Cryogenic thermal insulating and mechanical properties of rigid polyurethane foams blown with hydrofluoroolefin: Effect of perfluoroalkane

The effect of perfluoroalkane (PFA) on the morphology, thermal conductivity, mechanical properties and thermal stability of rigid polyurethane (PU) foams was investigated under ambient and cryogenic conditions. The PU foams were blown with hydrofluorolefin. Morphological results showed that the minimum cell size (153 μm) was observed when the PFA content was 1.0 part per hundred polyols by weight (php). This was due to the lower surface tension of the mixed polyol solution when the PFA content was 1.0 php. The thermal conductivity of PU foams measured under ambient (0.0215 W/mK) and cryogenic (0.0179 W/mK at −100°C) conditions reached a minimum when the PFA content was 1.0 php. The low value of thermal conductivity was a result of the small cell size of the foams. The above results suggest that PFA acted as a nucleating agent to enhanced the thermal insulation properties of PU foams. The compressive and shear strengths of the PU foams did not appreciably change with PFA content at either −170°C or 20°C. However, it shows that the mechanical strengths at −170°C and 20°C for the PU foams meet the specification. Coefficient of thermal expansion, and thermal shock tests of the PU foams showed enough thermal stability for the LNG carrier’s operation temperature. Therefore, it is suggested that the PU foams blown by HFO with the PFA addition can be used as a thermal insulation material for a conventional LNG carrier.

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Rigid Polyurethane Foams Modified with Biochar

Materials ◽

10.3390/ma14195616 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5616

Author(s):

Katarzyna Uram ◽

Maria Kurańska ◽

Jacek Andrzejewski ◽

Aleksander Prociak

Keyword(s):

Thermal Conductivity ◽

Thermal Stability ◽

Thermal Insulation ◽

Foam Cells ◽

Polyurethane Foams ◽

Cross Sectional ◽

Rigid Polyurethane Foams ◽

Insulation Materials

This paper presents results of research on the preparation of biochar-modified rigid polyurethane foams that could be successfully used as thermal insulation materials. The biochar was introduced into polyurethane systems in an amount of up to 20 wt.%. As a result, foam cells became elongated in the direction of foam growth and their cross-sectional areas decreased. The filler-containing systems exhibited a reduction in their apparent densities of up to 20% compared to the unfilled system while maintaining a thermal conductivity of 25 mW/m·K. Biochar in rigid polyurethane foams improved their dimensional and thermal stability.

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Rigid Polyurethane Foam Thermal Insulation Protected with Mineral Intumescent Mat

Autex Research Journal ◽

10.2478/aut-2014-0026 ◽

2014 ◽

Vol 14 (4) ◽

pp. 259-269 ◽

Cited By ~ 25

Author(s):

Mikelis Kirpluks ◽

Ugis Cabulis ◽

Viesturs Zeltins ◽

Laura Stiebra ◽

Andris Avots

Keyword(s):

Thermal Conductivity ◽

Thermal Insulation ◽

Flame Retardants ◽

Health Hazard ◽

Expandable Graphite ◽

Main Concern ◽

Insulation Material ◽

Pu Foam ◽

Fibre Products ◽

Pu Foams

Abstract One of the biggest disadvantages of rigid polyurethane (PU) foams is its low thermal resistance, high flammability and high smoke production. Greatest advantage of this thermal insulation material is its low thermal conductivity (λ), which at 18-28 mW/(m•K) is superior to other materials. To lower the flammability of PU foams, different flame retardants (FR) are used. Usually, industrially viable are halogenated liquid FRs but recent trends in EU regulations show that they are not desirable any more. Main concern is toxicity of smoke and health hazard form volatiles in PU foam materials. Development of intumescent passive fire protection for foam materials would answer problems with flammability without using halogenated FRs. It is possible to add expandable graphite (EG) into PU foam structure but this increases the thermal conductivity greatly. Thus, the main advantage of PU foam is lost. To decrease the flammability of PU foams, three different contents 3%; 9% and 15% of EG were added to PU foam formulation. Sample with 15% of EG increased λ of PU foam from 24.0 to 30.0 mW/(m•K). This paper describes the study where PU foam developed from renewable resources is protected with thermally expandable intumescent mat from Technical Fibre Products Ltd. (TFP) as an alternative to EG added into PU material. TFP produces range of mineral fibre mats with EG that produce passive fire barrier. Two type mats were used to develop sandwich-type PU foams. Also, synergy effect of non-halogenated FR, dimethyl propyl phosphate and EG was studied. Flammability of developed materials was assessed using Cone Calorimeter equipment. Density, thermal conductivity, compression strength and modulus of elasticity were tested for developed PU foams. PU foam morphology was assessed from scanning electron microscopy images.

