Polystyrene Foam Research Articles

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.

Low-cost, disposable sensors based on polystyrene waste and V–TiO2 microneedle composites for diagnosis of renal malfunction and muscle dystrophy

A compact, cost-efficient, and disposable electrochemical creatinine sensor is designed using disposable screen-printed carbon electrodes coated with a composite receptor based on polystyrene foam (i.e., packaging material waste) and anatase-phase V–TiO2 microneedles. The electrochemical sensor is capable of monitoring 1–25 μM creatinine in a standard redox solution at 7.4 pH and room temperature. The electrochemical measurements are performed with a portable potentiostat using an android smartphone. Cyclic voltammetry and differential pulse voltammetry characteristics are measured to monitor the concentration of creatinine. The sensor exhibits excellent creatinine sensitivity of 30.95 ± 1.73 μA/cm2⸳μM and an extremely low threshold detection limit of 184 nM creatinine.

The Effect of Relative Humidity Dependent Thermal Conductivity on Building Insulation Layer Thickness Optimization

Optimization of insulation layer thickness is a significant factor in energy-efficient building design. Accurate determination of the thickness of the insulation layer will contribute to building energy conservation. In this study, ten typical cities in five thermal zones were selected, and the external thermal insulation of a typical residential building was taken as the research object. Using the degree day method and the economic model of full life cycle cost analysis, the optimal thickness of seven kinds of building insulation materials under absolute dry conditions, the lowest humidity and the highest humidity of the monthly average of the annual daily average were obtained. In addition, the carbon emission, energy saving and recovery period of materials under different working conditions were further obtained through numerical calculation. The results show that the optimum thickness of seven building insulation materials in ten typical cities under three working conditions is 18.21–346.05 mm. Their carbon emission change rate is between −2.7% and 38.6%, energy saving change rate is between −0.4% and 18.4%, and the payback period growth is within 1.5 years. Among them, polystyrene foam is the material least affected by humidity. It is recommended to be the main building insulation material in high humidity areas.

Classification of the collapse of a composite fairing during the oblique high-speed water entry

The crushing behaviors of the buffer devices for the projectile in the high-speed oblique water entry process were investigated numerically. The high-speed water entry tests of the aluminum alloy projectile with a sabot were conducted to study the cavity formation, also used to validate the numerical method. Detailed material parameters of three kinds of foams including expanded polystyrene foam (EPS), closed-cell aluminum foam, and rigid polyurethane foam (PU), and the composite material for the fairings were obtained from a series of statics and dynamics mechanics experiments. Twelve collapse modes of the thin-walled fairings were identified during the oblique water impact. The effects of the length of the fairing, foam type, and water entry angle on these failure modes, and the peak impact acceleration of the projectiles were revealed. The results showed that the load reduction efficiency (LRE) is dependent on both entry angle θ and dimensionless length LFA/DPJ. The critical load reduction water entry angle (CLRA) is linearly related to LFA/DPJ. Among the three kinds of foam materials, the closed-cell aluminum foam has the best load reduction performance (up to 72.82%) and the widest range of load reduction water entry angles. Meanwhile, the EPS foam makes the projectile withstand the largest impact overload (up to 11.43%).

FIRE EFFECT ON LIGHT WEIGHT CONCRETE BEAMS IN FLEXURAL

This research was commenced with the objective of investigating the lightweight concrete LWC behavior when exposed to fire by partial aggregate replacement with polystyrene foam under concentric loads, experimentally. This is attributed to the fact that the reduced mass concrete reduces the imposed lateral load during earthquakes, Literature review was carried out in the field of LWC in order to determine the research gaps or weak points to commence this research.From the analysis of tested results showed that the crack width increased and the numbers of cracks increased due to exposing the tested beam to fire .The ultimate load decreased by subjected to fire by average 26.263% while the deflection increased with average 15.42% for beam and the ductility slightly decreased by average 13.1% because of the decreasing in the deflection corresponding to the maximum load where the energy absorption capacity decreased with average 29.7% for beam.

