Polystyrene Polymer Research Articles

Lead-Free Inorganic Nanoparticles of Perovskite Embedded within Waterproof Nanofiber Films for White Color Emission

Organic polymers can enhance the environmental stability of inorganic perovskite nanocrystals (IPNCs) by encapsulation. We fabricated lead-free IPNCs embedded in waterproof and luminous polymer fibers. The encapsulated perovskite nanocrystals within polystyrene (PS) polymers, CsCu2I3@PS (Y-fiber), and Cs3Cu2I5@PS (B-fiber) were prepared by one-step electrospinning of the solutions containing the precursors (CsI and CuI) and PS. The embedded nanocrystals had highly uniform sizes, spatial distribution, and well-developed crystal structures. The Y- and B-fibers showed yellow and blue emission under ultraviolet (UV) light, respectively, and a white emission fiber layer was fabricated via dual-nozzle coelectrospinning using CsCu2I3 and Cs3Cu2I5 precursor solutions. The as-prepared B-fibers exhibited improved water stability without changing the crystal structure and photoluminescence (PL) emission in deionized water for 20 days. To enhance environmental stability and mechanical properties, transparent poly(dimethylsiloxane) (PDMS) films containing IPNCs@PS fibers presented strong PL emission without peak shift under 100% tensile strain, indicating highly flexible and humidity-durable characteristics.

Thermal and Thermal-Oxidative Molecular Degradation of Polystyrene and Acrylonitrile Butadiene Styrene during 3D Printing Starting from Filaments and Pellets

An important polymer processing technique is additive manufacturing (AM), which enables shape-free design of complex final parts with limited waste during the development change, at least if the impact of molecular degradation reactions is minimized. In the present work, polystyrene (PS) and acrylonitrile butadiene styrene (ABS) polymer have been processed via: (i) fused filament fabrication (FFF), separately accounting for the prior single screw extrusion (SSE) filament production; and (ii) pellet-based additive manufacturing (PBAM), which are two important AM techniques. The influence of printing temperature, layer thickness, printing velocity, and printing technique on the degradation of both polymeric materials is studied by means of thermogravimetric analysis (TGA), size exclusion chromatography (SEC), small amplitude oscillatory shearing tests (SAOS), Fourier-transform infrared spectroscopy (FTIR), and yellowness index (YI) measurements. For ABS, SSE-FF leads to more fission (higher mechanical loading) whereas PBAM results in more cross-linking (more thermal loading). For PS, fission is always dominant and this more evident under FFF conditions. ABS also exhibits yellowing upon processing, indicating thermo-oxidative degradation although below the FTIR sensitivity limit. The selected PBAM conditions with PS are already delivering printed specimens with good mechanical properties and lower degradation. For ABS, a further PBAM optimization is still desired compared to the FFF countercase, taking into account layer-by-layer adhesion.

Hybrid Polymer Composites Based on Polystyrene (PS) Used in the Melted and Extruded Manufacturing Technology.

As part of the work, innovative hybrid polymer composites dedicated to rapid prototyping, especially for 3D printing with the melted and extruded manufacturing (MEM) technique, were developed. For this purpose, the influence of modified fillers, such as alumina-modified silica, bentonite modified with quaternary ammonium salt, and lignin/silicon dioxide hybrid filler, on the functional properties of polystyrene-based composites was investigated. The introduced additives were selected to improve the processing properties of polystyrene (PS), in particular its thermal stability, while maintaining good mechanical properties. In the first part of the work, using the proprietary technological line, filaments from unfilled PS and its composites were obtained, which contain modified fillers in the amount of 1.5% to 3.0% by weight. Samples for testing functional properties were obtained by 3D printing in MEM technology and injection technique. The rheological properties-mass melt flow rate (MFR), viscosity, and mechanical properties-are presented in the further part of the work. The size and the respective dispersion in the polystyrene polymer matrix of the fillers used were determined by scanning electron microscopy with energy dispersion spectroscopy (SEM/EDS). The correct dispersion of additives in PS was also confirmed by wide-angle X-ray analysis (WAXS). A significant improvement in the thermal stability of the obtained composites after the introduction of fillers into the polymer matrix was confirmed on the basis of thermogravimetric analysis (TGA). The remaining tests of physicochemical properties, differential scanning calorimetry (DSC), and infrared spectroscopy with Fourier transform (FT-IR) allowed us to state no significant changes in relation to polystyrene. The obtained test results allowed us to conclude that the amount and type of fillers used in the PS polymer matrix significantly affect the performance properties of the tested hybrid composites. The composites obtained as part of the work can be successfully used in rapid prototyping technologies, especially for the production of details originally designed from PS, which are required to have higher thermal stability than is guaranteed only by the polymer matrix.

