Properties Of Flexible Polyurethane Foams Research Articles

Mechanical and physical properties of flexible polyurethane foam filled with waste tire material recycles

Mechanical and physical properties of flexible polyurethane foam filled with waste tire material recycles

Impact of ambient and vacuum pressure on the physico mechanical properties of flexible polyurethane foam reinforced withCaCO3

AbstractThis study investigates the effects of variable pressure conditions (550 and 1013 mbar) on the physico‐mechanical and structural properties of flexible polyurethane foam, incorporating different compositions of calcium carbonate (CaCO3) filler. The objective is to achieve sustained mechanical and structural properties of flexible polyurethane foam while reducing costs through variable pressure foaming technology. With CaCO3filler concentrations ranging from 20 to 100 parts per hundred (pphp) of polyol, it was found that foam produced at low pressure (550 mbar) demonstrated improved resilience and durability, particularly with CaCO3compositions up to 100 pphp. Conversely, foam produced at standard atmospheric pressure (1013 mbar) using compositions up to 100 pphp did not exhibit significant enhancements in physico‐mechanical properties. The study employs various characterization techniques, including mechanical testing, scanning electron microscopy, differential scanning calorimetry, thermal gravimetric analysis, and Fourier transform infrared spectroscopic analysis, to assess the flexible polyurethane foam. It provides a detailed examination of the effects of variable pressure on cellular structure, cell size, filler distributions, mechanical properties, and thermal stability of flexible polyurethane foam using CaCO3filler.

Impact of filler and gelling catalyst/agent on properties of flexible polyurethane foam

AbstractIn this study, the physiomechanical properties of carboxymethylcellulose sodium salt (Na‐CMC salt) filler‐loaded foam and its impact on the wicking capacity of the foam were investigated in juxtaposition with the increasing tin concentration. According to the study's findings, standard unfilled foam demonstrated no wicking at all, while flexible PU foam filled with Na‐CMC salt, even with low porosity and subpar mechanical traits, displayed wicking heights of 4 mm, 3.4 mm, and 2.8 mm in test specimens of thicknesses of 6 mm, 8 mm, and 10 mm. Moreover, filled foam with a higher porosity level exhibited significantly better wicking heights of 11.4 mm, 10.8 mm, and 8.2 mm. The inclusion of CMC filler in the PU foam matrix is the reason for enhanced wicking property in foam. The sample thickness and wicking height trends are consistent among all foams; as foam sample thickness increases, wicking height progressively falls. The correlation between the foam's porosity value and the number of closed cell windows is confirmed by stereomicroscopy and the porosity values. According to this study, the infused filler's characteristics have a greater influence on the foam's wicking capacity than the foam's porosity. This study contributes significant insights into ongoing initiatives to enhance user experience, well‐being, and hygiene through innovative and meticulously designed new developed mattress foam using Na‐CMC as a filler.Highlights Co‐relation between concentration of tin and infused filler on wicking property. Standard unfilled foam demonstrated no wicking at all. Na‐CMC salt filled foam displayed wicking heights. After 15% increase in tin level, mechanical properties of foam degrade. Wicking depends on nature of infused filler and the foam's porosity.

Enhanced flame retardancy and thermal stability in flexible polyurethane foam through synergistic core-shell structured DBDPE@PMA particles

This research presents the synthesis of core–shell structured flame retardant particles, DBDPE@PMA, which combines the flame-retardant and toughening functions. These particles utilize decabromodiphenyl ethane (DBDPE) as the core and a copolymer of methyl methacrylate and acrylic acid (MMA-AA) as the shell, which are created via emulsion polymerization. The process involved an initial reaction of DBDPE@PMA with isocyanate, followed by foaming with polyether polyol to fabricate flame retardant, and the flexible polyurethane foam (P/D-FPUF) was thermally insulated. The study examined the influence of DBDPE@PMA on the flame retardancy properties of flexible polyurethane foam. Scanning electron microscopy confirmed the encapsulation of DBDPE by the polymer, resulting in a core–shell composite particle. The interaction between the carboxylic groups (–COOH) on the DBDPE@PMA shell and isocyanate enhanced the interfacial bonding, thereby increasing the foam's apparent density and ensuring better integration with the polyurethane matrix. However, DBDPE@PMA had aggregates on the foam matrix bubble holes, resulting in uneven bubble holes. DBDPE@PMA markedly improved the flame retardancy and thermal stability of the foam, compared to both pure polyurethane and foam containing solely DBDPE (10D-FPUF). The oxygen index value of the foam with 20% DBDPE@PMA (20P/D-FPUF) reached 33.6%, with UL-94 horizontal and Vertical burning level tests achieving the highest classifications. The char residue after thermal degradation increased significantly from 1.93% in pure foam to 5.06%. While the smoke density level rose, the duration to peak smoke density was prolonged to 78 s, offering an enhanced margin for evacuation during the initial stages of a fire.