Analysis of Active and Passive Deformation of Expanded Polystyrene Foam under Short-Term Compression

In this paper, we undertake a detailed analysis of the active and passive deformation of expanded polystyrene (EPS), which is used as a thermal insulating layer in building partitions, under short-term compressive loading. The values of residual strain in 10-40 kg/m3 density EPS after monotonically increasing loading under active deformations of 20%, 30%, 40%, 50%, and 60% with the following complete removal are determined. These values are a physical sign of the elastic-plastic state of EPS. It has been shown that the final destruction of cells takes place in EPS when the active strain reaches 50%. Empirical equations are proposed to estimate the residual strain of EPS based on density with determination coefficients varying from 0.744 to 0.986 at a confidence level of 90%. Moreover, graphical interpretations with regression equations for residual strain dependence on density and compressive strength, as well as density and active strain, were proposed with determination coefficients equal to 0.779 and 0.717, respectively.

Concept of Sustainable Demolition Process for Brickwork Buildings with Expanded Polystyrene Foam Insulation Using Mealworms of Tenebrio molitor.

The traditional demolition process for brickwork buildings results in a significant volume of mixed debris. The debris consists of ceramic bricks (and other wall elements), mortar, thermal insulation (usually expanded polystyrene or rockwool), smaller steel elements, pieces of wood, and glass. Such mixed debris is difficult to recycle. Separating thermal insulation that is "glued" by cement mortar to brickwork is probably the most difficult and time-consuming task in processing mixed debris. This task can be performed in a very different and fully "automatized" manner using Tenebrio molitor mealworms. The mealworms remove expanded polystyrene from brickwork surfaces and transform it into frass. In the paper, a research program aiming to prove the concept of using the mealworms of Tenebrio molitor for processing mixed debris is presented. The tests were conducted using two models of a three-layered brickwork wall, which is very common in Europe. The proposed approached was successful. Both types of used expanded polystyrene foam (EPS) were fully removed from multilayer wall specimens. The possibilities and limitations of the proposed processing method were discussed and analyzed. The conducted research proved that it is feasible to clean brickwork debris from the EPS using Tenebrio molitor mealworms. Differences in the speed of cleaning process regarding the type of EPS were noted. More research is needed to scale the process, and to find the best method for using frass. By using Tenebrio molitor mealworms, one can make the demolition process much cleaner.

Mechanical, Physical, and Chemical Properties of Mycelium-Based Composites Produced from Various Lignocellulosic Residues and Fungal Species.

Mycelium-based composites (MBCs) are characterized as biodegradable materials derived from fungal species. These composites can be employed across a range of industrial applications that involve the manufacturing of packaging materials as well as the manufacturing of buildings, furniture, and various other household items. However, different fungal species and substrates can directly affect the functional properties of MBCs, which ultimately vary their potential to be used in many applications. In this study, the mechanical, physical, and chemical properties of MBCs made from four different fungal species (Ganoderma fornicatum, Ganoderma williamsianum, Lentinus sajor-caju, and Schizophyllum commune) combined with three different types of lignocellulosic residues (sawdust, corn husk, and rice straw) were investigated. The results indicate that differences in both the type of lignocellulosic residues and the fungal species could affect the properties of the obtained MBCs. It was found that the MBCs obtained from sawdust had the highest degree of density. Moreover, MBCs obtained from S. commune with all three types of lignocellulosic residues exhibited the highest shrinkage value. The greatest degree of water absorption was observed in the MBCs obtained from rice straw, followed by those obtained from corn husk and sawdust. Additionally, the thermal degradation ability of the MBCs was observed to be within a range of 200 to 325 °C, which was in accordance with the thermal degradation ability of each type of lignocellulosic residue. The greatest degrees of compressive, flexural, impact, and tensile strength were observed in the MBCs of G. williamsianum and L. sajor-caju. The results indicate that the MBCs made from corn husk, combined with each fungal species, exhibited the highest values of flexural, impact, and tensile strength. Subsequently, an analysis of the chemical properties indicated that the pH value, nitrogen content, and organic matter content of the obtained MBCs were within the following ranges: 4.67−6.12, 1.05−1.37%, and 70.40−86.28%, respectively. The highest degree of electrical conductivity was observed in MBCs obtained from rice straw. Most of the physical and mechanical properties of the obtained MBCs were similar to those of polyimide and polystyrene foam. Therefore, these composites could be used to further develop relevant strategies that may allow manufacturers to effectively replace polyimide and polystyrene foams in the future.

