Polypropylene Research Articles

Distribution and characteristics of Microplastics in leachate and underneath soil of two informal landfills.

Microplastics (MPs), an emerging pollutant, have garnered global attention as significant environmental concerns. Landfills are the major sources of MPs. However, research on the distribution and characteristics of MPs in leachate and underneath soil of informal landfills remains limited. This study investigated the abundance, polymer type, size, and morphology of MPs in 6 leachate samples and 18 underneath soil samples at different depths from two informal landfills. The ranges of MPs abundance in leachate and underneath soil from landfills were 4,010-33,213 items/Land 592-870 to 47,819 items/kg, related to the landfilled waste composition. MPs size between 20 and 100µm accounted for the highest proportion (70%). The fragmentation coefficient α in the underneath soil was higher than that in the leachate, indicating smaller MPs were more likely to migrate into underneath soil after filtration. The fibrous MPs proportion was below 22%, while the fragmented MPs was more than 78%. Large fibrous MPs were detected in the underneath soil in landfill A. Polyethylene Terephthalate (PET), Polyurethane (PU) and Polystyrene (PS) were the predominant MPs polymers types in leachate and underneath soil. Polypropylene (PP) was primarily concentrated in the upper and middle underneath soil layers, and Polyurethane (PU) was predominantly in the middle and lower layers. Principal component analysis (PCA) results indicated that geographical factors significantly influenced the distribution and characteristics of MPs. This study revealed the distribution of MPs in leachate and underneath soil at different depths, providing a valuable reference for the risk assessment of MPs pollution.

Bioresorbable Suture Anchor Clips for Soft Tissue Wound Repair.

Mesh suture is an emerging technology for closing high-tension soft tissue wounds. However, bulky mesh surgical knots can irritate surrounding tissue and harbor bacteria, leading to an increased risk of infection and palpability. Thus, a degradable knotless anchoring system is needed to secure mesh sutures. Here, novel anchor clip devices are fabricated via continuous liquid interface production (CLIP) three-dimensional (3D) printing using poly(propylene fumarate-co-propylene succinate) (PPFPS) oligomers. Thiol-ene cross-linking yields fully degradable thermoset devices with tunable mechanical properties. For comparison, high-resolution anchor clips are also fabricated via traditional injection molding using poly(l-lactide-co-glycolide) (PLGA). The PLGA anchor clips show similar mechanical performance to predicate soft tissue fixation techniques in a benchtop abdominal wall reconstruction model. Both PLGA and PPFPS anchor clips demonstrate satisfactory in vivo biocompatibility in a porcine abdominal implantation model. This work outlines the development of bioresorbable anchor clips for soft tissue fixation and illustrates their potential for clinical translation.

Influence of fiber concentration and length on the dielectric, mechanical, and thermal properties of maple wood fiber-reinforced polypropylene

Natural fiber-reinforced polymer composites are gaining popularity due to their sustainability and enhanced properties compared to pure polymers. Recently, these composites have been utilized as dielectric materials. In this study, polypropylene (PP) reinforced with maple wood fibers of different lengths (50, 75, and 100 µm) and various fiber concentrations (5%, 10%, 15%, and 20%) were examined. The effects of fiber length and concentration on the dielectric, mechanical, and thermal properties were investigated. All composites exhibited a higher dielectric constant and conductivity than pure PP, along with a lower loss factor. This suggests that adding maple wood fibers generally enhances the dielectric properties. As fiber concentration increases, the dielectric constant tends to rise while the loss factor tends to decrease. TGA results indicated that adding more fibers reduces thermal stability at low temperatures but increases stability at high temperatures. Mechanical testing revealed an increase in strength but a decrease in elongation. However, fiber length did not significantly impact the mechanical properties. SEM analysis showed a uniform distribution of fibers at 5% weight that improves strength, while a 20% weight leads to clustering that weakens the composite.

Investigation of the Interaction of Ionic Surfactants with Epoxy-Based Hydrogels by SANS.