Investigation of effects of bis(2-hydroxyethyl) terephthalate derived from glycolysis of polyethylene terephthalate on the properties of flexible polyurethane foam

Investigation of effects of bis(2-hydroxyethyl) terephthalate derived from glycolysis of polyethylene terephthalate on the properties of flexible polyurethane foam

Effect of flame‐retardant melamine and dispersants on the mechanical, thermal, and foaming properties of flexible polyurethane foam

AbstractThe objective of this study was to investigate the effect of adding flame‐retardant melamine and five different dispersants on the precipitation, foaming, mechanical, and thermal properties of flexible polyurethane foam (FPUF). Precipitation experiments were conducted to analyze the effect of dispersant on the separation of flame retardant and polyol, and the foaming characteristics of polyurethane (PU) foam after adding dispersant were analyzed. The effect of adding a dispersant on mechanical strength was characterized by measuring tensile strength, tearing strength, and hardness, and scanning electron microscopy analysis was performed to analyze morphological characteristics. Thermogravimetric analysis (TGA) was performed to analyze the thermal properties of PU foam. A horizontal flame test, limiting oxygen index test, and cone calorimeter tests were conducted to examine the flame retardancy of PU foam with flame retardant melamine and dispersant added. The dispersant ANTI‐TERRA‐U is a solution of a salt of unsaturated polyamine amides and low‐molecular acidic polyesters. And, the dispersant BYK‐220S is a solution of a low molecular weight, unsaturated acidic polycarboxylic acid polyester with a polysiloxane copolymer. The dispersants ANTI‐TERRA‐U and BYK‐220S improved the density, tensile strength, tear strength, and hardness of FPUF. TGA of the top and bottom portions of the foam showed less weight difference for samples containing dispersants, indicating better homogeneity due to improved dispersibility. Therefore, we conclude that dispersants are beneficial additives to improve the mechanical properties and dispersibility of PU foam.

Analysis of mechanical and flame‐retardant properties of flexible polyurethane foams

AbstractIn this study, the mechanical and flame‐retardant properties of flexible polyurethane foams (FPUF) were analyzed as a function of the type of flame retardant. FPUF containing equal amounts of two halogenated flame retardants (tris 2‐cloropropyl phosphate [TCPP] and phosphinyl alkyl phosphate ester) and three halogen‐free flame retardants (melamine, melamine cyanurate, and expandable graphite) were considered. The foaming properties of these samples were analyzed by studying the rise time and settling rate using cup foaming. Square foaming was used to analyze the mechanical properties, including density, elongation, tensile strength, and tear strength. In addition, Fourier‐transform infrared spectroscopy was performed, and flame retardancy was evaluated using a horizontal flame test and the limited oxygen index. A cone calorimeter test was also performed to evaluate the combustion characteristics. In FPUF containing the same ratio of flame retardant (15% of the total polyol), the properties of urethane foam blended with expandable graphite were improved; the tensile strength of this blend is 20% higher than that of samples containing melamine, and its peak heat release showed a 70% reduction compared to that of samples containing TCPP. These findings provide valuable reference information for developing flame retardants for fire safety FPUF in the near future.

Evaluation of the Effect of Waste from Agricultural Production on the Properties of Flexible Polyurethane Foams.

