Xingyu Zhao, Kunpeng Ruan, Hua Qiu*, Yali Zhang and Junwei Gu*. Polyacrylonitrile nanofiber reinforced polyimide composite aerogels with fiber-pore interpenetrating structures for sound absorption, air filtration and thermal insulation. Composites Science and Technology, 2023, 244:110275. 2022IF=9.1

https://doi.org/10.1016/j.compscitech.2023.110275

Abstrac

tProlonged noise pollution and its induced vibration would not only lead to the failure of instruments and equipment, but also endanger human health. In this work, with water-soluble polyamide acid (PAA) as the matrix and polyacrylonitrile nanofiber (PANNF) as the reinforcement, PANNF reinforced polyimide (PANNF/PI) composite aerogels with fiber-pore interpenetrating structures are fabricated by the method of “homogeneous mixing, freeze-drying and heat treatment”. PANNF that intersperses among pores can effectively inhibit the shrinkage of PI aerogels and enhance sound absorption and mechanical properties. With PANNF dosage of 10 wt %, the composite aerogels own the excellent sound absorption performance, with noise reduction coefficient (NRC) of 0.398, and average sound absorption coefficient (SAC) of 0.913 in the frequency range of 2000~6300 Hz. The composite aerogels also have excellent mechanical properties, with Young’s modulus of 12.42 kPa, stress loss of 3.64% and energy loss coefficient of 0.203. 10 wt% PANNF/PI composite aerogels also possess satisfying air filtration performance (97.2% filtration efficiency for PM2.5, quality factor (QF) value of 0.0396 Pa-1; and 99.4% filtration efficiency for PM10, QF value of 0.0567 Pa-1) and thermal insulation performance (thermal conductivity coefficient as low as 0.036 W/(m?K)).长时间的噪声污染及其带来的共振问题不仅会导致仪器设备失效，还会危害人类健康。本文以二氨基二苯醚（ODA）和均苯四甲酸二酐（PMDA）为单体并经三乙胺（TEA）改性合成的水溶性聚酰胺酸（PAA）为基体、聚丙烯腈纳米纤维（Polyacrylonitrile nanofiber，PANNF）为增强体，经均匀混合、冷冻干燥和热处理制得具有纤维-孔互穿结构的PANNF增强聚酰亚胺（PANNF/PI）复合气凝胶。穿插在孔道间的PANNF可以有效抑制PI气凝胶的收缩且不影响其孔隙率与孔壁厚度，协同提升PANNF/PI复合气凝胶的吸声性能和力学性能。当PANNF用量为10 wt%时，PANNF/PI复合气凝胶表现出最佳的吸声性能，优异的力学性能、空气过滤性能和隔热性能。其降噪系数（NRC）为0.398，2000~6300 Hz频率范围内平均吸声系数为0.913；杨氏模量为12.42 kPa、经历1000次压缩循环（最大应变为50%）后应力损耗为3.64%、能量损耗系数为0.203；对PM2.5过滤效率为97.2%、对应品质因子（Quality factor，QF）为0.0396 Pa-1，对PM10过滤效率为99.4%、对应QF值为0.0567 Pa-1；导热系数为0.036 W/m·K。