Preparation and properties of poly(methyltrifluoropropylsiloxane‐b‐imide) copolymer. I

Poly(methyltrifluoropropylsiloxane‐block‐imide) copolymers (PSBPI), containing various contents of fluorosiloxane, were prepared by the thermal imidization of 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA), 4,4′‐oxydianiline (ODA), and α,ω‐aminopropyl‐terminated poly(methyltrifluoropropylsiloxane) prepolymer (APMFS). APMFS was prepared from an equilibrium polymerization of (3,3,3‐trifluoropropyl)methylcyclotrisiloxane (D3Me,CH2,CH2,CF3) with 1,3‐bis(3‐aminopropyl)‐1,1,3,3‐tetramethyldisiloxane in the presence of the tetramethylammoniumhydroxide (TMAH) catalyst. The content of APMFS, in the reaction mixture, was varied from 0 to 30 wt % of diamine. The structure of copolymer was confirmed by FTIR spectroscopy. The thermal stability, linear coefficient of thermal expansion, modulus, X‐ray pattern, and other properties, such as surface enrichment behavior and solubility, were investigated. PSBPI exhibited relatively low crystallinity regardless of the APMFS content in the copolymer. On the other hand, thermogravimetric, thermomechanical, dynamic mechanical, and surface properties were affected by the content of APMFS segment in the copolymer backbone.