The management of by-products and waste from agriculture and the agri-food industry is a challenge for the plastics industry. Flexible polyurethane foams (EPPUR) containing ground corncake from corn oil production were obtained. The influence of the bio-filler on the physico-mechanical and thermal properties of synthesized flexible polyurethane foams was investigated. The content of corncake ranged from 0 php (part per 100 parts of polyol) to 10 php. Open-cell flexible polyurethane foams with a favorable comfort factor were obtained. The lower reactivity of the developed polyurethane systems was conducive to the formation of cells of slightly smaller sizes but of a more regular shape in comparison with the foam not modified with the bio-filler. Measurements of the mechanical properties indicated that the modified foams held had similar or even better properties than the reference sample without bio-filler.

Performances of green velvet material (PLON) used in upholstered furniture

Green Velvet Material (PLON), which is prepared from polyester slices, has been called a green material based on its ester composition, its ability to be degraded, and the possibility of recovering the value of used material by reprocessing. PLON is expected to be used as a material for the padding layer of upholstered furniture. This paper presented a comparative study of traditional flexible polyurethane foam and Green Velvet Material as the upholstered furniture’s padding layer. The compression mechanical properties of Green Velvet Material and flexible polyurethane foam, such as indentation force deflection, support performance, compression set, and resilience property, were analyzed. The results showed that Green Velvet Material had lower surface hardness and higher comfort compared to flexible polyurethane foam. In terms of resilience, both high-density and low-density Green Velvet Material performed better than the foam control group, but Green Velvet Material had a poorer ability to regain its shape after prolonged pressure. The 30 kg/m3 density Green Velvet Material was the closest to the compression and resilience properties of flexible polyurethane foam. The conclusions provide theoretical data for the effective and reasonable application of Green Velvet Material in upholstered furniture.

Flexible polyurethane foams reinforced with graphene and boron nitride nanofillers

AbstractThe effect of three types of nanofillers on the physical, mechanical, and thermal properties of flexible polyurethane foams (FPUF) was studied. FPUF with nanofillers are of interest to the automotive industry due to their potential for enhancing compression properties and enabling sustainable foams. Holey and wrinkled flash graphene, and untreated and silane coated boron nitride were tested as fillers up to 0.1 wt% loading level. Flash graphene filled FPUF showed significant improvement in compressive properties, especially at the 0.025 wt% loading level, showing a 22% increase in compressive force deflection at 25% strain and a 17% increase at 50% strain compared to the unfilled control foam sample. Boron nitride nanoparticles, treated and untreated, were shown to be an effective means of reducing wet compression set properties, addressing a key area of concern for sustainable polyols. Wet compression set was reduced by 20%–30% for most boron nitride foams compared to their unfilled control samples. Boron nitride may enable implementation of more sustainable polyols in automotive FPUF. Nanofillers did not significantly improve thermal stability of FPUF.

Phytic Acid-Iron/Laponite Coatings for Enhanced Flame Retardancy, Antidripping and Mechanical Properties of Flexible Polyurethane Foam.

The use of flexible polyurethane foam (FPUF) is severely limited due to its flammability and dripping, which can easily cause major fire hazards. Therefore, choosing an appropriate flame retardant to solve this problem is an urgent need. A coating was prepared on the FPUF surface by dipping with phytic acid (PA), Fe2(SO4)3·xH2O, and laponite (LAP). The influence of PA-Fe/LAP coating on FPUF flame-retardant performance was explored by thermal stability, flame retardancy, combustion behavior, and smoke density analysis. FPUF/PA-Fe/LAP has a good performance in the small fire test, which can pass the UL-94 V-0 rating and the limiting oxygen index reaches 24.5%. Meanwhile, the peak heat release rate values and maximum smoke density of FPUF/PA-Fe/LAP are reduced by 38.7% and 38.5% compared with those of neat FPUF. After applying PA-Fe/LAP coating, the value of fire growth rate index decreases from 10.5 kW/(m2·s) to 5.1 kW/(m2·s), dramatically reducing the fire risk. Encouragingly, the effect of PA-Fe/LAP coating on cyclic compression and permanent deformation is small, which is close to that of neat FPUF. This work provides an effective strategy for making a flame-retardant FPUF with antidripping and keeping mechanical properties.

