polycondensation is characterized by very high equilibrium constants ranging from 0.8 × 103 at 160 °C to 4.1 × 103 at 60 °C, corresponding to standard enthalpies and entropies of polymerization: −19 kJ mol−1 < ΔH0 < −11 kJ mol−1 and 13 J mol−1 K−1 < ΔS0 < 28 J mol−1 K−1. Without removal of the condensate, the system is shown to be dynamic and completely reversible when changing the temperature. Good predictability of this polycondensation is reported, where only at very low starting monomer concentrations, the formation of cyclics leads to deviations from the predicted behavior. [ABSTRACT FROM AUTHOR]

A new diagnosis method for the discriminative detection of laser-accelerated multi-MeV carbon ions from background oxygen ions utilizing solid-state nuclear track detectors (SSNTDs) is proposed. The idea is to combine two kinds of SSNTDs having different track registration sensitivities: Bisphenol A polycarbonate detects carbon and the heavier ions, and polyethylene terephthalate detects oxygen and the heavier ions. The method is calibrated with mono-energetic carbon and oxygen ion beams from the heavy ion accelerator. Based on the calibration data, the method is applied to identify carbon ions accelerated from multilayered graphene targets irradiated by a high-power laser, where the generation of high-energy high-purity carbon ions is expected. It is found that 93 ± 1% of the accelerated heavy ions with energies larger than 14 MeV are carbons. The results thus obtained support that carbon-rich heavy ion acceleration is achieved. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is used worldwide as a monomer in the production of polycarbonates and epoxy resins. It has been receiving growing attention over the years, as exposure to even low concentrations of this endocrine disruptor is being linked to serious health problems. This study aims to investigate the efficiency of powdered activated carbon (PAC) in removing BPA from water, as well as to apply a computational simulation to understand the behavior of BPA in solution and its interaction with a generic carbonaceous surface. In the adsorption studies, the mass of adsorbent (0.01–0.04 g) and the solution pH (2–12) were varied in order to understand their influence over the adsorption capacity (qe ) of PAC. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion were employed to evaluate kinetic data. Langmuir, Freundlich, Dubinin–Radushkevich, and Redlich–Peterson isotherm models were applied. A theoretical study using density functional theory (DFT) showed that adsorption is mainly caused by C–H…O, C–H…π, lone-pair…π and π…π interactions. Equilibrium was reached after 120 min, with PAC removing a total of 96.68% of BPA. The best condition was achieved using 0.01 g at pH 9 and 298 K (246.20 mg/g). Good fittings to Dubinin–Raduschkevich (R² = 0.985) and to Langmuir (R² = 0.925) models were achieved, with a calculated maximum monolayer adsorption capacity (qmax) of 367.88 mg/g. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA), a component of polycarbonate and epoxy resins, has been reported to induce learning and memory deficits. However, the mechanisms have not been fully elucidated. Growing evidence has suggested that N -methyl- d -aspartate receptors (NMDARs) are involved in cognitive impairments. In this study, BPA was administered to female Sprague–Dawley rats (six per dose group) at concentrations of 0 (control), 4, 40, and 400 μg/kg·body weight/day from gestation day 1 through lactation day 21. Spatial learning was evaluated using the Morris water maze on postnatal day 22. Expression levels of NMDARs were determined using real-time polymerase chain reaction and Western blot. The results showed that male offspring exposed to BPA exhibited increased latency in reaching the platform and reduced time in the target quadrant, and the number of crossing the platform was less, as compared with the control group. The mRNA and protein expression levels of NMDARs in the hippocampus were significantly downregulated when compared with the control group of male offspring. The data showed that maternal exposure to BPA at low dosage can cause cognitive deficits in male rat offspring, probably due to a decrease in NMDARs in the hippocampus. [ABSTRACT FROM AUTHOR]

Bisphenol A is a chemical used primarily as a monomer in the production of polycarbonate plastics and epoxy resins. It is a synthetic chemical compound that is produced in billions of pounds annually, and tagged as an endocrine disruptor. Bisphenol A is a high production synthetic chemical compound that is used in the production of many consumables and equipments of daily consumption and use by man. Growing interest in possible health threats posed by endocrine disrupting chemicals (bisphenol-A inclusive), as these substances are in our environment, food, and many consumer products. Therefore, this study aims to determine bisphenol-A effects on the hypothalamo-pituitary-ovarian axis, and role of melatonin in this regard. Forty-two Wistar rats were bred, grouped into 7, with each group consisting of 6 rats. Experimental groups were administered low and high doses of bisphenol-A and melatonin, starting from day 19, and was continued for 7 weeks orally. They were left to develop into full adults and were sacrificed on day 120±4 days. Blood samples, hypothalamus, pituitary and ovarian tissues were excised for biochemical and tissue antioxidants assays as well as genetic studies. Results show elevated gonadotropin and androgen levels. There was disruption of reactive oxygen species in the ovarian tissues, as well as alterations in the expression of genes that regulate reproduction at the hypothalamus and pituitary levels. Conclusion of early exposure to bisphenol-A is associated with prolonged duration of disruption of reproductive functions in female Wistar rats, which persist long after cessation of the exposure. Melatonin antioxidant effects give some promising outturns against bisphenol-A induced toxicities. [ABSTRACT FROM AUTHOR]

