Improvement of thermal conductivity of rigid polyurethane foams with aluminum nitride filler

2021 ◽  
pp. 026248932198897
Author(s):  
Serife Akkoyun ◽  
Meral Akkoyun
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Nitride ◽  
Polyurethane Foams ◽  
Thermal Transitions ◽  
Rigid Polyurethane Foams ◽  
Noticeable Increase ◽  
Polyurethane Composite ◽  
Composite Foams ◽  
Step Procedure ◽  
Electrical Conductivities

The aim of this work is the fabrication of electrically insulating composite rigid polyurethane foams with improved thermal conductivity. Therefore, this study is focused on the effect of aluminum nitride (AlN) on the thermal and electrical conductivities of rigid polyurethane foams. For this purpose, aluminum nitride/rigid polyurethane composite foams were prepared using a three-step procedure. The electrical and thermal conductivities of the foams were characterized. The thermal transitions, mechanical properties and morphology of the foams were also examined. The results reveal that AlN induces an increase of the thermal conductivity of rigid polyurethane foam of 24% which seems to be a relatively noticeable increase in polymeric foams. The low electrical conductivity of the foams is preserved.

scholarly journals Polyurethane Composite Foams Synthesized Using Bio-Polyols and Cellulose Filler

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3474
Author(s):  
Katarzyna Uram ◽  
Milena Leszczyńska ◽  
Aleksander Prociak ◽  
Anna Czajka ◽  
Michał Gloc ◽  
...  
Keyword(s):  
Cross Sections ◽  
Raw Materials ◽  
Polyurethane Foams ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Polyurethane Composite ◽  
Composite Foams ◽  
Closed Cell ◽  
Ft Ir ◽  
The Fourier Transform

Rigid polyurethane foams were obtained using two types of renewable raw materials: bio-polyols and a cellulose filler (ARBOCEL® P 4000 X, JRS Rettenmaier, Rosenberg, Germany). A polyurethane system containing 40 wt.% of rapeseed oil-based polyols was modified with the cellulose filler in amounts of 1, 2, and 3 php (per hundred polyols). The cellulose was incorporated into the polyol premix as filler dispersion in a petrochemical polyol made using calenders. The cellulose filler was examined in terms of the degree of crystallinity using the powder X-ray diffraction PXRD -and the presence of bonds by means of the fourier transform infrared spectroscopy FT-IR. It was found that the addition of the cellulose filler increased the number of cells in the foams in both cross-sections—parallel and perpendicular to the direction of the foam growth—while reducing the sizes of those cells. Additionally, the foams had closed cell contents of more than 90% and initial thermal conductivity coefficients of 24.8 mW/m∙K. The insulation materials were dimensionally stable, especially at temperatures close to 0 °C, which qualifies them for use as insulation at low temperatures.

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

2009 ◽  
Vol 1188 ◽  
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.

scholarly journals Rigid Polyurethane Foams Modified with Biochar

Materials ◽  
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.

The Synthesis and Application of a Novel Class of Polyols for Preparation of Polyurethane

2013 ◽  
Vol 357-360 ◽  
pp. 1441-1445
Author(s):  
Xiao Lin Li ◽  
Zheng Fang ◽  
Dong Ji ◽  
Zhi Dong Wan ◽  
Kai Guo
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Polyurethane Foams ◽  
Low Density ◽  
Cell Content ◽  
Low Thermal Conductivity ◽  
High Compressive Strength ◽  
Rigid Polyurethane Foams ◽  
Closed Cell ◽  
Rigid Foams

The synthesis of a novel class of diamine-based polyols derivatives and the potentials and the limitations of these polyols were reported. This class of diamine-based polyols with high hydroxyl values and no acid values can be used in rigid polyurethane foams. The prepared rigid foams show the properties of low density, high closed cell content, low thermal conductivity, and high compressive strength.

