Polystyrene Foam Research Articles

Experimental investigation of downward discrete flame spread of the thermoplastic material in exterior insulation walls: melt-flowing and -dripping

Discrete flame spread, accompanied with melt-flowing and -dripping behaviors, significantly increases fire hazards of thermoplastic materials in exterior insulation walls. The movement of melt-burning combustible materials brings rigorous challenges to the current fire protection system but has not been sufficiently studied. Thus, two modes of bench-scale experiments, covering melt-flowing and melt-dripping, have been conducted to explore the basic knowledge and threshold of melting-dominant discrete flame spread. The typical thermoplastic material in the exterior thermal insulation system, expanded polystyrene foam (EPS), was selected as the research objective. For melt-flowing dominant flame propagation, a critical fuel coverage (f = 0.40–0.50) when a barrier prevented molten flows was determined experimentally, and a dimensionless analysis was conducted to clarify the downward flowing stages. For dripping-dominant flame propagation, a threshold diameter for ignition (13.3 mm) was obtained via comparing burning time and ignition time without the impact of dripping height. Then, the influence of dripping height on the critical ignition diameter was investigated by coupling with the established theoretical dripping acceleration. This work attempts to provide a reference for enhancing fire protection in building exterior walls.

The pyrolysis behavior of poly(styrene–methyl methacrylate) copolymer and expanded polystyrene (EPS) foams using model-free and model fitting methods

The pyrolysis behavior of poly(styrene–methyl methacrylate) copolymer and expanded polystyrene (EPS) foams using model-free and model fitting methods

Compressive Strength Evaluation of Cured Cement Mortar including Rubber, Foam, Plastic, and Paper Wastes as Partial Replacement with Sand

Waste materials pollution has instigated a serious environmental problem for decades, therefore new initiatives have been taken around the world to recycle wastes into construction materials in recent years. This study applied the compressive strength as one of the key parameters to examine the characteristics of materials, it was conducted to investigate the efficiency of adding different waste materials to cement mortar mixture as partial replacement with sand. Crumbed rubber, expanded polystyrene (foam), shredded wastepaper, and shredded plastic bags were selected to examine the efficiency of adding them to cement mortar. These waste materials were mixed individually with cement, sand and water proportionally. The produced mixture of each waste materials was casted in standard cubes and cured in water for different ages 3, 7 and 28 days. The compressive strength of the cured cubes was tested, the results showed that over all tested ages, plastic-based mortar provided the lowest compressive strength variance values by -7.4, -6.7%, and -5.4% in comparison with tested reference mortar. Rubber-based mortar showed the highest variance by -58.5 % at 3 days, -58.3% after 7 days and -55.5 % after 28 days. Foam comes next to Plastic-based mortar then Paper-based mortar by -13.7 & -37 % after 3 days, -11.3 & -34 % after 7 days and -14 & -26 % after 28 days respectively. In comparison to ASTM C129, the results ranges supported the possibility of using cement mortar mixed with shredded plastic, foam and shredded wastepaper in producing non-loadbearing concrete masonry units.

Solid and gas thermal conductivity models improvement and validation in various porous insulation materials

In the past few decades, significant efforts have been made to improve the theoretical understanding of thermal transport mechanisms in thermal insulation materials and push the thermal conductivity's lower limits. However, most works focused singularly on specific types of materials, and the models used for thermal conductivity predictions are diverse - a model that fits one material might not fit others. Here, we improve and unify the gas and solid thermal conductivity models for porous materials. Through experimental characterization of several different materials as well as literature data for other materials, these models are validated. We have also found that the pressure-dependent gas thermal conductivity of most materials can be well fitted by using one or two pore sizes without using a complex pore size distribution. With the refined models, we decompose the effective thermal conductivity of several thermal insulation materials into gas, solid, and radiation contributions. For cellular (polystyrene and polyurethane) foams, the relative contributions from air, solid, and radiation are 58–75%, 3–11%, 16–38%, respectively. For granular porous materials (polyurethane and silica in this work), the contributions from air, solid, and radiation are 45–66%, 34–46%, and 0–8%, respectively. This work is expected to provide guidance on the design and optimization of the next generation of thermal insulation materials, for example, through the effort of reducing gas conduction and radiation in foams and suppressing gas and solid conduction in aerogels.

