Polystyrene Foam Research Articles

Use of Cement Hydration Heat as Heating Resource in Curing of Precast Concrete - Temperature Rise Simulation

In the present paper, the effects of the thermal insulation layer on the temperature field of concrete board and further on the development of mechanical properties of the concrete are investigated by a temperature field model that takes cement hydration heat into account. In the modeling, factors that may influence the development of temperature in the board, including the thickness of the insulating polystyrene foam board, concrete strength, and casting seasons are considered. The effect of temperature rise on the mechanical properties of the concrete is evaluated through a model of degrees of cement hydration and compressive strength of concrete. The results show that the temperature inside the concrete board is greatly increased after placing a thermal insulation layer on the surface of the concrete after casting. More uniform temperature distribution along the slab thickness is observed compared to that without the thermal insulation layer. Temperature rise inside concrete board can greatly speed up cement hydration and the development of concrete strength. Curing with a reasonable thermal insulation layer allows the heat of cement hydration to be used effectively to increase the strength of concrete and to realize demoulding around 24 hours after casting.

Prediction of open porosity of polystyrene foams based on simulation of bubble wall rupture during bubble growth

The bubble wall rupture (BWR) behaviour and the resultant cell connections of polystyrene (PS) foams were thoroughly investigated. The experimental results indicated that the open porosity ψ of the PS foams was highly dependent on the nucleation density ρn but had multiple varying paths at different expansion ratios Er. The non-uniformity of the bubble wall during bubble growth was considered herein as the key to explaining the multiple paths; the non-uniformity was quantified in terms of a heterogeneity factor γ. The bubble wall shape evolution model was employed to theoretically calculate the bubble wall shape after the bubble growth. The open porosity ψ and bubble wall non-uniformity γ had good regularity because the macroscopic changes in ψ were governed by the microscopic BWR. The functional image of ψ with respect to Er and ρn, considered as two independent variables, was obtained, and the image accuracy was further verified experimentally.

Different plastics ingestion preferences and efficiencies of superworm (Zophobas atratus Fab.) and yellow mealworm (Tenebrio molitor Linn.) associated with distinct gut microbiome changes.

Larvae of superworms (Zophobas atratus Fab.) and yellow mealworms (Tenebrio molitor Linn.) can survive on sole plastic diets. However, no side-by-side comparison of plastics degradation by both species is available yet. Here, superworms and yellow mealworms were fed with polystyrene (PS) or polyurethane (PU) foam plastics as sole diets for 35 days with bran as control. Superworms survived 100% on all diets but decreased weights were observed after 20 days with sole plastic diets. In contrast, yellow mealworms survived 84.67% or 62.67% with PS or PU diet, respectively, both plastics diet groups showed increased weights. Cumulative consumption of plastics by superworms were 49.24 mg-PS/larva and 26.23 mg-PU/larva, which were 18 and 11 folds of that of yellow mealworms, respectively. When converted into mg/g-larvae, superworms had a higher PS consumption rate but both species had similar PU consumption rates. Similar changes of the plastic chemical functional groups in frass indicated occurrences of oxidation and biodegradation of plastics in the guts of both species. Changes of gut microbial communities were found associated with plastics feedstocks and larvae species. The increased relative abundances of unclassified Enterobacteriaceae, Klebsiella, Enterococcus, Dysgonomonas and Sphingobacterium were strongly associated with PS diet in superworms, while Hafnia was strongly associated with PS diet in yellow mealworms. Enterococcus and Mangrovibacter were dominant in PU-fed superworm guts, while unclassified Enterobacteriaceae and Hafnia were strongly associated with PU feeding in yellow mealworms. The results demonstrated that different plastics ingestion preferences and efficiencies of both species were associated with distinct dominant microbiomes although similar changes of chemical groups in plastics were observed.

