聚酰亚胺
材料科学
热稳定性
二亚胺
无定形固体
分子间力
玻璃化转变
小角X射线散射
化学工程
复合材料
结晶学
散射
聚合物
分子
有机化学
光学
工程类
化学
物理
苝
图层(电子)
作者
Senjie Jiang,Zhijun Bi,Junkang Wang,Jiaxin Zhao,Long Fan,Liyong Tian,Yancheng Wu,Ningbo Yi,Zhenzhen Wei,Feng Gan
标识
DOI:10.1016/j.jmrt.2023.06.064
摘要
The new-generation polyimide films with simultaneously outstanding thermal stability and low coefficient of linear thermal expansion (CTE) are urgently needed. Herein, coordination bonds were employed to improve polyimide films' heat resistance and dimensional stability. Polyimide-Cu complex films were fabricated by incorporating α-diimide units (bidentate ligands) into the BPDA-ODA (the structure of commercially available Upilex-R® polyimide films) backbones. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Energy dispersive X-ray mapping results showed that the coordination interactions occur between α-diimide and copper ions. Wide-angle X-ray diffraction (WAXD) and two-dimensional small-angle X-ray scattering (SAXS) spectra demonstrated that Cu-α-diimide coordination structures introduced in intermolecular chains leading polyimide films transformed from a semi-crystalline state to amorphous state, and inhibited the long-period formation structures. The plateau modulus and longer characteristic relaxation time (τ∗ = 1996.5 s) revealed by dynamic thermomechanical analysis indicated that crosslink networks were successfully formed by constructing coordination bonds. As a result, polyimide films' thermal resistance and dimensional stability were simultaneously enhanced. The typical PI-Cu50 films exhibited elevated glass transition temperatures of 353 °C (pristine PI-Cu0 ∼ 302 °C) and a lower CTE of 47.4 ppm/K (pristine PI-Cu0 films ∼ 64.4 ppm/K) in ranges of 300–400 °C, showing a promising application in the field of high-temperature environments.
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