scholarly journals Ethylene-bridged polysilsesquioxane/hollow silica particle hybrid film for thermal insulation material

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 24968-24975
Author(s):  
Satoru Tsukada ◽  
Yuki Nakanishi ◽  
Takashi Hamada ◽  
Kenta Okada ◽  
Susumu Mineoi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Insulation ◽  
Silica Particle ◽  
Hybrid Film ◽  
Sol Gel ◽  
Insulation Material ◽  
Hybrid Films ◽  
Hollow Silica ◽  
Bridged Polysilsesquioxane ◽  
Hollow Silica Particles

Ethylene-bridged polysilsesquioxane/hollow silica particle hybrid films were prepared by the sol–gel reaction. The hybrid film containing hollow silica particles exhibited good thermal insulation properties and thermal stability.

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

2021 ◽  
pp. 0021955X2110626
Author(s):  
Tae Seok Kim ◽  
Yeongbeom Lee ◽  
Chul Hyun Hwang ◽  
Kwang Ho Song ◽  
Woo Nyon Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Stability ◽  
Cell Size ◽  
Thermal Insulation ◽  
Coefficient Of Thermal Expansion ◽  
Lower Surface ◽  
Polyurethane Foams ◽  
Insulation Material ◽  
Pu Foams

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.

Synthesis and Second-Order Optical Nonlinearity of Inorganic-Organic Hybrid Films Bearing Y-Type NLO Active Chromophore

2007 ◽  
Vol 336-338 ◽  
pp. 552-554
Author(s):  
Xiao Nan Mei ◽  
Hai Yao Lin ◽  
Yuan Jing Cui ◽  
Ping Lv ◽  
Guo Dong Qian
Keyword(s):  
Thermal Stability ◽  
Sol Gel ◽  
Optical Nonlinearity ◽  
Second Order ◽  
Inorganic Materials ◽  
Hybrid Films ◽  
Organic Hybrid ◽  
Type Silicon ◽  
Sol Gel Process ◽  
Organic Chromophore

In order to achieve a large hyperpolarizability (β) value and thermal stability, a novel Y-type silicon precursor ICTES-DBPNPI was synthesized. By the sol-gel process, the new organic-inorganic materials having organic chromophore were prepared.

scholarly journals Fabrication of Flexible Agnws/Cellulose Hybrid Film with Heat Preservation and Antibacterial Properties for Agriculture Application

2021 ◽  
Author(s):  
Yu Chen ◽  
Shuanghong Yang ◽  
Zhiwei Qiu ◽  
Yuqi Li ◽  
Fengxian Qiu ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Hybrid Film ◽  
Supply Voltage ◽  
Silver Nanowires ◽  
Antibacterial Properties ◽  
Building Blocks ◽  
Electrical Heating ◽  
General Strategy ◽  
Hybrid Films ◽  
Agricultural Films

Abstract In the view of sustainable development and environment protection, degradable agricultural films with on-demand thermal insulation properties have attracted growing research interest in the last few decades due to the deteriorating environment and extreme climate on the growth and existence of crops. Here, a general strategy has been developed to fabricate degradable silver nanowires modified cellulose (AgNWs/cellulose) hybrid film with controllable thermal insulation and antibacterial properties by using plant cellulose and AgNWs as building blocks, as well as their agriculture application. The results showed that the AgNWs were evenly dispersed in the three-dimensional grid of cellulose, formed a film that could withstand a certain tensile force, and have good thermal stability. Due to the excellent electrical conductivity, the AgNWs/cellulose hybrid films can provide excellent Joule heating, generating rapid thermal response and uniform electrical heating at a low supply voltage of 3 V for extra warmth. In the antibacterial tests against Escherichia coli and Staphylococcus aureus, the AgNWs/cellulose hybrid film exhibit large diameters of inhibition zones, revealing the high antibacterial activity. Additionally, the AgNWs/cellulose hybrid films showed highly stretchable behavior by delivering a breaking strain of 1.5% with a tensile stress of 0.45 MPa owing to the cross-linked structures of cellulose and AgNWs. Based on the above properties, this study not only provides a potential strategy for the fabrication of flexible and biodegradable agricultural films but also may provide new insights for agricultural thermal management.

