Synthesis of silicon-containing bisnadiimide Preparation and characterization of semi-interpenetrating network systems of silicon- and fluorine-containing polyimides

摘要

Silicon-containing thermosetting bisnadiimide (BNI) was synthesized using Bis (amino propyl) tetramethyl disiloxane and nadic anhydride, and fluorine-containing thermoplastic polyamic acid (FPA) was synthesized from 4,4′-(hexafluoroisopropylidene) bis phenoxy dianiline and 4,4′-(hexafluoroisopropylidene) dipthalic anhydride [6-FDA]. The semi-interpenetrating network (s-IPN) systems in various ratios were prepared via solution casting of FAA and crosslinkable BNI, and then curing them up to 370 °C in order to achieve an optimum combination to be used for advanced high temperature composite applications. The polyimides and s-IPN were characterized using NMR and FTIR spectroscopy. The thermo-oxidative and water uptake properties of these polyimides and s-IPNs were investigated. The thermogravimetric analysis (TG) showed increase in thermal stability with the increase in thermoplastic polyimide proportion.