Sustainability assessment of half-sandwich panels based on alkali-activated ceramic/slag wastes cement versus conventional building solutions

This study assessed the sustainability of two partition walls and intended to contribute to the Circular Economy in the construction sector. A life cycle approach and a multi-criteria decision support method were applied to know the environmental, functional, and economic performances of the production process of half-sandwich panels based on alkali-activated ceramic/slag waste cement, choosing as system boundary the method “cradle to gate”. The proposed building solutions differ from each other in the type of insulating material used, either extruded polystyrene foam (APXPS) or expanded cork agglomerate board (APICB). Besides, a comparative analysis of the developed building solutions versus three reference constructive solutions: i) a conventional heavyweight partition wall, ii) a lightweight gypsum wall panel, and iii) a conceptual lightweight sandwich membrane building solution was performed. Results showed that the two proposed half-sandwich wall panels (APXPS and APICB) resulted in the most sustainable alternatives, of which the APXPS obtained the best overall results since it combined the best environmental, functional, and economic behavior. Besides, the environmental contribution analysis determined that the greatest environmental burden to the Global Warming Potential (GWP), in the case of the APXPS was associated with the XPS (57%), being the alkali activator (23%) placed as the second major contributor. When the ICB was used as the insulation layer, the energy used (nearly 38%) and the sodium silicate (about 17%) were the larger contributors to CO2 emissions. It is worth mentioning that the use of ICB represented a negative contribution (of about −34%) to the GWP category.

Integration of Energy Simulations and Life Cycle Assessment in Building Refurbishment: An Affordability Comparison of Thermal Insulation Materials through a New Sustainability Index

Energy efficiency and greenhouse gas reduction have become two of the most important issues to address in fighting climate change. Focused strategies have been implemented aiming at reducing the energy consumption of buildings since it is one of the most energy-intensive sectors, but they are mainly concerned with energy reduction without considering their environmental impact. The present work therefore aims at assessing the energy and environmental impacts of the use of insulation materials for building envelope refurbishment as the thermal coating. Reference buildings were used to perform energy simulations in representative cities of Italy and energy and environmental impacts of the most common and sustainable insulation materials were thus evaluated. Relevant outcomes have been focused on defining a new Economic and Environmental Sustainability Index (EESI) capable of considering both economic and environmental aspects; particularly, sustainable materials (such as cellulose fiber) can have the same affordability as traditional ones (such as polystyrene foam slab, glass wool, or stone wool) if environmental impact is also taken into account, despite their higher cost. However, according to EESI, the affordability of traditional insulation materials remains evident in the warmest climatic zones because of the lower energy needs of buildings.

Retention and Determination of Polycyclic Aromatic Hydrocarbons from Urban Air Based on Recycled Polyurethane Foam Modified with Expanded Polystyrene

Expanded polystyrene (EPS) and polyurethane foams (PUFs) are widely produced and used due to their properties and, recently, it has been described that polystyrene present π–π interactions. Therefore, this work proposes to use recycled EPS to modify the surface of PUFs for the retention of 12 polycyclic aromatic hydrocarbons (PAHs) in air samples. PUF cylinders were modified with recycled polystyrene and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and affinity experiments. The proposed material is suitable for the retention-elution of PAHs from air samples, and can be incorporated to liquid chromatography generating a quantitative methodology. This methodology is efficient, fast and use lower volumes of organic solvents compared with other methodologies. Eighteen urban air samples were collected and analyzed weekly, using principal component analysis (PCA), and a relation between meteorological parameters and concentration of PAHs was observed.

