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

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DOI：https://doi.org/10.1021/acsapm.2c01900

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High-performance thermal insulation materials are in great demand in energy-efficient applications. Nanopore formation is a promising strategy for enhancing the thermal insulating properties of polysilsesquioxane (PSQ)-based thermal insulation. Herein, PSQ films containing hydrosilyl group and tert-butoxycarbonyl (Boc) groups (GSQ-Boc film) were prepared via a hydrosilylation reaction and dehydrogenation. GSQ-Boc films containing Boc at 3–16 wt % exhibited lower thermal diffusivities (0.87 × 10–7–1.11 × 10–7 m2/s) than the MSQ film (1.44 × 10–7 m2/s) prepared through dehydrogenation of hydrodimethyl-silylated oligomethylsilsesquioxane (MSQ-SiH). Incorporating sterically large substituents (here, the Boc group) improved the thermal insulating properties of PSQ materials. The 1-adamantyl carbamate groups and tert-butyl ester groups exhibited a similar effect. The Boc groups in GSQ-Boc film thermally degraded to isobutene and carbon dioxide via thermal treatment. The thermal diffusivities of the thermally degraded GSQ-Boc films increased to 1.21 × 10–7–1.38 × 10–7 m2/s, probably because the films shrank during the thermal degradation of the Boc groups. The GSQ-Boc film with divinylbenzene crosslinkers exhibited a higher thermal diffusivity following the thermal degradation of the Boc group (1.10 × 10–7 vs 0.82 × 10–7 m2/s before thermal degradation). The density also increased from 1.10 to 1.12 g/cm3; however, the rate of increase in density was effectively suppressed. Overall, the crosslinker might be useful for preventing shrinkage after thermal degradation and can potentially realize PSQ-based thermal insulation materials.