Effect of Expanded Polystyrene Foam Aggregate on Strength and Shrinkage Characteristics of Foamed Concrete

A study has been undertaken to assess some characteristics of foamed concrete, with a given density of 1200 kg/m³, made with expanded polystyrene foam aggregate (EPS). In addition, EPS particles were thermally treated to produce modified expanded polystyrene foam aggregate (MEPS). Thermally treating approach was applied as an effective method to enhance strength of expanded polystyrene foam particles leading to enhance the properties of produced concrete. To investigate the effect of foam presence, normal concrete mix was designed and compared with foamed concrete mix produced with the same mortar content. Properties such as compressive strength, tensile strength and drying shrinkage were assessed. It was found that adding recycled expanded polystyrene foam (EPS) as aggregates helped in slightly enhancing both the strength and shrinkage of foamed concrete. However, thermally treated of EPS to produce MEPS particles resulted in increasing the compressive and tensile strengths by about 68% and 79%, respectively; and reducing the shrinkage by about 52% of that of conventional foamed concrete mix, without EPS. In addition, adding polystyrene aggregates in both states (EPS and MEPS) slightly reduced the spread diameter.

Possibilities of Full Waveform Inversion as an imaging method in heterogeneous solids

Ultrasonic imaging of single objects in heterogeneous solids such as concrete is mainly performed using linearized methods that are limited to one wave type and neglect geometric reflections and mode conversions. This limits the reconstruction accuracy and can induce artifacts. By considering more information of the complete resulting wavefield, full waveform inversion (FWI) promises a more accurate imaging. The method compares the measured signals with the results of the forward calculation of the scattered field of the source signals. The distribution of all three isotropic material parameters is iteratively adjusted to minimize the difference between the calculated and measured signals. By using a viable forward model, no limiting assumptions about wave propagation are necessary. Since the problem is ill-posed, regularization techniques are used for stabilization. The paper explains the operation and possibilities of the model-based approach considering both synthetic and experimental measurement data. First results on idealized scatterer geometries in homogeneous and heterogeneous solids are presented. Beginning with synthetic measurement results for the identification of anomalies in the solid body, the method is then applied to laboratory experimental data in the ultrasonic frequency regime. In both cases the same concrete structure is adressed where a known inclusion made of extruded polystyrene foam (XPS) is representing the anomaly to be detected.

Understanding the Influence of Gypsum upon a Hybrid Flame Retardant Coating on Expanded Polystyrene Beads.

A low-cost and effective flame retarding expanded polystyrene (EPS) foam was prepared herein by using a hybrid flame retardant (HFR) system, and the influence of gypsum was studied. The surface morphology and flame retardant properties of the synthesized flame retardant EPS were characterized using scanning electron microscopy (SEM) and cone calorimetry testing (CCT). The SEM micrographs revealed the uniform coating of the gypsum-based HFR on the EPS microspheres. The CCT and thermal conductivity study demonstrated that the incorporation of gypsum greatly decreases the peak heat release rate (PHRR) and total heat release (THR) of the flame retarding EPS samples with acceptable thermal insulation performance. The EPS/HFR with a uniform coating and the optimum amount of gypsum provides excellent flame retardant performance, with a THR of 8 MJ/m2, a PHRR of 53.1 kW/m2, and a fire growth rate (FIGRA) of 1682.95 W/m2s. However, an excessive amount of gypsum weakens the flame retardant performance. The CCT results demonstrate that a moderate gypsum content in the EPS/HFR sample provides appropriate flame retarding properties to meet the fire safety standards.

Cellulose–Chitosan Biodegradable Materials for Insulating Applications

Bio-based lightweight porous materials have attracted attention due to their unique properties and have become an interesting alternative to petroleum-based foams such as expanded polystyrene (EPS) and polyurethane foams. In this work, biodegradable cellulose pulp–chitosan foams were obtained through a low-cost, simple, and scalable method. A full factorial design was carried out to study the effects of three experimental factors (chitosan content, foaming agent concentration, and foaming time) on apparent density and mechanical properties. The prepared foams displayed low apparent densities (0.06–0.12 g/cm3), good mechanical performance (elastic modulus: 0.18–1.20 MPa, compressive strength: 0.02–0.11 MPa), excellent thermal insulation properties (thermal conductivities: 0.03–0.04 W/mK), and high biodegradation rates. The increase of chitosan content improved the water resistance and mechanical strength. Finally, these materials could be suitable for several applications in which thermal insulation, mechanical resistance, and water stability are crucial, including packaging and construction, as an alternative to traditional nonbiodegradable materials.

