Plastic Polymers Research Articles

Development and implementation of in-process, orbiting laser-assisted healing technique on fused filament fabrication

Fused filament fabrication is one of the most widely used additive manufacturing processes for producing thermal plastic polymer materials due to the affordable cost and capability to build objects with complex structures. However, parts fabricated with this process exhibit lower mechanical strength when compared to parts manufactured using traditional methods. In this work, an in-process orbiting laser healing technique is developed and implemented on a 3D printer to enhance mechanical strength by improving interlayer adhesion. The orbiting laser assembly can position and align the laser-heated spot before the change of nozzle direction occurs, ensuring that the previous layer is heated prior to material deposition. This laser-heating technique increases the bending strength along the build direction by 40% and reaches 88.9% of the strength along the longitudinal direction. With this technique, the displacement at fracture also increased by 54.3% compared to control sample. The thermal profile of the melting pool and fracture surface was further characterized using a thermal camera and SEM to support the effect of laser heating on polymer microstructure, respectively. Due to its enhanced print quality and lower cost, this technique has the potential to expand the application field of fused filament fabrication to small batch and series production that are currently dominated by injection molding, as well as the high-quality prototyping field.

Disain Kebutuhan Tulangan Glass Fiber Reinforced Polymer (GFRP) Untuk Elemen Struktur Pada Bangunan Beton Bertulang

Fiber Reinforced Polymer is a combination of two main materials Resin Polymer (plastic) as a binder matrix and Fiber (fiber) as reinforcement. This material has three fibers, namely Carbon, Glass, and Aramid. Glass fiber was used in this study, because it has a greater strain compared to other fibers. This study aims to design reinforced concrete structures using steel reinforcement and GFRP as well as to compare the reinforcement requirements of each reinforced concrete. Calculation of reinforcement for steel reinforced concrete refers to SNI 1726-2019, while for GFRP reinforced concrete it is based on ACI 440 1R-2015. This research begins by collecting data in the form of a design structure drawing of a 6-storey hypothetical building, with a total building height of 23 m. The hypothesis building has the number of spans in the X-axis direction is 5 with a distance between columns of 6 m, while the number of spans in the Y direction is 3 with a distance between columns of 5 m. The column dimensions for all floors are 60 cm x 60 cm, while the beam dimensions are 40 cm x 40 cm. The thickness of the floor and roof slabs is 12 cm and the concrete quality is 30 MPa. For the calculation of structural loading, dead load, live load and earthquake load are used and the design of reinforcement for conventional steel reinforced concrete structures and GFRP is carried out. Steel reinforced concrete structures with GFRP reinforced concrete have differences in the amount and diameter of reinforcement required. For beam elements bearing steel reinforcement, 24 pieces of flexural reinforcement are needed with a diameter of 19 mm, while for beam elements, GFRP reinforcement requires 12 pieces of flexural reinforcement with a diameter of 1 inch to 1,128 inches. For the field area, steel reinforcement beam elements need 12 pieces with a diameter of 19 mm, while for GFRP reinforcing beam elements require 8 pieces of flexural reinforcement with a diameter of 0.875 inch to 1.128 inch. In column elements, steel reinforcement and GFRP reinforcement require the same amount of main reinforcement, which is 32 pieces. However, in terms of diameter, steel reinforcement requires 25 mm diameter reinforcement, while GFRP is 1 inch in diameter.

A novel approach to plasticizer content calculation in an acrylonitrile-butadiene rubber real-time aging study (NBR)

This study presents an analysis of plasticizers and other additives in elastomers using several techniques to obtain relevant information for aging investigations. Thermogravimetric quantification of polymeric matrix, polymeric matrix char, carbon black, inorganic substances, plasticizers and other additives is commonly used. However, the thermogravimetric weight loss attributed to plasticizers and other additives contains additional components whose contribution to the weight loss has not been considered. Unreported components include water and carbonyl sulfide, which develop over long-term elastomer aging, and should be separately accounted for. This study employed Karl-Fischer oven techniques for calculating water content and linked thermogravimetric analysis with Fourier-transform infrared spectroscopy to measure carbonyl sulfide. Chromatoprobe-GC/MS was used to determine the ratio between rubber-related substances and JP-8 fuel and its additives, which can diffuse into rubbers. In fuel bladders, this occurrence is frequently observed, and the ratio consistently decreases over time.

