Types Of Polymers Research Articles

Epiplastic Algal Communities on Different Types of Polymers in Freshwater Bodies: A Short-Term Experiment in Karst Lakes

The increasing amount of plastic debris in water ecosystems provides a new substrate (epiplastic microhabitats) for aquatic organisms. The majority of research about epiplastic communities has focused on seawater environments, while research is still quite limited and scattered concerning freshwater systems. In this study, we analyze the first stages of colonization on different types of plastic by a periphytic algae community (its composition and dominant species complex) in freshwater bodies located in a nature reserve (within the Middle Volga Basin). A four-week-long incubation experiment on common plastic polymers (PET, LDPE, PP, and PS), both floating and dipped (~1 m), was conducted in two hydrologically connected karst water bodies in July 2023. The composition of periphytic algae was more diverse (due to the presence of planktonic, benthic, and periphytic species) than the phytoplankton composition found in the water column, being weakly similar to it (less than 30%). Significant taxonomic diversity and the dominant role of periphytic algae were noted for diatoms (up to 60% of the total composition), cyanobacteria (up to 35%), and green (including Charophyta) algae (up to 25%). The composition and structure of periphytic algae communities were distinct between habitats (biotope specificity) but not between the types of plastic, determined primarily by a local combination of factors. Statistically significant higher values of abundance and biomass were demonstrated for some species, particularly for Oedogonium on PP and Nitzschia on LDPE (p-value ≤ 0.05). As colonization progressed, the number of species, abundance, and dominance of individual taxa increased. In hydrologically connected habitats, different starts of colonization are possible, as well as different types of primary succession (initiated by potentially toxic planktonic cyanobacteria or benthic cyanobacteria and mobile raphid diatoms). Within the transparency zone, colonization was more active on the surface (for example, in relation to green algae on PP (p-value ≤ 0.05)). These results indicate a tendency for microalgae communities to colonize actively submerged plastic materials in freshwater, and they may be useful in assessing the ecological status of these aquatic ecosystems.

Pedestrian traffic is the main driver of macro- and large microplastic debris deposition in urban stormwater drains

Land-based sources are the greatest contributors of plastic pollution found in aquatic environments. Although plastic debris items spilling into natural watercourses from stormwater outflow sites have been investigated, this study provides details of the plastic items that can be trapped within stormwater drains prior to release. We examined macroplastic (>5 mm) and large microplastic (1–5 mm) debris that accumulated in LittaTrapTM devices at six drains over four seasonal periods in London, Ontario, Canada. Flotation, visual identification, microscopy and Fourier transform infrared spectroscopy (FTIR) were used to determine the drivers of plastic debris deposition. Macroplastics (MaPs) and microplastics (MPs) were identified in all 36 samples, and the totals ranged from 5–158 MaPs and 18–359 MPs per trap. Out of the 118 different MaPs found, the most common items were cigarette butts, wrappers, and expanded polystyrene. The main MPs were fragments, foams, and fibres. The most common macroplastic applications were “smoking”, “food/beverage packaging”, “household”, and non-food or beverage “packaging”. Microplastic particle compositions were mainly polyethylene and polypropylene, but other polymer types fall within the applications of construction (paints and resins), automotive/transportation, and electronics. The summer samples contained the greatest averages of plastic debris, and the drains located in busy pedestrian areas were associated with the highest debris counts. The results support pedestrian traffic as the main driver of plastic debris accumulation in urban London stormwater drains, which is controlled by seasonal weather conditions.