Application of noise reduction and heat insulation based on controlled-size polystyrene hollow microspheres

Core/shell polymer microspheres containing carboxyl group were prepared by emulsion polymerization, and then the hollow polymer microspheres (PHMs) were formed by infiltration and swelling after alkali solution post-treatment. Effects of emulsifier types and initial pH of alkali post-treatment on the particle size distribution and morphology of PHMs emulsion were investigated. Foamed animal skin material (FAS) was obtained by cross-linking and curing the skin collagen materials with PHMs. The results showed that the optimal initial pH was 9, and a stable PHMs emulsion with a maximum average particle size of 888.5 nm was obtained. The average particle size order of the PHMs emulsions obtained with different emulsifiers was: sodium stearate (1028.0 nm) > SDBS (823.6 nm) > cetyltrimethylammonium chloride (607.4 nm). The mechanical strength, porosity, and thermal stability of FAS were enhanced by PHMs dispersing and fixing, while its natural permeability and softness were retained. In addition, the whiteness and ultraviolet aging resistance of FAS were improved obviously. The thermal conductivity of FAS was reduced to 0.034 W/(K·m), which was in line with the standard of polystyrene foam board for building materials. In the range of 2000 ∼ 7000 Hz, the sound transmission loss of FAS reaches 25 ∼ 40 dB.

Rancang Bangun Bilah Berbahan Expanded Polystyrene (EPS) Foam untuk Kecepatan Angin Rendah pada Produk Horizontal Axial Wind Turbine

The increasing use of electrical energy is inversely proportional to the diminishing fossil energy sources. New and Renewable Energy is one of the alternative energy that is being developed now. One of the energy used in the utilization of new and renewable energy is wind energy. In this study, we will discuss the manufacture of blades made from Expanded Polystyrene (EPS) Foam which is intended for wind turbines at low wind speeds. The use of this material is used and is able to form a blade with a weight of ± 300gram. This blade uses an Inverse Tapper type blade, which is a blade with an enlarged geometry at the tip, this geometry has a large surface so that it can receive more wind so that it can rotate at low wind speeds. The design and manufacture of blades is carried out using Aeolus ASP software which is open source on several analysis features and serves to determine the performance of the blades as well as to analyze aerodynamics and optimization of the shape of the blades designed to use Blade Element Momentum (BEM). This blade is capable of producing a voltage of 12.09 V. In the process of making the blade using wire cut to create geometry with National Advisory Committee for National Aeronautics (NACA) 4412 airfoil. The blade uses layers of balsa wood and monocote plastic sheets, and uses wood plywood as the base of the blade.

The Effect of Variation of Latex Mixed Storage Time Polystyrene and Natural Rubber Concentrate Latex on the Stability of the Emulsion by Using Emulsifier Sodium Lauryl Sulfate

Preparation of latex polystyrene with emulsifier ammonium lauryl sulfate (ALS) has been carried out by dissolving styrofoam (foam polystyrene) in toluene (30/70). And then polystyrene solution was mixed with aquadest, at ratios polystyrene and aquadest (v/v) were 90:10, 70:30, 50:50, 70:30, and 10:90 then added 10 mL of sodium lauryl sulfate (NLS) solution at concentrations 30%. The characterizations of the latex polystyrene included the stability determination during storage by density measurement and the determination of particle sizes and forms by microscopic optic observation. The results show that latex polystyrene ratio 90:10 is the most stable with density value constant during storage, are 0,848 g/mL for 30%. The particle sizes average is 1,56 mm with the distribution particle sizes decreasing as latex is 8,3 mm. Photomicrograph microscope optic shows that latex polystyrene NLS 30% has familiar particle forms and sizes

