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URN etd-0206107-135126 Statistics This thesis had been viewed 3789 times. Download 2023 times. Author Yu-Yang Su Author's Email Address No Public. Department Chemical Engineering Year 2006 Semester 1 Degree Ph.D. Type of Document Doctoral Dissertation Language English Page Count 173 Title SYNTHESIS AND CHARACTERIZATION OF COLORLESS FLUORINATED POLYIMIDES, ORGANOSOLUBLE POLYNAPHTHALIMIDES AND POLYIMIDE/SILICA HYBRIDS DERIVED FROM AROMATIC BIS(ETHER AMINE)S BEARING TRIFLUOROMETHYL GROUPS Keyword solubility trifluoromethyl groups colorless polyimides polynaphthalimides polyimide/silica hybrids aromatic bis(ether amine)s aromatic bis(ether amine)s polyimide/silica hybrids polynaphthalimides colorless polyimides trifluoromethyl groups solubility Abstract This dissertation deals with the synthesis and properties of colorless polyimides, organosoluble polynaphthalimides, and fluorine-containing polyimide/silica composite films based on trifluoromethyl-substituted bis(ether amine).
Three series of novel, colorless polyimides (3A, 3B, 3C) were synthesized from trifluoromethyl-substituted bis(ether amine)s with 2,3,3’,4’-biphenyltetracarboxylic dianhydride (a-BPDA), 2,5-bis(3,4-dicarboxyphenoxy)-tert-butylbenzene dianhydride [bis(ether anhydride) B], and 3,3-bis[4-(3,4-dicarboxyphenoxy)phenyl]phthalide dianhydride [bis(ether anhydride) C], respectively, via two-step method with thermal or chemical imidization of poly(amic acid)s. These fluorinated polyimide films showed excellent solubility in a variety of organic solvents, high optical transparency, low color intensity, and good tensile property as well as high thermal stability. Besides, the analogous non-fluorinated or isomeric polyimides were also prepared and characterized. The fluorinated polyimides were apparently characterized by higher solubility, lighter color, and lower dielectric constants and moisture absorption than their analogous non-fluorinated polyimides.
In addition, a series of polynaphthalimides (PNIs), co-PNI-3, were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) with common aromatic diamines and 3,3-bis[4-(4-aminophenoxy)phenyl]phthalide, which was used as a solubility-enhancing agent, via a one stage process with high-temperature condensation. These PNIs could afford transparent and tough films by m-cresol solvent casting with a tensile strength of 76-103 MPa. However, their solubility was limited, only some of them were soluble in 1-methy-2-pyrrolidone and m-cresol at 5–10 wt %. In order to improve the solubility of PNIs, we used the trifluoromethyl-substituted aromatic bis(ether amine)s as the diamine monomers to prepare a series of fluorinated PNI-2a-g. This series of PNIs are highly organosoluble and can be solution-cast into transparent and tough films with a tensile strength ranging from 93 to 134 MPa. The softening temperature (Ts) of these PNIs were in the range of 234-331 °C, and the 10% weight-loss temperatures were above 528 °C in nitrogen or air, with more than 50% char yield at 800 °C in nitrogen.
Moreover, a series of polyimide precursors, poly(amic acid)s, containing propyltrimethoxysliane at two chain ends were prepared from 4,4’-bis(4-amino-2-trifluoromethylphenoxy)biphenyl with six commercially available dianhydrides, followed by end-capping with 3-aminopropyltrimethoxysilane (APrTMOS). A new class of fluorine-containing polyimide/silica composite films (PI/silica-3) with chemical bonds between the fluorinated polyimide backbone and the silica network has been synthesized from the APrTMOS-terminated precursors with tetramethoxysilane (TMOS) via the sol-gel process and thermal cyclodehydration. The resultant hybrid films were light-colored, flexible and tough and had high levels of thermal stability. Besides, the hybrid films of the fluorinated PI/silica-3 series showed a higher transparency and less color intensity as compared to the non-fluorinated PI/silica-3’ analogs. They also revealed a lower refraction index and birefringence than pure polyimides (PI-4).
Advisor Committee Chin-Ping Yang - advisor
Sheng-Huei Hsiao - advisor
Chin-Tsou Kuo - co-chair
Guey-Sheng Liou - co-chair
Wen-Fu Lee - co-chair
Wen-Zheng Guo - co-chair
Yaw-Terng Chern - co-chair
Files Date of Defense 2007-01-12 Date of Submission 2007-02-06