Microplastic contamination and microbial colonization in coastal area of Busan City, Korea

This study investigated the potential role of the concentration, shape, size, and polymer type of microplastics (MP), in addition to the microbial community in six coastal areas of Busan city, South Korea. The results showed that the average MP concentration was 94 ± 41 particles·m-3, and particles sized 20 μm –300 μm accounted for 67.5 ± 9.6% of the total MP abundance throughout the study sites. Further, polyethylene (PE), polypropylene (PP), and polystyrene (PS) polymers were abundant among the collected fragment- and fiber-shaped MPs, implying that highly populated and industrialized areas are major sources of MPs contamination. Moreover, the bacterial diversity and taxa-based on 16S rRNA gene sequencing was significantly different between MPs and seawater (SW) samples. Specifically, Psychrobacter, Pseudomonas, Flavobacterium, and Winogradskyella were significantly enriched in MPs compared with SW (p <0.05). Redundancy analysis revealed that nutrient concentrations, salinity, and temperature potentially contributed to shaping the microbial communities on MPs. These results indicate the dynamic and complicated interactions of MP contamination with the physiochemical and environmental factors of the surrounding area. Our findings would help in understanding of MP contamination levels in marine environments and their characteristics, as well as bacterial colonization on plastics in urban coastal areas of Busan, South Korea.

Thermodiffusion of polymer solutions and colloidal dispersions in mixed solvents.

Two-color optical measurements of thermodiffusion in ternary mixtures frequently suffer from ill-conditioned contrast factor matrices, whose inversion leads to very large experimental errors. In this contribution, we show how the error amplification can be avoided in situations where a priori knowledge about the directions of the eigenvectors of the diffusion matrix is available. We present optical beam deflection experiments on solutions of the polymer polystyrene of Mw = 4880g/mol in a mixed solvent of toluene and cyclohexane. In this system, the two diffusion eigenvalues differ by almost one order of magnitude. The large eigenvalue can be attributed to the interdiffusion of the two solvents and the small one to the polymer diffusion relative to the mixed solvent. The pre-selection of the eigenvectors renders the method stable against fluctuations of the experimental parameters. Both the diffusion and the Soret coefficients attributed to the two modes agree very well with the respective values of corresponding binary mixtures.

Influence of Polymer Size on Polystyrene Biodegradation in Mealworms (Tenebrio molitor): Responses of Depolymerization Pattern, Gut Microbiome, and Metabolome to Polymers with Low to Ultrahigh Molecular Weight.

Biodegradation of polystyrene (PS) in mealworms (Tenebrio molitor lavae) has been identified with commercial PS foams. However, there is currently limited understanding of the influence of molecular weight (MW) on insect-mediated plastic biodegradation and the corresponding responses of mealworms. In this study, we provided the results of PS biodegradation, gut microbiome, and metabolome by feeding mealworms with high-purity PS microplastics with a wide variety of MW. Over 24 days, mealworms (50 individuals) fed with 0.20 g of PS showed decreasing removal of 74.1 ± 1.7, 64.1 ± 1.6, 64.4 ± 4.0, 73.5 ± 0.9, 60.6 ± 2.6, and 39.7 ± 4.3% for PS polymers with respective weight-average molecular weights (Mw) of 6.70, 29.17, 88.63, 192.9, 612.2, and 1346 kDa. The mealworms degraded most PS polymers via broad depolymerization but ultrahigh-MW PS via limited-extent depolymerization. The gut microbiome was strongly associated with biodegradation, but that with low- and medium-MW PS was significantly distinct from that with ultrahigh-MW PS. Metabolomic analysis indicated that PS biodegradation reprogrammed the metabolome and caused intestinal dysbiosis depending on MW. Our findings demonstrate that mealworms alter their gut microbiome and intestinal metabolic pathways in response to in vivo biodegradation of PS polymers of various MWs.

