Isocyanate-crosslinked silica aerogel monolith with low thermal conductivity and much enhanced mechanical properties: Fabrication and analysis of forming mechanisms

Wu, Xiaodong; Man, Jianwei; Liu, Sijia; Huang, Shuntian; Lu, Jiaxin; Tai, Juxiang; Zhong, Ya; Shen, Xiaodong; Cui, Sheng; Chen, Xiangbao

doi:10.1016/j.ceramint.2021.06.074

Cited by 19 publications

(10 citation statements)

References 39 publications

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“…The occurrence of SAP in the MPLA/TBFP composites decreased their k value. A spider web structure formed by the SAP, MPLA, and BFP prevented heat transmission into the composite and significantly decreased its heat transfer ability, thus increasing its heat resistance …”

Section: Resultsmentioning

confidence: 99%

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Preparation and Characterization of Polylactic Acid/Bamboo Fiber Composites

Wang

2022

ACS Appl. Bio Mater.

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The development of green and renewable materials has attracted increasing attention in recent years. Hence, biocomposite-based packaging materials have been investigated to replace petrochemical materials in several industries, such as the food packaging and electronics packaging industries. The tensile and thermal properties of biocomposite-based packaging materials composed of polylactic acid and plant fiber were mainly investigated in the current literature, but fewer studies on the improvement of water resistance and water vapor/oxygen barrier properties of composite materials were performed. Herein, we describe a composite film comprising TBFP [a mixture of bamboo fiber powder (BFP) and silica aerogel powder] that was combined with modified polylactic acid (MPLA) in a melt-mixing process. The structure, morphology, tensile strength, thermal properties, water absorption properties, water vapor/oxygen barrier effect, cytocompatibility, and biodegradability of the composites were characterized. MPLA and TBFP improved the properties of these composites. Fourier transform infrared and X-ray diffraction spectra have shown interfacial adhesion of MPLA/TBFP, resulting in a tighter structure. Hence, the MPLA/TBFP composite had higher elongation at failure (ε), tensile strength at failure (δ), Young’s modulus (E), initial decomposition temperature at 5 wt % loss (T 5%), residual yields, oxygen transmission rate, contact angles, lower thermal conductivity (k) values, water vapor transmission rate, and water absorption and biodegradability compared with PLA and PLA/BFP. It indicates that the MPLA/TBFP composites exhibited more favorable tensile strength, water resistance, and water vapor/oxygen barrier than the PLA and PLA/BFP composites. Cell growth analysis showed that the MPLA/TBFP and PLA/BFP composites own good cytocompatibility. Moreover, the biodegradability of the PLA/BFP and MPLA/TBFP composites increased with the filler (BFP or TBFP) concentration. Because of these improvements in their properties, composites can be used as packing materials in many perspectives.

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Section: Resultsmentioning

confidence: 99%

“…A spider web structure formed by the SAP, MPLA, and BFP prevented heat transmission into the composite and significantly decreased its heat transfer ability, thus increasing its heat resistance. 48 3.4. Analysis of Barrier Properties.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Polylactic Acid/Bamboo Fiber Composites

Wang

2022

ACS Appl. Bio Mater.

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“…(a) TGA curves of the PSA resin; (b) TGA curves of the SiO 2 /PSA aerogels; (c) density (dark color) and thermal conductivity (light color) of SiO 2 /PSA aerogels; and (d) thermal conductivity comparison of the SiO 2 /PSA aerogels and other porous materials (25 °C). Samples: FPU/Alag areogel, PFR/SiO 2 aerogel, PU/SiO 2 aerogel, cellulose aerogel, KGM/SiO 2 aerogel, PVA/CNF/GONS, NFC/SiO 2 aerogel, MXene/ANFs, PA aerogel, ANF aerogel, , KNF aerogel, and PI aerogel …”

Section: Resultsmentioning

confidence: 99%

“…When compared to PSA resin with a residue weight of 91.2% at 800 and 623 °C at a 5% weight loss, the thermal stability of the PSA aerogel is reduced due to the thermogravimetric effect of alkyl chains introduced by MPTES. FPU/Alag areogel, 22 PFR/SiO 2 aerogel, 23 PU/SiO 2 aerogel, 24 cellulose aerogel, 25 KGM/SiO 2 aerogel, 26 PVA/CNF/GONS, 27 NFC/SiO 2 aerogel, 28 MXene/ANFs, 29 PA aerogel, 30 ANF aerogel, 31,32 KNF aerogel, 33 and PI aerogel. TGA data of the SiO 2 /PSA aerogel in air has been listed in Supporting Information Table S1 and Figures S4 and S5.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Thermally Insulating SiO₂/PSA Composite Aerogels with Heat Resistance and Mechanical Properties via the Thiol–Yne Click Reaction