Unveiling the Potential of Ultraviolet Fluorescence Imaging as a Versatile Inspection Tool: Insights from Extensive Photovoltaic Module Inspections in Multi‐MWp Photovoltaic Power Stations

UV fluorescence imaging (UVF) has the potential to grow into a powerful, informative, and economically attractive inspection method for photovoltaic (PV) power stations. UVF demonstrates the ability to indicate differences in polymer types and degradation states in backsheets and encapsulation materials of PV modules. The data acquisition rate of UVF measurements is 10 to 15 times higher than that achieved by state‐of‐the‐art near‐infrared spectroscopy, enabling the mapping of the bill of materials (BoMs) and degradation state for every module in large PV arrays. Combinations of UVF with vibrational spectroscopies allow the polymer BoMs to be recognized and correlated with aging phenomena such as metal corrosion or potential induced degradation. UVF imaging can also be used for conventional visualization of nonmaterial‐related anomalies, such as hot cells or cell cracks. The low purchase cost of the equipment makes UVF an affordable and high‐throughput diagnostic method yielding comprehensive information that would otherwise only be accessible by combining several slower and more laborious methods. Automated UVF image analysis and refinements of correlations between different BoMs and UVF pattern geometry can further unlock the potential of UVF as a straightforward tool accessible to all stakeholders and promote proactive strategies for the optimization of the reliability and performance of PV power stations.

Microplastic diversity increases the abundance of antibiotic resistance genes in soil.

The impact of microplastics on antibiotic resistance has attracted widespread attention. However, previous studies primarily focused on the effects of individual microplastics. In reality, diverse microplastic types accumulate in soil, and it remains less well studied whether microplastic diversity (i.e., variations in color, shape or polymer type) can be an important driver of increased antibiotic resistance gene (ARG) abundance. Here, we employed microcosm studies to investigate the effects of microplastic diversity on soil ARG dynamics through metagenomic analysis. Additionally, we evaluated the associated potential health risks by profiling virulence factor genes (VFGs) and mobile genetic elements (MGEs). Our findings reveal that as microplastic diversity increases, there is a corresponding rise in the abundance of soil ARGs, VFGs and MGEs. We further identified microbial adaptive strategies involving genes (changed genetic diversity), community (increased specific microbes), and functions (enriched metabolic pathways) that correlate with increased ARG abundance and may thus contribute to ARG dissemination. Additional global change factors, including fungicide application and plant diversity reduction, also contributed to elevated ARG abundance. Our findings suggest that, in addition to considering contamination levels, it is crucial to monitor microplastic diversity in ecosystems due to their potential role in driving the dissemination of antibiotic resistance through multiple pathways.

High Charge Carrier Mobility in Porphyrin Nanoribbons.

Polydisperse edge-fused nickel(II) porphyrin nanoribbons have been synthesized by Yamamoto coupling followed by gold(III)-mediated fusion, with average degrees of polymerization of up to 37 repeat units (length 31 nm). Time-resolved optical-pump terahertz spectroscopy measurements indicate that photo-generated charge carriers have dc mobilities of up to 205 cm2 V-1 s-1 in these nanoribbons, exceeding the values previously reported for most other types of nanoribbon or π-conjugated polymer.

Quantitative Examination and Mechanistic Insights of Polymer Chain Conformation Confined in Nanopores by Time-Resolved Fluorescence Resonance Energy Transfer.

The conformational studies of polymers confined at the nanoscale remain challenging and controversial due to the limitations of characterization techniques. In this study, we utilized the high sensitivity of time-resolved fluorescence resonance energy transfer (trFRET) and a site-specific dye-labeling strategy to characterize the conformation of polymer chains confined in anodic aluminum oxide (AAO) nanopores. This strategy introduced a fluorescent donor (carbazole) and acceptor (anthracene) at the center of poly(butyl methacrylate) (PBMA) chains grown by atom transfer radical polymerization (ATRP). By quantitatively analyzing fluorescence decay through the Förster mechanism and the Drake-Klafter-Levitz (DKL) formalism, we can determine both the energy transfer efficiency and the spatial distribution of the dyes. This analysis revealed that the PBMA chains, with a molecular weight of 40 kDa, maintained their bulk-like conformation even when confined within nanopores as small as 10 nm in diameter. This study is the first to demonstrate the use of trFRET for investigating chain conformation in confined polymer systems, which can be generalized to other polymer types and polymer topologies in different confined geometries.