Mechanical Behavior of Polyurethane Composite Foams from Kenaf Fiber and Recycled Tire Rubber Particles

2013 ◽  
Vol 315 ◽  
pp. 861-866 ◽  
Author(s):  
S. Kanna Subramaniyan ◽  
Shahruddin Mahzan ◽  
Mohd Imran bin Ghazali ◽  
Maznan Ismon ◽  
Ahmad Mujahid Ahmad Zaidi
Keyword(s):  
Mechanical Behavior ◽  
Filler Content ◽  
Compression Modulus ◽  
Polyurethane Foams ◽  
Kenaf Fiber ◽  
Tire Rubber ◽  
Polyurethane Composite ◽  
Composite Foams ◽  
Filler Reinforcement ◽  
Spherical Cells

In the present work polyurethane foams containing various content loadings of kenaf fiber and recycled tire rubber particulates were prepared and studied, with the objective of developing alternative composite rigid foams. The influence of the filler content on the foam microstructure and its physical and mechanical behavior has been studied for three different polyurethane resin densities. Microstructural observation on fracture surface of composites was carried out using scanning electron microscopy. It has shown closed spherical cells with reduced size when the fillers are added. Nevertheless, the incorporation of kenaf fiber and recycled tire rubber particulates that refined at 80 mesh led to higher mechanical properties than that unfilled polyurethane foam. A 6% filler content loading exhibited the optimum compression stress and compression modulus, while further increase of filler content loading resulted in decline in mechanical behavior. The presence of larger filler content deteriorated the polyurethane system cellular structure and lead to poor composites strength. Overall, the use of kenaf fiber and recycled tire rubber particulates gives composite foams with comparable mechanical behavior for the studied filler reinforcement level.

scholarly journals Rigid polyurethane foams with infused nanoclays: Relationship between cellular structure and thermal conductivity

2016 ◽  
Vol 80 ◽  
pp. 1-15 ◽  
Author(s):  
Sergio Estravís ◽  
Josías Tirado-Mediavilla ◽  
Mercedes Santiago-Calvo ◽  
José Luis Ruiz-Herrero ◽  
Fernando Villafañe ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Cellular Structure ◽  
Polyurethane Foams ◽  
Rigid Polyurethane Foams

scholarly journals Modification of Rigid Polyurethane Foams with the Addition of Nano-SiO2 or Lignocellulosic Biomass

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 107 ◽  
Author(s):  
Qinqin Zhang ◽  
Xiaoqi Lin ◽  
Weisheng Chen ◽  
Heng Zhang ◽  
Dezhi Han
Keyword(s):  
Cell Structure ◽  
Chemical Characterization ◽  
Polyurethane Foams ◽  
Peanut Shell ◽  
Step Method ◽  
Residual Content ◽  
Nano Sio2 ◽  
Rigid Polyurethane Foams ◽  
Building Insulation ◽  
Composite Foams

Many achievements have been made on the research of composite polyurethane foams to improve their structure and mechanical properties, and the composite foams have been widely utilized in building insulation and furniture. In this work, rigid polyurethane foams (RPUFs) with the addition of different fillers (nano-SiO2, peanut shell, pine bark) were prepared through the one-step method. The effects of inorganic nano-SiO2 and organic biomass on foam properties were evaluated by means of physical and chemical characterization. The characterization results indicate that the compressive strength values of prepared foams could fully meet the specification requirement for the building insulation materials. The inorganic and organic fillers have no effect on the hydrogen bonding states in composite RPUFs. Furthermore, compared to the biomass fillers, the addition of nano-SiO2 greatly influenced the final residual content of the fabricated foam. All composite foams exhibit closed-cell structure with smaller cell size in comparison with the parent foam. The prepared composite foams have the potential for utilization in building insulation.

scholarly journals Aging of Rigid Polyurethane Foams: Thermal Conductivity of N2 and Cyclopentane Gas Mixtures

2005 ◽  
Vol 41 (3) ◽  
pp. 207-224 ◽  
Author(s):  
Isabel M. Marrucho ◽  
Filipe Santos ◽  
Nelson S. Oliveira ◽  
Ralf Dohrn
Keyword(s):  
Thermal Conductivity ◽  
Gas Mixtures ◽  
Polyurethane Foams ◽  
Rigid Polyurethane Foams
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