Flexible and coatable insulating silica aerogel/polyurethane composites via soft segment control

Cho, Jaehyun; Jang, Han Gyeol; Kim, Seong Yun; Yang, Beomjoo

doi:10.1016/j.compscitech.2018.12.027

Cited by 41 publications

(18 citation statements)

References 49 publications

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“…The temperature range was 25 to 600°C, under N 2 atmosphere (20 ml/min) and a heating rate of 10°C/min. To analyze the samples thermal resistance in heat flow, the heat‐resistance index ( T HRI ) was calculated for neat PU, PU‐ZnO, and hybrid PU composites using Equation ) [22]:

T_{HRI} = 0.49 \times ([], T_{5} + 0.6 \times ((), T_{30} - T_{5})) .

where T 5 is referring to a 5% weight loss of the foam (start of decomposition of hard segments such as urethane bonds); T 30 is referring to a 30% weight loss of the foam (decomposition of soft segments) [23].…”

Section: Methodsmentioning

confidence: 99%

A novel hybrid polyurethane composites with ZnO particles and sheath palm residues: Synergistic effect

et al. 2020

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Technological advances related to the development of new sustainable materials have driven the search for composites containing green fillers. Polyurethane (PU) composites with natural fibers have stood out; however, these materials have limited mechanical and thermal properties. This study developed hybrid PU composites filled with ZnO and palm sheath residues and evaluated the fiber loading (0, 5, 10, 15, and 20 wt%) on morphological, chemical, thermal, crystalline, and mechanical properties. Microscopic and scanning electron microscopy images showed that ZnO promoted homogeneous and isotropic cell structures. Sheath palm residues were well dispersed throughout the PU matrix and increased the foam's density and further decreased the cell sizes due to limited expansion caused by the fibers that altered nucleation and growth mechanisms. Strong hydrogen bonds formed between the fillers and the PU matrix resulted in a new network that improved thermal resistance. Also, crystallinity enhanced PU chains' organization due to filler incorporation, and these changes on the PU matrix increased impact resistance. The best results were obtained for the hybrid PU composite with 20 wt% of palm fiber. The properties improvements show the reinforcements' character in PU foams with environmentally friendly materials.

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T_{HRI} = 0.49 \times ([], T_{5} + 0.6 \times ((), T_{30} - T_{5})) .

Section: Methodsmentioning

confidence: 99%

A novel hybrid polyurethane composites with ZnO particles and sheath palm residues: Synergistic effect

et al. 2020

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“…Especially, these disadvantages are fatal and prohibit in the field of coal mining. To overcome these disadvantages, inorganic modification is a promising strategy in improving the performance of the composites 15 , 16 . Hybrid organic/inorganic composites made from polyisocyanate and sodium silicate have low-cost, good permeability, low heat release and fire resistance, but have poor mechanical properties due to the interface incompatibility between organic and inorganic phase 17 .…”

Section: Introductionmentioning

confidence: 99%

Mechanism confirmation of organofunctional silanes modified sodium silicate/polyurethane composites for remarkably enhanced mechanical properties

Liang

Gao

Sun

et al. 2021

Sci Rep

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Hybrid reinforced sodium silicate/polyurethane (SS/PU) composites mainly derived from low-cost SS and polyisocyanate are produced by a one-step method based on the addition of 3-chloropropyltrimethoxysilane (CTS). The wettability of SS on PU substrate surface is much improved as CTS content increases from 0.0 to 3.5 wt%. Furthermore, with 2.5 wt% of CTS optimal addition, the fracture surface morphology and elemental composition of the resulting SS/PU composites are characterized, as well as mechanical properties, chemical structure and thermal properties. The results indicate that the CTS forms multiple physical and chemical interactions with the SS/PU composites to induce an optimized organic–inorganic hybrid network structure thus achieving simultaneous improvement of compressive strength, flexural strength, flexural modulus and fracture toughness of the SS/PU composites, with the improvement of 12.9%, 6.6%, 17.5% and 9.7%, respectively. Moreover, a reasonable mechanism explanation for CTS modified SS/PU composites is confirmed. Additionally, the high interface areas of the organic–inorganic phase and the active crosslinking effect of the CTS are the main factors to determine the curing process of the SS/PU composites.

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“…The results showed that the thermal insulation properties of aerogel–polyurethane composites were enhanced by a 72% reduction in thermal conductivity upon 30 wt.% aerogel loading. Furthermore, these results were theoretically verified by a micromechanics-based thermal conductivity model [ 15 ]. Although several studies aiming to enhance the performance of PUF have been carried out, most of them focused on compressive mechanical and thermal tests at room temperature (25 °C).…”

Section: Introductionmentioning

confidence: 80%

Influence of Silica-Aerogel on Mechanical Characteristics of Polyurethane-Based Composites: Thermal Conductivity and Strength

et al. 2021

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Polyurethane foam (PUF) has generally been used in liquefied natural gas (LNG) carrier cargo containment systems (CCSs) owing to its excellent mechanical and thermal properties over a wide range of temperatures. An LNG CCS must be designed to withstand extreme environmental conditions. However, as the insulation material for LNGC CCSs, PUF has two major limitations: its strength and thermal conductivity. In the present study, PUFs were synthesized with various weight percentages of porous silica aerogel to reinforce the characteristics of PUF used in LNG carrier insulation systems. To evaluate the mechanical strength of the PUF-silica aerogel composites considering LNG loading/unloading environmental conditions, compressive tests were conducted at room temperature (20 °C) and a cryogenic temperature (−163 °C). In addition, the thermal insulation performance and cellular structure were identified to analyze the effects of silica aerogels on cell morphology. The cell morphology of PUF-silica aerogel composites was relatively homogeneous, and the cell shape remained closed at 1 wt.% in comparison to the other concentrations. As a result, the mechanical and thermal properties were significantly improved by the addition of 1 wt.% silica aerogel to the PUF. The mechanical properties were reduced by increasing the silica aerogel content to 3 wt.% and 5 wt.%, mainly because of the pores generated on the surface of the composites.

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Flexible and coatable insulating silica aerogel/polyurethane composites via soft segment control

Cited by 41 publications

References 49 publications

A novel hybrid polyurethane composites with ZnO particles and sheath palm residues: Synergistic effect

A novel hybrid polyurethane composites with ZnO particles and sheath palm residues: Synergistic effect

Mechanism confirmation of organofunctional silanes modified sodium silicate/polyurethane composites for remarkably enhanced mechanical properties

Influence of Silica-Aerogel on Mechanical Characteristics of Polyurethane-Based Composites: Thermal Conductivity and Strength

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