We investigated the effect of two ionic surfactants on the composition and structure of hydrogels obtained by swelling an epoxy amphiphilic polymer network (APN) using a combination of gravimetry and small-angle neutron scattering (SANS). Stoichiometric epoxy APN was synthesized by the reaction of diamino and diepoxy-terminated polypropylene (POP) and polyoxyethylene (POE). Sub- and supercritical solutions of surfactants with either cationic (myristyltrimethylammonium bromide (C14TAB)) or anionic (sodium dodecyl sulfate (SDS)) headgroups in heavy water were used in the preparation of the hydrogels. At supercritical concentrations, SDS exhibited a much stronger effect on the composition and structure of the hydrogels than C14TAB. The details of the hydrogel structure were deduced by general analysis and fitting of the experimental SANS profiles to two model scattering functions exploiting the Percus-Yevick hard-sphere (HS) model and rescaled mean spherical approximation (RMSA), respectively. In the former model, valid for the hydrogels prepared in low concentrated surfactant solutions, spherical domains of average radius of ca. 39-45 Å from a highly swollen network dispersed in a matrix of a poorly swollen network mixed with the bound alkyl surfactant tails were revealed. In the latter model, hydrogels prepared in surfactant solutions of sufficiently high concentrations consist of surfactant micelles dispersed in a matrix of a highly swollen network. The average radii of the C14TAB and SDS micelles formed in the hydrogels were ca. 28 and 17 Å, respectively. The strong binding of surfactant tails with POP chains and dragging of large amounts of highly mobile counterions inside the hydrogels were responsible for the effects observed. This study provides important information about the surfactant organization inside polymer hydrogels, which is important for their applications.

Enhancing biotextile applications with nanocomposite fibers: Molecular dynamics and interferometric analysis of the structural and mechanical properties of treated polypropylene

AbstractThis study explores the enhancement of polypropylene (PP) fibers through the incorporation of titanium oxide nanoparticles (TiO2), with a comprehensive characterization of their molecular, optical, mechanical, and antimicrobial properties. Density functional theory (DFT) and the PM6 semiempirical method were used to investigate the electronic properties and structure–activity relationships of the fibers. Experimental analyses, including FTIR, mechanical testing, and interferometric measurements using a Mach–Zehnder interferometer, were conducted to assess the impact of TiO2 nanoparticles on the fibers' performance. The antimicrobial efficacy was evaluated using the shake flask method. Results indicate that the addition of TiO2 nanoparticles significantly improved the material's polarity, mechanical strength, and antimicrobial properties. Specifically, the total dipole moment (TDM) increased from 0.0706 Debye in neat PP to 3.7180 Debye in PP‐TiO2, and the band gap energy decreased from 10.58 to 1.14 eV, indicating a transition to semiconducting behavior. The mechanical properties of PP‐TiO2 demonstrated a yield strength of 206.83 MPa and an elastic shear modulus of 439.58 MPa, a notable improvement over neat PP. Moreover, PP‐TiO2 fibers exhibited enhanced birefringence and strong antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida species, underlining their potential for advanced applications in medical and hygiene‐related fields.Highlights Structural and optical properties of PP and PP‐TiO2 have been analyzed. Advanced characterization with Mach–Zehnder interferometry and modeling has been used. Opto‐mechanical behavior was studied via stress–strain and refractive index. Antimicrobial efficacy was evaluated using the shake flask method. PP‐TiO2 shows potential for biomedical applications like suture and dressings.

Enhanced strain transfer and optoelectronic performance in MoS2 devices via Formvar encapsulation

Abstract We systematically investigate the influence of polyvinyl formal (PVFM), commonly known as Formvar, in comparison to polycarbonate (PC) and polymethyl methacrylate (PMMA), as encapsulation materials on the strain performance of MoS2 monolayer and bilayer flakes on flexible polypropylene (PP) substrates. Notably, optical differential reflectance measurements reveal that PVFM and PMMA encapsulation significantly enhances the mechanical and thermal strain gauge factors by approximately 2-fold (up to ∼−50 meV/%) and 6-fold (up to ∼−1.5 meV/°C), respectively, while PC shows a slightly lower enhancement. Moreover, all three polymers increase the maximum achievable strain from approximately 1.4% to 2.3%. Furthermore, devices fabricated on PP substrates exhibit improved optoelectronic performance when encapsulated with PVFM, including increased and faster photocurrent response and extended device lifetime.