The surface modification of extruded polystyrene foams through UV curing and its stable adhesion to mortar

The hydrophobic surface of extruded polystyrene foams (XPSF) was modified by UV curable adhesives to enhance the interfacial bonding strength (BS) with mortar. The UV adhesive contained epoxy acrylate resin, acrylic acid and butyl acrylate (denoted as EAB). After EAB modification, the BS value in dry state (BS-D) increased from 0.050 MPa of unmodified XPSF with mortar to 0.210 MPa. Then, 3-aminopropyltriethoxysilane (APTES) was further introduced into EAB to form the water-resistant coatings (denoted as EABT) to enhance the BS value in wet state (BS-W). By optimizing the composition, the maximum BS-D and BS-W of 0.216 and 0.158 MPa in 7-day curing were obtained. The bonding mechanism illustrated that the modified XPSF was chemically bonded with mortar.

Scalable Production of Biodegradable, Recyclable, Sustainable Cellulose-Mineral Foams via Coordination Interaction Assisted Ambient Drying.

Heavy reliance on petrochemical-based plastic foams in both industry and society has led to severe plastic pollution (the so-called "white pollution"). In this work, we develop a biodegradable, recyclable, and sustainable cellulose/bentonite (Cel/BT) foam material directly from resource-abundant natural materials (i.e., lignocellulosic biomass and minerals) via ambient drying. The strong resistance to the capillary force-driven structural collapse of the preformed three-dimensional (3D) network during the ambient drying process can be ascribed to the purpose-designed cellulose-bentonite coordination interaction, which provides a practical way for the locally scalable production of foam materials with designed shapes without complex processing and intensive energy consumption. Benefiting from the strong cellulose-bentonite coordination interaction, the Cel/BT foam material demonstrates high mechanical strength and outstanding thermal stability, outperforming commercial plastic polystyrene foam. Furthermore, the Cel/BT foam presents environmental impacts much lower than those of petrochemical-based plastic foams as it can be 100% recycled in a closed-loop recycling process and easily biodegraded in the environment (natural cellulose goes back to the carbon cycle, and bentonite minerals return to the geological cycle). This study demonstrates an energy-efficient ambient drying approach for the local and scalable production of an all-natural cellulose/bentonite foam for sustainable packaging, buildings, and beyond, presenting great potential in response to "white pollution" and resource shortage.

Расчетно-экспериментальная оценка применимости экструдированного пенополистирола бытового назначения в трехслойных конструкциях корпуса маломерного судна

Object and purpose of research. This paper is an integrated study of extruded polystyrene foam (XPS) practicability for three-layered composite hull structures of small craft. Subject matter and methods. Mechanical properties of composite materials and their components are determined experimentally (three-point bending, longitudinal tension/compression). Elastic properties and limit-state characteristics are obtained from beam theory, mixed model of composite beam, finite-element method, as well as solution of geometrically non-linear contact problems as per Newton-Raphson iterative technique. Main results. The study illustrates final diagrams for structural responses of investigated composite beam, filler and binder as functions of pre-defined displacement of test rigging. It also gives the estimates for equivalent Young’s moduli, as well as preliminary positive opinion about the practicability of XPS as a substitute for the conventional wood veneer in composite structures of small ships. The paper also presents a structurally similar FE model suitable for prediction calculations of large complex structures that can be tested only when the whole full-scale hull is available. Conclusion. This study formulates and solves the elastic problem for the investigated XPS-based sandwich panels. The results give an idea about the practicability of this material for shipbuilding applications.

