| Summary: | 碩士 === 國立雲林科技大學 === 工業化學與災害防治研究所 === 94 === In this study, the reactive fluorine POSS was introduced in polyimide structure to form a curing framework of PI-OFG nanocomposite and it was expected to enhance the thermal and mechanical properties and decreased the dielectric constant of PI. The OFG chemical structure was characterized by FTIR and 1H-NMR. The OFG possessed average four epoxy and four fluorine groups. In the thermal properties, the OFG was able to cured with PAA to form curing structure during the imidization. Due to the curing structure of PI-OFG nanocomposite, the Tg of PI was increased with increasing OFG. The thermal stability of PI-OFG was decreased with increasing OFG, due to the damage of curing structure of PI-OFG and low thermal stability of OFG. The 14Si-NMR revealed the curing structure was broken of PI-OFG. In mechanical property, the lower OFG content of PI-OFG possessed good mechanical property. For high OFG content, the OFG aggregation form phase interconnected to decrease the mechanical property. In morphology, the lower OFG content of PI-OFG (OFG3、7 wt%) displayed good dispersion (<10 nm). The model compound results show that the curing reaction of OFG and PAA POSS was earlier than imidization of PAA. For higher OFG content, the poor miscibility between OFG and PAA to form severe POSS aggregation (phase interconnected). The factors of decreasing the dielectric constant of polymer was free volume, hydrophobic and polarity of polymer. In free volume, the relative porosity and free volume was determined by measurement of density of polymer. The relative porosity and free volume of PI-OFG were increased with increasing OFG(PI：FFV=0.044；PI-OFG 15wt%：FFV=0.319；PI：Ψr =0.044；PI-OFG 15wt%：Ψr =0.044). The hydrophobic and polarity of PI-OFG was measured by static contact angle and it revealed that the decreasing polarity and increasing hydrophobic of PI-OFG(PI：γs=47.7 mN/m；PI-OFG 15wt%：γs =29.0 mＮ/m；PI： =0.044；PI-OFG 15wt%： =0.319). Therefore, the OFG was introduced into the PI structure to enhance the thermal and mechanical properties and reducing the dielectric constant of PI.
|
|---|
