scholarly journals Effect of Foaming Formulation and Operating Pressure on Thermoregulating Polyurethane Foams

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2328
Author(s):  
Angel Serrano ◽  
Ana M. Borreguero ◽  
Juan Catalá ◽  
Juan F. Rodríguez ◽  
Manuel Carmona
Keyword(s):  
Thermal Analyses ◽  
Young Modulus ◽  
Polyurethane Foams ◽  
Energy Storage Materials ◽  
Strong Impact ◽  
Operating Pressure ◽  
Heat Accumulator ◽  
Reduced Pressure ◽  
Pu Foam ◽  
Foam Properties

The synthesis of rigid polyurethane (RPU) foams containing thermoregulatory microcapsules has been carried out under reduced pressure conditions with a new foaming formulation to reduce the final composite densities. These optimized RPU foams were able to overpass the drawbacks exhibited by the previous composites over the studied temperature range, working as insulating and thermal energy storage materials. The change in the formulation allowed to decrease the final foam density and enhance their mechanical strength. The effect of the operating pressure (atmospheric, 800 mbar, and 700 mbar) and microcapsules content (up to 30 wt%) on the physical, mechanical, and thermal PU foam properties was studied. The reduction of the pressure from atmospheric to 800 mbar did not have any effect on the cell size, strut thickness, and compression strength 10% of deformation, the Young modulus being even higher at 800 mbar. Nevertheless, a strong impact on the microstructure and mechanical properties was observed for the foam composites obtained at 700 mbar. A deleterious impact on the RPU foams thermal conductivity was observed when using low-pressure conditions. Thermal analyses showed that a composite able to work as heat accumulator and thermal insulation both at transient and at steady state was achieved.

A Research of the Polyurethane Foams Modified by Polyisobutylene

2013 ◽  
Vol 631-632 ◽  
pp. 314-317
Author(s):  
Hong Jun Huang ◽  
Kang Wang ◽  
Jian Jiang Wang ◽  
Guo Shun Wan ◽  
Lei Jiang
Keyword(s):  
Polyurethane Foams ◽  
Pu Foam ◽  
Initial Adhesion

A series of spongy foams based on polyurethane (PU) modified by polyisobutylene (PIB) were prepared. The spongy foams with different PIB content were investigated. The results showed that initial adhesion increased with the increment of PIB content, and gained the highest value when the content reached to 30%; FTIR suggested the formation of PU foam modified by PIB; the density also increased with the increasing content of PIB.

scholarly journals Viscoelastic Polyurethane Foams with Reduced Flammability and Cytotoxicity

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 151
Author(s):  
Małgorzata Okrasa ◽  
Milena Leszczyńska ◽  
Kamila Sałasińska ◽  
Leonard Szczepkowski ◽  
Paweł Kozikowski ◽  
...  
Keyword(s):  
Polyurethane Foams ◽  
Test Results ◽  
Scanning Calorimetry ◽  
Simultaneous Reduction ◽  
Protective Devices ◽  
Respiratory Protective Devices ◽  
The Face ◽  
Foam Properties ◽  
Risk Of Exposure ◽  
The Impact

Consistent and proper use of respiratory protective devices (RPD) is one of the essential actions that can be taken to reduce the risk of exposure to airborne hazards, i.e., biological and nonbiological aerosols, vapours, and gases. Proper fit of the facepiece and comfort properties of RPDs play a crucial role in effective protection and acceptance of RPDs by workers. The objective of the present paper was to develop viscoelastic polyurethane foams for use in RPD seals characterised by proper elasticity, allowing for the enhancement of the device fit to the face and the capability of removing moisture from the skin in order to improve the comfort of RPD use. Moreover, it was pivotal to ensure the non-flammability of the foams, as well as a simultaneous reduction in their cytotoxicity. The obtained foams were characterised using scanning electron microscopy, infrared spectroscopy, thermogravimetry, and differential scanning calorimetry. Measurements also involved gel fraction, apparent density, compression set, rebound resilience, wettability, flammability, and cytotoxicity. The results are discussed in the context of the impact of modifications to the foam formulation (i.e., flame-retardant type and content) on the desired foam properties. The test results set directions for future works aimed to develop viscoelastic polyurethane foams that could be applied in the design of respiratory protective devices.

Studies of the Influence of Graphite on the Physical Mechanical and Thermal Properties of Polyurethane Foams for Construction Applications

2021 ◽  
Vol 887 ◽  
pp. 399-405
Author(s):  
L.N. Shafigullin ◽  
N.V. Romanova ◽  
G.R. Shafigullina
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Polyurethane Foams ◽  
Onset Temperature ◽  
Sound Absorption Coefficient ◽  
Expandable Graphite ◽  
Mechanical And Thermal Properties ◽  
Pu Foam

The paper shows the applicability of expandable graphite METOPAC EG 350-50 (80) in a rigid PU foam system as a substance that reduces the flammability (flame retardant) and improves the usability. The studies of the physical mechanical and thermal properties of PU foam with a higher graphite content revealed a higher normal sound absorption coefficient; insignificant influence on the thermal conductivity; a higher decomposition onset temperature; more difficult ignition. PU foam sample with a ratio of 15 graphite weight fractions to 100 polyol weight fractions has the highest physical mechanical and thermal properties, and, as compared to the starting PU foam, it features an increase in normal sound absorption coefficient by an average of 3 times; a decrease in the thermal conductivity by 8 %; an increase in the decomposition onset temperature by 6.7 °С. Therefore, the modification of PU foam with expandable graphite makes it possible not only to develop hardly combustible polyurethanes but also to improve its physical mechanical and thermal properties.

