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URN etd-0817106-132335 Statistics This thesis had been viewed 2895 times. Download 1104 times. Author Sheng-Yu Huang Author's Email Address No Public. Department Chemical Engineering Year 2005 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 79 Title SYNTHESIS AND PROPERTIES OF LOW COLOR POLY(ETHER IMIDE)S AND PI/SiO2 HYBRID FILMS Keyword low color hybrid material organic-inorganic material poly(ether imide) poly(ether imide) organic-inorganic material hybrid material low color Abstract ABSTRACT
In part I, a series of novel organosoluble and light-colored fluorinated poly(ether imide)s (IV) having inherent viscosities of 0.43-0.59 dL/g were prepared from 4,4’-[1,4-phenylenbis(isopropylidene-1,4-phenyleneoxy)]diphthalic anhydride (I) and various trifluoromethyl-substituted aromatic bis(ether amine)s by a standard two-step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s showed excellent solubility in many organic solvents and could be solution-cast into transparent, flexible, and tough films. These films were essentially colorless, with an UV-visible absorption edge of 361-375 nm and a very low b* value (a yellowness index) of 15.3 to 17.0. They series also showed good thermal stability with glass-transition temperature of 191-248oC, 10% weight loss temperature in excess of 494oC, and char yields at 800oC in nitrogen more than 39%. The thermally cured poly(ether imide) films showed good mechanical properties with tensile strengths of 83-96 MPa, elongations at break of 8-11%, initial moduli of 1.7-2.0 GPa. They possessed lower dielectric constants of 3.25-3.72 (1MHz). In comparison with the V series nonfluorinated poly(ether imide)s, the IV series showed better solubility, lower color intensity and lower dielectric constants.
In part II, hybrid organic-inorganic materials based on polyimide-silica system have been produced by the sol-gel route from solution mixture of hydrolysed tetramethoxysilane (TMOS) and an aromatic poly(amic acid) prepared from 4,4’-oxydiphthalic dianhydride (ODPA) and 4,4’-bis(4-aminophenoxy)biphenyl (I”) with or without the use of 3-aminopropyltrimethoxysilane (APrTMOS) as a chain-end capper. The APrTMOS-modified hybrid films (V series) containing up to 40 wt% silica were mechanically robust and optically transparent. The V series hybrid films showed a higher optical transparency than the VI series analogs (without APrTMOS as the coupling agent). All the hybrid films showed excellent thermal stability, including moderately high Tgs of 243-254℃, 10% weight loss temperatures higher than 560 oC, and high char yields at 800oC in nitrogen (＞60%).
In part III, an alkoxysilane terminated amide acid prepolymer was prepared from 4,4’-bis(4-aminophenoxy)biphenyl (I”) or 4,4’-bis(4-amino-2-trifluoromethylphenoxy)- biphenyl (I’) with 4,4’-oxydiphthalic dianhydride (ODPA) using 3-aminopropyltrimethoxysilane (APrTMOS) as an end capper. Two series of polyimide/silica (PI/SiO2) hybrid films with chemical bonding between the polyimide backbone and silica network have been prepared from the mixture of APrTMOS-terminated prepolymer, tetramethoxysilane (TMOS), and water via a sol-gel reaction, followed by solution casting and multistep heating. The hybrid films containing up to 40 wt% silica were mechanically robust, transparent, and light-colored. The fluorine-containing PI/SiO2 hybrid films (IX series) showed a higher optical transparency and less color intensity than the non-fluorinated (VIII series). All the hybrid films showed excellent thermal stability, including moduately high Tgs of 242-266 ℃, 10% weight loss temperatures higher then 535 ℃, and high char yield at 800 ℃ in nitrogen (＞ 54%).
Advisor Committee Sheng-Huei Hsiao - advisor
Guey-Sheng Liou - co-chair
Wen-Fu Lee - co-chair
Files Date of Defense 2006-07-07 Date of Submission 2006-08-17