Search Results (144)

Growing concerns over the toxicity and sustainability of dental materials have driven the search for alternatives to bisphenol A-glycidyl methacrylate (Bis-GMA), a widely used dental resin monomer associated with health risks. This study highlights the potential of less health-hazardous dental formulations by incorporating high-value materials derived from the glycolysis of poly(ethylene terephthalate) (PET). Dimethacrylated oligoesters (PET-GLY-DM), synthesized through the methacrylation of PET glycolysis products, were blended with Bis-GMA and triethylene glycol dimethacrylate (TEGDMA), toward the gradual replacement of Bis-GMA content. The innovative PET-GLY-DM-based resins exhibited a higher degree of conversion compared to traditional Bis-GMA/TEGDMA formulations, as measured by FTIR spectroscopy, accompanied by an increase in polymerization shrinkage, evaluated via a linear variable displacement transducer system. While the incorporation of PET-GLY-DM slightly reduced flexural strength and elastic modulus, it significantly decreased water sorption, resulting in a smaller reduction in mechanical properties after water immersion for 7 days at 37 °C and improved long-term performance. Furthermore, PET-GLY-DM resins exhibited low bisphenol-A (BPA) release measured with HPLC. It was thus confirmed that PET-GLY-DM resins derived from the glycolysis of PET wastes represent a promising alternative to conventional light-cured dental resins, offering reduced BPA release and improved water resistance. Full article

To address the brittle matrix failure frequently observed in filament-wound composite layers of onboard pressure vessels operating under cryogenic and high-pressure conditions, we studied a bisphenol-A epoxy resin (DGEBA) system modified with polyetheramine (T5000) and 3,4-Epoxycyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate (CY179). The curing and rheological behavior of the modified resin were first evaluated, revealing a favorable processing, with viscosity suitable for wet-filament winding. Subsequently, its coefficient of thermal expansion (CTE) and tensile properties were characterized over the 300 K–90 K range, demonstrating a linear increase in elastic modulus and tensile strength with decreasing temperature. Carbon fibre-reinforced polymer composites (CFRP) were then fabricated using this resin system, and both longitudinal and transverse tensile tests, along with microscopic fracture surface analyses, were conducted. The results showed that CFRP-0° specimens exhibited an initial increase followed by a decrease in elastic modulus with decreasing temperature, whereas CFRP-90° specimens demonstrated pronounced cryogenic strengthening, with tensile strength and modulus enhanced by 52.2% and 82.4%, respectively. The findings provide comprehensive properties for the studied resin system and its CFRP under room temperature (RT) to cryogenic conditions, offering a basis for the design and engineering of cryo-compressed hydrogen storage vessels. Full article

Lost circulation, a prevalent challenge in drilling engineering, poses significant risks including drilling fluid loss, wellbore instability, and environmental contamination. Conventional plugging materials often exhibit an inadequate performance under high-temperature, high-pressure (HTHP), and complex formation conditions. To address that, this study developed a high-performance gel–resin composite plugging material resistant to HTHP environments. By optimizing the formulation of bisphenol-A epoxy resin (20%), hexamethylenetetramine (3%), and hydroxyethyl cellulose (1%), and incorporating fillers such as nano-silica and walnut shell particles, a controllable high-strength plugging system was constructed. Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed the structural stability of the resin, with an initial decomposition temperature of 220 °C and a compressive strength retention of 14.4 MPa after 45 days of aging at 140 °C. Rheological tests revealed shear-thinning behavior (initial viscosity: 300–350 mPa·s), with viscosity increasing marginally to 51 mPa·s after 10 h of stirring at ambient temperature, demonstrating superior pumpability. Experimental results indicated excellent adaptability of the system to drilling fluid contamination (compressive strength: 5.04 MPa at 20% dosage), high salinity (formation water salinity: 166.5 g/L), and elevated temperatures (140 °C). In pressure-bearing plugging tests, the resin achieved a breakthrough pressure of 15.19 MPa in wedge-shaped fractures (inlet: 7 mm/outlet: 5 mm) and a sand-packed tube sealing pressure of 11.25 MPa. Acid solubility tests further demonstrated outstanding degradability, with a 97.69% degradation rate after 24 h in 15% hydrochloric acid at 140 °C. This study provides an efficient, stable, and environmentally friendly solution for mitigating drilling fluid loss in complex formations, exhibiting significant potential for engineering applications. Full article