Физико-химические и термические превращения газонаполненной полимерной теплоизоляции естественного старения

Introduction. In the process of operation, various materials are subjected to prolonged exposure to environmental factors, which can lead to irreversible physical and chemical changes that affect not only their service life, but also fire safety. In this regard, the study of the influence of natural ageing on the features of the combustion process, fire hazard characteristics of thermal insulation materials is relevant. Aims and objectives. The aim of the work is to evaluate the physicochemical and thermal transformations of polymer gas-filled thermal insulation (expanded polystyrene foam) of long-term natural ageing. Methods. A set of physicochemical methods, namely X-ray phase analysis, infrared spectroscopy and thermal analysis methods (TG, DTG, DSC) were used to study the physicochemical nature and thermal stability of naturally aged polystyrene foam. Results and discussion. In the work the technical condition of polymer thermal insulation was assessed on the objects: cinema "Udarnik" (Russia, Moscow), 1927-1930 year of construction and a residential building (Tajikistan, Vahdat), 2014 year of construction. The method of X-ray phase analysis for polystyrene foam of natural ageing revealed a decrease in crystallinity. The change in the phase state of polymer thermal insulation indicates the thermal fluctuation nature of the processes associated with its natural aging and leading to a change in the ordering of the arrangement of individual macromolecular sites of aromatic hydrocarbon. At the same time, under the conditions of natural ageing there is a decrease in the apparent density of polystyrene foam by 20-41 %. By method of infrared spectroscopy the greatest changes are established in areas of characteristic absorption bands 3057...2846 cm-1, and also 1500...1450 cm-1, that testifies to destabilisation of hydrocarbon chains of macromolecules of polystyrene foam of natural ageing. The character of thermo-destructive transformations is established for the investigated samples, the tendency of expansion of the main section (335...470 °С) in comparison with the samples without natural ageing (360...450 °С) is revealed. The identified features of physicochemical and thermal transformations of naturally aged polystyrene foam can lead to changes in the intensity of the combustion process and heat release. Conclusion. According to the results of the study it is established that in the process of natural ageing in gas-filled polymers irreversible physical and chemical changes occur under the influence of environmental factors. Deterioration of the technical condition of polymer thermal insulation during its operation can lead to changes in the characteristics of fire hazard, features of its combustion and heat release when exposed to fire. Keywords: thermal insulation; polymers; polystyrene foam; fire hazard; service life; natural ageing.

Humidity conditions of brick enclosures heat-insulated by polystyrene foam from various manufacturers

The most appropriate way to select materials for a heat-insulating coating of an exterior wall depends on the opportunity to prevent water condensate to appear in this enclosure and, during the development of design and detail documentation, to prevent harmful effects on the building structures (damages of enclosing structures, improved heat conductivity of materials and heat leaks from premises resulting in reduced energy efficiency of buildings) during operation. The analytical study has been conducted for the most efficient grades of heat insulators made of polystyrene foam for the bearing layer of a wall made of silicate bricks. Two options for heat-insulating layer materials are investigated: A) polystyrene foam by Radoslav, Pereslavl-Zalessky, plate No. 18; B) polystyrene foam by BASF, model Styropor PS 15. Based on the characteristics of the heat insulators selected for the study, the calculation and analytical method was used to determine probability of water condensate to appear in the wall structure at the exterior temperatures of –9.9 °С to –27 °С. The findings showed that when any heat insulators selected for the study is used as a heat-insulating layer, the bearing structure excludes condensate formation and strength characteristics of the enclosure will not be reduced due to the brickwork freezing.

Copper oxide nanorods based nanofibers membrane for solar-driven interfacial evaporation

Solar-driven interfacial evaporation system has attracted intensive attention owing to its great potential in harnessing renewable solar energy to purify water. To further enhance the solar-driven interfacial evaporation system performance, solar absorber structure with high light-thermal energy conversion efficiency is especially critical. In this work, polyvinyl pyrrolidone/poly(vinylidene fluoride co hexa fluoropropylene)/CuO-nanorods (PVP/PVDF-HFP/CuO-nanorods) membrane was prepared sequentially by electrospinning, heating and hydrothermal processes. The flexible electrospun membrane was used as the photothermal layer in the solar-driven interfacial evaporation system. The evenly distributed CuO nanorods function as solar energy absorbers. The polystyrene foam was used as an insulating layer, and filter paper was inserted in the middle of the polystyrene foam to transport water to the photothermal layer. The designed evaporator was used for the solar evaporation using pure water. As a result, the evaporation rate was 1.11 kg/m2h and the light-thermal energy conversion rate was 75.36%. The outcome of this work provides the potential of solar-driven interfacial evaporation system for water desalination and wastewater purification.

