SWCNT Induced Crystallization in an Amorphous All-Aromatic Poly(ether imide)

Abstract

We have selected two amorphous all-aromatic poly(ether imide)s with similar chemical structures but with different backbone geometries as matrices for SWCNT-based nanocomposites. Up to 4.4 vol %, SWCNTs could be incorporated using an in situ polymerization method. Nanocomposites prepared from aBPDA-P3, a nonlinear matrix polymer with a Tg of 230 °C, remains amorphous, and the presence of the SWCNTs reduces the Tg by 11 °C. No effect on E′ or stress–strain behavior was observed. When ODPA-P3 was used as the matrix, the SWCNTs appear to be highly compatible with this more linear polymer host. The SWCNTs act as a nucleating agent at concentrations as low as 0.1 vol %. XRD and TEM measurements show that the SWCNTs become embedded in a highly crystalline polymer matrix. The result is a significant change in thermomechanical properties. The polymer Tg was increased by 12 °C, from 196 to 208 °C, and due to the induced crystallinity, the modulus above Tg showed a dramatic increase. The neat polymer fails at Tg, b...