Review and prospect on Metal-organic framework-based Separators for Lithium–Sulfur Battery

With the continuous advancement of technology, wearable smart devices and electric vehicles (EVs) have become an integral part of our daily lives. The increasing demand for energy from these devices and vehicles has driven the pursuit of high-performance rechargeable battery technology. In particular, the widespread adoption of electric vehicles has set higher standards for the energy density and cycle life of batteries. However, the energy density of the widely used lithium-ion batteries is currently limited by the theoretical capacity of commercial cathode materials, and there are certain challenges in terms of safety and cost-effectiveness. Therefore, the development of a new generation of rechargeable batteries with higher energy density, better safety, and more economical cost is particularly urgent. Lithium-sulfur batteries, due to their high energy density, high economic benefits, and high environmental friendliness, are considered to be one of the most promising successors to the widely used lithium-ion batteries. However, in practical applications, the electrochemical performance of lithium-sulfur batteries still needs to be improved. In particular, the poor conductivity of sulfur/lithium and the shuttle effect of polysulfides make the cycle life of the battery less than ideal, and lithium-sulfur batteries (LSB) are still far from achieving large-scale commercialization. The separator used in lithium-sulfur batteries plays a crucial role in its cycle performance and safety. The current commercial separator lacks the ability to effectively regulate the shuttle of polysulfides and is prone to thermal runaway at high temperatures. Therefore, to improve these issues, various functional materials have been used to modify the separator. Among them, as a new type of porous coordination polymer, metal organic frameworks (MOFs) have become a promising material for modifying separators due to their large specific surface area and highly ordered tunable nano-holes.At the same time, their rich inorganic nodes and designable organic ligands allow for the customization of pore chemistry at the molecular level, which can interact with the electroactive components in lithium-sulfur batteries in a tunable manner. This article reviews the reaction mechanism of lithium-sulfur batteries and the structural advantages of MOFs in terms of pore chemistry and morphology and briefly introduces the research progress of MOF-based interfacial layers for the functionalization of LSB separators in recent years. It elaborates on the mechanisms by which various modified separators improve electrochemical performance and provides a prospect for the development prospects of the field.

Classification of black plastic types by hyperspectral imaging based on long-wave infrared emission spectroscopy

Identification of black plastics poses a significant challenge in recycling due to the absorptive nature of carbon black additives. This work introduces a method where hyperspectral imaging in the long-wave infrared regime is used to distinguish between twelve samples of commercially available black plastics encompassing nine distinct polymer types. The spectral scanner comprises a scanning Fabry-Pérot interferometer and a thermal camera based on an uncooled microbolometer detector sensitive to wavelengths from 8 μm to 15 μm. A principal component model is combined with k-nearest neighbors to differentiate between plastic samples in hyperspectral images. The model successfully classifies five (PET, POM, PMMA, PA6, and PA66) out of nine black polymers, and the overall accuracy of the model is A=73.1 %.

Luminescent Multifunctional Nanomaterials: Capacitive Removal and Enhanced Detection Efficiency of Heavy Metals Ions for Advanced Water and Wastewater Treatment Application

AbstractIn recent years, heavy metal ions pollution in the industrialized environment of the societies threaten human health that flaunt ill‐sorted blueprints in freshwater resources obviously. The paradigm of designing luminescent multifunctional nanomaterials finds directions to the strategies of synthesizing cost‐effective, green, and versatile nanomaterials not only for detection, but also removal process of heavy metal ions in large scale applications. Among them, discovering the advances of luminescent multifunctional nanomaterials provides broad types of biomaterials, polymers and porous nanoparticles that grabs focal of investigations over the past several years due to their unique advantages such as enhanced detection efficiency with lowest limit of detection (LOD), minimum ions interference in versatile removal process, fast responsivity and selectivity as outstanding as unique physicochemical properties. This review paper tries to highlight the paradigm of principles for design, development, and utilization of luminescence nanomaterials for considering fundamental detection and removal mechanisms of heavy metal ions. In particular, these nanomaterials increase the remediation quality that are tackled in detail by focusing on opportunities and challenges in the field. Finally, design methods of these nanomaterials and concentrating on empowered detection and removal efficiency for heavy metals ions highlights novel prospective and strategies for largescale applications.