Technical and Economic Feasibility Investigation for the Treatment of Microplastic-Contaminated Marine Sediments Through an Environmentally Sustainable Separation Process

This work provides a comprehensive study of a density separation treatment through sucrose solution for the removal of microplastics (MPs) from marine sediments. The theoretical determination of flotation velocities for 1.0 mm diameter spherical MPs with a density of 1.3 g/cm3 at various solution temperatures and sucrose contents was performed. An optimal velocity of 1.03 m/h was observed with a 70% sucrose solution at 50 °C. The validation of theoretical velocities was carried out through experimental tests at optimal operating conditions for polypropylene (PP), high-density polyethylene (HDPE), polylactic acid (PLA), and polyvinyl chloride (PVC) as target MPs. The results showed an experimental floating velocity slightly lower than the theoretical predictions for PP, HDPE, and PLA. PVC, instead, characterized by a higher density than the separation solution, showed a settling velocity 42% lower than the theoretical one. Further tests were performed to assess the solid-to-liquid (S/L) ratio effect on MPs’ separation efficiency. The results showed an optimal S/L of 75 kg/m3 with 80% PVC removal and total PP, HDPE, and PLA removal. Finally, the design and cost optimization of a longitudinal settling tank were proposed for the pilot/real-scale treatment. The observed outcomes provided in-depth details useful for the development of an environmentally sustainable treatment for the preservation of marine areas.

Enhanced thermal stability and mechanical properties of polypropylene matrices reinforced with SiO2 nanoparticles

Abstract The current study focuses on incorporating SiO2 nano-fillers into a polypropylene matrix to enhance and regulate the coefficient of thermal expansion (CTE), while simultaneously improving its physical, mechanical, and thermal properties. Our approach involves the addition of small quantities of SiO2 filler to occupy the vacant spaces between polymer chains, resulting in a reduction in the CTE of the polymer without affecting its structure. Hence, silicon dioxide nanoparticles (SiO2-NPs) were added to a polypropylene (PP) matrix at various concentrations (1%wt, 2%wt, 3%wt, 4%wt, 5%wt, 6%wt). The prepared samples underwent characterization through techniques including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC), along with analysis of the coefficient of thermal expansion, Young's modulus, and tensile strength. Observations revealed that the inclusion of small quantities of filler significantly enhances the mechanical and thermal properties of PP, particularly at 3%wt of SiO2, which exhibited the lowest CTE value. This methodology can be regarded as an effective approach for controlling the CTE value of polymers, potentially opening avenues for various industrial applications of these materials.

The Effect of Adding Waste Tire Rubber on Compressive Strength, Impact Resistance, and Damping Ratio of Fiber-Reinforced Foamed Concrete

Research was conducted to investigate the effects of incorporating optimal proportions of Waste Tire Rubber (WTR) on the compressive strength, impact resistance, and damping of fiber-reinforced Foamed Concrete (FC) modified with a Super-Plasticizer (SP). In this study, four FC types with a density of 1100 kg/m3 were produced: conventional FC, modified FC with SP, polypropylene (PP) fiber-reinforced FC, and fiber-reinforced rubberized FC (containing SP, PP, and WTR). To evaluate the effect of density on the FC properties, two additional fiber-reinforced rubberized FC mixtures were produced with densities of 800 and 1400 kg/m3. The sand in the FC was partially replaced with WTR at optimum ratios of 50% for coarse WTR (4.75–10 mm) and 34% for fine WTR (≤ 2.36 mm). Additionally, 53 kg/m3 of cement was substituted with fly ash. The results indicated that the addition of SP enhanced the properties of the fresh and hardened FC. For a given density of 1100 kg/m3, adding WTR led to decreased consistency and strength while increased the impact and damping compared to the reference containing only SP and PP. However, the fiber-reinforced rubberized FC mix with SP showed improvements of 79.5%, 3700%, and 21.45% in compressive strength, impact resistance, and damping, respectively compared to conventional FC (without SP and PP). With the exception of the damping ratio, the compressive strength and impact resistance increased when the rubberized FC density was elevated.

