Nanocomposite Synthesis and Charaterization base on Polyimide and Polyaniline Matrix

• Main Authors: Te-Cheng Mo, 莫德政
• Other Authors: San-Yuan Chen
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/76588068143554907035

博士 === 國立交通大學 === 材料科學與工程系所 === 95 === The major study of this thesis is adding different nano particle in Polyimide and Polyaniline to be nanocomposites. The effect of the nano particle in Polymer was carried out. We study on the nanocomposites thermal property、mechanical property、electric property etc. This study was divided into three parts, it includes （1）nano-silica adding into Polyimide and the silica modify with different fluorine-modified ,（2）MWNTs adding into Polyimide and （3）two type nano TiO2 adding into PANI. A series of PI-silica nanocomposites was synthesized by mixing and polymerizing the novel fluorine-modified silica nano particles into the PI matrix. By using the silica or the 6FBPA-modified silica nano particles, dielectric constants of PI films are greatly reduced. The modifier 6FBPA provides dual functions in the formation of uniform PI-SiO2 nanocomposites. The modifier BISAF possesses higher content of fluorine than that of 6FBPA but does not significantly affect the dielectric constant due to the flocculation of silica. It is believed that the free volume originated from the imperfection of the interface between PI and silica, when distributes uniformly, has significant contribution to the reduction of dielectric constants. Polyimide-MWNT nanocomposites were successfully prepared via a simple in-situ polymerization process. The addition of acid-modified MWNTs into a polyimide matrix led to obvious improvements in the thermal, mechanical and dielectric properties. For the nanocomposites containing 15 wt% MWNTs, the storage modulus reaches 28.457 GPa, about 9 times of pristine polyimide at room temperature. The tensile strength of the PI-7 wt% MWNT nanocomposite is almost double that of pristine PI. The PI polymer also gradually changes to a conductive system from an insulator at an identified percolation threshold at around 10 wt% MWNTs. A series of polyaniline-TiO2 nanocomposite materials were prepared using an in-situ polymerization process. From the characterization of SEM, TEM and X-ray diffraction, it was identified that the fine TiO2 colloids (Hombikat) form a relatively non-uniform distribution in the PANI matrix, while P25 is more uniformly distributed. Dielectric characterization demonstrated that TiO2 nanoparticles exhibit a strong effect on the dielectric properties of resultant PANI-TiO2 nanocomposites. The uniform packing of P25 TiO2 results an enhanced conductivity of the base form of the polyaniline film and thus enhances dielectric constants and losses. The increased conductivity is attributed to the formation of a better charge transport network in the relatively insulating polyaniline matrix.