Fate of microplastics during composting and their leachability

The occurrence of chemical compounds specific to individual plastic polymers allowed the determination of components in compost feedstock (urban greenery and bio bins of households). The total concentration of plastic polymers is 431 mg/kg. The main identified polymers are polystyrene, polyethylene terephthalate, polyethylene, polycarbonate, and polypropylene. Additives used to modify the properties of plastics are present in the concentration of 195 mg/kg. Twelve compounds used as additives in the production of plastics in both the feedstock and the compost were identified. A statistically significant relationship was found between the decrease of concentration of organic matter and concentrations of compounds that identify plastic polymers (polyethylene terephthalate and polystyrene). The decrease of concentrations of compounds specific to polymers after three months was observed in the range between 33 and 84%, while the decrease for additives was 68%. After 18 months, the loss was higher than 82% except for polypropylene (only 70%). Compound leachability after three months of composting decreased to one-quarter for most polymers (except polypropylene and polyethylene), and to one-third for additives.

Rationalizing the Effect of Polymer-Controlled Growth of Perovskite Single Crystals on Optoelectronic Properties.

To improve and modulate the optoelectronic properties of single-crystal (SC) metal halide perovskites (MHPs), significant progress has been achieved. Polymer-assisted techniques are a great approach to control the growth rate of SCs effectively. However, the resultant optoelectrical properties induced by polymers are ambiguous and need to be taken into the consideration. In this study, we have synthesized methylammonium lead triiodide (MAPbI3) SCs using polyethylene glycol (PEG) and polystyrene (PS) polymers where PEG contains oxygen functionalities and PS does not. We studied the electrical properties of these SCs under dark and illumination conditions. It was observed that PEG-assisted SCs showed few defects with lower photocurrent as compared to the PS-assisted ones because of defect-mediated conductivity. The results are further verified by transient current response, responsivity, and capacitance–frequency measurements. The present study sheds light on the polymer selection for the growth of MHP SCs and their optoelectronic properties.

Polivinilklorür/Polistiren Karışımlarına Uyumlaştırıcı Etkisinin Viskozimetrik İncelenmesi

In this study, polyvinyl chloride (PVC) and polystyrene (PS) polymers, which do not form a compatible blend with each other in certain concentration ranges and are widely used on an industrial scale, were used. The concentration range in which these two polymers do not form a compatible blend were determined viscometrically, and maleic anhydride-styrene (MAS) copolymer was added as a compatibilizing agent in this concentration range. The concentration range in which the polymer pair did not form a compatible blend was determined as 1.5 and 2.0 g dL-1. In this concentration range, 5.0 and 10.0 % MAS copolymer was added to the polymer couple and its compatibilizing effect was investigated. It was determined by viscometric method that the MAS copolymer was a good compatibilizer in the range where the polymer pair did not form a compatible blend.