Nanomaterials in PU Foam for Enhanced Sound Absorption at Low Frequency Region

2014 ◽  
Vol 938 ◽  
pp. 170-175 ◽  
Author(s):  
R. Gayathri ◽  
R. Vasanthakumari
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Foam Cell ◽  
Research Work ◽  
Low Frequency ◽  
Absorption Capacity ◽  
Polyurethane Foams ◽  
Sound Absorption Coefficient ◽  
Enhanced Absorption ◽  
Pu Foam

Lot of research is going on to develop materials suitable for absorbing sound and reducing noise. By virtue of their superior vibration damping capability and attractive characteristics such as visco elasticity, simple processing and commercial availability, polyurethane foams are extensively applied not only in automotive seats but also in various acoustical parts. However, the sound absorption coefficient of polyurethane foams is high (0.8 1.0) in high frequencies in the range 300 to 10000Hz while it is found to be low (0 to 0.5) at low frequencies (10 to 200 Hz). In this study new polyurethane based porous composites were synthesized by in situ foam rising polymerization of polyol and diisocyanate in the presence of fillers such as nanosilica (NS) and nanoclay (NC). The effect of these fillers at various concentrations up to 2% was studied for sound absorption characteristics in the frequency range 100-200Hz. Sound absorption coefficient was determined using standing wave impedance tube method. The sound absorption coefficient of filled PU foams increases from 0.5 to 0.8 with frequency increase from 100 to 200 Hz at higher content of the nanofillers employed. This research work is further extended to study the sound absorption capacity of unfilled PU foam with varying thickness and also hybrid foams with woven glass (GFC) and polyester cloth (PEC). The unfilled foam with 60mm of thickness gives sound absorption value same as that of 15mm of filled foam. Further enhanced absorption value is achieved with PU/NS-GFC hybrid. The results obtained are explained based on the porosity of composite structure and foam cell size.Key words Polyurethane foam, sound absorption coefficient, nanosilica, nanoclay, low frequency sound.

scholarly journals Development of Innovative Polyol Systems From Recycled Polyethylene Terephthalate and Renewable Raw Materials for Rigid Polyurethane Foams

2020 ◽  
Author(s):  
◽  
Aiga Ivdre
Keyword(s):  
Raw Materials ◽  
Polyurethane Foams ◽  
Raw Material ◽  
Insulation Material ◽  
Recycled Pet ◽  
Renewable Raw Materials ◽  
Material Resources ◽  
Pu Foam ◽  
Renewable Raw Material ◽  
Pu Foams

The Thesis aims to develop innovative polyols suitable for the production of rigid PU foam from recycled PET flakes and renewable raw material resources (rapeseed oil and tall oil) and to evaluate the effect of polyols on the most important properties of rigid PU foams as a thermal insulation material.

scholarly journals Reciprocal deformation of polyurethane foam sets in the construction of upholstered furniture

2009 ◽  
Vol 57 (1) ◽  
pp. 61-70
Author(s):  
Věra Jančová
Keyword(s):  
Polyurethane Foam ◽  
Test Methods ◽  
Polyurethane Foams ◽  
Material Composition ◽  
Pu Foam ◽  
Simple Tool ◽  
Upholstered Furniture ◽  
The Individual

The quality of upholstered furniture is currently evaluated through a set of attributes that reflect the „comfort“ of the product. Measurable features are evaluated using the test methods, which include an assessment of the product as a whole or only of the individual materials. Methodology to assess materials in the construction of material compositions has not yet been processed before. This work deals with the issue of a evaluation of the material sets of polyurethane foams and their mu­tual influence. New methodology has been proposed for evaluating mutual deformation of foams sets that has been named “reciprocal deformation of foam sets” in this work. Using this newly proposed method, selected types of polyurethane foams were assessed, in combination with recycled bonding polyurethane foam-type RE 80. The results of the measurements were evaluated and assembled into the graph in order to create a simple tool for the construction of material composition in the mold ­layer of upholstered furniture. The graph can easily be deducted; it answers the question of what ­value of deformation is to be considered in drawing up a set of foam materials and recycled PU foam in the construction of material composition.

