A new material with low density and low thermal conductivity using post-consumer Tetra Pak packages

A homogeneous low-density nano-porous medium of isotactic polypropylene (iPP) with a low thermal conductivity was fabricated using supercritical carbon dioxide (scCO2).

Download Full-text

Rigid Polyurethane Foam: A Versatile Energy Efficient Material

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.678.88 ◽

2016 ◽

Vol 678 ◽

pp. 88-98 ◽

Cited By ~ 2

Author(s):

Harpal Singh

Keyword(s):

Thermal Conductivity ◽

Polyurethane Foam ◽

Weight Ratio ◽

Building Envelope ◽

Polymerization Reaction ◽

Low Density ◽

High Porosity ◽

Rigid Polyurethane Foam ◽

Low Thermal Conductivity ◽

Moisture Permeability

Rigid polyurethane foam (RPUF) is typically prepared by the reaction of an isocyanate, such as methyl diphenyl diisocyanate (MDI) with a polyol blend. During the polymerization reaction, a blowing agent expands the reacting mixture. The finished product is a solid, cellular polymer with a high thermal resistance. RPUF is an outstanding material for different applications. It has many desirable properties such as low thermal conductivity, low density, low water absorption, low moisture permeability, excellent dimensional stability, high strength to weight ratio. So, it is the best insulating material for industrial buildings, cold storages, telecom and defense shelters due to low thermal conductivity, low density, low moisture permeability and high porosity. It works to reduce heating and cooling loss, improving the efficiency of the building envelope. Thus, RPUF insulation in building envelopes brings additional benefits in energy savings, resulting in lower energy bills and protecting the environment by cutting CO2 emissions.

Download Full-text

Conductivity studies of Ni and Gd substituted BiCoO3

Modern Physics Letters B ◽

10.1142/s0217984914500341 ◽

2014 ◽

Vol 28 (05) ◽

pp. 1450034 ◽

Cited By ~ 1

Author(s):

T. Ramachandran ◽

N. E. Rajeevan ◽

P. P. Pradyumnan

Keyword(s):

Thermal Conductivity ◽

Room Temperature ◽

Structural Studies ◽

Reaction Route ◽

Low Thermal Conductivity ◽

Sem Micrograph ◽

New Material ◽

Cubic Structure ◽

Solid State Reaction Route ◽

Room Temperature Raman Spectrum

In this paper, we report the synthesis, thermal and electrical property studies of Ni 0.5 Gd 0.2 Bi 0.3 CoO 3, a new material for thermoelectric applications. The material was synthesized by solid state reaction route taking BiCoO 3 as basic matrix by substituting bismuth with nickel and gadolinium. Structural studies using room temperature XRD and room temperature Raman spectrum established cubic structure for Ni 0.5 Bi 0.5 CoO 3 and tetragonal structure for Ni 0.5 Gd 0.2 Bi 0.3 CoO 3. The SEM micrograph of the samples revealed crystallites of micrometer dimension with varying grain size. The sample showed interestingly low thermal conductivity and VRH mechanism was found to dominate in the electrical conduction at low temperature regime. The low thermal conductivity and moderate electrical conductivity is suggestive of strong candidature of the material for thermoelectric applications.

Download Full-text

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.357-360.1441 ◽

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.

Download Full-text

Low density and low thermal conductivity chrome oxide refractories for glass-melting furnaces for fiber production

Refractories ◽

10.1007/bf01386593 ◽

1981 ◽

Vol 22 (3-4) ◽

pp. 228-233 ◽

Cited By ~ 1

Author(s):

P. P. Krivoruchko ◽

V. P. Kravchenko ◽

B. G. Alapin ◽

D. M. Shakhtin ◽

�. V. Degtyareva ◽

...

Keyword(s):

Thermal Conductivity ◽

Glass Melting ◽

Low Density ◽

Fiber Production ◽

Low Thermal Conductivity ◽

Chrome Oxide

Download Full-text

Mechanically Strong, Low Thermal Conductivity and Improved Thermal Stability Polyvinyl Alcohol–Graphene–Nanocellulose Aerogel

Gels ◽

10.3390/gels7040170 ◽

2021 ◽

Vol 7 (4) ◽

pp. 170

Author(s):

Xiuya Wang ◽

Pengbo Xie ◽

Ke Wan ◽

Yuanyuan Miao ◽

Zhenbo Liu ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Thermal Stability ◽