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Effect of Material Constitution on the Properties of Thermal Insulation Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.541-542.141 ◽

2014 ◽

Vol 541-542 ◽

pp. 141-145

Author(s):

Bo Liu ◽

Shou De Wang ◽

Shuai Yang ◽

Chen Chen Gong ◽

Ling Chao Lu

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Thermal Insulation ◽

Cementitious Materials ◽

Cellulose Ether ◽

Dry Density ◽

Ratio Test ◽

Insulation Material ◽

Material Constitution ◽

Insulation Materials

Cement-based foam insulation board is a lightweight thermal insulation and have a characteristic of energy saving. The effects of material constitution on the properties of mechanical properties, dry densityand thermal conductivity for thermal insulation materials. The subject of fast hardening sulphoaluminate cement as cementitious materials, polystyrene particles as a lightweight thermal insulation material, adding a certain amount of water reducer, cellulose ethers, air entraining agent to make thermal insulation materials. The experimental results shows that the appropriate material constitution is following: the cement-bead ratio is 12, the ratio is 0.65, the water-cement ratio is 0.4, the content of water reducer is 0.5%, the content of cellulose ether is 0.4%, the content of the air entraining agent is 0.4% .This mix ratio test of mechanical properties are: flexural strength is 0.72MPa, compressive strength is 1.24MPa, dry density is 375kg/m3, water content is 2.3%, water absorption is 10.8%, softening coefficient is 0.95 and coefficient of thermal conductivity is 0.053 W/ (m K).

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The Influence of Environmentally Friendly Flame Retardants on the Thermal Stability of Phase Change Polyurethane Foams

Materials ◽

10.3390/ma13030520 ◽

2020 ◽

Vol 13 (3) ◽

pp. 520 ◽

Cited By ~ 2

Author(s):

Dong Liu ◽

Anjie Hu

Keyword(s):

Thermal Stability ◽

Thermogravimetric Analysis ◽

Phase Change ◽

Thermal Insulation ◽

Polyurethane Foams ◽

Infrared Spectrometry ◽

Expandable Graphite ◽

Insulation Material ◽

Scanning Calorimetry ◽

Thermal Stability Of

To improve thermal insulation, microencapsulated phase change materials (micro-PCMs), expandable graphite (EG), and ammonium polyphosphate (APP) were introduced into polyurethane foam (PUF) to enhance the thermal stability and improve the thermal insulation behavior. The morphology of the PUF and micro-PCM was studied using a scanning electronic microscope (SEM), while the thermophysical properties of the PUF were investigated using a hot disk thermal constants analyzer and differential scanning calorimetry (DSC). The thermal stability of the PUF was investigated by thermogravimetric analysis (TGA), and the gas products volatilized from the PUF were analyzed by thermogravimetric analysis coupled with Fourier transform infrared spectrometry (TGA-FTIR). The results revealed that the thermal conductivities of the PUF were reduced because micro-PCM is effective in absorbing energy, showing that the PUF functions not only as a thermal insulation material but also as a heat sink for energy absorption. Moreover, the EG and APP were found to be effective in improving the thermal stabilities of the PUF, and the optimized formulation among EG, APP, and micro-PCMs in the PUF showed a significant synergistic effect.

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Development of Renewable Feedstock Based Rigid Polyurethane Foam and Nanoclay Composites

10.7250/9789934224706 ◽

2020 ◽

Author(s):

◽

Miķelis Kirpļuks

Keyword(s):