Function of silicon oil in the castor oil based rigid polyurethane foams

2013 ◽  
Vol 33 (9) ◽  
pp. 875-880 ◽  
Author(s):  
Raminder Kaur ◽  
Mukesh Kumar
Keyword(s):  
Mechanical Properties ◽  
Castor Oil ◽  
Oil Content ◽  
Polyurethane Foams ◽  
Rigid Polyurethane Foam ◽  
Rigid Polyurethane Foams ◽  
Silicon Oil ◽  
Foam Properties ◽  
Packed Structure ◽  
Scanning Electron

Abstract Rigid polyurethane foams are one of the most important cellular plastics. Castor oil was modified with glycerol to form the polyol and reacted with methyl diisocyanate and different proportions of silicon oil to achieve rigid polyurethane foam. Prepared foam was tested for its density and mechanical properties. It was found that compressive and flexural strength was improved with silicon oil content. The morphology of the resulted foams was also studied using scanning electron microscope, and it was observed that the cell size was reduced with silicon oil content, indicating a more dense and packed structure. With further increase in the silicon oil content, foam properties showed a slight decrease in value.

scholarly journals Application of Walnut Shells-Derived Biopolyol in the Synthesis of Rigid Polyurethane Foams

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2687 ◽  
Author(s):  
Sylwia Członka ◽  
Anna Strąkowska ◽  
Agnė Kairytė
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Characteristics ◽  
Cell Structure ◽  
Weight Ratio ◽  
Polyurethane Foams ◽  
Maximum Temperature ◽  
Walnut Shells ◽  
Foam Properties ◽  
The Fourier Transform ◽  
The Impact

This study aimed to examine rigid polyurethane (PUR) foam properties that were synthesized from walnut shells (WS)-based polyol. The Fourier Transform Infrared Spectroscopy (FTIR) results revealed that the liquefaction of walnut shells was successfully performed. The three types of polyurethane (PUR) foams were synthesized by replacement of 10, 20, and 30 wt% of a petrochemical polyol with WS-based polyol. The impact of WS-based polyol on the cellular morphology, mechanical, thermal, and insulating characteristics of PUR foams was examined. The produced PUR foams had apparent densities from 37 to 39 kg m−3, depending on the weight ratio of WS-based polyol. PUR foams that were obtained from WS-based polyol exhibited improved mechanical characteristics when compared with PUR foams that were derived from the petrochemical polyol. PUR foams produced from WS-based polyol showed compressive strength from 255 to 310 kPa, flexural strength from 420 to 458 kPa, and impact strength from 340 to 368 kPa. The foams that were produced from WS-based polyol exhibited less uniform cell structure than foams derived from the petrochemical polyol. The thermal conductivity of the PUR foams ranged between 0.026 and 0.032 W m−1K−1, depending on the concentration of WS-based polyol. The addition of WS-based polyol had no significant influence on the thermal degradation characteristics of PUR foams. The maximum temperature of thermal decomposition was observed for PUR foams with the highest loading of WS-based polyol.

scholarly journals High Functionality Bio-Polyols from Tall Oil and Rigid Polyurethane Foams Formulated Solely Using Bio-Polyols

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1985 ◽  
Author(s):  
Mikelis Kirpluks ◽  
Edgars Vanags ◽  
Arnis Abolins ◽  
Slawomir Michalowski ◽  
Anda Fridrihsone ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Polyurethane Foams ◽  
Insulation Material ◽  
Tall Oil ◽  
Cellulose Production ◽  
Thermal Insulation Material ◽  
Pu Foam ◽  
Side Stream ◽  
Esterification Reactions ◽  
Tall Oil Fatty Acids

High-quality rigid polyurethane (PU) foam thermal insulation material has been developed solely using bio-polyols synthesized from second-generation bio-based feedstock. High functionality bio-polyols were synthesized from cellulose production side stream—tall oil fatty acids by oxirane ring-opening as well as esterification reactions with different polyfunctional alcohols, such as diethylene glycol, trimethylolpropane, triethanolamine, and diethanolamine. Four different high functionality bio-polyols were combined with bio-polyol obtained from tall oil esterification with triethanolamine to develop rigid PU foam formulations applicable as thermal insulation material. The developed formulations were optimized using response surface modeling to find optimal bio-polyol and physical blowing agent: c-pentane content. The optimized bio-based rigid PU foam formulations delivered comparable thermal insulation properties to the petro-chemical alternative.

scholarly journals Morphological and thermal analyses of flexible polyurethane foams containing commercial calcium carbonate

2008 ◽  
Vol 33 (2) ◽  
pp. 55-60 ◽  
Author(s):  
S. S. Sant'Anna ◽  
D. A. Souza ◽  
C. F. Carvalho ◽  
M. I. Yoshida
Keyword(s):  
Calcium Carbonate ◽  
Thermal Analyses ◽  
Polyurethane Foams ◽  
Flexible Polyurethane

One filler often utilized in flexible polyurethane foams is calcium carbonate (CaCO3) because it is non-abrasiveness, non-toxicity and facilitated pigmentation. However, it is observed that the excess of commercial CaCO3 utilized in industry possibly causing permanent deformations and damaging the quality of the final product. The effect of different concentrations of commercial CaCO3, in flexible foams, was studied. Different concentrations of CaCO3 were used for the synthesis of flexible polyurethane foams, which were submitted to morphological and thermal analyses to verify the alterations provoked by the progressive introduction of this filler.

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