Polystyrene Foam Research Articles

The Comparison of Microwave Reflectance of Graphite and Reduced Graphene Oxide Used for Electronic Devices Protection

This work presents the investigation of graphite and reduced graphene oxide (RGO) reflectance as an important parameter for electronic devices’ protection. These materials should protect electronic circuits against external as well as internal reflected radiation. The investigation was focused on comparing the reflectance of both materials on the metal layers. The measurements of constant electromagnetic parameters, such as permittivity and permeability, were carried out on pure materials without any additives, such as polystyrene foam, resin, wax, etc. The measurements were implemented in a coaxial line within the microwave frequency range from 100 MHz to 10 GHz. The measurements show a high value of reflected power, over 90% for graphite while RGO reflects only 80% of incident power. In addition, due to the half-wavelength effect in reduced graphene oxide, the reflection coefficient is reduced to 70%.

Tenebrio molitor: possible source of polystyrene-degrading bacteria

BackgroundThe excessive use of polystyrene as a packaging material has resulted in a rise in environmental pollution. Polystyrene waste has continually increased water pollution, soil pollution and the closing of landfill sites since it is durable and resistant to biodegradation. Therefore, the challenge in polystyrene disposal has caused researchers to look for urgent innovative and eco-friendly solutions for plastic degradation. The current study focuses on the isolation and identification of bacteria produced by the larvae of beetle Tenebrio molitor (yellow mealworms), that enable them to survive when fed with polystyrene foam as their sole carbon diet.Materials and methodsThe biodegradation of polystyrene by Tenebrio molitor was investigated by breeding and rearing the mealworms in the presence and absence of polystyrene. A comparison was made between those fed with a normal diet and those fed on polystyrene. The mealworms which were fed with polystyrene were then dissected and the guts were collected to isolate and identify the bacteria in their guts. The viability and metabolic activity of the isolates were investigated. The polymerase chain reaction (PCR) followed by sequencing was used for molecular identification of the isolates. The PCR products were directly sequenced using Sanger’s method and the phylogenetic tree and molecular evolutionary analyses were constructed using MEGAX software with the Neighbour Joining algorithm. The evolutionary distances were computed using the Maximum Composite Likelihood method.ResultsThe decrease in mass of the polystyrene as feedstock confirmed that the mealworms were depending on polystyrene as their sole carbon diet. The frass egested by mealworms also confirmed the biodegradation of polystyrene as it contained very tiny residues of polystyrene. Three isolates were obtained from the mealworms guts, and all were found to be gram-negative. The sequencing results showed that the isolates were Klebsiella oxytoca ATCC 13182, Klebsiella oxytoca NBRC 102593 and Klebsiella oxytoca JCM 1665.ConclusionKlebsiella oxytoca ATCC 13182, Klebsiella oxytoca NBRC 102593 and Klebsiella oxytoca JCM 1665 maybe some of the bacteria responsible for polystyrene biodegradation.

Biodegradation and Bioremediation of Polymer by Microbial Assisted Novel Process

The degradation of polystyrene (PS) and polyurethane (PU), both are foams, is a budding challenge due to increasing white pollution. The present investigation has focused on the microbial assisted biodegradation. Various indigenous microorganisms were isolated from sewage soil. PS – PU foam and bioplastic was used to screen the soil bacteria with biodegradation potential. The screened bacteria were subjected to biodegradation assay such as soil burial and liquid culture in the presence of PS – PU foams and bioplastic in a growth medium. Two microorganism were isolated-- Pseudomonas aeruginosa and Aspergillus niger. The degradation rate based on weight loss is conducted by in vitro assay for 10 and 35 days. The maximum degraded foam was analyzed through Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy and PS – PU foam and bioplastic act as a control without microorganisms. Results of the present study showed that the maximum degradation and weight loss in the polyurethane foam occurred in the soil burial method by Pseudomonas aeruginosa compared with Aspergillus niger. The soil burial method is more significant than liquid culture method. There is no weight reduction in the polystyrene foam in both organism and methods. For the degradation of synthetic polymers the isolated Pseudomonas aeruginosa and Aspergillus niger were encapsulated for future studies.