Effect of shear thickening gel on structure and properties of flexible polyurethane foam

Compression and low-velocity impact properties of shear thickening gel/polyurethane foam (STG/PUF), a soft protective material, have been reported. In order to have a deeper understanding of the relationship between the structure and properties of this material, we utilized Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Proton nuclear magnetic resonance (1H-NMR) to study and prove that STG and polyurethane (PU) did not produce new chemical bonds during the blending process, which belongs to physical blending. Because the molecular chains of STG and PU are intertwined, the composites are endowed with higher thermal stability, safety protection performance, and shape memory performance. For instance, Young’s modulus (E) of the STG/PUF was automatically increased by 57% when stimulated by external forces at different rates and the Emax over 200 kPa, demonstrating a pronounced shear thickening effect. Shape memory tests showed that the shape fixity ratio of STG/PUF gradually increases with the increase of STG content, and the shape recovery ratio remained at 100%. More importantly, the STG/PUF was flexible and comfortable, had excellent mechanical properties and a longer service life, and can be extended to various human protective equipment.

Effect of multi-walled carbon nanotubes with different diameters on morphology and thermal and mechanical properties of flexible polyurethane foams

We report flexible polyurethane foams (PUFs) containing –OH functionalized multi-walled carbon nanotubes (MWCNTs) with different diameters (10–20 nm, 20–30 nm, >50 nm) from 0.1–0.6 wt% (per 100 resins of polyol by weight) prepared via in situ polymerization. After synthesis, the morphology of the MWCNT/PUF composites was observed through scanning electron microscopy (SEM) based on MWCNT amount. The MWCNTs acted as nucleating agents and increased the matrix viscosity. The pore size of the composites decreased and the number of pores increased with increasing MWCNT concentration. Dynamic mechanical analysis (DMA) showed that the storage modulus of the composites increased, the loss modulus decreased, and the Tg gradually decreased with increasing MWCNT content. The incorporation of MWCNTs induced remarkable thermal stabilization of the matrix. The increase in the degradation temperature from 294°C to 304°C resulted in a 50% weight loss. The mechanical properties of the MWCNT/PUF materials increased with increasing MWCNT proportion because of the excellent compatibility and strong interface interaction between the MWCNT and flexible PUF.

Fabrication and characterization of flame‐retardant and smoke‐suppressant of flexible polyurethane foam with modified hydrotalcite

AbstractThe hydrotalcite has been chemically modified by using the ion exchange method to insert dihydrogen phosphate between the carbonate‐type magnesium–aluminum hydrotalcite layers. And then, the effect of modified hydrotalcite on the flame retardancy and smoke suppression properties of flexible polyurethane foam (FPUF) has been investigated using limiting oxygen index (LOI) method, cone calorimeter test (CONE), smoke density chamber, flue gas analyzer, and scanning electron microscope (SEM). The current indicated that the LOI of flame‐retardant modified FPUF was increased to 25.4%. And the peak heat release rate (PHRR) and total heat release (THR) of the samples were decreased by 74.9 kW/m2 and by 9.7 MJ/m2, respectively. Additionally, the total amount of flue gas produced by combustion was reduced by 157.7 m2/m2, and the maximum concentration of carbon monoxide (CO) gas decreased from 51.3 to 23.8 mg/m3. Based on these data, it can be found that the hydrotalcite modified by dihydrogen phosphate intercalation had an excellent flame‐retardant and smoke‐suppressant effect, and 15% of modified hydrotalcite was the most appropriate amount during the combustion process of the modified FPUFs.