The current state and prospects for the development of the Lost Foam Casting process

Increasing the capacity of foundry production can play a decisive role in the recovery of the machine-building and defense sectors of the Ukrainian industry. The current state and prospects for the development of foundry technology — Lost Foam Casting (LFС) process, as well as its possibilities for increasing the volume of metal processing into finished parts on the example of China, are considered. For foundries of low-volume casting, which need fast production of foundry patterns, the LFС method contributes to the minimization of capital and current costs. The melting, casting and finishing processes in LFС are the same as in typical foundry processes, with the exception of the need for a 30—50 oC higher pour temperature. The process of making patterns from polystyrene foam (EPS) has been developed in several variants and can initially be implemented on a small scale to obtain trial castings. An existing foundry, after successful trials with a simplified LFC process, can increase batch sizes of castings along with increased investment in tooling and equipment to do so. Mechanical processing when obtaining foam patterns is beneficial for volumes of less than 100 castings, and for a series of more than 1000 castings (common use of LFС) sintering of granulated EPS in molds is used, including the use of automated equipment for this. In terms of the amount of solid and gaseous waste, LFС in forms with dry vacuumed sand is ecologically superior to most foundry processes. The LFС process is constantly developing and improving, easily includes 3D technologies in the sequence of its operations and is amenable to digitization, automation, robotization and scaling, refers to high-precision casting in sand molds using noncapital- intensive equipment. The example of China shows the possibility of a rapid increase in the production of castings in a wide range of their weight, nomenclature and type of used metal alloys.

Computational analysis and evaluation of thermal comfort environment of a space by reducing the inside air temperature

The tents are used as temporary shelters and evenly they sometimes become a home for a number of years when the returns to permanent shelter is very slow or unaffordable for any person so that the comfort of these shelters are very much essential like home. This paper is primarily concerned with identifying the objectives of reducing the inside air temperature of shelter using different retro-reflective materials. In the present work computational fluid dynamics analysis have been performed for a shelter under the summer climatic conditions to reduce the inside air temperature of shelter using different retro-reflective materials like polyvinyl chloride, wood-fibre, polystyrene, aerogel and phenolic foam. For CFD analysis free stream temperature of air is set 311 K taken with constant heat flux of 900 W/m2 solar radiations is used on roof, second order upwind discretization scheme is used to approximate the solution for momentum and pressure. Result show that that minimum temperature variation of 4.8 degreesK by using retro-reflective material as phenolic-foam and 18.74 % temperature percentage variation compared with other reflective materials.

Experimental research of energy absorbing structures within helmet samples made with the additive manufacturing method - preliminary study

Purpose This study aims to develop an energy-absorbing structure for bicycle helmets to minimize head injuries caused by collisions. The research team explores three geometric structures produced through additive methods and compares their energy absorption properties with a standard bicycle helmet made of Expanded Polystyrene (EPS) foam. Methods The study prepared samples of three geometric structures (a ball, a honeycomb, and a conical shape) and a fragment of a bicycle helmet made of EPS foam with the same overall dimensions. Laboratory tests were conducted using a pneumatic hammer, piston compressor, anvil, triaxial accelerometer, and data processing systems. Three crash tests were performed for each type of structure, and the anvil's maximum acceleration and stopping distance after the crash were analyzed. Results The study found that the energy absorption properties of the Polylactic Acid (PLA) material printed with the incremental method were comparable or better than those of the EPS material used in helmets. The geometric structure of the energy-absorbing material played a crucial role in its effectiveness. The most promising results were obtained for the ball samples. Conclusions The study concluded that further research on energy-absorbing structures made using the Fused Deposition Modeling (FDM) method could be useful in the production of bicycle helmets. The results show that the geometric structure of the energy-absorbing material is a crucial factor in its effectiveness. The findings suggest that the ball-shaped structure made with PLA material printed using the incremental method could be a promising design for bicycle helmets to minimize head injuries caused by collisions.