The preparation of an insulator material using renewable sources and application of palm oil tree – A Review

Excessive heat will cause discomfort while doing daily life even the use of electrical items such as fans and air conditioner are not entirely helpful. This is because the building does not have a layer to absorb the heat. Then, the best initiative to lessen the heat in building is by adding thermal insulation material into the building material. Past researcher shown most thermal insulators used are fiberglass, mineral wool, polystyrene and polyurethane foam. However, there are some flaws with the thermal insulator that cause new ideas to emerge namely cellulose. Cellulose is an insoluble substance that is a major component of plant cell walls and vegetable fibres such as cotton. Normally cellulose can be found in the plants. By cause to the increasing surplus of oil palm trees then the use of cellulose in oil palm is the best. This paper review discusses about preparation of an insulator material using renewable sources and application of palm oil tree.

Numerical study of effect of magnetic field on laser-driven Rayleigh-Taylor instability

Rayleigh-Taylor instability (RTI) is a fundamental physical phenomenon in fluids and plasmas, and plays a significant role in astrophysics, space physics, and engineering. Especially in inertial confinement fusion (ICF) research, numerous experimental and simulation results have identified RTI as one of the most significant barriers to achieving fusion. Understanding the origin and development of RTI will be conducive to formulating mitigation measures to curb the growth of instability, thereby improving the odds of ICF success. Although there have existed many theoretical and experimental studies of RTI under high energy density, there are few experiments to systematically explore the influence of magnetic fields on the evolution of magnetized RTI. Here, a new experimental scheme is proposed based on the Shenguang-II laser facility on which the nanosecond laser beams are used to drive modulation targets of polystyrene (CH) and low-density foam layers. A shock wave is generated after the laser’s CH modulation layer has been ablated, and propagates through CH to low-density foam. Moreover, Richtmyer-Meshkov instability is triggered off when the shock wave accelerates the target. When the laser pulse ends, the shock wave evolves into a blast wave, causing the system to decelerate, resulting in RTI in the reference system of the interface. In this paper the open-source radiation MHD simulation code (FLASH) is used to simulate the RTI generated by a laser-driven modulation target. The evolution of RTI under no magnetic field, under Biermann self-generated magnetic field, and under different applied magnetic fields are systematically investigated and compared with each other. The simulation results show that the Biermann self-generated magnetic field and the applied magnetic field parallel to flow direction do not change the interface dynamics in the evolution process of RTI. Nevertheless, the applied magnetic field perpendicular to flow direction can stabilize RTI and the Kelvin-Helmholtz vortex at the tail of the RTI spike. Magnetic pressure plays a decisive role. The present results provide a reference for the follow-up study of target physics related to ICF and deepen the understanding of the fluid mixing process.

Phase change materials influence on temperature variatio buildings

For the design of sustainable buildings, it is crucial with accurate methods to evaluate how alternative constructions will influence thermal comfort, as well as energy efficiency. This study introduces a model to investigate how the use of phase change materials (PCM)in building envelopes can influence the temperature stratification, which also influences the indoor thermal comfort. PCM is characterized by large latent heat in the melting/solidifying process during phase transition. Applications with PCM have been recognized as possible alternatives in building envelopes to improve thermal comfort as well as energy efficiency. The selection of the properties of the PCM, as well as how and where the PCM was installed in the building envelope, are crucial factors to be considered before application in practice. In this study, a simplified experimental set-up including a hot-box was used. The PCM material Climsel28 with different layers thicknesses was installed in the sidewall of a hot-box. Extruded polystyrene (XPS) foam boards were used as wall insulation material in the study. XPS was installed as a reference case and in different layer combinations with the PCM. The sequence of the XPS and PCM was varied. Temperature and heat flux were measured in different positions of the hot-box and on the tested walls. A 3D COMSOL model was developed to study the thermal performance of the system. The model was validated in the study using the collected experimental data. The results indicated that the developed COMSOL model can reasonably predict the performance of the system, both with and without the incorporation of PCM. Additionally, the measured temperature stratification were theoretically validated by the COMSOL model. The study gives indicative guidance of how PCMs can be installed in building constructions elements to reduce temperature peak loads and thus also contributing to an improvement of the indoor thermal comfort.

