Synthesis and optical properties of semi-fluorinated poly(ether imide)s derived from non-fluorinated 1,4-bis(3,4-dicarbo
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Synthesis and optical properties of semi-fluorinated poly (ether imide)s derived from non-fluorinated 1,4-bis(3,4dicarboxyphenoxy)benzene dianhydride (HQDPA) and trifluoromethyl-substituted diamines Yong Xu1,a)
, Linshuang Li1, Jianfei Che1, Zhifeng Ye1
1
School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China Address all correspondence to this author. e-mail: [email protected]
a)
Received: 17 July 2018; accepted: 1 November 2018
A series of optically transparent and colorless semi-fluorinated poly(ether imide)s (PEIs) (III) were prepared from non-fluorinated 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with various trifluoromethylsubstituted diamines. The III series showed more colorless and higher optical transparency with a cutoff absorption wavelength (k0) below 370 nm than the IV series based on the corresponding non-fluorinated analogues and V series derived from CF3-free pyromellitic dianhydride (PMDA). Compared with the fluorinated VI series based on fluorinated 4,49-hexafluoroisopropylidenediphthalic anhydride (6FDA), the semi-fluorinated III series not only exhibited much better optical transparency, but also had better mechanical and thermal properties. The III series had a tensile strength of 79.8–109.5 MPa, modulus of elasticity of 3.0–7.7 GPa and elongation at break of 14.2–26.7%, together with glass-transition temperatures (Tg) ranging from 214.3 to 265.1 °C and temperatures of 5% weight loss (T5%) beyond 530 °C. Meanwhile, the novel semi-fluorinated PEI IIIb was optically transparent and colorless with a k0 of 367 nm coupled with dielectric constants below 3.2 and contact angles against water over 112°. In particular, the optically transparent IIIa exhibited the best tensile strength of 109.5 MPa when compared with already reported counterparts.
Introduction Because of their excellent thermal stability, solvent resistance, remarkable mechanical properties and outstanding electrical properties, polyimides (PIs) offers important applications in the aerospace and electrical industries [1, 2, 3, 4, 5]. However, their further applications were limited by their low optical transparency and deep color intensity due to the formation of intra- and inter-molecular charge transfer complexation (CTC) between electron-withdrawing dianhydride residues and electron-donating diamine residues, leading to the strong absorption between ultraviolet and visible areas [6, 7, 8, 9, 10]. Hence, much efforts and attempts have been made to prepare optically transparent and colorless PIs to extend their applications on the flexible solar battery plate, nonlinear optical (NLO) waveguide materials, flexible active matrix organic light emitting display devices (AMOLEDs) and other fields of
ª Materials Research Society 2019
optoelectronics and photonics without sacrificing their outstanding properties [11, 12, 13, 14, 15]. The introduction of aliphatic dianhydride or aliphatic diamine monomers is an effective method to minimize or eliminate the formation of CTC to prepare tran
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