Silver Nanocatalyst Supported on Waste-Based Polystyrene Foam for Thermal and Plasmonic Reduction of p-Nitrophenol

Disposal of plastics into the environment has been one of the major problems for the environment. The accumulation of polystyrene (PS) occurs in an accelerated way and, therefore, its reuse is challenging. Polystyrene nanocomposites impregnated with Ag nanoparticles (PS/AgNP) are generated from polystyrene residues and can be applied in the catalytic and plasmonic photo-catalytic reduction of phenolic compounds such as p-nitrophenol (PNP) to p-aminophenol (PAP). The AgNP were synthesized by a reverse micelle method resulting in nanoparticles with sizes in a range of 31.1-34.0 nm. The organocolloid was characterized by UV-Vis and dynamic light scattering (DLS), demonstrating the preparation of spherical nanoparticles. The preparation of the PS/AgNP, obtained using a thermally induced phase separation method (TIPS), was confirmed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), laser-induced breakdown spectroscopy (LIBS), and Fourier transform visible infrared spectroscopy (FTIR). Nanocomposites showed impressive performance in the catalytic and plasmonic photocatalytic reduction under blue light irradiation, reaching up to 98% conversion, being a promising material for wastewater treatment as well as other various environmental issues. We used blue light to observe the plasmonic effect of silver nanoparticles, and no previous reports of this composite for PNP reduction using blue light photocatalysis were found.

Universal slabs for hydro- and heat insulation

The article deals with the creating of a universal material for protecting underground structures from groundwater as well as providing their thermal protection. The article presents a method for waterproofing and drainage of underground walling structures using drainage slabs made of filtration polystyrene foam and considers the possibility of using these slabs for reducing heat losses of heated underground structures. Thermal engineering characteristics of filtration polystyrene foam are determined, and calculations of heat losses of underground walling structures with slabs made of this material are given. The results of studies of the kinetics of water drainage by filtration polystyrene slabs are shown. The dependence of the heat conductivity of filtration polystyrene on humidity and other factors are also presented. Calculations of heat losses through the walls of heated underground premises are given, taking into account the temperature distribution in the ground along the depth of the structure. A comparative analysis of heat losses with the use of filtration polystyrene foam slabs and without them has been carried out. Based on the experimental results obtained, it was revealed that filtration polystyrene foam has not only high filtration characteristics, but is also an effective material for thermal protection of underground structures.

Porous carbons prepared from a novel hard wood composite waste for effective adsorption of Pb(ii) and Cd(ii) ions.

In our previous investigations, a hard wood composite (HWC) was formulated by adding rice straw, as a filler to the recycled polystyrene foam waste at mass ratio (50/50) at 170 °C and pressed under 40 kPa. Here, the disposed HWC product as a model scrap was applied for production of porous carbons enclosed with graphene sheets. To attain this approach, HWC was hydrothermally carbonized (S1) followed by either post-heat treatment (S2) or potassium hydroxide (KOH, S3) activation at 750 °C for 2 hours. The properties of prepared samples were evaluated using SEM, ATR-IR, and porosity measurements. The adsorption performance of the obtained porous carbons toward removal of lead (Pb(ii)) and cadmium (Cd(ii)) ions from aqueous solutions was investigated under different operating conditions like contact time, initial pH, initial metal ions concentration and adsorbent dose. Kinetic models such as pseudo-first order, pseudo-second order and intraparticle diffusion were used to analyze the adsorption data. Langmuir, Freundlich, Dubinin-Radushkevich and Redlich-Peterson isotherms were applied. Thermodynamics and regeneration studies were performed. The sample (S3) comprised a micro-mesoporous carbon structure encompassed by graphene sheets, with the largest total surface area (422 m2 g-1) and adsorption capacities for Pb(ii) and Cd(ii) ions of 207.9 and 119.6 mg g-1, respectively. The experimental adsorption data were best elucidated using Langmuir and pseudo second-order kinetic models. Thermodynamic experiments confirmed that adsorption is an endothermic and spontaneous process. Conclusively, the investigated HWC waste is a promising carbonaceous precursor for preparing effective porous graphene-carbons used in the removal heavy metals from their aqueous stream.

