Silicon‐containing polyarylacetylene aerogel with heat resistance and ablative property for high‐temperature insulation

Abstract

Owing to the high porosity and low thermal conductivity of organic aerogels, they have been widely used to develop lightweight heat insulation materials.However, their applications in high-temperature environments such as in aerospace applications are usually limited by the heat resistance or ablative property of the organic matrix. In this study, we prepared a novel organic aerogel for high-temperature insulation by the sol-gel method and freeze-drying. The matrix is the thermosetting silicon-containing polyarylacetylene (PSA) resin with excellent comprehensive properties, namely, high heat stability, low volatile component content, and high-temperature ceramic performance. The obtained PSA aerogel retains the heat resistance (T d5 = 634.8 C) and ablative properties (Y r800 = 92.6%) of the PSA resin, and the internal regular macropores and high porosity (70%) result in an extremely low weight (0.1200 g cm À3 ), low thermal conductivity (0.039 W m À1 K À1 )), and efficient heat insulation. Thus, this is an ideal material for high-temperature insulation in the aerospace field.

Polysilsesquioxane-Containing Thermally Degradable Groups for Potential Application as Thermal Insulation Materials

“…A large substituent on the side chain of the methylsilsesquioxane backbone might increase the pore size and decrease the thermal diffusivity of the film. 29 For example, the thermal diffusivity of the GSQ-Adoc12 film was as low as 1.04 × 10 −7 m 2 /s, and the density of GSQ-Adoc12 increased to 1.19 g/cm 3 because the adamantyl group is larger and more robust than the tert-butyl group in the GSQ-Boc films. The GSQ-Ester12 film without the amino group also exhibited low thermal diffusivity (1.07 × 10 −7 m 2 /s, similar to that of GSQ-Boc16).…”

“…The development of high-performance heat insulators can realize energy-efficient applications. Thermally stable heat insulators are particularly in demand in automobile and aircraft engines, space technology, and industrial heat-emitting equipment. − Organic frameworks are the basis of heat insulators such as polystyrene and polyurethane forms and nonwoven fabric materials, whereas inorganic frameworks are used in glass wool and porous ceramics . Most organic insulators are easily processed and deliver high heat insulation but are combustible and easily melt at high temperatures, rendering them unsuitable for the aforementioned applications .…”

Recent advances in flexible and soft gel-based pressure sensors

“…Suitable for the introduction of unsaturated double bonds Significantly low degree of ion movement; low conductivity [59] Aerogel Sol-gel and drying method Molecular level is uniform; easy to be doped with other trace elements Complex preparation process; difficult to large mass production [62,63] Figure 1. Summary of research on gel-based materials and devices.…”

“…The basis for the manufacture of aerogels is the formation of a porous solid material derived from a solventbased gel, in which the liquid component of the gel has been replaced with a gas during a supercritical drying process. The corresponding typical fabrication method is the sol-gel process, followed by a certain kind of drying process [Figure 4G] [62,63] . In detail, a stable colloidal system is firstly formed by changing the physical conditions (such as temperature and concentration of hydrogen ions) of the precursor solution or adding chemical reactants.…”

Effect of weaving parameter and resin structure of lightweight integrated multifunctional composite on thermal protection performance in extreme environment

“…[13,14] In recent years, low density polymer-matrix ablative thermal protection material was studied. [15][16][17] For example, phenolic impregnated carbon ablator (PICA) is a typical lightweight ablative material developed by NASA Ames Research in 1990s. PICA, with low density (0.22 g/cm 3 ), low thermal conductivity and excellent ablation resistance properties, was used as the heat shield of "Stardust" to withstand the maximum temperature of about 1600 C. [18] However, the lightweight composite would be ablated significantly when subjected to long time, oxidative environment.…”