A 75-year history of microplastic fragment accumulation rates in a semi-enclosed hypoxic basin

Plastic budgets in the marine environment and their long-term trends are yet to be fully understood. Measuring the accumulation rates in bottom sediments is crucial to solving the riddle of missing ocean plastics. Previous studies based on coastal sediment cores have found that accumulation rates have increased with increases in plastic production and/or regional populations. However, the correlations between the rates and bioactivities or ocean dynamics, which are crucial for modeling the microplastic sinking process, have not been examined. We revealed a 75-year microplastic fragment (0.3–5.0 mm) accumulation rate history in a hypoxic basin, Beppu Bay, Japan, based on multi-core analysis and 210Pb dating of the sediment which was cross-checked by time control with 137Cs radioactivity peaks. We found that a long-term linear increasing trend with an approximately 20-year variation overlapped with significant peaks around 1990 and 2014 with the first polypropylene microplastic fragment detected from a 1958.8–1961.0 CE sediment layer. The maximum rate was 203 pieces m−2 y−1 with an abundance of 86 pieces kg−1-dry in 2014. Smaller fragments in the size range of 0.3–2.0 mm have been consistently dominant in terms of the accumulation rate throughout the 1955–2015 period, accounting for 85.3 % of the total accumulation rate. The three major polymers (polyethylene, polypropylene, and polystyrene) accounted for 96.6 % of the total rate. The rate was highly and positively correlated with the chlorophyll-a accumulation rate and concentration in the sediment. Based on the microplastic accumulation rates and concentration in the seawater, the mean sinking velocity of microplastics was estimated to be in the order of 101 m d−1. Our results will contribute to significant progress in modeling the microplastic sinking process by offering the first field measurement-based mean sinking velocity and significant correlations between the rate and bioactivity-related signals.

Fabrication and Characterization of Nanozeolite-Modified High Impact Polystyrene (HIPS) Membranes for Nanofiltration

The present study utilized high-impact polystyrene, a polymer with good mechanical, thermal and chemical stability, for its potential as a filter material and matrix for nanozeolite – a well-known adsorbent for wastewater treatment. Different concentrations of nanozeolite (0.25%, 0.5%, and 0.75%) were added to the high-impact polystyrene matrix and were fabricated intocomposite membranes via hand-casting method. The membranes were characterized using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, and Contact Angle Goniometer to discuss their functionality in the removal of nanocontaminants from wastewater like dyes. Results showed that nanozeolite can control the porosity and pore size of the High-impact polystyrene polymer while also improving its hydrophilicity; these are important considerations in the removal of organic dyes from wastewater.

Microplastics in the Surface Sediment of the main Red River Estuary

Microplastics (< 5mm) are one emerging pollutant in the environment. These are the threats and challenges facing the global environment, economy, and society, especially in hotspot regions such as Asia. This paper presents the microplastic characteristics found in the surface sediment of the main Red River estuary (the Ba Lat) during four separate monitoring runs in 2020. The microplastic amount in the sediment samples varied from 800 items per kg of dried weight (dw) to 3,817 items.kg-1 dw, averaging 2,188 ± 1,499 items.kg-1 dw. Fiber and fragment microplastics were discovered to be primary shapes, of which fibers dominated (94%). Microplastic fiber sizes were found mainly in the < 500 µm (69%) range. The most primarily observed colors of microplastics were blue (36%), white (21%), and red (11%). There were five recognized polymer types (polypropylene (PP), polyethylene (PE), polyurethane (PU), polyamide (PA), and polystyrene (PS)) in the sediment samples, with PE and PP predominating. Seasonal fluctuations in microplastic concentrations at the Ba Lat site, a significant aquaculture zone, may indicate the contribution of multiple sources. Our research demonstrated the necessity of microplastic observation in organisms, particularly in the aquaculture zones in Vietnam. Our findings further underline the importance of managing and minimizing the amount of plastic garbage that enters the ecosystem.

Modified polymer nanopillars array for enhanced light trapping on large area

ABSTRACT Electroless plating is used to enhance the strength of anodised aluminium oxide (AAO) which can be further utilised as a mould to fabricate the structures on large area of polymer for anti-reflection properties. Nanopillars of high aspect ratio are fabricated on polymer (polystyrene) sheet by hot embossing process which has ensured repeatability with precision and high throughput. The height of nanopillars matches the depth of the mould cavity. The enhanced light trapping performance is attributed to the high aspect ratio nanopillars with cup-shaped top surface.