Effects of Polystyrene Diet on the Growth and Development of Tenebrio molitor.

In recent years, the role of Tenebrio molitor in degrading polystyrene foam through its gut microbes has become the focus of research. However, little literature has reported the effect of feeding on polystyrene foam on the growth and development of Tenebrio molitor. In this study, we investigated the impacts of different polystyrene by evaluating the vital signs of Tenebrio molitor fed in the intestines and excrement fluids using RNA-Seq t.echnology and then verifying the transcriptome sequencing findings using qRT-PCR technology. The average weight of Tenebrio molitor larvae in the wheat bran group increased significantly. Tenebrio molitor larvae in the PS group, on the other hand, didn’t grow as much and had a much lower average weight than those in the wheat bran group. Compared to the bran group, the excrement of Tenebrio molitor fed only on polystyrene foam was flaky and coarse, increased nitrogen and phosphorus atomic concentration ratios by about 50%, decreased potassium atomic concentration ratios by 63%, with the enterocytes and circular muscle of Tenebrio molitor falling as well. Kyoto Encyclopedia of Genes and Genomes enrichment indicated that the differential genes were mainly related to metabolic pathways. There was an agreement between qRT-PCR and RNA-Seq analyses for the growth and development genes chitinase, heat shock protein 70, and cytochrome P450. Only feeding polystyrene foam shall lead to the growth and development retardation of Tenebrio molitor.

Mechanical behaviour and stress-strain recovery characteristics of expanded polypropylene

Expanded polypropylene (EPP) foam has been widely recognized as an energy absorbing material, and it is routinely used for variety of industrial applications. However, EPP foam has a relatively limited scope in the construction industry, especially for load-bearing applications. To address this aspect, the mechanical behaviour of EPP foam was examined under unconfined conditions in this study, and the effects of different preloading/precompression strain histories (5% to 60%) on the stress-strain response and strain energy characteristics of EPP were evaluated. Additionally, the stress-strain recovery behaviour of EPP foam having different preloading histories was also studied while considering the effects of recovery time after preloading (0 to 28 Days). The results suggest that EPP foam subjected to different preloading histories has identical patterns of stress-strain response to other conventional closed-cell polymeric foams, such as expanded polystyrene (EPS) foam, and EPP can adequately be used for load-bearing applications under the recommended design limits. Furthermore, noticeable recovery in the stress-strain response of EPP was also witnessed during the initial 14 days after preloading. Based on these findings, it is anticipated that the promising stress-strain recovery characteristics of EPP foam enable it to be reused, even after experiencing large in situ deformations.

Compressive behavior of lightweight concrete using aerogel-reinforced expanded polystyrene foams

The continuous development of the construction industry is also pushing concrete to change. Lightweight and high-strength concrete is becoming more and more important. Aerogel reinforced Epoxy Macrospheres (AR-EMS) were obtained by the ball rolling method. The lightweight concrete was prepared by mixing AR-EMS, cement, and hollow glass beads into the mold by the molding method. In this experiment, the influencing factors such as stacking volume fraction, inner diameter, wall thickness of AR-EMS and different types of hollow glass microspheres (HGMS), different content and length of glass fibers (GF) in matrix were studied. The comprehensive microstructure and performance characterization results show that AR-EMS binds well to the concrete matrix, and the addition of long fibers effectively improves the compressive strength of lightweight concrete. The lightweight concrete can meet the requirements of both high strength (11.46 MPa) and low density (0.897 g/cm³) when the matrix is filled with 2 wt% of 12 mm GF and AR-EMS with 9–10 mm-2layers-90%. Compared to the concrete without GF and the EPS-filled concrete, the maximum compressive strength was increased by 69% and 398%, respectively.