Utilization of Used Polystyrene As Adhesive In Polymer Emulsion Asphalt

The utilization of used polystyrene as adhesive material for emulsion polymer asphalt has been carried out. Polystyrene foam was dissolved in toluene at the ratio of 30:70 mL, then the solution was mixed with aquadest at ratios of 90: 10 mL, 70: 30 mL, 50: 50 mL, 30:70 mL, and 10: 90 mL. Then added with 10 mL of Sodium Dodecyl Sulfate solution at concentrations of 10%, 20%, and 30%. The most stable latex polystyrene was mixed with 200 g of sand aggregate at volume ratios of 10 mL, 20 mL, 30 mL, 40 mL, and 50 mL. Then the mixture was pressed into a hotpress at 150ºC for 20 minutes. The mixture obtained was characterized using tensile strength testing, water absorption, and SEM spectroscopy. The results showed that the mixture of sand aggregate with 50 mL latex polystyrene has the best compressive strength and water absorption, at a load of 1606 Kg.f, a stroke of 14.93 mm/minutes, and a water absorption percentage of 18%. The morphology result showed that the surface of sand aggregate with 50 mL of latex polystyrene mixture contains smaller and least holes than the surface of sand aggregate with 10 mL of latex polystyrene mixture.

Rapid Solar Heating of Antimicrobial Ag and Cu2O Nanostructured Plasmonic Textile for Clean Water Production.

Solar steam generation is an attractive method to produce clean water, and high steam generation rates have been achieved using nanostructured light absorbers. However, since it usually takes minutes to reach the temperature for steady-state steam generation under solar illumination, a material that responds quickly to intermittent sunlight is strongly desired. Here, we report an unprecedented heating rate in an ultralight freestanding textile consisting of interconnected Ag and Cu2O nanoparticles. The textile demonstrated high solar absorption with low reflectance and transmittance, which were rationalized using our multiphysics simulations. A commercial polystyrene foam wrapped with this broadband light-absorbing textile showed the fastest response to sunlight together with a good steam generation rate compared to reported inorganic nanostructured steam generators. Furthermore, the textile exhibited antibacterial property, which might lower the risk of the vapor-induced transfer of bacteria during long-term intermittent use and the cost of subsequent water sanitization.

Impact behavior of energy absorbing helmet liners with PA12 lattice structures: A computational study

Existing helmets have a significant but limited ability to reduce the severity of brain injury and the fatality rate during motorcycle accidents. Helmet designs with a special focus on reducing head injuries caused by rotational effects have attracted great interest in recent times. This paper uses a computational approach to study the generation of new helmet designs with lattice liners made of polyamide12 (PA12) material. Three design possibilities and three distinct unit cell topologies were used to create the liners as the energy absorbing and dissipating part of the helmet. PA12 lattice samples were additively manufactured and tested under quasi-static and dynamic compression loads. The test data, showing ductile to brittle transition due to strain-rate effects, were used to validate the finite element models of the lattices. Simulations of the linear high energy and oblique impacts on the coupled headform and liner were carried out following the state-of-the-art helmet standard ECE R22.06. The findings of this study suggest that PA12 lattice liners have an excellent capability of reducing peak rotational acceleration. Many liners can outperform the protection levels offered by existing expandable polystyrene foam liners for single impacts, but at the expense of weight. The performance of the liners can be improved by choosing the topology in such a way that the stress can be distributed through the struts. Moreover, a lattice liner having a balanced energy absorption capability and stiffness would perform better than other lattice liners.

Reprocessing Post-Consumer Expanded Polystyrene: Mechanical and Thermal Properties of Lightweight Concrete Made With Postconsumer Expanded Polystyrene

Expanded polystyrene foams (EPS) are used as packaging materials and are often discarded by consumers after the goods are unpacked (WEPS). Most recycling centers do not accept them because their extremely low weight makes them uneconomic to transport. In the research described here, WEPS was collected from shipping containers and crushed in a blender into 2-4 mm spherical shapes that were used as a replacement for aggregates to make lightweight concretes (LWC) to build lightweight facilities. Eight types of concrete samples were prepared, with the WEPS replacing the natural aggregate at the levels of 0 to 85 percent by volume to study the effects of the WEPS on the properties of the LWC. The densities of the LWCs were less than that of those found from natural aggregate (NAG), as was expected (900–1700 kg/m3). The heat conductivity of the LWC samples was smaller than that of NAG when the composition of WEPS was below 50%. The 28-day compressive strengths of the LWC ranged from 11 MPa to 90 MPa, which satisfies the strength requirement of semi-structural LWC recommended by ASTM to be higher than 17 MPa.

