A simple attempt to change the solubility of polyimide by physical inclusion with β-cyclodextrin and its derivatives

Inclusion complex (IC) compounds such as 4,4′-oxydianiline (ODA) with β-cyclodextrin (β-CD), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) or heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD) were newly prepared by a simple solution method using water or methanol. These ICs were reacted with 4,4′-hexafluoroisopropylidenediphthalic anhydride (6FDA) in N,N-dimethylacetamide (DMAc) to form a polyamic acid intermediate, which imidized thermally to novel pseudopolyimiderotaxanes (Mw: 8400–31 100, contents of β-CDs: 4.3–11.2%). Polymers were characterized by FTIR, 1H NMR, and XRD. They showed good solubility in tetrahydrofuran, chloroform, methylene chloride, as well as polar aprotic solvents. All the β-CDs in the polymers were degraded under 380°C and polyimide moieties were stable up to 490°C in a N2 stream.