Optimization of heat dissipation in concrete ceiling

In majority of the situations, the rooftops are made up of concrete slabs. Concrete is a result of cement, water, air, sand and its aggregates being mixed in a specific proportionate. The thermal conductivity of concrete ranges from 1.25 to 2.25 W m−1 k−1 due to which it doesn’t fall into the category of insulating materials. In summer, the temperature shoots up beyond 35°Celsius in some parts of the world and these roofs are exposed to scorching heat of sun. The room underneath gets warm. This paper brings in perspective of reducing heat dissipation through concrete slabs into the room by coating insulating materials on the outer surface. The materials considered for coating are Cellulose, fiberglass, polystyrene, mineral wool and polyurethane foam. Then, thermal analysis is performed on the concrete slab coated with insulating materials using ANSYS Workbench 18.2. Considering thermal results, economic and environmental factors, fiber glass coated on concrete slab gives the optimum results.

Soil Invertebrates Generate Microplastics From Polystyrene Foam Debris

To fully understand microplastics' impact on soil ecosystems, one must recognize soil organisms as not just passively enduring their negative effects, but potentially contributing to microplastics' formation, distribution, and dynamics in soil. We investigated the ability of four soil invertebrates, the cricket Gryllodes sigillatus Walker (Orthoptera: Gryllidae), the isopod Oniscus asellus L. (Isopoda: Oniscidae), larvae of the beetle Zophobas morio Fabricius (Coleoptera: Tenebrionidae), and the snail Cornu aspersum Müller (Stylommatophora: Helicidae) to fragment macroscopic pieces of weathered or pristine polystyrene (PS) foam. We placed invertebrates into arenas with single PS foam pieces for 24 h, then collected and assessed the microplastic content of each invertebrate's fecal material, its cadaver, and the sand substrate of its arena via hydrogen peroxide digestion, filtration, and fluorescent staining. All taxa excreted PS particles, though snails only to a tiny extent. Beetle larvae produced significantly more microplastics than snails, and crickets and isopods fragmented the weathered PS foam pieces more than the pristine pieces, which they left untouched. A follow-up experiment with pristine PS foam assessed the effect of different treatments mimicking exposure to the elements on fragmentation by isopods. PS foam pieces soaked in a soil suspension were significantly more fragmented than untreated pieces or pieces exposed to UV light alone. These findings indicate that soil invertebrates may represent a source of microplastics to the environment in places polluted with PS foam trash, and that the condition of macroplastic debris likely affects its palatability to these organisms.

Polycyclic aromatic hydrocarbons (PAHs) in new unexposed and beached expanded polystyrene foams

Polycyclic aromatic hydrocarbons (PAHs) in new unexposed and beached expanded polystyrene foams

Analysis of Lightweight Polystyrene Foam Concrete Flat Slabs under Fire Condition

Lightweight reinforced concrete (LWC) is widely used in various reinforced concrete (RC) applications, such as its use in diverse types of reinforced concrete slabs. The aim of this study is to analyze the behavior of reinforced foam concrete slabs (flat slab type) that are exposed to fire conditions under the influence of eccentric loads as well as concentric loads. This analysis has been done using the finite element method by a (ANSYS) software program. The validity of the adopted models was verified through comparison with a previous experimental study. The studied specimens were eleven reinforced concrete flat slabs with a thickness of 150 mm. The lightweight polystyrene foam concrete was used in these specimens with a density of 1820 kg/m3. The results showed that the fire effect lead to a decrease in the maximum carrying load of foam concrete slabs by 25%. Also, by comparing the finite element results with the selected experimental study, the results showed a great agreement with the analytical study used in this research.