Structural Behaviour of Polystyrene Foam Lightweight Concrete Beams Strengthened with FRP Laminates

Lightweight concrete (LWC) is one of the most important building materials nowadays. Many research studies were focused on LWC produced using lightweight aggregates. However, limited work was cited for LWC produced using polystyrene beads. In this study, LWC beams strengthened with carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP) were experimentally tested to investigate the improvement in their flexural and shear behaviours. LWC in this investigation was achieved by partial replacement of normal aggregate by polystyrene beads and resulted in approximately 30% less weight compared to Normal weight concrete. Fourteen Reinforced Concrete (RC) LWC beams of 100 mm by 300 mm cross section having an overall length of 3250 mm were tested under four-point bending. These beams were designed, detailed, and tested to obtain flexural and shear mode of failure. These beams were divided into two groups based on the intended failure mode. In each group, six beams were strengthened using CFRP and GFRP laminates, while the remaining one beam was used as control. The tested parameters were the type of FRP, the width of the laminates used in shear strengthening, and the number of layers used in flexural strengthening. It was found that strengthening of LWC beams using CFRP and GFRP layers resulted in increasing the loading capacity and decreasing deflection as compared to control. The strengthening with CFRP and GFRP is also suitable in reducing the crack width and crack propagation which is more significant in LWC beams. The experimental results were also compared with the expressions in codes for forecasting the strength of LWC beams and it was that these expressions are compatible with the experimental results.

A robust adhesion between extruded polystyrene foam and mortar through different chemical linkages under ultraviolet-ozone irradiation

The inert surface of extruded polystyrene foam (XPSF) was activated by the ultraviolet-ozone (UVO) irradiation, followed by the surface coupling reactions with γ-mercaptopropyl trimethoxysilane (MPTMS) and vinyl triethylsilane (VTEO) to improve the interfacial affinity between the organic XPSF and inorganic mortar. The reaction conditions (including reaction time, concentration and pH of the silanes) were thoroughly investigated in order to reach the maximum bonding strength (BS) of XPSF/mortar composites. It was suggested that the presence of MPTMS could increase the BS value from 0.04 MPa to 0.178 MPa (reaction time: 10 min, concentration of MPTMS: 2% and pH value of the silane solution: 4). For VTEO, the maximum BS value reached to 0.140 MPa (activation and reaction time: 7 and 3 min, concentration of VTEO: 5% and pH value of the silane solution: 7). According to the mechanism analysis, the thiol groups in MPTMS have the strongest reactivity with activated XPSF surface after UVO exposure, leading to the maximized interfacial strength between the organic insulation materials and inorganic mortar.

Experimental and theoretical study on flexural behaviour of a new UHPC sandwich slab

In this study, a new type of prefabricated ultra-high performance concrete (UHPC) sandwich slab is proposed, which is composed of UHPC layer at the top and bottom, short UHPC columns and extruded polystyrene foam board (XPS) in the middle layer. The load-bearing and thermal-insulation integrated sandwich slab shows much lower self-weight and less reinforcement than traditional concrete slab, which are very beneficial for construction of precast structures. This paper first presents a reasonable and reliable casting method for the new sandwich structure. Then four-point bending tests on five slabs are conducted to reveal their flexural performance. The investigated parameters include the thickness of the UHPC layer, reinforcement ratio, short column spacing and XPS layout. Test results demonstrate that this type of sandwich slab, with 4500 mm span length, 150 mm thickness and one-way simply supported condition, has excellent anti-cracking and flexural performance, which can sustain an additional uniformly distributed load more than 9 kN/m2 before cracking even without reinforcement. A small ratio of reinforcement 0.13% in the bottom layer can further improve the ultimate bearing capacity by 20% and ultimate deformation by 61%. Finally, the calculation methods of cracking load, peak load and stiffness are proposed, together with design suggestions for typical slab dimensions, which offers valuable guidance for practical engineering.

