| Summary: | 碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 92 === The thermal properties of organic polymer materials are generally poor in comparison with the inorganic material. Hybridization of inorganic materials into organic materials offers the possibility to enhance their physical properties and may become new kind of optical materials. In this study, two kinds of hybrid materials were synthesized and characterized, including poly(vinylsilsesquixane) (VSQ)/acrylate and poly(silsesquioxane) (PSSQ)/polyimide hybrid system.
For the case of VSQ/acrylate materials, poly(vinylsilsesquioxane) (VSQ) was synthesized by sol-gel method. It was found that the chemical structures of the VSQ could be controlled by acid or water amount, including molecular weight and cage/network ratio. Higher acid and water amounts increase the degree of polymerization. On the other hand, lower acid and higher water amounts increase the cage structure of precursor. Thermal properties of hybrid materials are slightly enhanced by hybridizing VSQ. However, poor reactivity is found between the VSQ and MMA based on the analysis of FTIR, SEC, or reactivity ratio. But the hydrogen bonding is existed between OH of VSQ and C=O of PMMA and thus prevents the macrophase separation. Optical loss of VSQ/MMA hybrid thin film is 0.62 ~0.79 dB/cm and 0.46 ~0.64 dB/cm at 1310 and 1510nm, respectively. They are acceptable values for waveguide applications. Besides, refractive index of hybrid thin film decreases with the VSQ content increased. Thus, the tunable optical properties make the prepared hybrid materials potentially for optical device applications.
Polyimides (PMDA-ODA) encapped with aminopropyl trimethoxysilane (APrTMOS) was used to prepare hybrid materials with PSSQ. It was found that both PSSQ content and polyimides chain length affected the degree of phase separation. Appropriate control the phase separation behavior, the hybrid materials possess lower coefficient of thermal expansion (CTE) with increasing PSSQ content. The optical properties could also be adjusted by the ratio of hybrid materials. Birefringence of the polyimides/PSSQ hybrid materials is reduced in comparison with the parent polyimides because the molecular isotropy increases. MADE is added to the polyimide/PSSQ hybrid system for fabricating ionic-bonded photosensitive organic-inorganic hybrid material. Methacrylic propyl silsesquioxane (MAPSSQ) with a acrylic functional group was expected to react with MDAE for reducing the volume shrinkage during thermal imidization. It was found that by hybridizing MAPSSQ into polyimide lowered the shrinkage from 50% to 30% in comparison with the parent polyimide. Although nitrogen atom of MDAE in imidized hybrid material can not be clearly observed from XPS element analysis, the TGA analysis suggests that the MDAE remained in the hybrid films after thermal imidization. The prepared hybrid materials could be patterned by photolithography and might be used in optical channel waveguides.
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