Thermally conductive polymer composites are essential for effective heat dissipation in electronic packaging, where both thermal management and mechanical reliability are critical. Although diglycidyl ether of bisphenol-A (DGEBA)-based epoxies exhibit favorable properties, their intrinsically low thermal conductivity limits broader applications. Incorporating conductive fillers, such as expanded graphite (EG) and metal powders, enhances heat transport but often compromises mechanical strength due to poor filler–matrix compatibility. In this study, we address this trade-off by employing a titanate coupling agent to surface-modify aluminum (Al) fillers, thereby improving interfacial adhesion and dispersion within the DGEBA matrix. Our results show that incorporating 10 wt% untreated Al increases thermal conductivity from 7.35 to 9.60 W/m·K; however, this gain comes at the cost of flexural strength, which drops to 18.29 MPa. In contrast, titanate-modified Al (Ti@Al) not only preserves high thermal conductivity but also restores mechanical performance, achieving a flexural strength of 35.31 MPa (at 5 wt% Ti@Al) and increasing impact strength from 0.60 to 1.01 kJ/m². These findings demonstrate that interfacial engineering via titanate coupling offers a compelling strategy to overcome the thermal–mechanical trade-off in hybrid composites, enabling the development of high-performance materials for advanced thermal interface and structural applications. Full article

Gestational diabetes mellitus (GDM) requires lifestyle changes that may alter exposure to endocrine-disrupting chemicals (EDCs). This study aimed to assess maternal and fetal exposure to EDCs—including bisphenol-A (BPA), monoethyl phthalate (MEP), and perfluorooctanoic acid (PFOA)—during the COVID-19 pandemic and to evaluate their association with fetal birthweight. Maternal urine (second and third trimester) and paired cord blood samples were analyzed from 58 GDM and 118 non-GDM pregnancies using UPLC-MS/MS. Significant correlations were found between maternal urine and cord blood levels of BPA and MEP. Cord blood BPA levels were significantly lower in GDM mothers (0.35 vs. 0.72 μg/L, p < 0.05), suggesting reduced exposure due to dietary interventions. However, maternal urinary BPA levels in GDM pregnancies were positively associated with fetal birthweight (β = 2.69, p < 0.05), indicating increased susceptibility to obesogenic effects. PFOA was present in all cord blood but only 41% of maternal urine samples. These findings underscore the dual impact of GDM-related lifestyle changes: reduced EDC transfer to the fetus, yet persistent metabolic vulnerability. Full article

Ultra-processed foods (UPFs) are foods that have undergone extensive industrial processing with the addition of various substances in order to make them more tasty, eye-catching, and easy to consume. UPFs are usually rich in sugars, salt, and saturated fat, whereas they lack essential nutrients. The aim of this review is to elaborate upon the current evidence associating overconsumption of UPFs with the development of type 2 diabetes mellitus (T2DM). We will discuss data interconnecting UPFs and T2DM risk and will further describe specific ingredients that have been suggested to increase this risk. In addition, we will thoroughly explain how additives, such as emulsifiers or sweeteners, or other compounds formed during manufacturing, such as acrylamide and acrolein, and during packaging, such as bisphenol-A, are proposed to be implicated in the pathogenesis of insulin resistance and T2DM. Full article

