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.

交通运输业、工业以及建筑业的快速发展致使噪声污染加剧，长期生活在噪声环境中会引起各种疾病，严重危害人类的身心健康。本文以二氨基二苯醚和均苯四甲酸二酐为单体，经三乙胺改性合成水溶性聚酰胺酸，再以聚乙烯吡咯烷酮（PVP）为调孔剂，通过均匀混合、冷冻干燥和热亚胺化制得具有多级孔结构聚酰亚胺（PI）气凝胶。PVP可以有效调节PI气凝胶的孔结构并拓宽孔径分布，提升其宽频率范围内的吸声性能。当PVP的用量为45 wt%时，PI-PVP45%气凝胶表现出最佳的吸声性能、优异的力学性能、隔热性能和耐热性能。其降噪系数为0.34，2000~6300 Hz频率范围内平均吸声系数>0.9；杨氏模量为7.12 kPa，且在经历100次压缩循环（最大应变为50%）后应力损耗为14.7%，塑性形变为3.2%；导热系数为0.044 W/mK；空气中起始热分解温度为420^oC。

论文亮点

1. 采用“均匀混合-冷冻干燥-热亚胺化”法实现了气凝胶孔结构的二次构筑，成功制备出具有多级孔结构的PI吸声气凝胶；

2. 多级孔结构PI吸声气凝胶具有优异的吸声性能，其降噪系数为0.34，2000~6300 Hz频率范围内平均吸声系数>0.9；

3. 多级孔结构PI吸声气凝胶具有优异的力学性能（杨氏模量为7.12 kPa）、耐疲劳性（50%应变压缩循环100次应力损耗为14.7%，塑性形变为3.2%）、隔热性能（导热系数为0.044 W/mK）和耐热性能（热分解温度为420oC，耐热指数为259^oC）。

第一作者：赵兴宇

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