The study of palm‐oil‐based bio‐polyol on the morphological, acoustic and mechanical properties of flexible polyurethane foams

AbstractThe focus of this paper was to explore the acoustic properties of flexible polyurethane (FPU) foam modified by palm‐oil‐based polyol (POP). The presence of POP showed a marked influence on the microstructure and mechanical properties of FPU foam. A smaller mean pore diameter can be observed at lower POP content. Indeed, the introduction of POP caused a higher closed pore ratio and an increased air‐flow resistivity, which consequently improved the sound absorption coefficient and transmission loss. In particular, the acoustic performance of the all bio‐based FPU foam was enhanced at low frequency, and the density was lower than that of the reference foam. Additionally, the addition of POP also improved the compressive strength. Conversely, the tensile strength of FPU foam declined with increasing POP content. From this study, the outstanding acoustic ability of bio‐based FPU foam has been proved, with additional advantages of lower density and higher compressive strength. © 2019 Society of Chemical Industry

Layer-by-layer assembled nanocoating containing MoS2 nanosheets and C60 for enhancing flame retardancy properties of flexible polyurethane foam

A novel three bilayers nanocoating containing MoS2 nanosheets and C60 was constructed on the surface of flexible polyurethane (FPU) foam by a layer-by-layer assembly method. MoS2 nanosheets were prepared by ultrasonic-assistant exfoliation method in a mixed solvent of N-Methyl-2-pyrrolidinone (NMP) and aqueous hydrogen peroxide (30% H2O2). MoS2-C60/FPU foam was prepared by alternately submerging the FPU foam into C60/guargum and MoS2/sodium alginate suspensions. Scanning electron microscopy (SEM) characterization showed that MoS2 nanosheets and C60 nanoparticles were uniformly distributed on the surface of FPU foam matrix. Thermogravimetric analysis demonstrated that MoS2-C60/FPU foam exhibited better thermal stability than the control FPU foam. Cone calorimeter test results revealed that MoS2-C60/FPU foam with the incorporation of 5.24 wt% MoS2-C60 nanocoating had a remarkable reduction in peak heat release rate (pHRR, 47.5% reduction), total heat released (THR, 51.1% reduction) and total smoke production (TSP, 33.1% reduction) compared with those of the control FPU foam. Furthermore, the morphology and structure of char residue after cone calorimeter test were investigated by SEM and Raman spectroscopy. The possible flame-retardant mechanism of MoS2-C60/FPU foam was proposed, and this significant improvement in flame retardancy could be ascribed to the insulating barrier and adsorption effect of MoS2 nanosheets, free radicals-trapping ability of C60 in condensed phase, and the catalytic carbonization effect of the MoS2-C60 nanocoating. This work provides a new approach for producing high quality flame retardant polyurethane foam materials.

TDI 함량 변화에 따른 연질 폴리우레탄폼의 물리적 특성 연구

폴리우레탄폼은 광범위한 산업적 응용분야를 가지고 있다. 본 연구에서는 폴리우레탄폼 제조 시에 사용되는 이소시아네이트를 분자구조가 다른 toluene diisocyanate(TDI)와 methylene diphenyl diisocyanate(MDI)로 선택하고 이들의 함량을 변화시켜 폴리우레탄폼을 제조하고 조성에 따른 물리적 특성에 미치는 영향을 조사하였다. 폴리우레탄폼의 형태학은 TDI 함량이 증가함에 따라 공동크기는 증가함을 보였으며 공동벽 면적비는 70 wt%에서 최고값을 나타냈다. 이러한 형태학적 특성에 따라 공동벽 면적비가 최고값인 조성에서 이력손실과 압축응력이 가장 낮은 결과를 보였다. 또한 TDI 함량이 증가함에 따라 꺼짐인자는 감소하는 경향을 나타냈고 영구압축률은 증가하는 결과를 보였다. 이는 TDI 함량 증가가 폴리우레탄폼의 점탄성 강도를 저하시키게 되고 이로 인해 꺼짐인자 감소와 영구압축률 증가 결과를 가져온 것으로 나타났다. 이러한 폴리우레탄폼의 물리적 특성 변화는 동적 기계적 분석 결과를 통해서도 해석이 가능하였다.