Diffusion-Ordered Spectroscopy for Rapid and Facile Determination of Consumer Plastic Molecular Weight.

Molecular weight (MW) is a key control of plastic polymer properties and their fate in the environment. However, the primary tool used to determine plastic MW, gel permeation chromatography (GPC), has major limitations, such as low precision and accuracy, requirements for dedicated instrumentation, production of high volumes of hazardous waste, and large sample sizes. In this study, we describe, validate, and apply a diffusion-ordered spectroscopy (DOSY) method for polymer MW determinations, with a focus on applications for consumer plastics. Several experimental conditions were systematically optimized and tested to validate the DOSY method, including the selection of pulse sequences, the effect of sample concentration, cross-validation with multiple sets of external standards, and long-term instrumental stability. Validation was performed for a wide range of polymers, solvents, and temperatures, highlighting its potential for broad applicability. A preliminary screening of polystyrene and polyethylene terephthalate consumer products revealed widely varying MWs (up to two-fold) for products made of the same polymer type. A preliminary experiment was also conducted to track the decrease in polystyrene MW via photochemical chain scission reactions, finding a 20% reduction in MW after less than 1 week of irradiation. Collectively, our results demonstrate the potential for DOSY to provide high-throughput, accurate, and precise measures of polymer MW, as well as the evolution of polymer MW during environmental weathering processes, such as photochemical degradation. We conclude with a discussion of (i) the many advantages of DOSY compared to GPC, (ii) future developments to enhance the depth of information obtained from DOSY, and (iii) approaches to broaden the accessibility of this promising analytical method to the research community.

The presence of microplastics in the Indonesian environment and its effects on health

Introduction. Microplastics are plastic particles with a microscopic size of <5 mm in diameter. Microplastics are new contamination of the environment and can be bad for health. Objective. This paper aims to examine the presence of microplastics in the Indonesian environment based on the results of research in 2022 and its effects on health. Materials and Methods. Systematic review based on the results of research journals published in 2022. Journal obtained from a search on Google Scholar with keywords “microplastics”, “microplastics in Indonesia”, and “effect microplastic to health”. Results. The results of a review showed that the research location was dominated in East Jawa. The presence of microplastics in the environment in Indonesia is most widely studied, namely in river and sea sediments. The forms of microplastics identified are fiber, fragment, film, pellets, granule, foam, filament, and bead. In microplastic research on the environment in Indonesia in 2022, as much as 16% analyzed plastic polymer types. The study that identified the number, shape, and color of microplastics using visual methods with a microscope was 84%. Research on the effects of microplastics on health is still little done. Conclusions. Microplastics are widely studied in sediments, water, food, and air. Microplastics in the environment in Indonesia have been identified in number, shape, color, and polymer type. There have not been many studies that have conducted an analysis of the type of polymer. The environment in Indonesia has been polluted by microplastics that can have an impact on health.

Edible Biopolymers from Marine Algae used as an Alternate Packaging material: A Review on their characteristics and properties

Food packaging is estimated to account for two-thirds of all plastic waste. As a result, it is crucial to discover alternative packaging materials that are both environmentally friendly and safe for human health. Marine algae are becoming more well-known and in demand as cutting-edge resources for producing biopolymers like proteins and polysaccharides. Because of their biocompatibility, biodegradability, and lack of toxicity, biopolymers have been suggested as potential sources for food packaging materials. Numerous research has thoroughly examined the extraction, separation, and use of marine biopolymers in the creation of sustainable packaging. Marine algae are also rich in protein and mineral content, they also have anticancer, anti-obesity, and hypolipidemic properties due to the presence of polyunsaturated conjugated fatty acids. The edible films enhance the shelf life of food by controlling moisture without changing the elements of food. The marine algae are collected either in the intertidal or subtidal areas and they will be dried for further process. The edible films are environmentally friendly. The edible film made from marine algae is a mixture of protein, polysaccharides, lipids, and resins. The factors which affect the properties of the edible film are the source of raw material, surface charge, hydrophobicity, polymer chain length, plasticizer type, proportion, and synthesis method. There are numerous research has been conducted to develop edible film using various matrix constituents. This review provides an overview of Marine algae, its process, and edible films, its characteristics, and factors affecting the film.