Recently, toxicological and epidemiological research has provided strong support for the unfavorable effects of bisphenol-A (BPA, 2,2′-bis(4-hydroxyphenyl) propane) on myogenesis and its underlying mechanisms. Researchers have therefore been looking for new strategies to prevent or mitigate these injurious effects of BPA on the human body. It has been found that plant extracts may act as potential therapeutic agents or functional foods, preventing human diseases caused by BPA. We previously reported that Ficus lindsayana (FL) extract exhibits anti-inflammation activity in macrophages via suppressing the expression of inflammation-related molecules and anti-insulin resistance in inflammation-treated adipocytes. In this study, we investigated whether Ficus lindsayana leaf extract (FLLE) protects C2C12 mouse myoblasts against the suppressive effects of BPA on myogenic differentiation. The viability of BPA-stimulated C2C12 myoblasts was significantly increased when co-treated with FLLE (200 µg/mL), suggesting that the extract may lessen the inhibitory effects of BPA on cell division. We also found that FLLE significantly increased neo-myotube formation by inducing the fusion of myoblasts into multinucleated myotubes when compared to the BPA-treated control cells, without impacting cell viability. In addition, the levels of myogenin and myocyte enhancer factor 2A (MEF2A), which are crucial markers and regulators of myogenesis, were markedly increased by the addition of FLLE (50 µg/mL) to the BPA-treated C2C12 cells. This finding suggests that FLLE effectively improved myogenic differentiation in BPA-exposed myoblasts. FLLE treatment (50 µg/mL) significantly raised total Akt protein levels in the BPA-treated C2C12 cells, enhancing protein phosphorylation. In addition, FLLE (50 µg/mL) obviously increased the phosphorylation levels of p70S6K and 4E-BP1, key downstream targets of the Akt/mTOR signaling cascade, by elevating total p70S6K and 4E-BP1 levels. These results suggest that FLLE diminishes the decline in myogenic differentiation induced by BPA via the regulation of the myocyte differentiation-related signaling pathway. The information obtained from this study demonstrates the health benefits of this plant, which warrants further investigation as an alternative medicine, functional ingredient, or food supplement that can prevent the negative health effects of BPA or other toxicants. Full article

Epoxy resins exhibit outstanding curability, durability, and environmental compatibility, rendering them extensively utilized in the realm of engineering curing. Nevertheless, the current curing mechanism of epoxy-based resins in cohesion with sand remains inadequately elucidated, significantly impeding their applicability within the domain of soil curing. This study employed molecular dynamics simulations to investigate the adsorption behavior of three distinct types of epoxy resins on the sand surface: diglycidyl ether of bisphenol-A epoxy resin (DGEBA), diglycidyl ether 4,4′-dihydroxy diphenyl sulfone (DGEDDS), and aliphatic epoxidation of olefin resin (AEOR). The objective was to gain insights into the interactions between the sand surface and the epoxy resin polymers. The results demonstrated that DGEDDS formed a higher number of hydrogen bonds on the sand surface, leading to stronger intermolecular interactions compared to the other two resins. Furthermore, the mechanical properties of the adsorbed models of the three epoxy resins with sand were found to be relatively similar. This similarity can be attributed to their comparable chemical structures. Finally, analysis of the radius of gyration for the adsorbed epoxy resins revealed that AEOR exhibited a rigid structure due to strong molecular interactions, while DGEDDS displayed a flexible structure owing to weaker interactions. Full article

The ubiquitous presence of plastics represents a global threat for all ecosystems and human health. In this study, we evaluated, in vitro and in vivo, the genotoxic potential of different concentrations of polystyrene microplastics (PS-MPs) and their possible synergistic interactions with bisphenol-A (BPA). For the in vitro and the in vivo assays, we used human lymphocytes and hemocytes from Lymnaea stagnalis, respectively. The genomic damage was evaluated by the micronucleus assay, and differences in eggs laid and growth of L. stagnalis were also evaluated. In human lymphocytes, PS-MPs alone at the concentration of 200 μg/mL and in association with BPA 0.100 µg/mL significantly increased the frequencies of micronuclei and nuclear buds, indicating a possible in vitro genotoxic additive action of these two compounds. Vice versa, PS-MPs did not result in genotoxicity in hemocytes. Our results indicated that PS-MPs have genotoxic properties only in vitro and at a concentration of 200 µg/mL; moreover, this compound could intensify the genomic damage when tested with BPA, indicating possible cumulative effects. Finally, PS significantly reduced the growth and the number of laid eggs in L. stagnalis. Full article