Assessing the Compliance of Extrusion Foamed Polystyrene Production with the Environmental Standards Requirements

The development of modern construction requires the use of environmentally friendly building materials, including insulating materials, to ensure the energy efficiency of buildings and structures. The purpose of the work is relevant and was to develop a methodology for assessing the compliance of extruded polystyrene foam with environmental requirements. The problem is that the certification of such materials includes an examination of their physical and mechanical properties and does not allow assessment of materials’ environmental aspects. A comprehensive approach to assessing the quality of extruded polystyrene foam is proposed, which ensures not only the technical level of material quality, but also compliance with environmental requirements. The research methodology is based on the environmental risks’ identification at all stages of production and the determination of products environmental safety criteria. Each criterion is characterized by a set of indicators, among which a representative indicator is determined. A complex indicator is proposed for assessing the environmental safety of the production of extruded foamed polystyrene. The novelty of the work lies in the algorithm for calculating the material environmental friendliness complex criterion. The process model of the extruded polystyrene foam production analyses made it possible to establish representative indicators according to the products’ environmental safety criteria. As a result of the analysis, critical operations were identified where environmental risks are likely, and representative indicators’ limit values were set in accordance with regulatory documentation. Measures have been developed to minimize the release of harmful substances during each critical operation. To improve environmental management, the system for monitoring and assessing risks in the production of extruded foamed polystyrene has been optimized. As a result, a methodology has been developed for assessing the compliance of the production of extruded polystyrene foam with environmental requirements, which is necessary for product quality certification. Doi: 10.28991/CEJ-2022-08-10-018 Full Text: PDF

An Effective Green Porous Structural Adhesive for Thermal Insulating, Flame-Retardant, and Smoke-Suppressant Expandable Polystyrene Foam

To develop an efficient way to overcome the contradiction among flame retardancy, smoke suppression, and thermal insulation in expanded polystyrene (EPS) foams, which are widely used insulation materials in buildings, a novel “green” porous bio-based flame-retardant starch (FRS) coating was designed from starch modified with phytic acid (PA) that simultaneously acts as both a flame retardant and an adhesive. This porous FRS coating has open pores, which in combination with the closed cells formed by EPS beads, create a hierarchically porous structure in FRS–EPS that results in superior thermal insulation with a lower thermal conductivity of 27.0 mW·(m·K) − 1 . The resultant FRS–EPS foam showed extremely low heat-release rates and smoke-production release, indicating excellent fire retardancy and smoke suppression. The specific optical density was as low as 121, which was 80.6% lower than that of neat EPS, at 624. The FRS–EPS also exhibited self-extinguishing behavior in vertical burning tests and had a high limiting oxygen index (LOI) value of 35.5%. More interestingly, after being burnt with an alcohol lamp for 30 min, the top side temperature of the FRS–EPS remained at only 140 °C with ignition, thereby exhibiting excellent fire resistance. Mechanism analysis confirmed the intumescent action of FRS, which forms a compact phosphorus-rich hybrid barrier, and the phosphorus-containing compounds that formed in the gas phase contributed to the excellent flame retardancy and smoke suppression of FRS–EPS. This novel porous biomass-based FRS system provides a promising strategy for fabricating polymer foams with excellent flame retardancy, smoke suppression, and thermal insulation.

Measuring the effect of ground impedance on the vector field, both in air and underwater

One direct advantage to characterizing the acoustic field with a vector sensor is the ability to measure both components of acoustic energy, potential (pressure) and kinetic (particle velocity). While it is well known that the kinetic energy exceeds potential in the near-field of a source, equivalent and opposite imbalances are prevalent in the far-field due to propagation effects. For example, at normal incidence the field exhibits a distinct frequency dependent relationship that depends explicitly on the impedance of the ground reflector, including any internal reflections from sediment layers. In this paper, we examine the measured vector field, both in-air and underwater, with a specific focus the energy balance when a source is directly overhead. While the construction of a neutrally buoyant volume for use in dense media (such as water) is fairly straightforward, the application to airborne acoustics requires extremely lightweight materials. Airborne measurements are provided by an Accelerometer-based Intensity Vector Sensor (AIVS) system, which is constructed from a lightweight MEMS accelerometer and microphone embedded in a spherical, expanded polystyrene (EPS) foam volume.