Influence of polymer modification on intra-MOF self-diffusion in MOF-based mixed matrix membranes

Mixed-matrix membranes (MMMs) represent a promising membrane type for gas and liquid separations. Such membranes can be formed by dispersing crystals of metal–organic frameworks (MOFs) in polymers. For liquid separations, crosslinked polymers are desirable because crosslinking reduces polymer dilation and plasticization effects by liquid sorbates. However, polymer crosslinking processes can unfavorably change transport and related structural properties of MOF fillers. In this work, 13C pulsed field gradient (PFG) NMR was used to investigate possible changes in intra-MOF self-diffusion of p-xylene and o-xylene after MMM polymer crosslinking. The studied MMMs were formed by dispersing MOF crystals of the type ZIF-71 in Torlon (a poly(amide-imide)) or Matrimid (a polyimide) polymers. The reported PFG NMR data indicate that the polymer crosslinking process used does not influence the intra-ZIF diffusivities when all effects on these diffusivities that are related to diffusing molecules crossing over the crystal boundaries or reflected away from these boundaries are removed. In contrast, these data show that the crosslinking process resulted in a significant decrease of the effective size of ZIF-71 crystals inside the studied MMMs, especially in the ZIF-71/Matrimid MMM. This crystal size decrease is attributed to a partial degradation of the ZIF-71 crystals inside the MMMs due to the crosslinking process. This conclusion was found to be in agreement with the results of electron microscopy analysis. PFG NMR studies and data analysis similar to those presented here can be used for quantifying any types of MOF crystal degradation inside MOF-based MMMs.

Size-dependent response of the mussel collective behaviour to plastic leachates and predator cues

Both individual and collective anti-predator behaviours are essential for the survival of many species. This is particularly true for ecosystem engineers such as intertidal mussels, which through their collective behaviour create novel habitats for a range of organisms and biodiversity hotspots. However, contaminants may disrupt these behaviours and consequently indirectly affect exposure to predation risk at the population level. Among these, plastic litter is a major and ubiquitous contaminant of the marine environment. Here, we assessed the impact of microplastic (MP) leachates of the most produced plastic polymer, polypropylene (PlasticsEurope, 2022), at a high but locally relevant concentration (i.e. ca. 12 g L−1) on the collective behaviours and anti-predator responses of both small and large Mytilus edulis mussels. Indeed, in contrast to large mussels, small ones reacted to MP leachates, showing a taxis towards conspecifics and stronger aggregations. All mussels reacted to the chemical cues of the predatory crab, Hemigrapsus sanguineus, but with two different collective anti-predator behaviours. Small mussels only showed a taxis towards conspecifics when exposed to predator cues. This response was also found in large ones with a tendency to form more strongly bound aggregations and a considerable reduced activity, i.e. they significantly delayed their time to start to form aggregations and decreased their gross distance. These anti-predator behaviours were respectively inhibited and impaired in small and large mussels by MP leachates. The observed collective behavioural changes may reduce individual fitness by enhancing predation risk, particularly in small mussels that are the crab H. sanguineus's favourite preys. Given the key role of mussels as ecosystem engineers, our observations suggest that plastic pollution may have implication on M. edulis at the species level, but also enhancing a cascading effect towards a higher level of organisation such as population, community and ultimately structure and function of intertidal ecosystem.