Mechanical Properties ◽

Thermal Insulation ◽

Flame Retardants ◽

Polyol Synthesis ◽

Insulation Material ◽

Pu Foam ◽

Renewable Feedstock ◽

Pu Foams ◽

Impact Absorption ◽

Halogenated Flame Retardants

Rigid PU foams are versatile material commonly applied as a thermal insulation material. It can be applied as an impact absorption material in the automotive industry if material with sufficient mechanical properties has been developed. Further increase in mechanical properties can be achieved by developing nano-reinforced rigid PU foams. Majority of commercially used rigid PU foams are produced from non-renewable petrochemical-based raw materials. Although, renewable feedstock, as well as recycled materials, can be used to obtain rigid PU foams with equal properties. In this work, several bio-based, as well as APP polyols, have been used to develop rigid PU foams. Rigid PU foam thermal insulation material has to fulfil demanding flammability requirements. This is achieved by the introduction of different flame retardants into the material structure from which most common are halogenated flame retardants. Halogenated flame retardants are associated with different health hazards, thus their phase-out from the market can be expected. A good alternative to halogenated flame retardants are intumescent flame retardant solutions. The results and discussion of this thesis are divided into three parts: Part 1 describes the development of high-density rigid PU foam material for application as impact absorption material in the automotive industry. Sustainable origin polyols have been used to develop rigid PU foams and their influence on mechanical, thermal and morphological properties of the material has been studied. To further increase mechanical properties of the rigid PU foams a nano-composite with montmorillonite nano-clay was developed. Lastly, most optimal rigid PU foam formulations were upscaled to produce real scale automotive part, which was tested according to the European Union’s crash test requirements. Part 2 describes the development of rigid PU foam thermal insulation from bio-based polyols. Halogenated flame retardants were replaced using non-halogenated alternatives. Intumescent flame retardants, such as expandable graphite was used to significantly reduce the flammability of the rigid PU foam. Part 3; during high-density rigid PU foam development it was discovered that used bio-based polyols have too low OH group functionality. Thus, the functionality of the polyols was increased by developing different bio-polyol synthesis method. Rapeseed oil, as well as tall oil, were used as feedstock for high functionality bio-based polyol synthesis. The first step was an epoxidation of the unsaturated moieties of the bio-based oils. Afterwards, oxirane ring opening with different polyfunctional alcohols and simultaneous transesterification/esterification reactions were used to obtain desired polyol structures.

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Research on Thermal Stability and Properties of Ca3ZrSi2O9 as Potential T/EBC Materials

Coatings ◽

10.3390/coatings11050583 ◽

2021 ◽

Vol 11 (5) ◽

pp. 583

Author(s):

Yangyang Pan ◽

Bo Liang ◽

Yaran Niu ◽

Dijuan Han ◽

Dongdong Liu ◽

...

Keyword(s):

Thermal Conductivity ◽

Thermal Stability ◽

Fracture Toughness ◽

Room Temperature ◽

Coefficient Of Thermal Expansion ◽

Atmospheric Plasma ◽

Thermal Barrier ◽

Mechanical And Thermal Properties ◽

Self Healing ◽

Barrier Coating

In this study, a new coating material for thermal barrier coating (TBC) or environment barrier coating (EBC) application, Ca3ZrSi2O9 (CZSO), was synthesized and prepared by atmospheric plasma spray (APS) technology. The evolution of the phases and microstructures of the coatings with different thermal-aged were characterized by XRD, XRF, EDS and SEM, respectively. The thermal stability was measured by TG-DTA and DSC. The mechanical and thermal properties, including Vickers hardness (HV), fracture toughness (KIC), thermal conductivity () and coefficient of thermal expansion (CTE) were focused on. It was found that the as-sprayed CZSO coating contained amorphous phase. Crystalline transformation happened at 900–960 ∘C and no mass changes took place from room temperature (RT) to 1300 ∘C. The phenomena of microcrack self-healing and composition uniformity were observed during thermal aging. The of coating was very low at about 0.57–0.80 Wm−1K−1 in 200–1200 ∘C. The combined properties indicated that the CZSO coating might be a potential T/EBC material.

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Bio-based Polyurethane-clay Nanocomposite Foams: Systheses and Properties

MRS Proceedings ◽

10.1557/proc-1188-ll04-05 ◽

2009 ◽

Vol 1188 ◽

Cited By ~ 1

Author(s):

Min Liu ◽

Zoran S. Petrovic ◽

Yijin Xu

Keyword(s):

Thermal Conductivity ◽

Thermal Insulation ◽

Cell Structure ◽

Polyurethane Foams ◽

Mechanical And Thermal Properties ◽

Cell Content ◽

Modified Clay ◽

Rigid Polyurethane Foams ◽

Nanocomposite Foams ◽

Organically Modified

AbstractStarting from a bio-based polyol through modification of soybean oil, BIOH™ X-210, two series of bio-based polyurethanes-clay nanocomposite foams have been prepared. The effects of organically-modified clay types and loadings on foam morphology, cell structure, and the mechanical and thermal properties of these bio-based polyurethanes-clay nanocomposite foams have been studied with optical microscopy, compression test, thermal conductivity, DMA and TGA characterization. Density of nanocomposite foams decreases with the increase of clay loadings, while reduced 10% compressive stress and yield stress keep constant up to 2.5% clay loading in polyol. The friability of rigid polyurethane-clay nanocomposite foams is high than that of foam without clay, and the friability for nanofoams from Cloisite® 10A is higher than that from 30B at the same clay loadings. The incorporation of clay nanoplatelets decreases the cell size in nanocomposite foams, meanwhile increases the cell density; which would be helpful in terms of improving thermal insulation properties. All the nanocomposite foams were characterized by increased closed cell content compared with the control foam from X-210 without clay, suggesting the potential to improve thermal insulation of rigid polyurethane foams by utilizing organically modified clay. Incorporation of clay into rigid polyurethane foams results in the increase in glass transition temperature: the Tg increased from 186 to 197 to 204 °C when 30B concentration in X-210 increased from 0 to 0.5 to 2.5%, respectively. Even though the thermal conductivity of nanocomposite foams from 30B is lower than or equal to that of rigid polyurethane control foam from X-210, thermal conductivity of nanocomposite foams from 10A is higher than that of control at all 10A concentrations. The reason for this abnormal phenomenon is not clear at this moment; investigation on this is on progress.