Surface Modification of Intumescent Flame Retardant and Its Application in Polypropylene with Excellent Fire Performance and Water Resistance

Polypropylene (PP) has a wide range of applications in daily life but it is highly flammable. Intumescent flame retardants (IFRs) are used to improve the flame-retardant performance of polypropylene. However, the poor compatibility between IFRs and PP poses significant challenges. In this study, an IFR was reacted with γ-aminopropyl triethoxysilane (KH550) to introduce necessary reactive sites on the surface of the IFR. Subsequently, maleic anhydride-grafted SBS (SBS-g-MAH) was reacted with KH550 to further coat the IFR, resulting in a modified IFR named MA-IFR. The effects of MA-IFR on the flame retardancy, mechanical properties, and water resistance of PP composites were systematically investigated. The limiting oxygen index of the PP/MA-IFR composite reached up to 39.7%, with the vertical burning test (UL-94) achieving a V-0 rating. Moreover, compared to the control PP, the peak heat release rate and peak smoke release rate were reduced by 85.0% and 82.5%, respectively. In addition, the mechanical properties of the PP composites were significantly improved, with tensile strength and impact strength increasing by 29% and 18%, respectively, compared to those of the PP/IFR composite. Notably, the PP/MA-IFR composite maintained excellent flame retardancy, even after being immersed in water at 70 °C for 168 h. These results demonstrate that MA-IFR offers a promising solution for producing flame-retardant and water-resistant PP composites.

Balancing the Mechanical Toughness and Electrical Insulation of Polypropylene by Blending and Grafting Modifications

AbstractBalancing the mechanical toughness and electrical insulation of polypropylene (PP) for recyclable cable insulation application has attracted increasing attention. Due to the different molecular conformation, isotactic polypropylene (IPP) always delivers excellent electrical insulation but poor mechanical toughness, while block polypropylene (BPP) has been dramatically opposed properties. Blending IPP with BPP at an appropriate content may be beneficial to reconcile the toughness and insulation. In this study, the blending ratio of IPP and BPP is first investigated, and it is found that 60: 40 wt.% is the optimized ratio for achieving outstanding overall performance. Furthermore, polyolefin elastomer (POE) and styrene‐grafted POE (POE‐g‐St) are incorporated into IPP/BPP blends respectively to intensify the toughness as well as the insulation property. The microstructure, electrical properties, mechanical properties, and thermal properties of the composites are systematically analyzed and discussed. The results demonstrate that the composite with a grafting ratio of 1.21 wt.% styrene exhibits superior overall performances, the enhanced breakdown field strength of 314.02 kV mm−1, and reduced elastic modulus of 352.54 MPa are achieved. Additionally, the modified composites also possess a high melting temperature, high volume resistivity, and excellent space charge suppression capability, achieving the synergistic improvements of the electrical, mechanical, and thermal properties.

Constitutive Relation of Polypropylene-Fiber-Reinforced Mortar Under Uniaxial Compression at High Temperature

Exposure to elevated temperatures leads to the deterioration of the mechanical properties of cementitious materials. However, the inclusion of fibers can mitigate, to some extent, the negative effects of high temperatures on these materials. Specifically, polypropylene (PP) fibers, a synthetic fiber type, have been demonstrated to improve the performance of cement-based composites. Therefore, it is essential to investigate the impact of temperature on the behavior of fiber-reinforced mortar for its broader application in construction. This study explores the effects of varying PP fiber contents (0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1%) and different temperature exposures (25 °C, 200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C) on the performance of cement mortar. The experimental results show that elevated temperatures significantly degrade both the mechanical and thermal properties of fiber-reinforced mortar. As the temperature and fiber content increase, both the quality and thermal conductivity of the mortar decrease. Between 25 °C and 200 °C, the incorporation of PP fibers (ranging from 0% to 0.2%) significantly enhances the compressive and flexural strengths of the mortar. However, this improvement becomes less pronounced as the fiber content exceeds 0.2%. At temperatures above 200 °C, further increases in temperature, coupled with higher fiber contents, consistently lead to a reduction in the compressive and flexural strengths. Based on the principles of continuous damage mechanics (which describes the degradation and fracture of materials under loading) and the dual-parameter Weibull distribution theory, a constitutive model is proposed to describe the damage behavior of high-temperature PP-fiber-reinforced mortar under uniaxial compressive stress.