On the Effect of Monomeric and Polymeric Plasticizer on Polybutylene Succinate (PBS), Polyhydroxybutyrate (PHB), and Polylactic Acid (PLA) Films with 20wt%PCL for Flexible Packaging Application

Nowadays, biodegradable polymers such as Polybutylene succinate (PBS), Polyhydroxybutyrate (PHB), and Polylactic acid (PLA) are widely used commercially, especially in flexible packaging applications, but these polymers have certain limitations in their properties. The main aim of this study was to develop biodegradable polymer films with improved performance characteristics. This paper focused on developing and enhancing the characterization such as tensile properties, water barrier properties, and biodegradation properties of PBS-PCL(Polycaprolactone), PHB-PCL, and PLA-PCL blends, with the addition of 5wt% of plasticizer [GTA (Triacetin/ glycerol triacetate), a monomeric plasticizer P1, Ultramoll, a polymeric plasticizer P2; and mixed plasticizer P3 (1: 1 mix of P1 and P2)] for flexible packaging application. The plasticized polymer films (thickness 0.25mm) was prepared by injection molding and hot pressing method, and analyze the characterization such as tensile properties (ASTM D882-18 method), water vapor barrier properties (ASTM E96-16 method), and the biodegradation properties in compost (ASTM D5338-15 method), and seawater (ASTM D6991-17 method) medium, and analysis the effect of plasticizers on plasticized polymer blends. The research shows that compared to polymers blends such as PBS, PHB, and PLA, with 20wt% of PCL, there was a significant increase in tensile elongation by 22%,76.6%, and 139.3%, respectively and an increase in biodegradability by 19.5%, 3.6%, and 38.9% in compost medium, and 22.1%, 1.8%, and 41.0% in seawater medium, respectively, with the addition of all three 5wt% plasticizers (Ultramoll), though the tensile strength and water vapor properties were decreased. The plasticizer study shows that plasticized polymer blends using mixed plasticizer (P3) provide the best overall performance enhancement.

Gut microbiome of mealworms (Tenebrio molitor Larvae) show similar responses to polystyrene and corn straw diets

BackgroundSome insects can degrade both natural and synthetic plastic polymers, their host and gut microbes play crucial roles in this process. However, there is still a scientific gap in understanding how the insect adapted to the polystyrene (PS) diet from natural feed. In this study, we analyzed diet consumption, gut microbiota responses, and metabolic pathways of Tenebrio molitor larvae exposed to PS and corn straw (CS).ResultsT. molitor larvae were incubated under controlled conditions (25 ± 1 °C, 75 ± 5% humidity) for 30 days by using PS foam with weight-, number-, and size-average molecular weight (Mw, Mn, and Mz) of 120.0, 73.2, and 150.7 kDa as a diet, respectively. The larvae exhibited lower PS consumption (32.5%) than CS (52.0%), and these diets had no adverse effects on their survival. The gut microbiota structures, metabolic pathways, and enzymatic profiles of PS- and CS-fed larvae showed similar responses. The gut microbiota of larvae analysis indicated Serratia sp., Staphylococcus sp., and Rhodococcus sp. were associated with both PS and CS diets. Metatranscriptomic analysis revealed that xenobiotics, aromatic compounds, and fatty acid degradation pathways were enriched in PS- and CS-fed groups; laccase-like multicopper oxidases, cytochrome P450, monooxygenase, superoxidase, and dehydrogenase were involved in lignin and PS degradation. Furthermore, the upregulated gene lac640 in both PS- and CS-fed groups was overexpressed in E. coli and exhibited PS and lignin degradation ability.ConclusionsThe high similarity of gut microbiomes adapted to biodegradation of PS and CS indicated the plastics-degrading ability of the T. molitor larvae originated through an ancient mechanism that degrades the natural lignocellulose.C96ehShQjSBPouDCMhmhGsVideo Graphical