Zhao

Qiao

et al. 2023

Langmuir

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Polymer-reinforced silica aerogels are thermally insulating materials employed to enhance mechanical properties; however, they exhibit low heat stability and require a complex production process. The main body of this work concerns the synthesis of silicon-containing polyarylacetylene (PSA) resin, which has exceptional thermal properties and is used to strengthen the gel skeleton and significantly improve the heat resistance of the polymer reinforcement phase. The honeycomb-like porous SiO 2 / PSA aerogels derived from directional freezing were obtained via click reaction, gel aging, freeze-drying, and curing without the requirement for time-consuming solvent replacement. The prepared SiO 2 /PSA aerogel is low density (∼0.3 g/cm 3 ) and high porosity (∼80%), which provides the material with low levels of thermal conductivity (∼0.06 W/m•K) and excellent thermal insulation performance. When compared to the majority of polymer aerogels and aerogel-like materials, the prepared SiO 2 /PSA aerogels have high T d5 (∼460 °C) and Y r800 (∼80%) and compressive strength (compression strength > 1.5 MPa). SiO 2 /PSA composite aerogel has numerous functions in areas where materials must withstand extremely elevated temperatures, such as the aerospace industry.

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“…As shown in the figure, the new vibration peak at around 159.6 ppm is assigned to the newly formed amino groups, indicating that HDI reacted with the -NH 2 groups of silica clusters forming the -NH-C-O-NH- chains [ 39 ]. The intense peaks at 42.7 and 30.6 ppm are attributed to the -CH 2 groups of the HDI cross-linker [ 40 , 41 ]. The peak at around 60 ppm induced by ethoxylation is evident in the PSAM [ 42 ], while a very weak peak can be observed in the RSAM, further verifying the polymerization between -NH 2 and -NCO groups.…”

Section: Resultsmentioning

confidence: 99%

Auto-Continuous Synthesis of Robust and Hydrophobic Silica Aerogel Microspheres from Low-Cost Aqueous Sodium Silicate for Fast Dynamic Organics Removal

Sun

Zhao

Kong

et al. 2022

Gels

Self Cite

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An efficient auto-continuous globing process was developed with a self-built apparatus to synthesize pure silica aerogel microspheres (PSAMs) using sodium silicate as a precursor and water as a solvent. A hydrophobic silica aerogel microsphere (HSAM) was obtained by methyl grafting. A reinforced silica aerogel microsphere (RSAM) was prepared by polymer cross-linking on the framework of the silica gel. The pH value of the reaction system and the temperature of the coagulating bath were critical to form perfect SAMs with a diameter of 3.0 ± 0.2 mm. The grafted methyl groups are thermally stable up to 400 °C. Polymer cross-linking increased the strength significantly, owing to the polymer coating on the framework of silica aerogel. The pore volumes of HSAM (6.44 cm3/g) and RSAM (3.17 cm3/g) were much higher than their state-of-the-art counterparts. Their specific surface areas were also at a high level. The HSAM and RSAM showed high organic sorption capacities, i.e., 17.9 g/g of pump oil, 11.8 g/g of hexane, and 22.2 mg/g of 10 mg/L methyl orange. The novel preparation method was facile, cost-effective, safe, and eco-friendly, and the resulting SAM sorbents were exceptional in capacity, dynamics, regenerability, and stability.

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Isocyanate-crosslinked silica aerogel monolith with low thermal conductivity and much enhanced mechanical properties: Fabrication and analysis of forming mechanisms

Cited by 19 publications

References 39 publications

Preparation and Characterization of Polylactic Acid/Bamboo Fiber Composites

Preparation and Characterization of Polylactic Acid/Bamboo Fiber Composites

Thermally Insulating SiO₂/PSA Composite Aerogels with Heat Resistance and Mechanical Properties via the Thiol–Yne Click Reaction

Auto-Continuous Synthesis of Robust and Hydrophobic Silica Aerogel Microspheres from Low-Cost Aqueous Sodium Silicate for Fast Dynamic Organics Removal

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Isocyanate-crosslinked silica aerogel monolith with low thermal conductivity and much enhanced mechanical properties: Fabrication and analysis of forming mechanisms

Cited by 19 publications

References 39 publications

Preparation and Characterization of Polylactic Acid/Bamboo Fiber Composites

Preparation and Characterization of Polylactic Acid/Bamboo Fiber Composites

Thermally Insulating SiO2/PSA Composite Aerogels with Heat Resistance and Mechanical Properties via the Thiol–Yne Click Reaction

Auto-Continuous Synthesis of Robust and Hydrophobic Silica Aerogel Microspheres from Low-Cost Aqueous Sodium Silicate for Fast Dynamic Organics Removal

Contact Info

Product

Resources

About

Thermally Insulating SiO₂/PSA Composite Aerogels with Heat Resistance and Mechanical Properties via the Thiol–Yne Click Reaction