Microplastics as adsorbent for Pb2+ and Cd2+: A comparative study of polypropylene, polyvinyl chloride, high-density polyethylene, and low-density polyethylene.

Microplastics (MPs) in aquatic environments adsorb heavy metals, thereby posing potential environmental risks. However, further research is needed to elucidate the adsorption behavior of different types of MPs for various heavy metals. The aim of this study was to characterize four types of MPs: polypropylene (PP), polyvinyl chloride (PVC), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). Moreover, their Pb2+ and Cd2+ adsorption properties were determined to investigate the differences in their capacity to function as heavy metal adsorbents. MPs were characterized via scanning electron microscopy (SEM) using energy dispersive X-ray spectrometer (EDS), Brunauer-Emmett-Teller (BET) analysis, and Fourier transform infrared spectroscopy (FTIR). Adsorption experiment data were analyzed using the Langmuir and Freundlich isotherm models to evaluate the adsorption capacity of the MPs. Based on the results of the adsorption isotherm models and 2D-COS FTIR, the presence of oxygen-containing functional groups, including hydroxyl, carbonyl, and carboxyl groups influences the adsorption process of Pb2+ and Cd2+ onto PP and PVC, with the maximum adsorption capacities (Qm) being 0.759mg/g and 0.495mg/g, respectively. Combination of the adsorption isotherm data and characteristics of MPs revealed that the following order of adsorption efficiencies of MPs for each heavy metal: PP>LDPE > PVC>HDPE for Pb2+ and PP>PVC>LDPE > HDPE for Cd2+. The results of this study suggest that MPs, particularly PP and PVC, may serve as vectors for heavy metal transport in aquatic environments, highlighting the need for further research to assess their environmental impact.

Hazard assessment of airborne and foodborne biodegradable polyhydroxyalkanoates microplastics and non-biodegradable polypropylene microplastics.

Microplastics (MP) are ubiquitous in the environment, and are toxic to various living organisms. Proper application of biodegradable plastics may alleviate the hazards of conventional non-biodegradable plastics. In the current study, multi-omics analyses were performed to compare the biodegradable polyhydroxyalkanoates (PHA) and non-biodegradable polypropylene (PP) MP for their toxicity on mouse liver and lung. Airborne PHA MP induced nasal microbiome dysbiosis, pulmonary microbiome alteration, pulmonary and serum metabolome disruption, and hepatic transcriptome disturbances, resulting in mild pulmonary toxicity. By contrast, airborne PP MP caused greater alterations in nasal and pulmonary microbiome, pulmonary and serum metabolome, and hepatic transcriptome, resulting in pulmonary and hepatic toxicity. Both foodborne PHA and PP MP caused intestinal microbiome dysbiosis, while foodborne PHA MP caused slighter intestinal and serum metabolome disruption, hepatic transcriptome disturbances and hepatotoxicity (e.g., lower serum aspartate aminotransferase and alanine aminotransferase) compared to foodborne PP MP. Some potential differential biomarkers were determined between PP and PHA MP exposures, i.e., nasal Allobaculum and pulmonary Alloprevotella for airborne PHA; nasal Lactobacillus and pulmonary Acinetobacter for airborne PP; intestinal Faecalibacterium for foodborne PHA; and intestinal unclassified_Erysipelatoclostridiaceae for foodborne PP. The results show that PHA MP can induce less pulmonary and hepatic toxicity compared to PP MP, suggesting PHA is a potential substitution for PP. The findings can benefit the hazard assessment of airborne and foodborne PHA and PP MP.

Characterization of microplastics in human follicular fluid and assessment of their potential impact on mouse oocyte maturation in vitro.

