Xingyu Zhao, Kunpeng Ruan, Hua Qiu, Xiao Zhong* and Junwei Gu*. Fatigue-resistant polyimide aerogels with hierarchical cellular structure for broadband frequency sound absorption and thermal insulation. Advanced Composites and Hybrid Materials, 2023, 6:171. 2022IF=20.1
https://doi.org/10.1007/s42114-023-00747-9
Abstract
Living in the noisy environment for long time would cause various diseases and seriously harm physical and mental health of mankind. In this work, water-soluble polyamide acid was used to prepare the polyimide-polyvinylpyrrolidone (PI-PVP) aerogels with hierarchical cellular structures by homogeneous mixing with pore modifier of PVP, freeze-drying, and thermal treatment. PVP could adjust pore structures, widen pore size distribution, and improve sound absorption performances for PI aerogels in wide frequency range. When the amount of PVP is 45 wt%, PI-PVP aerogels exhibit excellent sound absorption, mechanical, thermal insulation, and heat resistances performance. The noise reduction coefficient is 0.34 and average sound absorption coefficient is over 0.9 in the frequency range of 2000~ 6300 Hz. Young’s modulus is 7.12 kPa. Stress loss and plastic deformation after 100 compression cycles (strain of 50%) are 14.7% and 3.2%, respectively. Meantime, the thermal conductivity coefficient and the initial thermal decomposition temperature in the air are 0.044 W/(m·K) and 420°C, respectively. Our fabricated PI-PVP aerogels in this work own broad application prospects in the fields of engineering, construction, vehicle noise reduction, and personal protection.
交通運輸業、工業以及建筑業的快速發展致使噪聲污染加劇，長期生活在噪聲環境中會引起各種疾病，嚴重危害人類的身心健康。本文以二氨基二苯醚和均苯四甲酸二酐為單體，經三乙胺改性合成水溶性聚酰胺酸，再以聚乙烯吡咯烷酮（PVP）為調孔劑，通過均勻混合、冷凍干燥和熱亞胺化制得具有多級孔結構聚酰亞胺（PI）氣凝膠。PVP可以有效調節PI氣凝膠的孔結構并拓寬孔徑分布，提升其寬頻率范圍內的吸聲性能。當PVP的用量為45 wt%時，PI-PVP45%氣凝膠表現出最佳的吸聲性能、優異的力學性能、隔熱性能和耐熱性能。其降噪系數為0.34，2000~6300 Hz頻率范圍內平均吸聲系數>0.9；楊氏模量為7.12 kPa，且在經歷100次壓縮循環（最大應變為50%）后應力損耗為14.7%，塑性形變為3.2%；導熱系數為0.044 W/mK；空氣中起始熱分解溫度為420oC。
論文亮點
1. 采用“均勻混合-冷凍干燥-熱亞胺化”法實現了氣凝膠孔結構的二次構筑，成功制備出具有多級孔結構的PI吸聲氣凝膠；
2. 多級孔結構PI吸聲氣凝膠具有優異的吸聲性能，其降噪系數為0.34，2000~6300 Hz頻率范圍內平均吸聲系數>0.9；
3. 多級孔結構PI吸聲氣凝膠具有優異的力學性能（楊氏模量為7.12 kPa）、耐疲勞性（50%應變壓縮循環100次應力損耗為14.7%，塑性形變為3.2%）、隔熱性能（導熱系數為0.044 W/mK）和耐熱性能（熱分解溫度為420oC，耐熱指數為259oC）。
第一作者：趙興宇
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