From source to sea: Floating macroplastic transport along the Rhine river

Rivers are pathways and storage zones for plastic pollution. Land-based plastic waste enters river systems through anthropogenic and hydrometeorological processes, after which they are transported and retained. Only a small fraction (<2%) is assumed to make it into the ocean. Understanding and quantifying river plastic transport are important to optimize prevention and reduction strategies and to evaluate the efficacy of new regulations and interventions. To achieve this, consistent and reliable data are crucial. River plastic pollution monitoring is still an emerging field, especially since river-scale plastic pollution assessments are limited to date. Here, we present an estimate of floating plastic transport and polymer characterization along the Rhine, from Switzerland to the river mouth in Netherlands. We show plastic transport is highly variable along the river, but with a significant increase towards the river mouth. High plastic transport was observed close to urban areas, and confluences with tributaries, suggesting both are likely entry points of plastic pollution. The largest plastic transport was measured in the estuary, which is explained by the tidal dynamics, limiting the transport of plastic into the sea. Our results can be used as a baseline to compare with future assessments. Furthermore, the plastic transport and composition estimates can be directly compared to other rivers that applied the same approach, which may reduce the uncertainty in global river plastic emission simulations. With our study, we aim to contribute to the development of a simple harmonized plastic monitoring approach to quantify plastic pollution at the river basin scale.

Abundance of microplastics in urban lakes of Chennai, India and their possible health risks

Microplastic debris is found all around us, from the food we eat to the water we drink. They primarily originate from macroplastic waste, which breaks down into tiny fragments. In this study, lakeshore sediments and lake water have been identified, characterized, and quantified to investigate the distribution of (MPs) particles. From 44 lakes, the lakeshore sediment and lake water samples have been collected. Fourier-transform infrared spectroscopy and a Leica stereomicroscope were used to identify and visually count microplastic particles. According to the findings, 25 particles in 5 g of dry sediments (d. s.) and 57 particles in 1 l of microplastics have been found on average. At all the sampling locations, microplastics with a size of 1 mm–500 μm were the most prevalent. Based on the FT-IR results, it was found that plastic polymers such as nylon, PE, PS, PVC, PETE, PC, PMMA, PU, and PP were present in lakeshore sediment and water samples. From the present research findings, it is found that the lake water and shore sediments of the study region are polluted by the presence of microplastics of various sizes, shapes, and types, which may pose a risk to the lake ecosystem. From the spatial variation map of lake water and shore sediments, it has been revealed that water supply lakes contains high concentration of MPs. The presence of MPs particles can be lifetime cancer risk among the children and adults on consumption of lake water. This study provides the information on the characteristics, quantification, and health risk assessment of microplastics in surface water environments.

Effect of Phosphorus and Chlorine Containing Plasticizers on the Physicochemical and Mechanical Properties of Epoxy Composites

The possibility of using tris(2-chloroethyl) phosphate, tris(1-chloro-2-propyl) phosphate and tris(4-methylphenyl) phosphate as effective plasticizers for epoxy polymers has been studied. As a result of the research the optimum content of plasticizers (40 parts by mass) has been determined, which has the best effect on the strength and fire safety properties of epoxy composites. Modification of the epoxy polymer with presented plasticizers influences carbonization process increasing char yield and reducing the amount of volatile thermolysis products released into the gas phase, thus improving fire safety parameters of epoxy composites, reducing mass loss on ignition in air from 78 to 2–9% and increasing limiting oxygen index (LOI) values from 19 to 25–31% by volume, giving good fire protective properties to epoxy composites (UL-94 rating—V-0/V-1). The thermo-protective properties and the structure of the char formed by polymer combustion have been studied and the correlation between the thermo-protective properties of the char and the combustibility of the composite has been determined. Furthermore, the behaviour of the modified composite during high rate pyrolysis has been analyzed.

Impedance analysis of PEG plasticized PEO-based composite polymer electrolytes for sodium-ion batteries

Solid-state sodium-ion batteries (SSIBs) will be the next generation batteries due to the high safety, low price, and availability of sodium resources. Composite polymer electrolytes (CPEs) are promising electrolytes because of easy fabrication, good stability, and high flexibility facilitating a good electrolyte-electrode interface, although their ionic conductivities are still unsatisfied. In this work, a CPE made of polyethylene oxide (PEO), Na3Zr2Si2PO12, and NaClO4 has been fabricated. To further enhance the ionic conductivity and a good electrolyte–electrode interface, polyethylene glycol (PEG) is added as a plasticizer. The electrochemical impedance spectroscopy (EIS) demonstrates effect on conductivity by introducing PEG.