Microplastics (MPs) have been identified in various human tissues and organs. This study aims to evaluate the presence of MPs in human follicular fluid (hFF) and their potential impact on oocyte maturation. Laser direct infrared spectroscopy of 19 hFF samples identified 7956 particles, including 1739 microplastics (21.9 %) from 30 types. Of these, 923 particles had matching degrees > 0.8, and 7033 had matching degrees between 0.65 and 0.8. The most abundant MPs were Chlorinated Polyethylene (CPE), Fluorosilicone rubber, Polyvinyl chloride (PVC), Butadiene rubber (BR), and Styrene-butadiene-styrene (SBS), with diameters ranging from 20 to 100 μm. Five random samples were analyzed by pyrolysis-gas chromatography-mass spectrometry, which detected four types of microplastics-Polyethylene (PE), Polypropylene (PP), Polystyrene (PS), and PVC-at varying concentrations. PE was the most abundant (22.284 mg/kg), followed by PVC (1.061 mg/kg), PP (0.837 mg/kg), and PS (0.600 mg/kg). Based on the diameter and concentration ranges of MPs in hFF, we used seven types of fluorescence-labeled MP beads-PE, PVC, PP, PS, CPE, Polymethylmethacrylate (PMMA), and Polytetrafluoroethylene (PTFE)-to assess their impact on mouse oocyte in vitro maturation. The results showed that smaller MP beads (e.g., 50 μm PE) were more likely to penetrate the zona pellucida and enter the oocyte, while larger beads (e.g., 500 nm PMMA) tended to adhere to the zona and remain outside the oocyte. All seven types of MP beads hindered oocyte maturation, resulting in varying reductions in maturation rates compared to the control group. Our findings suggest that MPs contaminate hFF and may impair oocyte maturation.

Disinfection inducing release of contaminants from baby play mats: Microplastics and volatile organic compounds.

Baby play mats serve as essential protective equipment widely utilized in residences, daycares, and kindergartens. Given their direct contact with infants and young children, the pollutants released from play mats may pose potential health risks. This study investigated the impact of disinfection on the release of microplastics (MPs) from play mats and offers an in-depth analysis of the derived volatile organic compounds (VOCs) release. The results revealed that various disinfection treatments promoted the release of MPs from play mats. Among them, chlorination bleaching induced play mats to produce 2-3 times less MPs than ultraviolet sterilization (UVS) and UV-bleaching disinfection. The generation potential of MPs derived from play mats of different materials was ranked as polyethylene terephthalate (PET)>polypropylene (PP)≈polyethylene (PE)>polyvinyl chloride (PVC). Furthermore, PE play mat released highest concentration of total VOC after disinfection, increasing from 1.82mg/m2 (control) to 15.82mg/m2 (UV-bleaching). However, PVC released the most species of VOCs, with 76 species identified through non-target screening, such as several alkanes, alkenes, alcohols, ketones, etc. Through toxicological prediction, VOCs with high toxic potential were identified. Individual VOCs from PP, such as Pentadecane (CAS: 629-62-9), exhibited high yields at 3.16ng/g after UV-bleaching treatment. In conclusion, chlorination bleaching is safer than UVS and UV-bleaching disinfection in mitigating the release of pollutants from play mats.

Mesophilic anaerobic digestion of mixed sludge in CSTR and AnMBR systems: A perspective on microplastics fate.

Most microplastics (MPs) end up in the biosolids produced in wastewater treatment plants (WWTPs) and can pose contamination risks when the biosolids are applied to agriculture. This study evaluated the impact of mesophilic anaerobic digestion on the fate of MPs in WWTP sludge. For this, two laboratory-scale anaerobic digesters were operated in parallel, consisting of a continuous stirred tank reactor (CSTR) and a membrane bioreactor (AnMBR) equipped with an ultrafiltration membrane to decouple the hydraulic and sludge retention times. Both digesters were continuously fed with mixed sludge from a municipal WWTP. The results showed a significant reduction in the MP concentration, with the AnMBR having the higher MP removal efficiency (88.6% vs. 62.1%) and obtaining a higher percentage of biomethanisation (58.3% vs. 43.7%). Polypropylene (PP) and polyacrylonitrile were the main polymers in the mixed sludge, while PP and polyethylene were the dominant polymers in the digested samples. The MP particles in all the samples were predominantly in the 500-104μm size range. Microbiological analysis indicates a greater species diversity in the microbial community of the AnMBR, the results also revealed a symbiotic relationship between the Firmicutes and Patescibacteria phyla in this digester.

