Novel Semicrystalline Thermoplastic R-Bapb Type Polyimide Matrix Reinforced by Graphite Nanoplatelets and Carbon Nanoparticles

Abstract

A new semicrystalline polyimide, based on 1.3-bis-(3,3′,4,4′-dicarboxyphenoxy)benzene (R) and 4,4′-bis-(4-aminophenoxy)biphenyl (BAPB), was modified by exfoliated graphite nanoplatelets of different shape, sizes and structure. This R-BAPB type polyimide, with a molecular weight Mw = 30000 g/mol has a low melting temperature of 320°C and a melt zero shear viscosity of about 1000 Pa s at 340°C, making it possible to mix it with particulates using classical melt-blending technology. By using calorimetric and rheological measurements, this study reports a dramatic crystal nucleating effect of the polyimide caused by the special nanographite platelets. In addition, the study shows that classical melt blending of R-BAPB type PI with exfoliated graphite nanoplatelets can be used to prepare useful polyimide nanocomposites with the added benefit of possibly accelerating the crystallization process of the polyimide matrix. Further, it was observed that the time of crystallization at 300°C for the nanocomposites filled with 5 wt% nanographite platelets was about 10 ± 5 minutes, a value corresponding to one-half that of the unfilled R-BAPB type PI matrix.