Effect of layer-by-layer self-assembled sepiolite-based nanocoating on flame retardant and smoke suppressant properties of flexible polyurethane foam

In this study, a facile and water-based route was developed for fabricating flame retardant and smoke suppressant flexible polyurethane foam (FPUF). FPUF was deposited with a multilayered coating by layer-by-layer (LbL) self-assembled method, which was composed of the positively charged polyethyleneimine (PEI) and negatively charged alginate and sepiolite. The prepared coatings were shown to be successfully constructed on the surface of FPUF, as characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy. Subsequently, the combustion behavior of FPUF was evaluated by cone calorimeter. Results showed that, with 6 bilayers PEI/sepiolite + alginate coating, the peak heat release rate and total heat release of PU-6 were reduced 76% and 27%, respectively, as compared with those of untreated sample. Meanwhile, the deposited coating could effectively reduce the smoke production of FPUF, as evidenced by the remarkable reduction of smoke production rate and total smoke production for the treated FPUF.

Effects of Bulk Densities and Inlet Airflow Velocities on Forward Smoldering Propagation Properties of Flexible Polyurethane Foam

Abstract Smoldering processes of flexible polyurethane foam (FPUF) with densities of 20.0, 30.0 and 35.0 kg/m3 were simulated in a self-designed mesoscale generator with dimensions of 60.0 cm × 25.0 cm × 25.0 cm. Characteristic parameters like smoldering establishment time, average smoldering rate, smoldering temperature, and high temperature duration were proposed and analyzed at five different air flow rates of 1.0, 2.0, 3.0, 5.0 and 7.0 L/min. Scanning Electron Microscopy (SEM) was used to investigate the morphological evolution of bulk materials before establishment and propagation of smoldering. Air was forced in the direction of approximately one-dimensional forward propagation. Results show that FPUF (20.0 kg/m3) has the shortest average smoldering establishment time of 1828.0 s at five airflow rates, FPUF (30.0 kg/m3) has the longest average smoldering establishment time of 2646.0 s. The average smoldering rate of FPUF (35.0 kg/m3) is higher than that of FPUF (30.0 kg/m). Smoldering of FPUF (20.0 kg/m3) cannot be self-sustained, due to largest porosity and insufficient heat accumulation. The average smoldering temperature and duration of high temperature values of FPUF (30.0 kg/m3) are higher than those of FPUF (35.0 kg/m3), and the highest average smoldering temperature of FPUF (30.0 kg/m3) is 410.0 ℃. Since smoldering is derived from chemical reactions of oxygen transported and pyrolyzed products, the bulk material with low density shows higher porosity and contains more oxygen, it burns more fully and thus smoldering establishment time is less. In the process of smoldering, the oxidation and exothermic effects of porous carbon-based chars and oxygen is the main source of energy for the self-sustaining propagation of smoldering. The porosity of FPUF with high density (35.0 kg/m3) is lower, the burning produces a porous carbonate residue and limits the heat loss on the surface, so the smoldering rate of FPUF (35.0 kg/m3) is faster.

Effects of multiwall carbon nanotube and perfluoroalkane additives on the sound absorption properties of flexible polyurethane foams

The sound absorption properties and airflow resistivity of polyurethane foams (PUFs) with multiwall carbon nanotube (MWCNT), perfluoroalkane (PFA), dimethylsiloxane (HMDS), and MWCNT/PFA hybrid additives were investigated with varying additive content. The results show the close relationship of the sound absorption coefficient and airflow resistivity, and increasing flow resistivity was found to improve the sound absorption coefficient of the PUF. For the PUF with MWCNT (at 0.50 phr)/PFA (at 1.25 phr) hybrid additives, the sound absorption coefficient and airflow resistivity were 0.80 (in the frequency range of 1,600–2,500 Hz) and 439,900 Ns/m4, respectively, which were the highest values among the investigated additive species and additive content. The sound absorption coefficient of the PUF with MWCNT (at 0.50 phr)/PFA (at 1.25 phr) was increased by 82.0% compared to that of the PUF without additives, probably because the PUF has the smallest cell size among the additive species and compositions investigated in this study. The results of the sound absorption coefficient, airflow resistivity, and cell size of the PUF suggest that to decrease the cell size and to increase the tortuous paths of the foams, MWCNT/PFA hybrid additives appeared to be the most effective additives and showed synergistic effects in the formation of PUF, and its small cell size increased the sound absorption properties of PUF. POLYM. COMPOS., 39:E1087–E1098, 2018. © 2017 Society of Plastics Engineers