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

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 520 ◽  
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.

Robust and superhydrophobic thiourethane bridged polysilsesquioxane aerogels as potential thermal insulation materials

2016 ◽  
Vol 4 (28) ◽  
pp. 10801-10805 ◽  
Author(s):  
Fangxin Zou ◽  
Peng Yue ◽  
Xinghua Zheng ◽  
Dawei Tang ◽  
Wenxin Fu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Sol Gel ◽  
Vacuum Drying ◽  
Drying Method ◽  
Low Thermal Conductivity ◽  
Insulation Materials ◽  
Sol Gel Process ◽  
Bridged Polysilsesquioxane

Novel thiourethane bridged polysilsesquioxane aerogels prepared by a sol–gel process and vacuum drying method exhibit extraordinary mechanical properties and low thermal conductivity.

MORPHOLOGY AND CHARACTERIZATION OF POLYIMIDE/POLYSILSESQUIOXANE HYBRID FILMS WITH MESO/MACRO DOUBLE POROUS STRUCTURE

2004 ◽  
Vol 13 (03n04) ◽  
pp. 541-545
Author(s):  
KYUNG-IL KIM ◽  
JUN-YOUNG LEE ◽  
JOON-HYUN AN ◽  
JUNG-HYUN KIM
Keyword(s):  
Porous Structure ◽  
Organic Molecules ◽  
Hybrid Film ◽  
Sol Gel ◽  
Matrix Material ◽  
Hybrid Films ◽  
Hybrid Thin Film ◽  
Sol Gel Process ◽  
Temperature And Pressure

Supercritical CO 2 ( ScCO 2) can dissolve organic materials easily just by changing temperature and pressure. This property of ScCO 2 can be applied to extract some ScCO 2-philic organic molecules from matrix material. The ScCO 2 was used to generate the meso/macro double porous structure of polyimide/polysilsesquioxane (PI/PSSQ) hybrid film. The morphology of the porous structure was measured by scanning electron microscope (SEM). Here, we demonstrate that the ScCO 2 could penetrate into the hybrid thin film and take away the small molecules, which are the by-product ( CO 2) from the imidization reaction of the PI segment and the solvent remained in the PSSQ segment by sol-gel process.

Bismaleimide bridged silsesquioxane aerogels with excellent heat resistance: effect of sol–gel solvent polarity

Soft Matter ◽  
2020 ◽  
Vol 16 (14) ◽  
pp. 3548-3554
Author(s):  
Juan Zhao ◽  
Guanjie Zeng ◽  
Fangxin Zou ◽  
Shaohua Jiang ◽  
Yeqing Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heat Resistance ◽  
Thermal Insulation ◽  
Sol Gel ◽  
Solvent Polarity ◽  
Good Thermal Stability ◽  
Bridged Silsesquioxane ◽  
Micro Structures

Bismaleimide bridged silsesquioxane aerogels with tailorable micro-structures exhibit superhydrophobicity, stable wettability, good compressive toughness, good thermal stability and thermal insulation.

Synthesis of Hollow Silica Particle by Combination of Bubble Templating Method and Sol-Gel Transformation

2006 ◽  
Vol 11-12 ◽  
pp. 673-676 ◽  
Author(s):  
Yong Sheng Han ◽  
Y. Tarutani ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Hydrochloric Acid ◽  
Silica Particle ◽  
Capillary Tube ◽  
Sol Gel ◽  
Silica Sol ◽  
Gel Point ◽  
Hollow Silica ◽  
Templating Method ◽  
Hollow Particles ◽  
Water Alcohol

The feasibility of bubble templating method to prepare hollow particles was tested in this paper by passing a bubble into a silica sol. The silica sol was prepared by mixing TEOS, water, alcohol and hydrochloric acid. To control the gel point, the reactants and their concentrations were varied in each experiment. After the sol was prepared, an ammonia bubble was introduced into the prepared sol through a capillary tube. With the catalysis of ammonia, the silica sol gelled on the surface of bubble and formed a hollow gel particle. The nucleation of silica gel on the surface of bubble was discussed in this paper.

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