Influence of halloysite nanotubes on processing, structural and thermal properties of poly(vinyl chloride)/high-density polyethylene composites with wood flour

ABSTRACT The aim of this work was to investigate the effect of halloysite nanotubes (HNT) on the processing, structural and thermal properties of poly(vinyl chloride) (PVC), high-density polyethylene (HDPE), and PVC–HDPE composites with various proportions of both polymer components containing 30 wt% wood flour (WF) and 5 wt% halloysite processed in the Brabender measuring mixer. The HNT content in the composites leads to a slight increase in the maximum torque and a reduction in the gelation time for PVC and PVC–HDPE matrix composites with the 90:10 component ratio. In addition, microscopic images of these materials showed a homogeneous distribution of HNT in the polymer matrix. The addition of mineral filler to the matrix, regardless of the polymer type, resulted in a slight increase in the torque values at the kneading endpoint. The PVC–HDPE–wood flour composites are characterized by higher thermal stability at processing temperature when HNT is loaded. The introduction of 5 wt% HNT into the PVC–HDPE 90:10 30 wt% WF blend resulted in an increase of the 2% weight loss temperature by 16°C. The simultaneous use of wood flour and halloysite as fillers for PVC–HDPE blends could be an eco-efficient solution for the new composite material sector.

Effect of Joining Mechanism on the Mechanical Recycling of Polymer–Metal Composite Parts

In order to be able to recycle composite components made of polymer and metal, which are used in the automotive industry, the joints must be broken. The success of the separation is influenced by the stress and also by the joining mechanism between the polymer and the metal. Here, force-fit and form-fit connected components are produced and crushed in a rotor impact mill with two different rotors. The results show that the crushing results differ significantly for the different rotors and for the various joining processes. In short, the hammer-type rotor provides much finer and better-separated fragments and the force-fit joints enable a better separation of metal and polymers. The additional cooling of the samples also changes the result in a way, where deep cooling significantly improves the separation of the metal and the polymer. Different types of polymers also led to a different separation result with both rotors.

Advances and Challenges of Microneedle Assisted Drug Delivery for Biomedicals Applications: A Review.

Microneedles have been explored as a novel way of delivering active ingredients into the skin. They have various advantages, such as quick and efficient drug delivery, mechanical stability, minimal pain, variable capacity and easy use. Microneedles are enabled for the delivery of vaccine, peptides, medicinal components and in cosmetology, which couldn't go unnoticed. The novel approaches in the transdermal drug delivery system have increased the efficiency of drug delivery into the skin by crossing the skin barriers. This platform has a wide range of applications and can also be used to deliver non-transdermal biomedicals. The variety in the design of microneedles has demanded similar diversity in their methods of fabrication; micro molding and drawing lithography may be useful methods. There are different types of polymers and materials for the fabrication of microneedles. Several synthetic and natural materials are used in the fabrication of microneedles. Unique shapes, materials, and mechanical properties are modified for organ-specific applications in microneedle engineering. In this review, we discuss several factors and their roles to cross the biological barriers for transdermal drug delivery in various sites, such as in ocular, vascular, oral, and mucosal tissue. Additionally, this article highlights the future scope of transdermal drug delivery systems through microneedles.