The Surface Modification of Extruded Polystyrene Foams Through Uv Curing and its Stable Adhesion to Mortar

The Surface Modification of Extruded Polystyrene Foams Through Uv Curing and its Stable Adhesion to Mortar

Co-pyrolysis of Coffee Ground and Waste Polystyrene foam in a Tilted-slide Reactor

Co-pyrolysis of coffee ground and waste polystyrene foam was performed to produce pyrolysis oil in a tilted-slide reactor. The pretreated waste polystyrene foam was mixed in the ratios of 0%, 25%, 50%, 75%, and 100% with the dried coffee ground by weight. The yield and characteristics of the pyrolysis oil were compared at various mixing ratios. The pyrolysis oil yield increased almost linearly with the mixing ratio of the waste polystyrene foam, and it was 96.95wt% in the case of 100% waste polystyrene foam. The higher heating value of the pyrolysis oil also increased up to 41.44 MJ/kg. Mixing at least 25% of waste polystyrene foam to the coffee ground could significantly reduce the pyrolysis oil viscosity. It can be an efficient method to improve the quality of the pyrolysis oil by enhancing the heating value, and by reducing the viscosity.

Effects of temperature and thermal cycles on the mechanical properties of expanded polystyrene foam

Understanding the effects of high temperature and thermal cycles on the mechanical properties of expanded polystyrene (EPS) foam is critical for its use in sandwich panels. This paper presents an experimental investigation of these effects in typical environmental conditions that exist in construction applications. A total of 117 small specimens were cut from metal-faced sandwich panels with EPS core and were exposed to different numbers of thermal cycles and/or sustained high temperatures. The specimens were then loaded under compression, tension, and four-point bending for evaluating the degradation of the mechanical properties of the foam. The thermal cycles reflect typical surface temperature during daily summer conditions, with a period of 24 h each and with a temperature varying between 24°C to 80°C. The results show that the modulus of elasticity of EPS foam in compression reduced by about 38% after exposure to thermal cycles for 45 days, whereas the tensile and shear moduli reduced by about 5.7% and 13.8%, respectively. Exposure to sustained high temperature after thermal cycles led to larger degradation of the elastic and shear moduli in the range of 38%–50%. These degradations can lead to early failures in applications that rely on the EPS foam as a structural component like in insulating sandwich panels.

Blue LED lighting improves the postharvest quality of tomato (Solanum lycopersicum L. cv. Zahide F1) fruits

Objective: The objective of this study was to investigate the effects of different wavelengths of LED lighting on the postharvest quality of tomatoes (Solanum lycopersicum L. cv. Zahide) during breaker harvest stages..
 Material and Methods: Harvested tomato fruits were placed on 500 g polystyrene foam dishes and wrapped with stretch film. They then were stored in 4±1ºC temperature and 85-90% relative humidity for 42 days under the red (R), blue (B), green (G) and white (W) LED light conditions. The fruits stored in the dark were used as control (C). 
 Results: R and W LED treatments increased hue angle value, yellowness index value, and fruit firmness of tomatoes Blue LED lighting, also decreased electrolyte leakage that indicates delaying senescence. It was also found that blue and red LED lighting delayed fruit decay.
 Conclusion: As a conclusion, it could be satated that the blue LED lighting was found to be more effective than the red, white and green LED light in maintaining the quality of the tomatoes harvested at the breaking stage.

