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RISS 인기검색어
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- 저자 : Linshuang Li (검색결과 2 건)
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Linshuang Li,Yong Xu,Jianfei Che,Xiaohong Liu,Wei Zhao,Zhifeng Ye 한국고분자학회 2019 Macromolecular Research Vol.27 No.9
The objective of this study was to investigate the effects of diamines with ether group or/and trifluoromethyl (-CF3) group on the optical properties of polyimides. A series of poly(ether imide)s (PEIs) (III) were prepared from 2,2-bis[4-(3,4-dicarboxyphenoxy) phenyl]propane dianhydride (BPADA) with various aromatic diamines (Ia-h) including non-fluorinated diamines (Ia-d) and the corresponding trifluoromethyl-substituted diamines (Ie-h). The fluorinated PEIs IIIe-h based on fluorinated diamines were nearly colorless with cutoff absorption wavelength (λ0) below 370 nm and with solubility higher than that of the corresponding CF3-free analogues (IIIa-d). Meanwhile, they had lower dielectric constants in the range of 2.91-3.21 at 1 MHz coupled with water absorptions below 0.70% and contact angles against water beyond 108o. The III series had tensile strength of 84.3-94.4 MPa, modulus of elasticity of 3.6-8.9 GPa and elongation at break of 9.4-25.3%, together with temperatures of 5% weight loss (T5%) beyond 510 °C. Compared to the IV series based on 4,4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), the corresponding III series exhibited better thermal and mechanical properties coupled with good optical properties, especially the fluorinated PEIs IIIe-h.
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Transparent Fluorinated Poly(imide siloxane) Copolymers with Good Adhesivity
Linshuang Li,Yong Xu,Jianfei Che,Xu Su,Chaoran Song,Xiuping Ma 한국고분자학회 2017 Macromolecular Research Vol.25 No.11
A series of fluorinated poly(imide siloxane) (PIS) copolymers were prepared with fluorine dianhydride 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and two kinds of functional diamine, 2,2'-bis(trifluoromethyl)-[ 1,1'-biphenyl]-4,4'-diamine (TFMB) and 1,3-bis(3-aminopropyl) tetramethyldisiloxane (GAPD) via a conventional two-stage process with thermal imidization. The soft and hard segments in the copolymer chain were composed of 6FDA-GAPD and 6FDA-TFMB, respectively. The structure of the resulting copolymers was determined by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. Optical, adhesion, mechanical, and thermal properties of these PIS copolymers have been evaluated with respect to real siloxane loading kept to 0, 1.4, 2.6, 4.1, and 5.5wt% in the copolymers, which is lower than the theoretical content of siloxane loading due to a disproportionation reaction of the siloxane chain. The resulting PIS copolymers showed excellent optical transparency in the UV-visible range and good adhesion property. The cutoff absorption wavelength (λ0) of the resulting PIS copolymers films was less than 345 nm and the maximum transmittance (λmax) was up to 91%. The introduction of siloxane segment dramatically improved the adhesion property of PIS copolymers from 1.29 to 2.26MPa (measured by means of shear strength) compared to the fluorinated homopolyimide (6FDA-TFMB) synthesized without siloxane moiety. The thermal and mechanical properties of the resulting PIS copolymers decreased slightly with the increase in siloxane loading but still remain a good level. Due to the addition of trifluoromethyl (-CF3) group and siloxane moiety, the solubility of PIS films was greatly enhanced and they were able to be dissolved in polar aprotic solvents, such as DMAC, DMF, and NMP. The contact angle, surface energy and water absorption were also studied in order to discuss their hydrophobic property.
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