Improving asphalt concrete resistance to rapid freeze–thaw effect using HIPS polymer

Two methods of high-impact polystyrene (HIPS) polymer addition to asphalt concrete (AC) mixtures were used to evaluate the effect of freeze–thaw (FT) cycles on the performance of unmodified AC and AC modified by using supplementary and additional HIPS polymer as asphalt aggregates. Various polymer contents were used to modify AC in both methods – namely, 0 (control), 5, 10, 15 and 20%. Marshall stability, flow, bulk density and indirect tensile strength (ITS) tests were performed on control and modified samples. A non-destructive test was performed by using the ultrasonic pulse velocity method. In the first method, replacing the mineral filler in AC with 10% HIPS polymer increased the density by 1%, the stability by 113%, the retained stability by 52% and the ITS by 56% compared with those of the control specimen. The results also show a 14% reduction in the damage caused by 8 weeks of FT cycles for modified AC compared with that of unmodified AC. However, modifying AC by using the second method did not provide promising results. The velocity within the specimen dropped by 20.9% at 10% HIPS addition before the FT effect compared with that of the control. The results of the first method revealed the feasibility of improving AC by using HIPS polymer to resist effective FT cycles.

UV curing-assisted 3D plotting of ceramic feedstock containing thermo-regulated phase-separable, photocurable vehicle for dual-scale porosity structure

We propose a novel approach for manufacturing dual-scale porosity alumina structures by UV curing-assisted 3D plotting of a specially formulated alumina feedstock using a thermo-regulated phase separable, photocurable camphene/triethylene glycol dimethacrylate (TEGDMA) vehicle. In particular, 3D plotting process was conducted at - 5 °C, and thus an alumina suspension prepared using liquid camphene/TEGDMA at room temperature could undergo phase separation, resulting in camphene crystals surrounded by walls comprised of liquid photopolymer enclosing alumina particles. To enhance the shape retention ability of extruded filaments, polystyrene (PS) polymer was used as the tackifier . The phase-separated feedrod could be extruded favorably through a nozzle and rapidly photopolymerized by UV light during the 3D plotting process. Thr ee-dimensionally interconnected macropores were tightly constructed, which were separated by microporous alumina filaments, where micropores were created by the removal of camphene crystals via freeze-dying. The macroporosity of porous alumina ceramics was controlled by adjusting the distance between deposited filaments, while their microporosity was kept constant, leading to tightly tailored overall porosity and mechanical properties.

MODIFICATION OF WASTE POLYSTYRENE AND INVESTIGATION OF ITS CONDUCTIVE CHARACTERISTICS WITH THE ADDITION OF ANTHOCANDIEN PIGMENT DERIVED FROM EGGPLANT PEEL

Anthocyanin dye was produced from eggplant peels in this study, and the influence of this dye on the electrical characteristics of polystyrene polymer was investigated. The conventional casting procedure was used to create thin films. The materials employed in these films were investigated using FTIR infrared spectroscopy, and if the results showed the presence of effective aggregates within the measured region, the chance to study the feature of voltage and current using the Keithley Series 2400 Source was given. It demonstrated a rise in current with rising voltage, indicating ohmic behavior, and the electrical conductivity value is 4.7*10- 12

Fabrication of hierarchically porous silicon carbonitride monolith using branched polysilazane and freeze casting method without crosslinking step: Effect of polymer additive to aligned macropore structure

AbstractA hierarchically porous SiCN monolith with aligned macropores was prepared using a branch‐structured polysilazane, silsesquiazane (SSQZ), as a precursor and polymer additive, through the freeze casting method. As polymer additives, polystyrene (PS) and poly(methyl methacrylate), which have different compatibilities with SSQZ, were used to confirm the effect on the pore formation. In addition, the pore formability according to the molecular weight was investigated using PSs with different molecular weights. When the SSQZ and high‐molecular‐weight PS (HPS) were used, a porous SiCN with micro/meso/macropore structure could be fabricated because of the structural stability of the SSQZ and high molecular weight of HPS. The hierarchically porous SiCN monolith was successfully manufactured using SSQZ and HPS with 639 m2/g of specific surface area, 0.36 cm3/g of pore volume, and 2.1 nm of average pore size. The hierarchically porous SiCN monolith with high HPS content has improved dimensional stability to show its compressive fracture energy.