Characterizing Fragmentation of Polystyrene Foam Debris by Isopods Oniscus asellus (Isopoda: Oniscidae) and Trachelipus rathkii (Isopoda: Trachelipodidae).

Microplastics present a novel and potentially unique threat to soil ecosystems, one whose effects may be mediated by soil organisms themselves. We investigated fragmentation of polystyrene (PS) foam into microplastic particles by two isopods, Oniscus asellus L. and Trachelipus rathkii Brandt, in laboratory arena experiments. First, we examined the temporal dynamics of fragmentation across a time span of 96 h. O. asellus produced more fragments than T. rathkii, and neither species significantly fragmented the PS foam until 48 h had passed. Second, we asked whether O. asellus would still fragment PS foam in the presence of an alternate, more natural substrate like wood. Wood did not significantly affect fragmentation rates, in line with the few other studies examining the effect of alternate food on soil invertebrates' propensity to consume and/or fragment plastics. Our results provide additional characterization of PS foam fragmentation by isopods and indicate that laboratory experiments involving soil invertebrates and plastic debris can take place over relatively short timespans of four or fewer days, but do not necessarily need to provide alternate food to prove that plastic consumption would still occur in its presence.

Synthesis of a novel triazine-based intumescent flame retardant and its effects on the fire performance of expanded polystyrene foams

A novel intumescent flame retardant, phosphorylated histidine-amino triazine-diaminopropane (PHTD) was synthesized and utilized as both a flame retardant and a binder addition. Flame retardant expanded polystyrene (EPS) foams containing PHTD was successfully prepared by coating method. The limited oxygen index (LOI) and vertical burning (UL-94) tests were used to determine the flammability of EPS/PHTD composite foams, and an apparent flame retardant effect could be obtained with up to 28.8% LOI value and UL-94 V-0 rating when 41.9 wt.% PHTD was added. The cone calorimetric test results showed that the treat EPS sample showed significantly depressed peak heat release rate (pHRR) by 74.9% and peak smoke production rate (pSPR) by 77.3%. Additionally, the flame retardant could be evenly coated on the surface of EPS beads. Even though part of the foam was damaged, it could still keep good flame retardant performance. Furthermore, the thermal conductivity of coated foam was not affected and remained at a comparatively low level, and the compressive strength was increased by 20.0%.

Optimal insulation’s thickness of pipes in Variable Refrigerant Flow (VRF) system—An-Najah Child Institute as a case study

Buildings use a significant amount of the world’s total primary energy, particularly in heating and cooling systems. Energy consumption of air conditioning systems can be lowered by installing energy-efficient systems that take into account piping thermal insulation. The objective of this research is to calculate the optimal thickness of insulation for piping networks with variable refrigerant flow and to investigate the environmental and economic impacts of using the optimal insulation thickness. The case study of this research is An-Najah Child Institute. The research is based on the current cost over the life cycle of the insulation, which is assumed to be 15 years, to determine the optimal thickness of the common insulation types (rock wool, extruded polystyrene, and flexible foam) for different pipe diameters and different refrigerant flow rates. The research results show that the optimum insulation thicknesses for pipe diameters from 12.7 to 50.8 mm using Rockwool are 32 to 44 mm, 28 to 38 mm for extruded polystyrene, and 11to 13 mm for flexible foam insulation. The reduction in energy losses from the optimal Rockwool insulation thickness in the case study piping system ranges from 78.5% to 81.6% compared to the uninsulated insulated piping system. In addition, the carbon emission saving by the optimal Rockwool insulation thickness is 1737, 1541, 1033, and 1160 kg CO2 for coal, oil, natural gas, and LPG fuel used in electricity generation, respectively. In addition, the study found that the physical parameters of the refrigerant, such as quality and flow rate, do not affect the optimal insulation thickness for all insulation types studied. And the thermal power saved corresponds to only 1.2% of the total system capacity