Humidity Sensing Using Polymers: A Critical Review of Current Technologies and Emerging Trends

In the post-pandemic era, human demand for a healthy lifestyle and a smart society has surged, leading to vibrant growth in the field of flexible electronic sensor technology for health monitoring. Flexible polymer humidity sensors are not only capable of the real-time monitoring of human respiration and skin moisture information but also serve as a non-contact human–machine interaction method. In addition, the development of moist-electric generation technology is expected to break free from the traditional reliance of flexible electronic devices on power equipment, which is of significant importance for the miniaturization, reliability, and environmentally friendly development of flexible devices. Currently, flexible polymer humidity sensors are playing a significant role in the field of wearable electronic devices and thus have attracted considerable attention. This review begins by introducing the structural types and working principles of various humidity sensors, including the types of capacitive, impedance/resistive, frequency-based, fiber optic, and voltage-based sensors. It mainly focuses on the latest research advancements in flexible polymer humidity sensors, particularly in the modification of humidity-sensitive materials, sensor fabrication, and hygrosensitivity mechanisms. Studies on material composites including different types of polymers, polymers combined with porous nanostructured materials, polymers combined with metal oxides, and two-dimensional materials are reviewed, along with a comparative summary of the fabrication and performance mechanisms of related devices. This paper concludes with a discussion on the current challenges and opportunities faced by flexible polymer humidity sensors, providing new research perspectives for their future development.

Potential ecological risk assessment of microplastics in environmental compartments in Mexico: A meta-analysis.

Microplastic (MP) environmental contamination has been widely studied in Mexico; however, the evaluation of the associated risk to MP in environmental compartments is scarce. Therefore, this study addresses this issue using diverse indicators such as the Pollution Load Index (PLI), the Polymer Risk Index (PRI), and the Potential Ecological Risk Index (PERI). The results of a meta-analysis revealed high MP contamination levels in most of the studied compartments, which included marine and estuarine waters, beach sand, freshwater, sediments, and biota. Regarding the risk assessment indicators, PLIs indicated low (56%), dangerous (22%), moderate (12%), and high (10%) levels across compartments. Meanwhile, PRIs displayed concerning values, with 36%, 35%, 20%, and 9% exhibiting dangerous, high, moderate, and low levels, respectively. Thus, high PRI values emphasized the significant rise in MP pollution, largely attributed to high-hazard polymer compositions. Otherwise, PERIs showed low (56%), very dangerous (29%), moderate (6%), high (5%), and dangerous (4%) levels. Thus, the ecological risk in Mexico is widespread and mainly linked to MP abundance, polymer type, environmental matrix, and organisms' characteristics. This study represents the first attempt at MP ecological risk assessment in Mexico, providing crucial insights for developing mitigation strategies to address concerns about MP contamination.

Does short-span chemical oxidation induce more weathering than prolonged thermal aging on polypropylene microplastics? Its consequence during the interaction with cadmium

Weathering and degradation of plastics in the environment are evident in almost all conditions. However, the difference is the changes in the polymer properties, which varies with the aging mechanism, polymer type, and other prevailing environmental conditions. Aging is an essential factor that further determines the fate and transportation of smaller plastics. Apart from UV radiation for microplastics (MPs) aging, other mechanisms also play a crucial role in changing the physicochemical properties of polymers in natural environments. Other aging mechanisms, such as chemical and thermal oxidation, were used in this study. Also, thermally stable and chemical resistant polypropylene MP is used in this study to understand the oxidation mechanisms and to know the breakpoint where it becomes susceptible to the reactions. From the results, the aged MPs showed roughness, pore formation, and cracks on the surface; more specifically, PP MPs were more weathered during thermal oxidation, revealed in both physicochemical characterizations of MPs. However, the chemical oxidation reached almost half the aging of the thermal process within a short period. The additives in the PP MPs make it resistant to the treatment, where it takes time to break during the thermal treatment, which was contradictory with Fenton aging. Further, the adsorption study was conducted to determine its interaction with Cd2+ and which aged MPs adsorb more. It can be concluded that PP MPs are more vulnerable towards chemical aging within a short duration, but it takes time to stimulate weathering under increased temperature.