Endocrine-disrupting chemicals (EDCs) are chemical substances that can interfere with any hormone action. They are categorized according to origin and use, such as industrial chemicals like polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs), plastics like bisphenol A (BPA), plasticizers like phthalates, pesticides like dichlorodiphenyltrichloroethane (DDT), fungicides like vinclozolin, and pharmaceuticals like diethylstilbestrol (DES). Natural EDCs, such as phytoestrogens, are present in the diet of both humans and animals. Polyphenols are a large group of natural compounds derived from plants and are found in beverages and food. They are grouped based on their chemical structure into flavonoids and nonflavonoids and are reported to have many beneficial effects on health, including, but not limited to, anticancer, antioxidant, and anti-inflammatory effects. Moreover, polyphenols have both pro- and antioxidant characteristics, and due to their antioxidant and anti-inflammatory potential, they presumably have a protective effect against damage induced by EDCs. However, polyphenols may act as EDCs. In this review, we report that polyphenols regulate the activity of EDCs, having both positive and negative effects. Hence, a better understanding of the associations between EDCs and polyphenols will allow the establishment of improved approaches to protect human health from EDCs. Full article

This study aims to investigate the toughening effects of rubber and thermoplastic particles on epoxy resin (EP), and to understand the mechanism underlying their synergistic effect. For this purpose, three EP systems were prepared using diglycidyl ether of bisphenol-A (DGEBA) epoxy resin (E-54) and 4,4-Diamino diphenyl methane (Ag-80) as matrix resin, 4,4-diaminodiphenyl sulfone (DDS) as a curing agent, and phenolphthalein poly (aryl ether ketone) particles (PEK-C) and carboxyl-terminated butyl liquid rubber (CTBN) as toughening agents. These systems are classified as an EP/PEK-C toughening system, EP/CTBN toughening system, and EP/PEK-C/CTBN synergistic toughening system. The curing behavior, thermal properties, mechanical properties, and phase structure of the synergistic-toughened EP systems were comprehensively investigated. The results showed that PEK-C did not react with EP, while CTBN reacted with EP to form a flexible block polymer. The impact toughness of EP toughened by PEK-C/CTBN was improved obviously without significantly increasing viscosity or decreasing thermal stability, flexural strength, and modulus, and the synergistic toughening effect was significantly higher than that of the single toughening system. The notable improvement in toughness is believed to be due to the synergistic energy dissipation effect of PEK-C/CTBN. Full article

This study investigates the correlation between the interface structure and macroscopic dielectric properties of polymer-based nanocomposite materials. Utilizing bisphenol-A (BPA) epoxy resin (EP) as the polymer matrix and the commonly employed layered phyllosilicate montmorillonoid (MMT) as the nanometer-scale dispersive phase, nano-MMT/EP composites were synthesized using composite technology. The microstructure of the composite samples was characterized through XRD, FTIR, SEM, and TEM. Changes in the morphology of the nanocomposite interface were observed with varying MMT content, subsequently impacting dielectric polarization and loss. Experimental measurements of the dielectric spectrum of the nano-MMT/EP were conducted, and the influence of the material interface, at different nano-MMT contents, on the dielectric relaxation was analyzed. The study delves into the effect of the nanocomposite interface structure on ion dissociation and migration barriers, exploring the ionic conductivity of nano-MMT/EP. Lastly, an analysis of the impact of different nano-MMT contents on the dielectric conductivity is presented. From the experimental results, the arranging regularity of polymer molecules in the interface area raises. In the matrix, the ion migration barriers decrease significantly. The higher the MMT content in the interface, the lower the migration barrier is. Until the MMT content exceeds the threshold, the agglomerated micro-particles form, which decreases the polymers’ space distribution regularity, and the ions migration barrier raises. According to the changes in the rule of the ions migration barrier with the composite interface structure content, the reason for dielectric conductivity changes can be judged. Full article