Polyvinyl Alcohol ◽

Low Density ◽

Composite Aerogel ◽

Ternary Composite ◽

Low Thermal Conductivity ◽

Good Thermal Stability ◽

Composite Aerogels

Porous aerogel materials have advantages of a low density, low thermal conductivity and high porosity, and they have broad application prospects in heat insulation and building energy conservation. However, aerogel materials usually exhibit poor mechanical properties. Single-component aerogels are less likely to possess a good thermal stability and mechanical properties. It is necessary to prepare multiple-composite aerogels by reinforcement to meet practical application needs. In this experiment, a simple preparation method for polyvinyl alcohol (PVA)–graphene (GA)–nanocellulose (CNF) ternary composite aerogels was proposed. This is also the first time to prepare ternary composite aerogels by mixing graphene, nanocellulose and polyvinyl alcohol. A GA–CNF hydrogel was prepared by a one-step hydrothermal method, and soaked in PVA solution for 48 h to obtain a PVA–GA–CNF hydrogel. PVA–GA–CNF aerogels were prepared by freeze drying. The ternary composite aerogel has advantages of excellent mechanical properties, a low thermal conductivity and an improved thermal stability, because strong hydrogen bonds form between the PVA, GA and CNF. The composite aerogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometry, Brunauer–Emmett–Teller analysis, dynamic thermal analysis, thermogravimetry and thermal constant analysis to characterize the properties of the ternary composite aerogels. The lightweight, low-density and porous PVA–GA–CNF composite aerogels withstood 628 times their mass. The thermal conductivity of the composite aerogels was 0.044 ± 0.005 W/mK at room temperature and 0.045 ± 0.005 W/mK at 70 °C. This solid, low thermal conductivity and good thermal stability PVA–GA–CNF ternary composite aerogel has potential application in thermal insulation.

Download Full-text

Facile synthesis of highly flexible polymethylsilsesquioxane aerogel monoliths with low density, low thermal conductivity and superhydrophobicity

Vacuum ◽

10.1016/j.vacuum.2020.109825 ◽

2021 ◽

Vol 183 ◽

pp. 109825

Author(s):

Tan Guo ◽

Shan Yun ◽

Yanxing Li ◽

Zhang Chen ◽

Chuanxiang Cao ◽

...

Keyword(s):

Thermal Conductivity ◽

Low Density ◽

Facile Synthesis ◽

Low Thermal Conductivity

Download Full-text

High Temperature Thermal Barrier Coating Made by the Solution Precursor Plasma Spray Process

Volume 6: Ceramics; Controls, Diagnostics and Instrumentation; Education; Manufacturing Materials and Metallurgy ◽

10.1115/gt2014-26254 ◽

2014 ◽

Cited By ~ 7

Author(s):

Eric H. Jordan ◽

Maurice Gell ◽

Chen Jiang ◽

Jiwen Wang ◽

Balakrishnan Nair

Keyword(s):

Thermal Conductivity ◽

High Temperature ◽

Plasma Spray ◽

High Hardness ◽

Temperature Phase ◽

Low Density ◽

Solution Precursor Plasma Spray ◽

Low Thermal Conductivity ◽

Solution Precursor ◽

Stress Relieving

Yttrium aluminum garnet (YAG) is well-known to have desirable physical and mechanical properties, including high temperature phase stability, relatively low thermal conductivity, high hardness, and low density. This combination of properties makes it desirable to pursue YAG as an advanced TBC. Unfortunately, thermal cycle durability is poor because it has higher thermal expansion mismatch stresses compared to conventional 7YSZ. Recently, 250 micron thick YAG TBCs have been produced by the solution precursor plasma spray (SPPS) process. These SPPS YAG TBCs exhibit good thermal cycling properties compared to APS 7YSZ because of the presence of stress-relieving, through-thickness cracks. The SPPS YAG TBCs also exhibit low thermal conductivity, low density and high hardness.

Download Full-text

Low-density graphene/carbon composite aerogels prepared at ambient pressure with high mechanical strength and low thermal conductivity

RSC Advances ◽

10.1039/c4ra08800j ◽

2015 ◽

Vol 5 (7) ◽

pp. 5197-5204 ◽

Cited By ~ 30

Author(s):

Kang Guo ◽

Zijun Hu ◽

Huaihe Song ◽

Xian Du ◽

Liang Zhong ◽

...

Keyword(s):

Thermal Conductivity ◽

Mechanical Strength ◽

Compression Strength ◽

Ambient Pressure ◽

Carbon Matrix ◽

Carbon Composite ◽

Low Density ◽

High Mechanical Strength ◽

Low Thermal Conductivity ◽

Composite Aerogels

SEM and TEM pictures show that GNSs can be well-dispersed in a carbon matrix. The resultant composite CAs exhibited high compression strength and extremely low thermal conductivity of 0.028 W m−1 K−1.

Download Full-text