Experimental investigation into the structural behaviour of ultra-high performance fibre-reinforced concrete box-celled composite panels

The present study investigates and advances on existing research on the structural performance of box-celled composite structures for its use as a wind-resistant roof system. The box-celled panel system is produced by casting ultra-high performance fibre-reinforced concrete (UHPFRC) into galvanised steel roofing profiled sheets with anchor screws and expanded polystyrene foam (EPS) placed in-situ to produce a light-weight system. Three reinforcement-based variations of the design are investigated and two panels for each variation are cast to produce six specimens. The structural responses of the variations as one-way panels under three-point flexure are experimentally studied for both positive and negative bending moment capacities. Test specimens showed flexural failure with significantly ductility and post-failure load capacity, and anchor screws preventing full delamination of steel profile and shear failure. Analysis based on the test results confirmed that the proposed system is compliant to various design standards based on upper limits for combined loading actions, and permissible deflections, highlighting its optimal performance.

Effects of various logistics packaging on the quality and microbial variation of bigeye tuna (Thunnus obesus).

Bigeye tuna (Thunnus obesus) is an economically valuable ocean fish species. It is susceptible to contamination during storage and transportation. Having proper transportation packaging and stable temperature during transportation are critical to prevent quality deterioration. However, the influence of packaging on retaining freshness in transit remains unknown. Here, the impact of different transportation packaging on the quality and microbiological variation of bigeye tuna during the logistics process was investigated by measuring physical-chemical indexes and microbial diversity. It turned out that aluminum foil paper (AFP) group had minimum temperature fluctuation, exhibited preferable water retaining capacity and color protection effect. AFP packaging could efficiently prevent TVB-N increase and microbial growth. After 40 h, the TVB-N value was 21.28 mg/100 g and microbial total plate count was 3.53 lg CFU/g, which was within the acceptable range. Temperature fluctuations and packaging materials had a major effect on the microbial community structure of bigeye tuna. Chitinophagaceae, Acinetobacter, and Knoellia were dominant in the AFP group, while Pseudomonas, Acinetobacter, and Macrococcus were dominant in the expanded polystyrene foam (EPSF) and European logistics (EUL) groups. AFP packaging could effectively slow down the growth and reproduction of Pseudomonas, restraining the growth of microorganisms and preserve the quality of bigeye tuna. This study provides insights into understanding the effects of packaging material on maintaining quality during logistics transportation.

Influence of drone carriage material on maintenance of storage temperature and quality of blood samples during transportation in an equatorial climate

The disruptive potentials of drones are rapidly growing including for the delivery of blood samples in healthcare. Maintenance of the quality of blood samples is important to ascertain that the drone is a safe mode of transportation, particularly during emergencies and in critical cases. The influence of the drone carriage material on blood samples transportation was investigated in this study. Two phases of drone simulation flights were conducted in Cyberjaya, Malaysia. In Phase 1, the effect of drone carriage material on the internal storage temperature during blood samples transportation was determined. Three types of carriage materials were compared: aluminium, expanded polystyrene (EPS) foam, and polypropylene (PP) plastic. In Phase 2, the quality of drone-transported blood samples was assessed, using the best material from Phase 1 as the drone carriage material. Biochemical and hematological analyses of 60 blood samples were conducted using five parameters. In Phase 1, EPS foam was found to be the best material to maintain a stable and favorable internal storage temperature at mean kinetic temperature ±SD of 4.70 ±1.14°C. Much higher and unfavorable mean kinetic temperatures were recorded for aluminium (11.46 ±0.35°C) and plastic (14.17 ±0.05°C). In Phase 2, laboratory tests show that the quality of blood samples was well maintained, and the mean biochemical and hematological parameters of drone-transported blood samples showed no significant alteration compared to ground controls. Drone carriage material is an important determinant of the quality of blood samples transported by drone, particularly in hot equatorial climates as in Malaysia. The blood storage temperature was best maintained using EPS foam, as evidenced by the favorable average temperature and preservation of hematological and biochemical parameters of the blood samples.