Thermoset-based polymer composites containing functional fillers are promising materials for a variety of applications, such as in the aerospace and medical fields. However, the resin viscosity is often unsuitably high and thus impedes a successful filler dispersion in the matrix. This challenge can be overcome by incorporating suitable low-viscosity modifiers into the prepolymer. While modifiers can aptly influence the prepolymer rheology, they can also affect the prepolymer curing behavior and the mechanical and thermal properties of the resulting matrix material. Therefore, this study investigates the effects that a commercial-grade low-viscosity additive (butyl glycidyl ether) has on a common epoxy polymer system (diglycidyl ether of bisphenol-A epoxy with a methylene dianiline curative). The weight percentage of the modifier inside the epoxy was varied from 0 to 20%. The rheological properties and cure kinetics of the resulting materials were investigated. The prepolymer viscosity decreased by 97% with 20 wt% modifier content at room temperature. Upon curing, 20 wt% modifier addition reduced the exothermic peak temperature by 12% and prolonged the time to reach the peak by 60%. For cured material samples, physical and thermo-mechanical properties were characterized. A moderate reduction in glass transition temperature and an increase in elastic modulus was observed with 20 wt% modifier content (in the order of 10%). Based on these findings, the selected material system is seen as an expedient base for material design due to the ease of processing and material availability. The present study thus provides guidance to researchers developing polymer composites requiring reduced prepolymer viscosity for successful functional filler addition. Full article

Bisphenol-A (BPA), a synthetic compound ubiquitously present in the environment, can act as an endocrine disruptor by binding to both canonical and non-canonical estrogen receptors (ERs). Exposure to BPA has been linked to various cancers, in particular, those arising in hormone-targeted tissues such as the breast. In this study, we evaluated the effect of BPA intake through drinking water on ErbB2/neu-driven cancerogenesis in BALB–neuT mice, transgenic for a mutated ErbB2/neu receptor gene, which reproducibly develop carcinomas in all mammary glands. In this model, BPA accelerated mammary cancerogenesis with an increase in the number of tumors per mouse and a concurrent decrease in tumor-free and overall survival. As assessed by immunohistochemistry, BALB–neuT tumors were ER-negative but expressed high levels of the alternative estrogen receptor GPR30, regardless of BPA exposure. On the other hand, BPA exposure resulted in a marked upregulation of progesterone receptors in preinvasive tumors and of Ki67, CD31, and phosphorylated Akt in invasive tumors. Moreover, based on several infiltration markers of immune cells, BPA favored an immunosuppressive tumor microenvironment. Finally, in vitro cell survival studies performed on a cell line established from a BALB–neuT breast carcinoma confirmed that BPA’s impact on cancer progression can be particularly relevant after chronic, low-dose exposure. Full article

Bio-based epoxy resins have received significant attention in terms of concerns regarding carbon emission. Epoxidized soybean oil (ESO) derived from sustainable feedstock has been widely used to blend with traditional diglycidyl ether of bisphenol-A (DGEBA) to replace some of the petroleum-based components. In this work, molecular dynamics (MD) simulations were applied to track the network formation and predict the performance of methyl hexahydrophthalic anhydride (MHHPA)-cured ESO/DGEBA blend systems. The effects of ESO content and cross-linking degree on the mass density, volumetric shrinkage, glass transition temperature (T_g), coefficient of thermal expansion (CTE), Young’s modulus, yield strength, and Poisson’s ratio of the epoxy resin were systematically investigated. The results show that systems with high ESO content achieve gelation at low cross-linking degree. The T_g value, Young’s modulus, and yield strength increase with the increase in cross-linking degree, but the CTE at the glassy state and Poisson’s ratio decrease. The comparison results between the simulated and experimental data demonstrated that the MD simulations can accurately predict the thermal and mechanical properties of ESO-based thermosets. This study gains insight into the variation in thermo-mechanical properties of anhydride-cured ESO/DGEBA-based epoxy resins during the cross-linking process and provides a rational strategy for optimizing bio-based epoxy resins. Full article