Mathematical model of polylactic acid biodegradation under controlled composting conditions

The environment suffers constant damage due to the excessive manufacture of non-degradable materials. Since petroleum-derived plastic polymers degrade slowly, it is necessary to promote the use of biodegradable plastics, such as polylactic acid. Polylactic acid is produced from natural and renewable resources, it has suitable physical and chemical properties, and biodegrades under appropriate temperature and humidity conditions, which are achieved in the composting process. Currently, there are models that are based on the measurement of carbon dioxide, and mass loss, among others. However, there are no models that describe the biodegradation of polylactic acid considering the effect of the influencing factors of the composting process. The objective of this work is to model the dynamics of polylactic acid biodegradation under controlled composting conditions, considering the main influencing factors, such as temperature, moisture content, and oxygen. Using mathematical modeling from ordinary differential equations as a methodology, simulations were carried out based on the degradation of dry matter from different substrates. The results aim to predict the dynamics of polylactic acid biodegradation, through a model that integrates the influencing factors of the composting process.

A novel process to produce stratified structures in food

A method to create stratified structures with static mixing elements initially developed for the plastic polymer industry is investigated here as a new route for structuring food dispersions. Food dispersions of different viscosities were structured with static mixing elements to investigate the potential of the method for foods. Differently coloured chocolates were used as the model products. The viscosity of the chocolate was controlled through the addition of pea fibre. The first step was the formation of 2–8 layers, with the two differently coloured chocolates. Then, the chocolate dispersions were layered into 256 layers with an approximate layer thickness of 60 μm. Layer formation was facilitated when using similar paste viscosity and when slip was induced through wall coating with vegetable oil. Uniaxial cutting tests of the layered chocolate indicated that layering resulted in different mechanical properties, parallel and perpendicular to the layers. Fibre orientation in the direction of flow was observed, resulting in the potential to induce anisotropy, additional to the layers. The higher viscous dispersions, wheat dough and melt cheese, could also be structured into layers, although the force constraints of the experimental set-up were reached. Mid-stream additions were added to produce strand structures instead of layers, resulting in higher hierarchy structures but less uniformity.

Preparation of Nanocellulose Whisker/Polyacrylamide/Xanthan Gum Double Network Conductive Hydrogels

Hydrogels’ poor mechanical and recovery characteristics inhibited their application as a plastic deformable three-dimensional cross-linked network polymer with electrical properties for intelligent sensing and human motion detection. Cellulose has also been added to the hydrogel to enhance its mechanical properties. The hydrogel has been enhanced this way, and the double-network hydrogel has superior recovery and mechanical capabilities. This study used the traditional free radical polymerization method to prepare double-mesh hydrogels, with polyacrylamide as the backbone network, xanthan gum double-helix structure, and Al3+ complex structure as the second cross-linked network, and endowing the hydrogels with good mechanical recovery and mechanical properties. Adding cellulose nanowafers (CNWs) improved the mechanical properties of the hydrogels. The hydrogel could detect body movements and various postures in the same environment. Moreover, the hydrogel has excellent recovery, mechanical properties, and tensile strain; the maximum fracture stress is 0.14 MPa, and the maximum strain is 707.1%. In addition, Fourier infrared spectroscopy (FTIR) of xanthan gum and Xanthan gum—Al3+ were analyzed, and thermogravimetric analysis (TGA) and LCR bridge were used to analyze the properties of hydrogels. Notably, hydrogel-based wearable sensors have been successfully constructed to detect human movement. Its mechanical properties, sensitivity, and wide range of properties make hydrogel a great potential for various applications in wearable sensors.