Polymer‐Bound Halogen Bonding Organocatalysis**

AbstractNoncovalent organocatalysts utilizing halogen bonding have emerged in the last decade as efficient alternatives to more established hydrogen bonding donors. However, currently they often cannot be recycled and, in some cases, even stoichiometric amounts need to be used. Herein, we present the first generation of recyclable, polymer‐bound halogen bonding catalysts which are able to catalyze a halide‐abstraction reaction. To this end, bis(benzimidazolium)‐based halogen bonding units were attached to a polystyrene polymer, yielding insoluble catalysts. These could be recycled up to three times with little loss in catalytic activity. The overall performance of the catalysts is comparable to that of a free (non‐polymer‐bound) halogen bond donor. Interestingly, catalysts featuring a preorganized and a non‐preorganized halogen bond donating unit showed comparable activity, in contrast to the situation of the free donors. This proof‐of‐principle study provides the basis for further steps towards more sustainable halogen bonding organocatalysts.

Enhanced settling of microplastics after biofilm development: A laboratory column study mimicking wastewater clarifiers

The settling of microplastics (MPs) is crucial for their removal from municipal wastewater treatment plants (WWTPs) and sedimentation in static waterbodies, where they can accumulate in bottom sediments. Biofilm formation on MPs enhances their aggregation with other particles, thereby changing their density and size and altering their settling rates. However, only a few studies have investigated the settling of MPs of different sizes and materials. Specifically, the settling of small-sized MPs (<150 μm) has been poorly documented. In this study, cylindrical and fragmented particles of four polymer types (high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), and poly(ethylene terephthalate) (PET)) were used to investigate the settling or floating of reference MPs (20–130 μm) in a custom-made column that simulated a primary sedimentation tank in a typical WWTP before and after incubation in wastewater influent. The settling velocity of the reference MP particles was strongly influenced by the particle size and density. The settled fractions of all the cylindrical reference MPs increased significantly (up to 5 times) due to biofilm formation at overflow velocities of 0.15, 0.26, and 0.40 mm s−1. This was observed even for HDPE and PP (density <1 g cm−3) after biofilm formation. The fragmented reference MPs showed complex and rather unpredictable behavior, possibly due to their irregular shape. Generally, the settling of pristine PS and PET in the laboratory tests was consistent with the theoretical predictions obtained using Stokes’ law. The experimental findings of this study can be used to develop models that predict the removal efficiencies of MPs in WWTPs and to estimate the sinking of MPs to bottom sediments of static waterbodies.

Manganese phosphide nano-clusters embedded in a polystyrene matrix

A procedure is reported to obtain MnP nanoparticles in powder form or embedded within a polymer (polystyrene) matrix, referred to as Ps:MnP. Ps:MnP nanoaggregates are obtained starting from bulk crystalline MnP or from polycrystalline films grown from the vapor phase on glass substrates. Laser ablation (100 to 200 mW power) is used to produce the nanoparticles within a solvent. This method to produce nanoparticles shows a large dispersion of particle size near the 30 nm range. Ablated nanoparticles are distributed into the polymeric solution and solidified. A study of the nanoparticles structure and magnetic properties of the Ps:MnP nanoaggregates were carried out. The magnetization near room temperature characterizes the ferro- to para-magnetic transition. A critical region extending for more than 4 K, rather than a critical point, has been determined with an apparent or average TC≈284.6±0.5K for the Ps:MnP. A spontaneous magnetization is observed above 300 K, showing that there are nanoaggregates which exhibit ferromagnetism beyond the Curie temperature (∼291 K) of bulk MnP. It is suggested that finite size effects, as well as a wide distribution of sizes, determine the critical behavior in the Ps:MnP magnetically inhomogeneous mesoscopic system.