The European Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation has been in force since 2007 and is intended to ensure a high level of protection for human health and the environment. The REACH regulation is based on the principle that manufacturers, importers, and downstream users take responsibility for their chemicals. Currently about 23 000 single chemicals are registered within the REACH legislation. A large proportion of substances registered under REACH end up in technical mixtures, intentionally manufactured as such, or generated mixtures containing byproducts of processes. Such mixtures that contain a number of different components are, for example, ink, paint, lacquer, mortar, or cleaning agents. However, REACH focuses on single substances and addresses the safe use of substances as such (e.g., bisphenol A) or substances in mixtures (e.g., bisphenol A used as an antioxidant in mixtures) and in articles (e.g., bisphenol A used as a monomer for polycarbonate production from which greenhouse sheets may be made). In contrast to other substance regulations, under REACH the registrants and downstream users of chemicals are responsible for the risk assessment. According to the REACH regulation, they also have the obligation to derive and communicate safe use conditions for their technical mixtures. Currently, no guidance document and no distinct obligations for an assessment of technical mixtures exist. In light of the available evidence for the joint exposures and effects of chemicals due to co-exposures, the need for approaches for a mixture assessment and improved data communications were highlighted by various stakeholders from industry, European member states, and the European Chemicals Agency (ECHA). The lead component identification (LCID) methodology and the safe use of mixtures information (SUMI) tool were proposed by the European Chemical Industry Council (Cefic) as working tools for the evaluation of the hazard potential, derivation of safe use conditions, and data communication for mixtures along the supply chain. The present paper analyzes the workability and pitfalls of these proposed methodologies from a regulatory perspective, aiming at a safe use of technical mixtures which considers the joint effects and exposures of its components. [ABSTRACT FROM AUTHOR]

For the purpose of promoting mechanical properties of bisphenol‐A polycarbonate (PC) reinforced by rigid organic styrene–acrylonitrile copolymer (SAN) particles, styrene/acrylonitrile/glycidyl methacrylate terpolymer (SAG) was synthesized and applied as compatibilizer for PC/SAN blends. It is found that the phase morphology of PC/SAN/SAG blends is closely related with their mechanical properties. Large continuously distributed SAN phase or spherical dispersed SAN particles with average diameter over 2 μm tend to trigger premature tensile failure of blends due to stress concentration. The incorporation of SAG can simultaneously reinforce and toughen PC/SAN blends by controlling the size and distribution of the dispersed SAN particles. For the blends with fixed PC/SAN ratio, the elongation at break and fracture energy are markedly improved when SAN domain size is reduced by adding appropriate amount of SAG. Typically, for blends with a PC/SAN ratio of 75/25, adding 3 wt% SAG will cause the average diameter of SAN particles to reduce from 2.35 ± 1.20 to 0.74 ± 0.25 μm, meanwhile up to 95% increment in elongation at break and 115% increment in fracture energy is achieved. [ABSTRACT FROM AUTHOR]

Study Question: Do daily manipulations of preimplantation embryos with polycarbonate (PC)-made bisphenol A (BPA)-releasing strippers influence embryo development?Summary Answer: Compared to glass strippers, PC strippers enhance the blastocyst development rate but this does not seem to be BPA-related.What Is Known Already: PC strippers have been shown to release tiny amounts (around 0.5 ng/ml BPA) of BPA in routine human IVF procedures. A chronic exposure to BPA either in vivo or in vitro during the preimplantation period can impact post-implantation and post-natal development. BPA can act rapidly by binding to membrane receptors and inducing rapid non-genomic effects.Study Design, Size, Duration: This experimental study using mouse embryos had a balanced design and blinded evaluations of the endpoints.Participants/materials, Setting, Methods: In vivo fertilized zygotes were obtained from outbred Swiss CD1 mice crossings after an ovarian stimulation. The zygotes were allocated to three daily handling conditions (HCs) and cultured until Day 4 in a single human commercial medium. Each day, the embryos were handled for 20 s either in a PC stripper (HC1) or in a glass stripper (HC2). In HC3, the embryos were pre-exposed to 0.5 ng/ml BPA before being handled for 20 s in a glass stripper. Handling operations were repeated on Days 1, 2 and 3. Embryo development was assessed blindly on Day 4. Expanded blastocysts were selected for a transcriptomic analysis using Agilent Sureprint G3 Mouse GE v2 microarrays and the retrotransposon LINE1-Orf2 expression was analysed using qRT-PCR, as a proxy for a global evaluation of the epigenetic status.Main Results and the Role Of Chance: Compared to the embryos manipulated in HC2 (n = 243), those in HC1 (n = 228) developed significantly more often to the blastocyst stage (55 vs 46%; P < 0.05). It appears the effect of these PC strippers was not BPA-related because embryos pre-exposed to BPA (HC3, n = 230) showed no difference in the blastocyst rate when compared to HC2 (43 vs 46%). When analysing same-stage blastocysts, we noticed no difference in the embryo gene expression between the three HC groups.Large Scale Data: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE148868.Limitations, Reasons For Caution: Our results using a mouse model designed to mimic human conditions (outbred strain, human commercial IVF dishes and a unique commercial human embryonic culture media) are reassuring since no gene was found to be differentially expressed, including LINE-1 genes, as a proxy for a global evaluation of the epigenetic status. However, no global epigenetic analysis of the genome has been performed. Furthermore, we did not evaluate post-implantation events, although BPA exposure during peri-conception could affect foeto-placental and post-natal development.Wider Implications Of the Findings: Based on the precautionary principle, several European countries banned the use of BPA in baby bottles and food packaging several years before European Agencies took an official position. The question of applying this principle to plastics in closed contact with human embryos is raised. Further studies are needed for a decision to be made.Study Funding/competing Interest(s): This study was supported by a grant from the Agence de Biomédecine (AOR 2016). The authors declare no competing interest. [ABSTRACT FROM AUTHOR]