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The effect of organofluorine additives on the morphology, thermal conductivity and mechanical properties of rigid polyurethane and polyisocyanurate foams

Journal of Cellular Plastics ◽

10.1177/0021955x20987152 ◽

2021 ◽

pp. 0021955X2098715

Author(s):

Cosimo Brondi ◽

Ernesto Di Maio ◽

Luigi Bertucelli ◽

Vanni Parenti ◽

Thomas Mosciatti

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Cell Size ◽

Flexural Properties ◽

Anisotropy Ratio ◽

Cell Content ◽

Average Cell Size ◽

Average Cell ◽

Thermal Insulating ◽

Liquid Type

This study investigates the effect of liquid-type organofluorine additives (OFAs) on the morphology, thermal conductivity and mechanical properties of rigid polyurethane (PU) and polyisocyanurate (PIR) foams. Foams were characterized in terms of their morphology (density, average cell size, anisotropy ratio, open cell content), thermal conductivity and compressive as well as flexural properties. Based on the results, we observed that OFAs efficiently reduced the average cell size of both PU and PIR foams, leading to improved thermal insulating and mechanical properties.

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Unused Plant Waste and Thermal Insulation Composition Boards on their Basis

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.887.480 ◽

2021 ◽

Vol 887 ◽

pp. 480-486

Author(s):

T.N. Vachnina ◽

I.V. Susoeva ◽

A.A. Titunin ◽

S.V. Tsybakin

Keyword(s):

Thermal Conductivity ◽

Thermal Insulation ◽

Wood Fiber ◽

Mineral Wool ◽

Wood Waste ◽

Insulation Material ◽

Plant Fibers ◽

Coefficient Of Thermal Conductivity ◽

Plant Waste ◽

Technology Of Production

Many plant wastes are not currently used in production, they are disposed of in landfills or incinerated. The aim of this study is to develop a composite thermal insulation material from unused spinning waste of flax and cotton fibers and soft wood waste. Samples of thermal insulation materials from plant waste were made by drying using the technology of production of soft wood fiber boards. For composite board defined physico-mechanical characteristics and thermal conductivity. The experiment was carried out according to a second-order plan, regression models of the dependences of the material indicators on the proportion of the binder additive, drying temperature and the proportion of wood waste additives were developed. The study showed that composites from unused spinning waste of plant fibers and soft wood waste have the necessary strength under static bending, the swelling in thickness after staying in water is much lower in comparison with the performance of boards from other plant fillers. The coefficient of thermal conductivity of the boards is comparable with the indicator for mineral wool boards.

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Reinforcement Efficiency of Cellulose Microfibers for the Tensile Stiffness and Strength of Rigid Low-Density Polyurethane Foams

Materials ◽

10.3390/ma13122725 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2725 ◽

Cited By ~ 1

Author(s):

Jānis Andersons ◽

Mikelis Kirpluks ◽

Ugis Cabulis

Keyword(s):

Mechanical Properties ◽

Polyurethane Foams ◽

Low Density ◽

Mechanical Reinforcement ◽

Tensile Stiffness ◽

Structural Applications ◽

Cellulose Microfibers ◽

Renewable Material ◽

Reinforcement Efficiency ◽

Pu Foams

Rigid low-density closed-cell polyurethane (PU) foams are widely used in both thermal insulation and structural applications. The sustainability of PU foam production can be increased by using bio-based components and fillers that ensure both enhanced mechanical properties and higher renewable material content. Such bio-based foams were produced using polyols derived from rapeseed oil and microcrystalline cellulose (MCC) fibers as filler. The effect of MCC fiber loading of up to 10 wt % on the morphology, tensile stiffness, and strength of foams has been evaluated. For estimation of the mechanical reinforcement efficiency of foams, a model allowing for the partial alignment of filler fibers in foam struts was developed and validated against test results. It is shown that although applying MCC fibers leads to modest gains in the mechanical properties of PU foams compared with cellulose nanocrystal reinforcement, it may provide a higher content of renewable material in the foams.

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