Carbonized sawdust/barium titanate composite solar absorber for solar driven seawater desalination

A low cost and feasible fabrication of novel photothermal conversion material and solar absorber was widely studied for enhanced solar-to-vapor performance in solar driven vapor generation. In this work, a novel hybrid carbonized sawdust/barium titanate composite was fabricated by sol-gel method, where it was later incorporated with a cotton towel using a dip-coating process to produce a solar absorber. The solar driven seawater desalination setup was made up of i) solar absorber where heat was localized and the evaporation occurs, ii) thermal insulation using polystyrene foam and air gap to minimize the heat loss, and iii) water pathway for continuous supply of seawater to the solar absorber. Carbonized sawdust/barium titanate composite solar absorber was tested under direct solar radiation for about 2 h using seawater collected from the beach coast of Universiti Malaysia Sabah, where it was repeated three times to observe the stability of the solar absorber. The average efficiency of the carbonized sawdust/barium titanate composite solar absorber was about 72.04% with average evaporation rate of 1.32 kg/m2 h. Salinity of the clean water was significantly reduced about 99.8% from the initial seawater salinity at 29300 ppm to 50 ppm, and the pH value was observed at 7.40. The salinity and pH value of the generated clean water was within the safe water limit based on the World Health Organization (WHO) standard.

Effect of rhamnolipid biosurfactant on biodegradation of untreated and UV-pretreated non-degradable thermoplastics: Part 2

The capabilities of a microbial consortium, composed of Penicillium raperi, Aspergillus flavus, Penicillium glaucoroseum and Pseudomonas spp, for biodegrading of ultraviolet (UV)-pretreated and un-pretreated mixed plastics (polyethylene (PE), polystyrene foam (PS) and polyethylene terephthalate (PET)) in the presence of biosurfactant (rhamnolipid) was examined. The “UV-pretreated & bio-treated + biosurfactant” was found the most effective condition for PS samples with the highest physical weight loss (7.47%), surface degradation, wettability (< 5˚). The highest biofilm formation was observed on PS for “UV-pretreated & bio-treated + biosurfactant” and “UV-pretreated & bio-treated” with OD 595 nm of 1.53 and 1.31 conditions, respectively. Atomic force (AFM) and scanning electron microscopy (SEM) showed considerable surface degradation (cracks and holes) for the PS sample incubated at “UV-pretreated & bio-treated + biosurfactant” condition compared to PE and PET in the same condition. In contrast, PE and PET had a higher biodegradation efficiency only in “UV-pretreated & bio-treated” condition. The utilisation of biosurfactant had negative effects on biodegradation and wettability of PE and PET, due to the consumption of rhamnolipid as food source rather than the plastic itself. Chemical transformation indicated a new peak (C-O) in PS at both “UV-pretreated & bio-treated” and UV-pretreated & bio-treated + biosurfactant) conditions. However, the chemical transformation of PE and PET remained unchanged in all conditions except “UV-pretreated & bio-treated”. Thermogravimetric analysis showed 20 ˚C lower thermal stability of PS incubated at “UV-pretreated & bio-treated + biosurfactant” than other conditions.

Ağır Aromatik Atık ve Polistirenin Eş-pirolizi: Sıvı Ürünün GC-MS ile Analizi

Plastic wastes forms 18.46 % of total municipal solid wastes in 2018 around the world. Heavy hydrocarbons occur as the waste of refinery processes. In this study co-pyrolysis of waste polystyrene foam (PS) and heavy aromatic waste (HAW) was carried out for the first time in literature. It was aimed to investigate the effect of temperature (420, 450, 480 ⁰C) and mixing ratio (1/5, 3/5, 1/1) on liquid product yield and compound distribution in the pyrolytic liquids. Whole experiments were done in semi-batch reactor configuration under nitrogen atmosphere. Gas chromatography-Mass spectrometry (GC-MS) was utilized to analyze the pyrolytic liquids. At 480 ⁰C it was obtained maximum liquid yield as 87.24 % in 1/5 HAW/PS feedstock ratio. Compared to the pure PS pyrolysis, it was achieved relatively low styrene, toluene yield. However yields of ethyl benzene and cumene increased with HAW adding to the feed. Naphthalene was not detected in liquid of PS pyrolysis. Maximum naphthalene yield was taken as 12.71% at 480 ⁰C with 1/5 HAW/PS feedstock ratio.