Significant effects of Rural Wastewater Treatment Plants in Reducing Microplastic Pollution: A Perspective from China's Southwest Area

Sewage systems are a major source for microplastics in riverine exports to oceans. Urban areas are generally considered hotspots for microplastic discharge, whereas emissions from rural areas remain largely understudied. Hence, this study investigated the abundance, characteristics, and polymer types of microplastics in rural wastewater treatment plants (WWTPs) in Guiyang and estimated the annual microplastic emissions of China based on sewage discharge. The influent abundance of microplastics was 3.8-8.2 items/L, the effluent abundance was 3.1-5.9 items/L, with a lower removal rate of 14.4%-54.6%, which might be influenced by lower operating loads and influent concentrations. Raman spectroscopy analysis revealed that polyvinyl alcohol (PVA) was the predominant polymer type. Rural WWTPs were more effective at removing large-sized particles (> 0.1mm) and films, resulting in higher removal effectiveness by weight (49.1%) compared to urban WWTPs (30.8%). Based on the abundance of microplastics in WWTPs within the study area and China's annual sewage discharge, this study estimated the microplastic emissions released through sewage in China in 2022. The annual microplastic emissions through sewage in China were estimated to be 2995.7 tons, with rural and urban areas contributing 25.1% and 74.9%, respectively. Approximately 724.8 tons and 1001.6 tons of microplastics were removed from rural and urban WWTPs, respectively. This work indicates the unignorable emissions of microplastics from rural sewage and highlights the crucial role of rural WWTPs in reducing microplastic pollution.

Organ-specific bioaccumulation of microplastics in market fish of Dhaka and size-dependent impacts of PVC microplastics on growth of Anabustestudineus

Microplastics (MPs), a growing environmental concern with potential ecotoxicological risks, are ubiquitous in aquatic environment. This study investigated the organ-specific distribution and variation of MPs in commercially caught fishes (7 species, 140 individuals) collected from Dhaka's two main fish distribution hubs (Uttara and Jatrabari). Additionally, the impact of different-sized MPs on fish growth (Anabas testudineus) was examined in a control experiment. Results revealed that kidneys of market fish bioaccumulated the highest concentration of MPs (average, 59.1 MPs/g), followed by liver (24.6 MPs/g) and intestine (18.6 MPs/g). On average, fish from Uttara had a higher MPs concentration (36 MPs/g) compared to Jatrabari (25 MPs/g). Among fish species, Glossogobius giuris showed the highest MPs bioaccumulation due to its feeding habits and morphology. Fiber-shaped MPs were most prevalent in all fishes (79–93%) except Glossogobius giuris (fragments, 51%). Fourier-transform infrared spectroscopy (FTIR) analysis identified 19 different polymer types, with high density polyethylene (HDPE), ethylene vinyl acetate (EVA) and polyamide (PA) being commonly found in all organs. The experimental study confirmed that large-sized PVC MPs (1.18 mm-300 μm) had a greater negative impact on fish growth (length) and caused more physical deformities (particularly intestinal injuries) compared to small-sized PVC MPs (150 μm–75 μm). Moreover, fish exposed to larger diameter MPs experienced highest physical weight and depth loss among exposed groups. Large-sized PVC MPs bioaccumulated highest in fish compared to small-sized PVC MPs. Similar to market fish, kidney in the experimental fish had the highest MPs bioaccumulation (6.5 MPs/g), followed by liver (5.2 MPs/g) and intestine (4.8 MPs/g), with a dominance of fibers despite the presence of high concentration of fragments in the food source. Statistical analysis also supported a clear correlation between increasing MPs size and adverse effects on fish growth and health. Urgent action is needed to curb microplastic pollution and protect ecosystems and human health.