Vacuum pyrolysis depolymerization of waste polystyrene foam into high-purity styrene using a spirit lamp flame for convenient chemical recycling

Vacuum pyrolysis of waste polystyrene foam over a spirit lamp flame for 20 minutes produced 98% pure styrene without needing fractionation or purification, which promises a convenient closed-loop chemical recycling system.

Efficient removal of viscous crude oil by a super-hydrophobic polystyrene/carbon black foam with photo-thermal conversion

In this study, carbon black nanoparticles were introduced in one-step to develop a super-hydrophobic polystyrene foam with efficient photo-thermal conversion and adsorption for highly viscous crude oil.

A new strategy to synthesis of porous polymers from plastic waste for highly efficient adsorption of rhodamine B, malachite green and I2 vapor

Plastic waste has been becoming a severe environmental issue. Developing low-cost and facile strategy to converse them into the high value-added materials for remediation of ecosystem is a big challenge. In this manuscript, Polystyrene foam waste (PSF) was employed as starting material to react with the different mass ratio of cyanuric chloride (CC) to synthesize a series of hyper-cross-linked polymers (HPPCs). HPPCs were porous polymers and mainly composed of micro-pores and meso-pores. Their apparent surface areas (SBET) and pore volumes were in range of 622.9 ± 11 and 719.2 ± 15 m2 g−1, 0.87 and 1.01 cm3 g−1, respectively. The SBET and pore volume could be tuned by the mass ratio of PSF and CC. Adsorption experiments revealed that HPPC-3 showed high adsorption quantities of rhodamine B (RhB) and malachite green (MG) with the maximum adsorption capacities of 2354.0 ± 60.8 and 1331.9 ± 30.6 mg g−1, respectively. The adsorption isotherm and kinetics data suggested that the adsorption behaviors of RhB and MG on HPPC-3 followed the Langmuir models and pseudo-second-order models. Additionally, HPPC-3 displayed high adsorption capacity of iodine vapor up to 188 ± 3.2 wt%. Therefore, this work suggested a new approach for converting plastic waste into the promising adsorbent for removal of dyes and radioactive iodine vapor from contaminated ecosystem.

Cassava starch-derived aerogels as biodegradable packaging materials

Biodegradable and natural materials can provide transformational solutions to environmental issues, particularly those associated with ubiquitous fossil-resources-derived conventional polymers like polyolefin thermoplastics and polystyrene foam as packaging materials. Herein, a facile approach is presented for preparing biodegradable and biocompatible lightweight structural scaffolds as an alternative to conventional plastic-based packaging materials. A variable dosage of polyvinyl alcohol (PVA) is used along with cassava starch to govern the structural integrity, mechanical properties, and porosity of resultant aerogels. The incorporation of PVA as a strengthening precursor improved the compressive modulus of starch aerogel from 2.0 to 18.2 MPa. Hydrogen-based interactions between the starch and PVA components, as revealed by infrared spectroscopic and differential scanning calorimetric measurements, extended the structural integrity. The high and regulated porosity of these aerogels furnished significantly low density (0.13–0.21 mg mm−3). A 98.5% of the starch-PVA aerogel is converted to CO2 by the microbial consortia within 23 days, signifying excellent biodegradability of these aerogels. Moreover, cassava starch-PVA aerogel is demonstrated as alternative packing material to conventional non-biodegradable black plastic bags for growing, transporting, and transplanting young plants. The improved thermal stability (<270 °C), low density, good compressive modulus (2.0–18.2 MPa), and excellent biodegradability reveal the potential of starch-based aerogels as excellent alternatives to conventional polyolefin thermoplastics and polymer-foam-based packaging materials.