Improvement in liquid absorption of open‐cell polymeric foam by plasma treatment for food packaging applications

AbstractFree‐moving meat exudate in plastic packaging is perceived as unhygienic and unattractive by consumers. It facilitates the deterioration of meat quality and safety, increasing meat waste and loss. This work discusses an innovative approach in scavenging meat exudate within commercial plastic packaging. This involves improving the liquid absorption capabilities of open‐cell polystyrene (PS) foam through the application of oxygen plasma treatment rather than chemical wetting agents. The excited plasma species diffuse into the porous foam structure introducing polar oxygen groups onto the pore walls and improves their surface hydrophilicity. Hence, the foam pores, with enhanced wettability towards water‐based liquids, are proposed to have a larger sucking capillary pressure thus increasing the absorption capacity of the porous PS foam. The specific liquid absorption capacity of PS foam sheets (thickness: 5 mm) increased from 1.09 g g−1 (grams of exudate simulant liquid absorbed per gram of PS foam) to 8.78 g g−1 as a result of plasma treatment; an eightfold increase in liquid capacity (g g−1) that persisted even 60 days post treatment. This study demonstrates the practicality of using plasma treatment as a non‐chemical and efficient technology in scavenging meat and food exudates in plastic packaging.

Rapid preparation of a composite insulating block comprising waste expanded polystyrene (EPS) foam and rice straw

Due to the world’s decreasing energy supply, reducing the energy consumption of building envelopes has become an urgent issue with economic benefits. Rice straw is a generally available agricultural residue. The purpose of this study was to estimate the effects of rapid pretreatment methods and slaked lime on the molding of rice straw insulation blocks and to evaluate the effectiveness of integrating expanded polystyrene (EPS) particle waste with rice straw as building materials to reduce the energy loss in buildings. The pretreatment time was shortened from 6 h to 3 h by mechanical stirring combined with lye soaking. The molding of the insulation block could be improved by the hardening of slaked lime through contrast experiments and electron microscope scanning. Moreover, the influences of the mass ratio of slaked lime to rice straw (RSR) and the dosage of the EPS particles (ωEPS) on the dry apparent density and the thermal conductivity of the insulation blocks were studied. The results showed that the slaked lime would increase the dry apparent density and weight of the insulation block, but the EPS can effectively reduce this negative effect and keep the thermal conductivity of the insulation block below 0.049 W·m-1·K-1. Ultimately, the rapid pretreatment technology was determined to include lye soaking for 3 h and mechanical stirring for 5 min. The material matching ratio scheme was determined to have a ωEPS value of less than 3% and an RSR value equal to 1/7.5.

Formation mechanism of bi-modal cell structure polystyrene foams by synergistic effect of CO2-philic additive and co-blowing agent

A new method was developed for the formation of bi-modal cell structure polystyrene (PS) foams by synergistic effect of CO2-philic additive (PDMS) and co-blowing agent (alcohol). The results showed that PDMS and alcohol synergistically increased the solubility and diffusion coefficient of CO2 into PS and reduced the desorption rate from PS. The blowing agent formed a high-concentration area in the PDMS (6000 g/mol) phase to promote bubble nucleation and growth in advance. The moderate size and number of cells were pre-formed, slowing the CO2 desorption and increasing the duration of bubble growth, so that bi-modal cell structure PS foams with high cell density and volume expansion ratio were obtained. Moreover, the solution and diffusion behavior of CO2 and the cell morphology could be easily tuned by changing the composition of complex additives, which might be a promising strategy for preparing bi-modal cell structure in different foaming processes.