Physicochemical evaluation of poultry farming materials for bacterial adhesion and biofilm formation: implications for contamination prevention

ABSTRACT In poultry production, various substrates and the adhesive properties of pathogenic bacteria lead to biofilm formation and bio-contamination. This study investigates bacterial attachment behaviour on materials commonly used in poultry farming to aid in selecting appropriate materials and mitigating bio-contamination risks. We compared the hygienic profiles of these materials and elucidated the physicochemical mechanisms governing adhesion. Physicochemical properties and surface interaction energies between Escherichia coli ATCC25922 and five substrates were estimated using the contact angle method, and the number of adherent cells was quantified experimentally. Results showed that all substrates, except for the underside of straw (SUS), were predominantly hydrophobic. The E. coli ATCC25922 strain showed strong affinity towards polypropylene (PP) and high-density polyethylene (PEHD). The difference in adherence abilities of E. coli ATCC25922 was significantly affected by quantitative hydrophobicity and electron donor character. This study highlights factors influencing bacterial adhesion, aiding in the prevention of biofilm.

Microplastics occurrence in commercial crab Scylla serrata from Kaveri River of Tamil Nadu: An emerging concern for community health.

Microplastic (MPs) pollution has engulfed global aquatic systems, and the concerns about MPs translocation and bioaccumulation in fish, crabs, and other marine organisms are now an unpleasant truth. In the past few years, MPs pollution in freshwater systems, particularly rivers, and subsequently in freshwater organisms, especially in crabs, has caught the attention of researchers. Rivers provide livelihood to approximately 40% of the global population through food and potable water. Hence, assessment of emerging contaminants like MPs in waterways and the associated fauna is crucial. This study assessed MPs in crab S. serrata across the largest riverine system of south India, the Kaveri River. The MPs were characterized by optical microscopy, and field emission scanning electron microscopy-energy dispersive X-ray (FESEM-EDX) analysis for their number, shape, size, and color. Polymer composition was analyzed using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. Polypropylene (PP), polystyrene (PS), polyamide (PA), and polyvinyl chloride (PVC) were the dominant plastic polymers in the crab intestine. Additionally, the FE-SEM analysis revealed that the MPs have differential surface morphology with rough surfaces, porous structures, fissures, and severe damage. Most MPs comprised Na, Si, Mg, Cl, K, and Ca, according to EDX analyses. The findings might provide insight into the status of MPs in S. serrata at Kavery river that could help in formulating regulations for MPs reduction and contamination in rivers eventually to protect the environment and human health. PRACTITIONER POINTS: The first findings on the identity and properties of MPs in crabs from the Kaveri River at Mettur Dam. A simple and cost-effective approach for extracting microplastics from crab samples from Mettur Dam, Kaveri River, Salem District, Tamil Nadu, India. Microplastics were detected using optical microscopy, ATR-FTIR, and FE-SEM.

Occurrence and migration of synthetic phenolic antioxidants in food packaging materials: Effects of plastic types and storage temperature.

Synthetic phenolic antioxidants (SPAs) are widely used in food packaging materials to extend product shelf life. Not much attention has been paid to high molecular weight SPAs (HMW SPAs) so far, despite their potential health risks. In this study, we first analyzed the concentrations of ten HMW SPAs in food plastic packaging materials (including 6 plastic categories, n=116). The total concentrations of HMW SPAs (∑SPAs) ranged from 0.0844 to 894mg/kg, with a geometric mean of 71.7mg/kg. The predominant HMW SPAs included AO1010 (accounting for 71.8% of total concentrations of HMW SPAs), AO1076 (21.4%), and AO3114 (3.14%), with AO1010 detected in all samples. Higher concentrations were notably found in polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) materials. Migration tests revealed that HMW SPAs could readily transfer into food simulants, with PP exhibiting the lowest migration levels. Migration of SPAs into fatty foods was pronounced, increasing with temperature (temperature gradients: 4°C, 25°C, and 60°C). In the 95% ethanol food simulants, the maximum migration amounts of AO1076 in PE (7.05mg/kg at 25°C) and PET (9.79mg/kg at 25°C; 10.8mg/kg at 60°C) surpassed the specific migration limit (SML) set by the national standards, posing potential food safety risks. This was the first report on the presence and migration patterns of ten HMW SPAs in food plastic packaging materials, providing crucial insights into food packaging material safety.