Thermal evaluation of MHD Jeffrey fluid flow in the presence of a heat source and chemical reaction

In this paper, the flow of an incompressible fluid is thermally studied. Investigations into the heat transfer process have been conducted in non-Newtonian fluid flows with chemical reactions and heat sources present. The application of this work is the fluid flow around the stretching sheet; fluid flow on a stretching sheet can be applied to polymer extrusion, drawing or plastic films, hot rolling, casting and other engineering problems. The novelty of this paper is that the governing equations have been solved by a new and efficient semi-analytical approach, the Akbari–Ganji method (AGM). In order to investigate the issue, the finite element method (FEM) has also been applied. Comparing the results of problem-solving with the applied methods with the results of the previous research shows a perfect agreement. The results show that the parameters of Hartmann number and interaction improve the velocity profiles. Additionally, for greater Hartmann number values, raising the parameter of interaction decreases the temperature value, but a smaller value has the reverse effect. As the Hartmann number increases, the fluid velocity decreases and it shows that with the increase of electromagnetic force, the velocity of fluid flow decreases.

The microscopic threat with a macroscopic impact: Microplastics along the southeast Florida reef tract

Microplastics decrease oceanic water quality and negatively impact marine life. This research quantified and classified marine plastic pollution along the Southeast Florida Reef Tract (SEFRT) to estimate the risk of microplastic damage to corals in this region. Surface and bottom water samples were collected at seven sites along the SEFRT over the course of six months and were analyzed for microplastic content. FTIR spectrophotometry was used to evaluate microplastic composition. Overall, seven plastic polymers were found across a total of 1204 microplastic items. Five contaminants were also identified, indicating that microplastics may be congregators of these hazardous contaminants. Significantly more total plastics were found in surface samples than in bottom samples, but plastic quantities were not significantly different when month, depth, and location were combined. Plastics were determined to have entered the ocean from multiple sources; in order to protect vulnerable reef ecosystems in this area, a two-factor approach is necessary to halt the release of microplastics into the ocean, including widespread plastic clean-up efforts and improvements to plastic waste management.

Single inhalation exposure to polyamide micro and nanoplastic particles impairs vascular dilation without generating pulmonary inflammation in virgin female Sprague Dawley rats

BackgroundExposure to micro- and nanoplastic particles (MNPs) in humans is being identified in both the indoor and outdoor environment. Detection of these materials in the air has made inhalation exposure to MNPs a major cause for concern. One type of plastic polymer found in indoor and outdoor settings is polyamide, often referred to as nylon. Inhalation of combustion-derived, metallic, and carbonaceous aerosols generate pulmonary inflammation, cardiovascular dysfunction, and systemic inflammation. Additionally, due to the additives present in plastics, MNPs may act as endocrine disruptors. Currently there is limited knowledge on potential health effects caused by polyamide or general MNP inhalation.ObjectiveThe purpose of this study is to assess the toxicological consequences of a single inhalation exposure of female rats to polyamide MNP during estrus by means of aerosolization of MNP.MethodsBulk polyamide powder (i.e., nylon) served as a representative MNP. Polyamide aerosolization was characterized using particle sizers, cascade impactors, and aerosol samplers. Multiple-Path Particle Dosimetry (MPPD) modeling was used to evaluate pulmonary deposition of MNPs. Pulmonary inflammation was assessed by bronchoalveolar lavage (BAL) cell content and H&E-stained tissue sections. Mean arterial pressure (MAP), wire myography of the aorta and uterine artery, and pressure myography of the radial artery was used to assess cardiovascular function. Systemic inflammation and endocrine disruption were quantified by measurement of proinflammatory cytokines and reproductive hormones.ResultsOur aerosolization exposure platform was found to generate particles within the micro- and nano-size ranges (thereby constituting MNPs). Inhaled particles were predicted to deposit in all regions of the lung; no overt pulmonary inflammation was observed. Conversely, increased blood pressure and impaired dilation in the uterine vasculature was noted while aortic vascular reactivity was unaffected. Inhalation of MNPs resulted in systemic inflammation as measured by increased plasma levels of IL-6. Decreased levels of 17β-estradiol were also observed suggesting that MNPs have endocrine disrupting activity.ConclusionsThese data demonstrate aerosolization of MNPs in our inhalation exposure platform. Inhaled MNP aerosols were found to alter inflammatory, cardiovascular, and endocrine activity. These novel findings will contribute to a better understanding of inhaled plastic particle toxicity.