Unveiling the Impact of Absorbent Polymers on Self-healing Efficiency of Sludge-derived Capsules in Cementitious Composites

A novel green capsule for self-healing cementitious material using a combination of waste-based materials with an inorganic substance was developed. A mix of alum sludge (AS), a typical waste from the water industry, and calcium hydroxide were used as the primary healing agents. Also, two types of natural and synthetic absorbent polymers (AP), microcrystalline cellulose (MCC) and sodium polyacrylate (SPA), were added to the core mixture to assess their impact on the healing efficiency. The morphology of the produced capsules, the self-healing proficiency of cracked mortars, and the resulting healing materials were characterised. Outcomes revealed that cracks up to 400µm could be healed by the plain capsule. The closure width was dramatically increased to 500µm and 800µm with the inclusion of MCC and SPA, respectively, mainly in 3 days. The expansion, water retention, and bridging properties of the APs enhanced the sealing performance of the capsules by providing nucleation sites and increasing the reaction rates of core materials to generate further calcium-based products inside the cracks. Therefore, higher recovery rates of mechanical strengths, along with a significant reduction in water ingress were achieved. The main healing products were identified as calcite crystals, C-S-H, calcium silicate, and aluminium-bearing phases.

Development of 3D-Printed Two-Compartment Capsular Devices for Pulsatile Release of Peptide and Permeation Enhancer.

The oral absorption of a peptide is driven by a high local concentration of a permeation enhancer (PE) in the gastrointestinal tract. We hypothesized that a controlled release of both PE and peptide from a solid formulation, capable of maintaining an effective co-localized concentration of PE and peptide could enhance oral peptide absorption. In this study, we aimed to develop a 3D-printed two-compartment capsular device with controlled pulsatile release of peptide and sodium caprate (C10). 3D-printed two-compartment capsular device was fabricated using a fused deposition modeling method. This device was then filled with LY peptide and C10. The release profile was modulated by changing the thickness and polymer type of the capsular device. USP apparatus II dissolution test was used to evaluate the impacts of device thickness and polymer selection on release profile in vitro. An optimal device was then enteric coated with HPMCAS. A strong linear relationship between the thickness of capsular devices and the delay in the release onset time was observed. An increase in the device thickness or the use of PLA decreased the release rate. The capsular device with compartment 1, compartment 2 and fence thickness of 0.4; 0.95 and 0.5mm, respectively, and the use of PVA achieved desired pulsatile release profiles of both peptide and C10. Furthermore, enteric-coated capsular devices with HPMCAS had similar pulsatile release profiles compared to non-enteric coated devices. These findings suggest potential application of 3D-printing techniques in the formulation development for complex modified drug release products.

Microplastics in indoor and outdoor environments in China: characteristic and human exposure risk assessment

Human exposure to microplastics (MPs) has led to global health concerns, but our knowledge of the characteristics and human exposure of airborne MPs is limited. Adults may have different exposure patterns and lifestyles from other age groups. Therefore, this study aims to determine the MPs exposure among adults at various locations and during different time periods. MPs were collected and detected through passive sampling and laser direct infrared (LDIR) imaging (Agilent 8700) at five locations including: dormitory, dining hall, office, library, and outdoor; the sampling lasted for 3 months. The highest concentration of indoor MPs was detected in the dining hall (193 ± 8 MPs/m2/day), whereas the lowest was detected in the library (113 ± 4 MPs/m2/day). Among all sampling points, the outdoor locations had the lowest MPs concentrations (92 ± 4 MPs/m2/day). The length of the MPs ranged from 10 μm－760 μm. Pellets (54.6%), fibres (21.6%), and fragments (23.8%) were the shapes identified in this research. Polyamide (51.7%) was the most prevalent polymer type at all sampling points. This article conducted respiratory exposure assessments of MPs for males and females of different ages (age ranges: 18－21; 21－30; 31－40; 41－60) in different environments and at different times. For both weekends and weekdays, dormitories contributed the most to MPs respiratory exposure. Males aged 31－40 years had the highest exposure with an average of 266 particles/day, whereas females aged 18－21 (157 particles/day) had the lowest exposure. Differences in respiratory rate according to age and gender may be the main reason for these results. These findings indicate that further research into the adult MPs inhalation exposure under indoor and outdoor conditions is crucial.